Search results for: biodegradable plastic

Authors: Saravanan Govindaraju, Kyusik Yun

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The purpose of this study is to develop the chitosan doped curcumin gold cluster nanofiber for wound healing and skin cancer drug delivery applications. Chitosan is a typical marine polysaccharide composed of glucosamine and n-acetyl glucosamine biodegradable and biocompatible polymer. Curcumin is a natural bioactive molecule obtained from Curcuma longo, it mostly occurs in some Asian countries like India and China. It has naturally antioxidant, antimicrobial, wound healing and anticancer property. Due to this advantage, we prepared a combination of natural polymer chitosan with Curcumin and gold nanocluster nanofiber (CH-CUR-AuNCs nanofibers). The prepared nanofiber was characterized by using Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). Antibacterial studies were performed with E.coli and S.aureus. Antioxidant assay, drug release test, and cytotoxicity will be evaluated. Prepared nanofiber emits low intensity of red fluorescent. The FTIR confirm the presence of chitosan and Curcumin in the nanofiber. In vitro study clearly shows the antibacterial activity against the gram negative and gram positive bacteria. Particularly, synthesised nanofibers provide better antibacterial activity against gram negative than gram positive. Cytotoxicity study also provides better killing rate in cancer cell, biocompatible with normal cell. Prepared CH-CUR-AuNCs nanofibers provide the better killing rate to bacterial strains and cancer cells. Finally, prepared nanofiber can be possible to use for wound healing dressing, patch for skin cancer and other biomedical applications.

Keywords: curcumin, chitosan, gold clusters, nanofibers

Procedia PDF Downloads 261

Authors: Andres Nieto-Leal, Victor N. Kaliakin, Tania P. Molina

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The nature of most engineering materials is quite complex. It is, therefore, difficult to devise a general mathematical model that will cover all possible ranges and types of excitation and behavior of a given material. As a result, the development of mathematical models is based upon simplifying assumptions regarding material behavior. Such simplifications result in some material idealization; for example, one of the simplest material idealization is to assume that the material behavior obeys the elasticity. However, soils are nonhomogeneous, anisotropic, path-dependent materials that exhibit nonlinear stress-strain relationships, changes in volume under shear, dilatancy, as well as time-, rate- and temperature-dependent behavior. Over the years, many constitutive models, possessing different levels of sophistication, have been developed to simulate the behavior geomaterials, particularly cohesive soils. Early in the development of constitutive models, it became evident that elastic or standard elastoplastic formulations, employing purely isotropic hardening and predicated in the existence of a yield surface surrounding a purely elastic domain, were incapable of realistically simulating the behavior of geomaterials. Accordingly, more sophisticated constitutive models have been developed; for example, the bounding surface elastoplasticity. The essence of the bounding surface concept is the hypothesis that plastic deformations can occur for stress states either within or on the bounding surface. Thus, unlike classical yield surface elastoplasticity, the plastic states are not restricted only to those lying on a surface. Elastoplastic bounding surface models have been improved; however, there is still need to improve their capabilities in simulating the response of anisotropically consolidated cohesive soils, especially the response in extension tests. Thus, in this work an improved constitutive model that can more accurately predict diverse stress-strain phenomena exhibited by cohesive soils was developed. Particularly, an improved rotational hardening rule that better simulate the response of cohesive soils in extension. The generalized definition of the bounding surface model provides a convenient and elegant framework for unifying various previous versions of the model for anisotropically consolidated cohesive soils. The Generalized Bounding Surface Model for cohesive soils is a fully three-dimensional, time-dependent model that accounts for both inherent and stress induced anisotropy employing a non-associative flow rule. The model numerical implementation in a computer code followed an adaptive multistep integration scheme in conjunction with local iteration and radial return. The one-step trapezoidal rule was used to get the stiffness matrix that defines the relationship between the stress increment and the strain increment. After testing the model in simulating the response of cohesive soils through extensive comparisons of model simulations to experimental data, it has been shown to give quite good simulations. The new model successfully simulates the response of different cohesive soils; for example, Cardiff Kaolin, Spestone Kaolin, and Lower Cromer Till. The simulated undrained stress paths, stress-strain response, and excess pore pressures are in very good agreement with the experimental values, especially in extension.

Keywords: bounding surface elastoplasticity, cohesive soils, constitutive model, modeling of geomaterials

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Authors: Saeed Talamkhani, Seyed Abolhassan Naeini

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In recent years, the occurrence of several liquefactions in sandy soils containing various values of clay content has shown that in addition to silty sands, clayey sands are also susceptible to liquefaction. Therefore, it is necessary to investigate the properties of these soil compositions and their behavioral characteristics. This paper presents the effect of clay fines on the undrained shear strength of sands at various confining pressures. For this purpose, a series of unconsolidated undrained triaxial shear tests were carried out on clean sand and sand mixed with 5, 10, 15, 20, and 30 percent of clay fines. It was found that the presence of clay particle in sandy specimens change the dilative behavior to contraction. The result also showed that increasing the clay fines up to 10 percent causes to increase the potential for liquefaction, and decreases it at higher values fine content. These results reveal the important role of clay particles in changing the undrained strength of the sandy soil.

Keywords: clayey sand, liquefaction, triaxial test, undrained shear strength

Procedia PDF Downloads 196

Authors: Nurul-Akidah M. Yusak, Rahmah Mohamed, Noor Zuhaira Abd Aziz

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The introduction of degradable plastic materials into agricultural sectors has represented a promising alternative to promote green agriculture and environmental friendly of modern farming practices. Major challenges of developing degradable agricultural films are to identify the most feasible types of degradation mechanisms, composition of degradable polymers and related processing techniques. The incorrect choice of degradable mechanisms to be applied during the degradation process will cause premature losses of mechanical performance and strength. In order to achieve controlled process of agricultural film degradation, the compositions of degradable agricultural film also important in order to stimulate degradation reaction at required interval of time and to achieve sustainability of the modern agricultural practices. A set of photodegradable polyethylene based agricultural film was developed and produced, following the selective optimization of processing parameters of the agricultural film manufacturing system. Example of agricultural films application for oil palm seedlings cultivation is presented.

Keywords: photodegradable polyethylene, plasticulture, processing schemes

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Authors: A. Kouadri-Henni, L. Barrallier

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The objective of the study was to characterize the properties of a magnesium alloy welded by friction stir welding (FSW). The results led to a better understanding of the relationship between this process, the microstructure and anisotropic properties of alloy materials. Welding principally leads to a large reduction in grain size in welded zones due to the phenomenon of dynamic recrystallization. The most remarkable observation was that crystallographic textures changed from a base metal with one texture in two zones: the thermo-mechanically affected and stir welded zones. The latter zone has the peculiarity of possessing a marked texture with two components on the basal plane and the pyramidal plane. These characteristics disappeared in the TMAZ, which had only one component following the basal plane. These modifications have been explained by the nature of the plastic deformation in these zones, which occurs at a moderate temperature in the TMAZ and high temperature in the SWZ. In the same time, we compared this evolution with the nature and the level of the residual stresses obtained by X-ray diffraction.

Keywords: texture christallography, residual stresses, FSW process

Procedia PDF Downloads 367

Authors: Seongwon Im, Jimin Kim, Kyeongcheol Kim, Dong-Hoon Kim

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Cattle manure (CM) produced from farmhas been utilized to soils for increasing crop production owing to high nutrients content and effective microorganisms. Some cities with the concentrated activity of livestock industry have suffered from environmental problems, such as odorous gas emissions and soil and water pollution, caused by excessive use of compost. As an alternative option, the anaerobic digestion (AD) process can be utilized, which can reduce the volume of organic waste but also produce energy. According to Korea-Ministry of Trade, Industry, and Energy (KMTIE), the energy potential of CM via biogas production was estimated to be 0.8 million TOE per year, which is higher than that of other organic wastes. However, limited energy is recovered since useful organic matter, capable of converting to biogas, may be degraded during the long storage period (1-6 months).In this study, the effect of storage period on biogas potential of CM was investigated. Compared to fresh CM (VS 14±1 g/L, COD 205±5 g/L, TKN 7.4±0.8 g/L, NH4+-N 1.5±0.1), old CM has higher organic (35-37%) and nitrogen content (50-100%) due to the drying process during storage. After stabilization period, biogas potential of 0.09 L CH4/g VS was obtained in R1 (old CM supplement) at HRT of 150-100 d, and it was decreased further to 0.06 L CH4/g VS at HRT of 80 d. The drop of pH and organic acids accumulation were not observed during the whole operation of R1. Ammonia stripping and pretreatment of CM were found to be not effective to increase CH4 yield. On the other hand, a sudden increase of biogas potential to 0.19-0.22 L CH4/g VS was achieved in R2 after changing feedstock to fresh CM. The expected reason for the low biogas potential of old CM might be related with the composition of organic matters in CM. Easily biodegradable organic matters in the fresh CM were contained in high concentration, butthey were removed by microorganisms during storing CM in a farm, resulting low biogas yield. This study implies that fresh storage is important to make AD process applicable for CM.

Keywords: storage period, cattle manure, biogas potential, microbial analysis

Procedia PDF Downloads 173

Authors: Supriady R. P. Siregar, Rizki Barkah Aulia, Dhiya Fadilla Dewi

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Polybag is a plastic that is used to seed plants. The common type that used for polybag is a synthetic that made from petroleum such as polyethylene. Beside the character of the raw material that are non-renewable and limited, synthetic polybag ability to disintegrate in the environment is very low. According to that situation, we need a solution to overcome these problems by creating an environmentally friendly polybag. In this research, using the water hyacinth plant fibers (Eichornia crassipes) as a major component in manufacturing the environmentally friendly polybag, the water hyacinth (Eichornia crassipes) contains approximately 60% cellulose. The research method used is an experiment by testing the mechanical characters and biodegradability bio-polybag water hyacinth fibers (Eichornia crassipes) on three medium that is dissolved in water, river water and buried in soil. The research shows bio-polybag of hyacinth fibers can rapidly degraded. This study is expected to be the beginning of the creation bio-polybag of water hyacinth fiber (Eichornia crassipes) and can be applied in agriculture.

Keywords: revolution, biopolybag, renewable, environment

Procedia PDF Downloads 240

Authors: Gi-Hoon Yang, JongHan Ha, MyungGu Yeo, JaeYoon Lee, SeungHyun Ahn, Hyeongjin Lee, HoJun Jeon, YongBok Kim, Minseong Kim, GeunHyung Kim

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Tissue engineering scaffolds must be biocompatible and biodegradable, provide adequate mechanical strength and cell attachment site for proliferation and differentiation. Furthermore, the scaffold morphology (such as pore size, porosity and pore interconnectivity) plays an important role. The electrospinning process has been widely used to fabricate micro/nano-sized fibres. Electrospinning allows for the fabrication of non-woven meshes containing micro- to nano-sized fibers providing high surface-to-volume area for cell attachment. Due to its advantageous characteristics, electrospinning is a useful method for skin, cartilage, bone, and nerve regeneration. In this study, we fabricated PCL scaffolds (SP) consisting of spiral-like struts using 3D melt-plotting system and micro/nanofibers using direct electrospinning writing. By altering the conditions of the conventional melt-plotting method, spiral-like struts were generated. Then, micro/nanofibers were deposited selectively. The control scaffold composed of perpendicular PCL struts was fabricated using the conventional melt-plotting method to compare the cellular activities. The effect on the attached cells (osteoblast-like cells (MG63)) was evaluated depending on the bending instability of the struts. The SP scaffolds showed enhanced biological properties such as initial cell attachment, proliferation and osteogenic differentiation. These results suggest that the SP scaffolds has potential as a bioengineered substitute for soft and hard tissue regeneration.

Keywords: cell attachment, electrospinning, mechanical strength, melt-plotting

Procedia PDF Downloads 317

Authors: Erol Kam, Z. U. Yümün

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Natural and artificial radionuclides cause radioactive contamination in environments, just as the other non-biodegradable pollutants (heavy metals, etc.) sink to the sea floor and accumulate in sediments. Especially the habitat of benthic foraminifera living on the surface of sediments or in sediments at the seafloor are affected by radioactive pollution in the marine environment. Thus, it is important for pollution analysis to determine the radionuclides. Radioactive pollution accumulates in the lowest level of the food chain and reaches humans at the highest level. The more the accumulation, the more the environment is endangered. This study used gamma spectrometry to investigate the natural and artificial radionuclide distribution of sediment samples taken from living benthic foraminifera habitats in the Western Marmara Sea. The radionuclides, K-40, Cs-137, Ra-226, Mn 54, Zr-95+ and Th-232, were identified in the sediment samples. For this purpose, 18 core samples were taken from depths of about 25-30 meters in the Marmara Sea in 2016. The locations of the core samples were specifically selected exclusively from discharge points for domestic and industrial areas, port locations, and so forth to represent pollution in the study area. Gamma spectrometric analysis was used to determine the radioactive properties of sediments. The radionuclide concentration activity values in the sediment samples obtained were Cs-137=0.9-9.4 Bq/kg, Th-232=18.9-86 Bq/kg, Ra-226=10-50 Bq/kg, K-40=24.4–670 Bq/kg, Mn 54=0.71–0.9 Bq/kg and Zr-95+=0.18–0.19 Bq/kg. These values were compared with the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) data, and an environmental analysis was carried out. The Ra-226 series, the Th-232 series, and the K-40 radionuclides accumulate naturally and are increasing every day due to anthropogenic pollution. Although the Ra-226 values obtained in the study areas remained within normal limits according to the UNSCEAR values, the K-40, and Th-232 series values were found to be high in almost all the locations.

Keywords: Ra-226, Th-232, K-40, Cs-137, Mn 54, Zr-95+, radionuclides, Western Marmara Sea

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Authors: Amirhossein Lotfi, Huaizhong Li, Dzung Viet Dao

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Interest in natural fiber-reinforced composites (NFRC) is progressively growing both in terms of academia research and industrial applications thanks to their abundant advantages such as low cost, biodegradability, eco-friendly nature and relatively good mechanical properties. However, their widespread use is still presumed as challenging because of the specificity of their non-homogeneous structure, limited knowledge on their machinability characteristics and parameter settings, to avoid defects associated with the machining process. The present work is aimed to investigate the effect of the cutting tool geometry and material on the drilling-induced delamination, thrust force and hole quality produced when drilling a fully biodegradable flax/poly (lactic acid) composite laminate. Three drills with different geometries and material were used at different drilling conditions to evaluate the machinability of the fabricated composites. The experimental results indicated that the choice of cutting tool, in terms of material and geometry, has a noticeable influence on the cutting thrust force and subsequently drilling-induced damages. The lower value of thrust force and better hole quality was observed using high-speed steel (HSS) drill, whereas Carbide drill (with point angle of 130^o) resulted in the highest value of thrust force. Carbide drill presented higher wear resistance and stability in variation of thrust force with a number of holes drilled, while HSS drill showed the lower value of thrust force during the drilling process. Finally, within the selected cutting range, the delamination damage increased noticeably with feed rate and moderately with spindle speed.

Keywords: natural fiber reinforced composites, delamination, thrust force, machinability

Procedia PDF Downloads 128

Authors: Sujitra Ruengdechawiwat, Robert Molloy, Jintana Siripitayananon, Runglawan Somsunan, Paul D. Topham, Brian J. Tighe

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The main aim of this research has been to design and synthesize some completely soluble liquid tin(II) alkoxide initiators for use in the ring-opening polymerisation (ROP) of cyclic ester monomers. This is in contrast to conventional tin(II) alkoxides in solid form which tend to be molecular aggregates and difficult to dissolve. The liquid initiators prepared were bis(tin(II) monooctoate) diethylene glycol ([Sn(Oct)]2DEG) and bis(tin(II) monooctoate) ethylene glycol ([Sn(Oct)]2EG). Their efficiencies as initiators in the bulk ROP of ε-caprolactone (CL) at 130oC were studied kinetically by dilatometry. Kinetic data over the 20-70% conversion range was used to construct both first-order and zero-order rate plots. It was found that the rate data fitted more closely to first-order kinetics with respect to the monomer concentration and gave higher first-order rate constants than the corresponding tin(II) octoate/diol initiating systems normally used to generate the tin(II) alkoxide in situ. Since the ultimate objective of this work is to produce copolymers suitable for biomedical use as absorbable monofilament surgical sutures, poly(L-lactide-co-ε-caprolactone) 75:25 mol %, P(LL-co-CL), copolymers were synthesized using both solid and liquid tin(II) alkoxide initiators at 130°C for 48 hrs. The statistical copolymers were obtained in near-quantitative yields with compositions (from 1H-NMR) close to the initial comonomer feed ratios. The monomer sequencing (from 13C-NMR) was partly random and partly blocky (gradient-type) due to the much differing monomer reactivity ratios (rLL >> rCL). From GPC, the copolymers obtained using the soluble liquid tin(II) alkoxides were found to have higher molecular weights (Mn = 40,000-100,000) than those from the only partially soluble solid initiators (Mn = 30,000-52,000).

Keywords: biodegradable polyesters, poly(L-lactide-co-ε-caprolactone), ring-opening polymerisation, tin(II) alkoxide

Procedia PDF Downloads 194

Authors: Lay Poh Tan, Chor Yong Tay, Haiyang Yu

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Micro-contact printing is a form of soft lithography that uses the relief patterns on a master polydimethylsiloxane (PDMS) stamp to form patterns of self-assembled monolayers (SAMs) of ink on the surface of a substrate through conformal contact technique. Here, we adopt this method to print proteins of different dimensions on our biodegradable polymer substrates. We started off with printing 20-500 μm scale lanes of fibronectin to engineer the shape of bone marrow derived human mesenchymal stem cell (hMSCs). After 8 hours of culture, the hMSCs adopted elongated shapes, and upon analysis of the gene expressions, genes commonly associated with myogenesis (GATA-4, MyoD1, cTnT and β-MHC) and neurogenesis (NeuroD, Nestin, GFAP, and MAP2) were up-regulated but gene expression associated to osteogenesis (ALPL, RUNX2, and SPARC) were either down modulated or remained at the nominal level. This is the first evidence that cellular morphology control via micropatterning could be used to modulate stem cell fate without external biochemical stimuli. We further our studies to modulate the focal adhesion (FA) instead of the macro shape of cells. Micro-contact printed islands of different smaller dimensions were investigated. We successfully regulated the FAs into dense FAs and elongated FAs by micropatterning. Additionally, the combined effects of hard (40.4 kPa), and intermediate (10.6 kPa) PA gel and FAs patterning on hMSCs differentiation were studied. Results showed that FA and matrix compliance plays an important role in hMSCs differentiation, and there is a cross-talk between different physical stimulants and the significance of these stimuli can only be realized if they are combined at the optimum level.

Keywords: micro-contact printing, polymer substrate, cell-material interaction, stem cell differentiation

Procedia PDF Downloads 172

Authors: Marzie Shahini, Alireza Bagheri Sabbagh, Rasoul Mirghaderi, Paul C. Davidson

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The focus of this paper is to incorporating the slotted bolted connection into the cold-formed steel (CFS) beams with aim of increasing inelastic bending capacity through bolt slip. An extensive finite element analysis was conducted on the through plate CFS bolted connections which are equipped with the slotted hole. The studied parameters in this paper included the following: CFS beam section geometry, the value of slip force, CFS beam thickness. The numerical results indicate that CFS slotted bolted connection exhibit higher inelastic capacity in terms of ductility compare to connection with standards holes. Moreover, the effect of slip force was analysed by comparing the moment-rotation curves of different models with different slip force value. As a result, as the slip force became lower, there was a tendency for the plastic strain to extend from the CFS member to the connection region.

Keywords: slip-critical bolted connection, inelastic capacity, slotted holes, cold-formed steel, bolt slippage, slip force

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Authors: Miroslava Rysová, Zdena Syrová, Tomáš Zajíc, Petr Exnar

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Currently, attention of tissue engineers has been attracted to novel nanofibrous materials having advanced properties and ability to mimic extracellular matrix (ECM) by structure which makes them interesting candidates for application in regenerative medicine as scaffolding and/or drug delivering material. Throughout the last decade, more than 200 synthetic and natural polymers have been successfully electrospun leading to the formation of nanofibres with a wide range of chemical, mechanical and degradation properties. In this family, inorganic nanofibres represent very specific group offering an opportunity to manufacture inert to body, well degradable and in properties tunable material. Aim of this work, was to reveal unique properties of silica (SiO2, CAS 7631-86-9) nanofibres and their potential in field of regenerative medicine. Silica nanofibres were prepared by sol-gel method from tetraethyl orthosilicate (TEOS, CAS 78-10-4) as a precursor and subsequently manufactured by needleless electrospinning on NanospiderTM device. Silica nanofibres thermally stabilized under 200°C were confirmed to be fully biodegradable and soluble in several simulated body fluids. In vitro cytotoxicity tests of eluate (ES ISO 10993-5:1999) and in direct contact (ES ISO 10993-5:2009) showed no toxicity - e.g. cell viabilities reached values exceeding 80%. Those results were obtained equally from two different cell lines (Vero, 3T3). Non-toxicity of silaca nanofibres´ eluate was additionally confirmed in real time by testing on xCelligence (ACEA Biosciences, Inc.) device. Both cell types also showed good adhesion to material. To conclude, all mentioned results lead to resumption that silica nanofibres have a potential as material for regenerative medicine which opens door to further research.

Keywords: cytotoxicity, electrospinning, nanofibres, silica, tissue engineering

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Authors: Mokhlisur Rahman

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Ocean inhibits one of the most complex ecosystems on the planet that regulates the earth's climate and weather by providing us with compatible weather to live. Ocean provides food by extending various ways of lifestyles that are dependent on it, transportation by accommodating the world's biggest carriers, recreation by offering its beauty in many moods, and home to countless species. At the essence of receiving various forms of entertainment, consumers choose to be close to the ocean while performing many fun activities. Which, at some point, upsets the stomach of the ocean by threatening marine life and the environment. Consumers throw the waste into the ocean after using it. Most of them are plastics that float over the ocean and turn into thousands of micro pieces that are hard to observe with the naked eye but easily eaten by the sea species. Eventually, that conflicts with the natural consumption process of any living species, making them sick. This information is not known by most consumers who go to the sea or seashores occasionally to spend time, nor is it widely discussed, which creates an information gap among consumers. However, advertising is a powerful tool to educate people about ocean pollution. This abstract analyzes three major ocean-saving advertisement campaigns that use innovative and advanced technology to get maximum exposure. The study collects data from the selected campaigns' websites and retrieves all available content related to messages, videos, and images. First, the SeaLegacy campaign uses stunning images to create awareness among the people; they use social media content, videos, and other educational content. They create content and strategies to build an emotional connection among the consumers that encourage them to move on an action. All the messages in their campaign empower consumers by using powerful words. Second, Ocean Conservancy Campaign uses social media marketing, events, and educational content to protect the ocean from various pollutants, including plastics, climate change, and overfishing. They use powerful images and videos of marine life. Their mission is to create evidence-based solutions toward a healthy ocean. Their message includes the message regarding the local communities along with the sea species. Third, ocean clean-up is a campaign that applies strategies using innovative technologies to remove plastic waste from the ocean. They use social media, digital, and email marketing to reach people and raise awareness. They also use images and videos to evoke an emotional response to take action. These tree advertisements use realistic images, powerful words, and the presence of living species in the imagery presentation, which are eye-catching and can grow emotional connection among the consumers. Identifying the effectiveness of the messages these advertisements carry and their strategies highlights the knowledge gap of mass people between real pollution and its consequences, making the message more accessible to the mass of people. This study aims to provide insights into the effectiveness of ocean-saving advertisement campaigns and their impact on the public's awareness of ocean conservation. The findings from this study help shape future campaigns.

Keywords: advertising-campaign, content-creation, images ocean-saving technology, videos

Procedia PDF Downloads 78

Authors: John Tolentino, Yong Seok Park

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There are currently many people living with limb loss in the USA. The main causes for amputation can range from vascular disease, to trauma, or cancer. This number is expected increase over the next decade. Many patients have a single prosthetic for the first year but end up getting a second one to accommodate their changing physique. Afterwards, the prosthesis gets replaced every three to five years depending on how often it is used. This could cost the patient up to $500,000 throughout their lifetime. Complications do not end there, however. Due to the absence of nerves, it becomes more difficult to traverse terrain with a prosthetic. Moving on an incline or decline becomes difficult, thus curbs and stairs can be a challenge. Certain physical activities, such as cycling, could be even more strenuous. It will need to be relearned to accommodate for the change in weight, center of gravity, and transfer of energy from the leg to the pedal. The purpose of this research project is to develop a new, alternate below-knee cycling prosthetic using Dieter & Schmidt’s design process approach. It will be subjected to fatigue analysis under dynamic loading to observe the limitations as well as the strengths and weaknesses of the prosthetic. Benchmark comparisons will be made between existing prosthetics and the proposed one, examining the benefits and disadvantages. The resulting prosthetic will be 3D printed using acrylonitrile butadiene styrene (ABS) or polycarbonate (PC) plastic.

Keywords: 3D Printing, Cycling, Prosthetic design, Synthetic design.

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Authors: Mohammad Befkin, Alireza Momtaz

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Structural design is the challenging aspect of every project due to limitations in dimensions, functionality of the structure, and more importantly, the allocated budget for construction. This research study aims to investigate the optimized design for three steel moment frame buildings with different number of stories using genetic algorithm code. The number and length of spans, and height of each floor were constant in all three buildings. The design of structures are carried out according to AISC code within the provisions of plastic design with allowable stress values. Genetic code for optimization is produced using MATLAB program, while buildings modeled in Opensees program and connected to the MATLAB code to perform iterations in optimization steps. In the end designs resulted from genetic algorithm code were compared with the analysis of buildings in ETABS program. The results demonstrated that suggested structural elements by the code utilize their full capacity, indicating the desirable efficiency of produced code.

Keywords: genetic algorithm, structural analysis, steel moment frame, structural design

Procedia PDF Downloads 118

Authors: Maksim Barsakov

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Introduction. In modern plastic surgery, there are a large number of breast lift techniques.Due to the spreading information about the "side effects" of silicone implants, interest in implant-free mastopexy is increasing year after year. However, despite the variety of techniques, patients sometimes do not get full satisfaction from the results of mastopexy because of the unexpressed filling of the upper pole, extended anchoring postoperative scars and sometimes because of obtaining an aesthetically unattractive breast shape. The stability of the result after mastopexy depends on many factors, including postoperative rehabilitation. Stability of weight and hormonal background, stretchability of tissues. The high recurrence rate of ptosis and short-term aesthetic effect of mastopexy indicate the urgency of improving surgical techniques and increasing the stabilization of breast tissue. Purpose of the study. To develop and introduce into practice a technique of mastopexy based on the use of a modified Ribeiro flap, as well as elements of tissue movement and fixation designed to increase the stability of postoperative mastopexy. In addition, to give indications for the application of this surgical technique. Materials and Methods. it operated on 103 patients aged 18 to 53 years from 2019 to 2023 according to the reported method. These were patients with primary mastopexy, secondary mastopexy, and also patient with implant removal and one-stage mastopexy. The patients were followed up for 12 months to assess the stability of the result. Results and their discussion. Observing the patients, we noted greater stability of the breast shape and upper pole filling compared to the conventional classical methods. We did not have to resort to anchoring scars. In 90 percent of cases, a inverted T-shape scar was used. In 10 percent, the J-scar was used. The quantitative distribution of complications identified among the operated patients is as follows: worsened healing of the junction of vertical and horizontal sutures at the period of 1-1.5 months after surgery - 15 patients; at treatment with ointment method healing was observed in 7-30 days; permanent loss of NAC sensitivity - 0 patients; vascular disorders in the area of NAC/areola necrosis - 0 patients; marginal necrosis of the areola-2 patients. independent healing within 3-4 weeks without aesthetic defects. Aesthetically unacceptable mature scars-3 patients; partial liponecrosis of the autoflap unilaterally - 1 patient. recurrence of ptosis - 1 patient (after weight loss of 12 kg). In the late postoperative period, 2 patients became pregnant, gave birth, and no lactation problems were observed. Conclusion. Thus, in the world of plastic surgery methods of breast lift continue to improve, which is especially relevant in modern times, due to the increased attention to this operation. The author's proposed method of mastopexy with glandular autoflap allows obtaining in most cases a stable result, a fuller breast shape, avoiding the presence of extended anchoring scars, and also preserves the possibility of lactation. The author of this article has obtained a patent for invention for this method of mastopexy.

Keywords: mastopexy, mammoplasty, autoflap, personal technique

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Authors: Esra Turker, Umit Hakan Yildiz, Ahu Arslan Yildiz

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The key of regenerative medicine is mimicking natural three dimensional (3D) microenvironment of tissues by utilizing appropriate biomaterials. In this study, a synthetic biodegradable polymer; poly (L-lactide-co-ε-caprolactone) (PLLCL) and a natural polymer; collagen was used to mimic the biochemical structure of the natural extracellular matrix (ECM), and by means of electrospinning technique the real physical structure of ECM has mimicked. PLLCL/Collagen biocomposite scaffolds enables cell attachment, proliferation and nutrient transport through fabrication of micro to nanometer scale nanofibers. Biocomposite materials are commonly preferred due to limitations of physical and biocompatible properties of natural and synthetic materials. Combination of both materials improves the strength, degradation and biocompatibility of scaffold. Literature studies have shown that collagen is mostly solved with heavy chemicals, which is not suitable for cell culturing. To overcome this problem, a new approach has been developed in this study where polyvinylpyrrolidone (PVP) is used as co-electrospinning agent. PVP is preferred due to its water solubility, so PLLCL/collagen biocomposite scaffold can be easily and rapidly produced. Hydrolytic and enzymatic biodegradation as well as mechanical strength of scaffolds were examined in vitro. Cell adhesion, proliferation and cell morphology characterization studies have been performed as well. Further, on-chip drug screening analysis has been performed over 3D tumor models. Overall, the developed biocomposite scaffold was used for 3D tumor model formation and obtained results confirmed that developed model could be used for drug screening studies to predict clinical efficacy of a drug.

Keywords: biomaterials, 3D cell culture, drug screening, electrospinning, lab-on-a-chip, tissue engineering

Procedia PDF Downloads 312

Authors: Mahsa Fathollahzadeh

Abstract:

The various nanoparticles employed in drug delivery applications include micelles, liposomes, solid lipid nanoparticles, polymeric nanoparticles, functionalized nanoparticles, nanocrystals, cyclodextrins, dendrimers, and nanotubes. Micelles, composed of amphiphilic block copolymers, can encapsulate hydrophobic molecules, allowing for targeted delivery. Liposomes, vesicular structures made up of phospholipids, can encapsulate both hydrophobic and hydrophilic molecules, providing a flexible platform for delivering therapeutic agents. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are designed to improve the stability and bioavailability of lipophilic drugs. Polymeric nanoparticles, such as poly(lactic-co-glycolic acid) (PLGA), are biodegradable and can be engineered to release drugs in a controlled manner. Functionalized nanoparticles, coated with targeting ligands or antibodies, can specifically target diseased cells or tissues. Nanocrystals, engineered to have specific surface properties, can enhance the solubility and bioavailability of poorly soluble drugs. Cyclodextrins, doughnut-shaped molecules with hydrophobic cavities, can be complex with hydrophobic molecules, allowing for improved solubility and bioavailability. Dendrimers, branched polymers with a central core, can be designed to deliver multiple therapeutic agents simultaneously. Nanotubes and metallic nanoparticles, such as gold nanoparticles, offer real-time tracking capabilities and can be used to detect biomolecular interactions. The use of these nanoparticles has revolutionized the field of drug delivery, enabling targeted and controlled release of therapeutic agents, reduced toxicity, and improved patient outcomes.

Keywords: nanotechnology, nanopharmaceuticals, drug-delivery, proteins, ligands, nanoparticles, chemistry

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Authors: Anusha Chanda, Reenu Singh

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Packaging is one of the major contributors to global waste. While efforts are being made to switch to more sustainable types of packaging, such as switching from single use plastics to paper, not all polluting materials, have been rethought in terms of recycling. Minimalism in packaging design can help reduce the amount of waste produced greatly. While online companies have shifted to using cardboard boxes for packages, a large amount of waste in still generated from other materials affiliated with cardboard packaging, such as tape, bubble wrap, plastic wrap, among others. Minimalism also works by reducing extra packaging and increasing the reusability of the material. This paper looks at research related to minimalism in packaging design, minimalism, and sustainability. A survey was conducted in order to find out the different ways in which minimalism can be implemented in packaging design. Information gathered from the research and responses from the survey was used to ideate product design alternatives for sustainable substitutes for bubble wrap in packaging. This would help greatly reduce the amount of packaging waste and improve environmental quality.

Keywords: environment, minimalism, packaging, product design, sustainable

Procedia PDF Downloads 253

Authors: J. H. O. Nascimento, F. R. Oliveira, K. K. O. S. Silva, J. Neves, V. Teixeira, J. Carneiro

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These the aliphatic polyesters such as Polylactic Acid (PLA) in the form of fibers, nanofibers or plastic films, generally possess chemically inert surfaces, free porosity, and surface free energy (ΔG) lesser than 32 mN/m. It is therefore considered a low surface energy material, consequently has a low work of adhesion. For this reason, the products manufactured using these polymers are often subjected to surface treatments in order to change its physic-chemical surface, improving their wettability and the Work of Adhesion (WA). Plasma Radio Frequency low pressure (RF) treatment was performed in order to improve the Work of Adhesion (WA) on PLA fibers. Different parameters, such as, power, ratio of working gas (Argon/Oxygen) and treatment time were used to optimize the plasma conditions to modify the PLA surface properties. With plasma treatment, a significant increase in the work of adhesion on PLA fiber surface was observed. The analysis performed by XPS showed an increase in polar functional groups and the SEM and AFM image revealed a considerable increase in roughness.

Keywords: RF plasma, surface modification, PLA fabric, atomic force macroscopic, Nanotechnology

Procedia PDF Downloads 536

Authors: Renzo Palomino, Alessandra Trujillo, Lidia Pacheco

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The document presents a study based on the incremental bearing capacity of silty clay soil with the incorporation of crushed PET fibers. For a better understanding of the behavior of soil, it is necessary to know its origin. The analyzed samples came from the subgrade layer of a highway that connects the cities of Muniches and Yurimaguas in Loreto, Peru. The material in this area usually has properties such as low support index, medium to high plasticity, and other characteristics that make it considered a ‘problematic’ soil due to factors such as climate, humidity, and geographical location. In addition, PET fibers are obtained from the decomposition of plastic bottles that are polluting agents with a high production rate in our country; in that sense, their use in a construction process represents a considerable reduction in environmental impact. Moreover, to perform a precise analysis of the behavior of this soil mixed with PET, tests such as the hydrometer test, Proctor and CBR with 15%, 10%, 5%, 4%, 3%, and 1% of PET with respect to the mass of the sample of natural soil were carried out. The results show that when a low percentage of PET is used, the support index increases.

Keywords: environmental impact, geotechnics, PET, silty clay soil

Procedia PDF Downloads 237

Authors: Behzad Mohammadzadeh, Huyk Chun Noh

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The plate is one of the popular structural elements used in a wide range of industries and structures. They may be subjected to blast loads during explosion events, missile attacks or aircraft attacks. This study is to investigate dynamic responses of the rectangular plate subjected to explosive loads. The effects of material properties and plate thickness on responses of the plate are to be investigated. The compressive pressure is applied to the surface of the plate. Different amounts of thickness in the range from 10mm to 30mm are considered for the plate to evaluate the changes in responses of the plate with respect to the plate thickness. Two different properties are considered for the steel. First, the analysis is performed by considering only the elastic-plastic properties for the steel plate. Later on damping is considered to investigate its effects on the responses of the plate. To do analysis, the numerical method using a finite element based package ABAQUS is applied. Finally, dynamic responses and graphs showing the relation between maximum displacement of the plate and aim parameters are provided.

Keywords: impulsive loaded plates, dynamic analysis, ABAQUS, material nonlinearity

Procedia PDF Downloads 523

Authors: Siti Nur Aida Mario, Farah Hafifee Ahmad, Rudy Tawie

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Soil Stabilization has been widely implemented in the construction industry nowadays. Peat soil is well known as one of the most problematic soil among the engineers. The procedures need to take into account both physical and engineering properties of the stabilized peat soil. This paper presents a result of plasticity index and hardening of treated peat soil with various dosage of additives. In order to determine plasticity of the treated peat soil, atterberg limit test which comprises plastic limit and liquid limit test has been conducted. Determination of liquid limit in this experimental study is by using cone penetrometer. Vicat testing apparatus has been used in the hardening test which the penetration of the plunger is recorded every one hour for 24 hours. The results show that the plasticity index of peat soil stabilized with 80% FAAC and 20% OPC has the lowest plasticity index and recorded the fastest initial setting time. The significant of this study is to promote greener solution for future soil stabilization industry.

Keywords: additives, hardening, peat soil, plasticity index, soil stabilization

Procedia PDF Downloads 329

Authors: Sajjad H. Kasanagh, Perviz Ahmedzade, Alexander Fainleib, Taylan Gunay

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Modification of asphalt is a fundamental method around the world mainly on the purpose of providing more durable pavements which lead to diminish repairing cost during the lifetime of highways. Various polymers such as styrene-butadiene-styrene (SBS) and ethylene vinyl acetate (EVA) make up the greater parts of the all-over asphalt modifiers generally providing better physical properties of asphalt by decreasing temperature dependency which eventually diminishes permanent deformation on highways such as rutting. However, some waste and low-cost materials such as recycled plastics and ground rubber tire have been attempted to utilize in asphalt as modifier instead of manufactured polymer modifiers due to decreasing the eventual highway cost. On the other hand, the usage of recycled plastics has become a worldwide requirement and awareness in order to decrease the pollution made by waste plastics. Hence, finding an area in which recycling plastics could be utilized has been targeted by many research teams so as to reduce polymer manufacturing and plastic pollution. To this end, in this paper, thermoplastic dynamic vulcanizate (TDV) obtained from recycled post-consumer polyethylene and ground tire rubber (GTR) were used to provide an efficient modifier for asphalt which decreases the production cost as well and finally might provide an ecological solution by decreasing polymer disposal problems. TDV was synthesized by the chemists in the research group by means of the abovementioned components that are considered as compatible physical characteristic of asphalt materials. TDV modified asphalt samples having different rate of proportions of 3, 4, 5, 6, 7 wt.% TDV modifier were prepared. Conventional tests, such as penetration, softening point and roll thin film oven (RTFO) tests were performed to obtain fundamental physical and aging properties of the base and modified binders. The high temperature performance grade (PG) of binders was determined by Superpave tests conducted on original and aged binders. The multiple stress creep and recovery (MSCR) test which is relatively up-to-date method for classifying asphalts taking account of their elasticity abilities was carried out to evaluate PG plus grades of binders. The results obtained from performance grading, and MSCR tests were also evaluated together so as to make a comparison between the methods both aiming to determine rheological parameters of asphalt. The test results revealed that TDV modification leads to a decrease in penetration, an increase in softening point, which proves an increasing stiffness of asphalt. DSR results indicate an improvement in PG for modified binders compared to base asphalt. On the other hand, MSCR results that are compatible with DSR results also indicate an enhancement on rheological properties of asphalt. However, according to the results, the improvement is not as distinct as observed in DSR results since elastic properties are fundamental in MSCR. At the end of the testing program, it can be concluded that TDV can be used as modifier which provides better rheological properties for asphalt and might diminish plastic waste pollution since the material is 100% recycled.

Keywords: asphalt, ground tire rubber, recycled polymer, thermoplastic dynamic vulcanizate

Procedia PDF Downloads 220

Authors: O. I. H. Dimitry, N. A. Mansour, A. L. G. Saad

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Natural sodium montmorillonite (NaMMT), Cloisite Na⁺ and two organophilic montmorillonites (OMMTs), Cloisites 20A and 15A were used. Polycaprolactone (PCL)/MMT composites containing 1, 3, 5, and 10 wt% of Cloisite Na⁺ and PCL/OMMT nanocomposites containing 5 and 10 wt% of Cloisites 20A and 15A were prepared via solution intercalation technique to study the influence of organic modifier loading on particle dispersion of PCL/ NaMMT composites. Thermal stabilities of the obtained composites were characterized by thermal analysis using the thermogravimetric analyzer (TGA) which showed that in the presence of nitrogen flow the incorporation of 5 and 10 wt% of filler brings some decrease in PCL thermal stability in the sequence: Cloisite Na+>Cloisite 15A > Cloisite 20A, while in the presence of air flow these fillers scarcely influenced the thermoxidative stability of PCL by slightly accelerating the process. The interaction between PCL and silicate layers was studied by Fourier transform infrared (FTIR) spectroscopy which confirmed moderate interactions between nanometric silicate layers and PCL segments. The electrical conductivity (σ) which describes the ionic mobility of the systems was studied as a function of temperature and showed that σ of PCL was enhanced on increasing the modifier loading at filler content of 5 wt%, especially at higher temperatures in the sequence: Cloisite Na⁺<Cloisite 20A<Cloisite 15A, and was then decreased to some extent with a further increase to 10 wt%. The activation energy E_σ obtained from the dependency of σ on temperature using Arrhenius equation was found to be lowest for the nanocomposite containing 5 wt% of Cloisite 15A. The dispersed behavior of clay in PCL matrix was evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses which revealed partial intercalated structures in PCL/NaMMT composites and semi-intercalated/semi-exfoliated structures in PCL/OMMT nanocomposites containing 5 wt% of Cloisite 20A or Cloisite 15A.

Keywords: electrical conductivity, montmorillonite, nanocomposite, organoclay, polycaprolactone

Procedia PDF Downloads 378

Authors: Noé D. Lazos-Gallardo, Sonia E. Ruiz, Federico Valenzuela-Beltran

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A simplified mathematical expression to estimate ductility reduction factors of the displacement spectra corresponding to the soft soil zone of Mexico City is proposed. The aim is to allow a better characterization of the displacement spectra and provide a simple expression to be used in displacement based design (DBD). Emphasis is on the Mexico City Building Code. The study is based on the analysis of single degree of freedom (SDOF) systems with elasto-plastic hysteretic behavior. Several seismic ground motions corresponding to subduction events with magnitudes equal to or greater than 6 and recorded in different stations of Mexico City are used. The proposed expression involves the ratio of elastic and inelastic pseudo-aceleration spectra, and depends on factors such the ductility demand and the vibration period of the structural system. The resulting ductility reduction factors obtained in this study are compared with others existing in the literature, and their advantages and disadvantages are discussed.

Keywords: displacement based design, displacements spectrum, ductility reduction factors, soft soil

Procedia PDF Downloads 173

Authors: Farid Amidi Fazli, Afshin Babazadeh, Farnaz Amidi Fazli

Abstract:

In contrast with literal meaning of nano, researchers have been achieving mega adventures in this area and every day more nanomaterials are being introduced to the market. After long time application of fossil-based plastics, nowadays accumulation of their waste seems to be a big problem to the environment. On the other hand, mankind has more attention to safety and living environment. Replacing common plastic packaging materials with degradable ones that degrade faster and convert to non-dangerous components like water and carbon dioxide have more attractions; these new materials are based on renewable and inexpensive sources of starch and cellulose. However, the functional properties of them do not suitable for packaging. At this point, nanotechnology has an important role. Utilizing of nanomaterials in polymer structure will improve mechanical and physical properties of them; nanocrystalline cellulose (NCC) has this ability. This work has employed a chemical method to produce NCC and starch bio nanocomposite containing NCC. X-Ray Diffraction technique has characterized the obtained materials. Results showed that applied method is a suitable one as well as applicable one to NCC production.

Keywords: biofilm, cellulose, nanocomposite, starch

Procedia PDF Downloads 405

Authors: Alaa H. J. Al-Rkaby, A. Chegenizadeh, H. R. Nikraz

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Anisotropy is one of the major aspects that affect soil behavior, and extensive efforts have investigated its effect on the mechanical properties of soil. However, very little attention has been given to the combined effect of anisotropy and fine contents. Therefore, in this paper, the anisotropic strength of sand containing different fine content (F) of 5%, 10%, 15%, and 20%, was investigated using hollow cylinder tests under different principal stress directions of α = 0° and α = 90°. For a given principal stress direction (α), it was found that increasing fine content resulted in decreasing deviator stress (q). Moreover, results revealed that all fine contents showed anisotropic strength where there is a clear difference between the strength under 0° and the strength under 90°. This anisotropy was greatest under F = 5% while it decreased with increasing fine contents, particularly at F = 10%. Mixtures with low fine content show low contractive behavior and tended to show more dilation. Moreover, all sand-clay mixtures exhibited less dilation and more compression at α = 90° compared with that at α = 0°.

Keywords: anisotropy, principal stress direction, fine content, hollow cylinder sample

Procedia PDF Downloads 312