Search results for: polymer matrix sisal fibre

Authors: Laura Santagostini, Vittoria Guglielmi

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The meaning of the word 'Nature' (literally 'that which is about to be born') has accompanied researchers throughout their study of the environment and has led to the design of technical means to improve the properties of the soil, modifying its structure and/or consistency, thus favouring the emergence and growth of plants. These include soil improvers, i.e. any substance, natural or synthetic, mineral or organic, capable of modifying and improving the chemical, physical, biological and mechanical properties and characteristics of the soil. In particular, GCSCs (Green Composted Soil Conditioners) are soil conditioners produced through a controlled process of transforming selected organic green waste materials, such as clippings from the maintenance of ornamental greenery, crop residues and other plant waste. The use of GCSC in horticulture, fruit growing, industrial cultivation and nursery gardening is an active way to return organic carbon to the soil, thus limiting CO2 emissions and the production of greenhouse gases, and also to limit the environmental impact of peat extraction, which is normally used in these areas of application. With a view to distinguish between GCSC and peats and to assess what further contributions GCSC can provide to the soil and growing plants, we studied the behaviour of the two substrates by chromatographic techniques. After treating the individual soil improvers with different solvents, used individually or by applying a polarity gradient, the extracts obtained were analysed by HPLC and LCMS in order to assess their composition mainly from a qualitative point of view. Data obtained show in GCSC the presence of polyphenolic derivatives attributable to the degradation of plant material and potentially useful for the development and growth of young plants, while commercial peat-based products only sporadically showed the presence of recognisable molecules, confirming the lower complexity of the matrix under analysis. These results allowed us to distinguish the two different types of soil conditioner based on their chromatographic profiles.

Keywords: chromatographic profile, HPLC, polyphenols, soil conditioners

Procedia PDF Downloads 109

Authors: Choupani Andisheh, Temucin Elif Sevval, Bediz Bekir

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Due to their various advantages compared to many other drug delivery systems such as hypodermic injections and oral medications, microneedle arrays (MNAs) are a promising drug delivery system. To achieve enhanced performance of the MN, it is crucial to develop numerical models, optimization methods, and simulations. Accordingly, in this work, the optimized design of dissolvable MNAs, as well as their manufacturing, is investigated. For this purpose, a mechanical model of a single MN, having the geometry of an obelisk, is developed using commercial finite element software. The model considers the condition in which the MN is under pressure at the tip caused by the reaction force when penetrating the skin. Then, a multi-objective optimization based on non-dominated sorting genetic algorithm II (NSGA-II) is performed to obtain geometrical properties such as needle width, tip (apex) angle, and base fillet radius. The objective of the optimization study is to reach a painless and effortless penetration into the skin along with minimizing its mechanical failures caused by the maximum stress occurring throughout the structure. Based on the obtained optimal design parameters, master (male) molds are then fabricated from PMMA using a mechanical micromachining process. This fabrication method is selected mainly due to the geometry capability, production speed, production cost, and the variety of materials that can be used. Then to remove any chip residues, the master molds are cleaned using ultrasonic cleaning. These fabricated master molds can then be used repeatedly to fabricate Polydimethylsiloxane (PDMS) production (female) molds through a micro-molding approach. Finally, Polyvinylpyrrolidone (PVP) as a dissolvable polymer is cast into the production molds under vacuum to produce the dissolvable MNAs. This fabrication methodology can also be used to fabricate MNAs that include bioactive cargo. To characterize and demonstrate the performance of the fabricated needles, (i) scanning electron microscope images are taken to show the accuracy of the fabricated geometries, and (ii) in-vitro piercing tests are performed on artificial skin. It is shown that optimized MN geometries can be precisely fabricated using the presented fabrication methodology and the fabricated MNAs effectively pierce the skin without failure.

Keywords: microneedle, microneedle array fabrication, micro-manufacturing structural optimization, finite element analysis

Procedia PDF Downloads 102

Authors: Jai Prakash, Promod Kumar, Chantel Swart, J. H. Neethling, A. Janse van Vuuren, H. C. Swart

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Ag nanoparticles (NPs) have been used as functional nanomaterials due to their optical and antibacterial properties. Similarly, TiO2 photocatalysts have also been used as suitable nanomaterials for killing cancer cells, viruses and bacteria. Here, we report on multifunctional plasmonic Ag-TiO2 nano-biocomposite synthesized by the sol-gel technique and their optical, surface enhanced Raman scattering (SERS) and antibacterial activities. The as-prepared composites of Ag–TiO2 with different silver content and TiO2 nanopowder were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersed X-ray analysis (EDX), UV-vis and Raman spectroscopy. The Ag NPs were found to be uniformly distributed and strongly attached to the TiO2 matrix. The novel optical response of the Ag-TiO2 nanocomposites is due to the strong electric field from the surface plasmon excitation of the Ag NPs. The Raman spectrum of Ag-TiO2 nanocomposite was found to be enhanced as compared to TiO2. The enhancement of the low frequency band is evident. This indicates the SERS effect of the TiO2 NPs in close vicinity of Ag NPs. In addition, nanocomposites showed enhancement in the SERS signals of methyl orange (MO) dye molecules with increasing Ag content. The localized electromagnetic field from the surface plasmon excitation of the Ag NPs was responsible for the SERS signals of the TiO2 NPs and MO molecules. The antimicrobial effect of the Ag–TiO2 nanocomposites with different silver content and TiO2 nanopowder were carried out against the bacterium Staphylococcus aureus. The Ag–TiO2 composites showed antibacterial activity towards S. aureus with increasing Ag content as compared to the TiO2 nanopowder. These results foresee promising applications of the functional plasmonic metal−semiconductor based nanobiocomposites for both chemical and biological samples.

Keywords: metal-Semiconductor, nano-Biocomposites, anti-microbial activity, surface enhanced Raman scattering

Procedia PDF Downloads 217

Authors: Mohammad W. Dewan, Jahangir Alam, Khurshida Sharmin

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Synthetic fibers (carbon, glass, aramid, etc.) are generally utilized to make composite materials for better mechanical and thermal properties. However, they are expensive and non-biodegradable. In the perspective of Bangladesh, jute fibers are available, inexpensive, and comprising good mechanical properties. The improved properties (i.e., low cost, low density, eco-friendly) of natural fibers have made them a promising reinforcement in hybrid composites without sacrificing mechanical properties. In this study, jute and e-glass fiber reinforced hybrid composite materials are fabricated utilizing hand lay-up followed by a compression molding technique. Room temperature cured two-part epoxy resin is used as a matrix. Approximate 6-7 mm thick composite panels are fabricated utilizing 17 layers of woven glass and jute fibers with different fiber layering sequences- only jute, only glass, glass, and jute alternatively (g/j/g/j---) and 4 glass - 9 jute – 4 glass (4g-9j-4g). The fabricated composite panels are analyzed through fiber volume calculation, tensile test, bending test, and water absorption test. The hybridization of jute and glass fiber results in better tensile, bending, and water absorption properties than only jute fiber-reinforced composites, but inferior properties as compared to only glass fiber reinforced composites. Among different fiber layering sequences, 4g-9j-4g fibers layering sequence resulted in better tensile, bending, and water absorption properties. The effect of chemical treatment on the woven jute fiber and chopped glass microfiber infusion are also investigated in this study. Chemically treated jute fiber and 2 wt. % chopped glass microfiber infused hybrid composite shows about 12% improvements in flexural strength as compared to untreated and no micro-fiber infused hybrid composite panel. However, fiber chemical treatment and micro-filler do not have a significant effect on tensile strength.

Keywords: compression molding, chemical treatment, hybrid composites, mechanical properties

Procedia PDF Downloads 146

Authors: Maryam Parsian, Pelin Mutlu, Ufuk Gunduz

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Two-dimensional cell culture affords simplicity and low cost, but it has serious limitations; lacking cell-cell and cell-matrix interactions that are present in tissues. Cancer cells grown in 3D culture systems have distinct phenotypes of adhesion, growth, migration, invasion as well as profiles of gene and protein expression. These interactions cause the 3D-cultured cells to acquire morphological and cellular characteristics relevant to in vivo tumors. Palbociclib is a chemotherapeutic agent for the treatment of ER-positive and HER-negative metastatic breast cancer. Poly-amidoamine (PAMAM) dendrimer is a well-defined, special three-dimensional structure and has a multivalent surface and internal cavities that can play an essential role in drug delivery systems. In this study, palbociclib is loaded onto the magnetic PAMAM dendrimer. Hanging droplet method was used in order to form 3D spheroids. The possible toxic effects of both free drug and drug loaded nanoparticles were evaluated in 2D and 3D MCF-7, MD-MB-231 and SKBR-3 breast cancer cell culture models by performing MTT cell viability and Alamar Blue assays. MTT analysis was performed with six different doses from 1000 µg/ml to 25 µg/ml. Drug unloaded PAMAM dendrimer did not demonstrate significant toxicity on all breast cancer cell lines. The results showed that 3D spheroids are clearly less sensitive than 2D cell cultures to free palbociclib. Also, palbociclib loaded PAMAM dendrimers showed more toxic effect than free palbociclib in all cell lines at 2D and 3D cultures. The results suggest that the traditional cell culture method (2D) is insufficient for mimicking the actual tumor tissue. The response of the cancer cells to anticancer drugs is different in the 2D and 3D culture conditions. This study showed that breast cancer cells are more resistant to free palbociclib in 3D cultures than in 2D cultures. However, nanoparticle loaded drugs can be more cytotoxic when compared to free drug.

Keywords: 2D and 3D cell culture, breast cancer, palbociclibe, PAMAM magnetic nanoparticles

Procedia PDF Downloads 139

Authors: Aniela Pop, Ianina Birsan, Corina Orha, Rodica Pode, Florica Manea

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Carbon nanofiber-epoxy composite electrode has been investigated through voltammetric and amperometric techniques in order to detect parabens from aqueous solutions. The occurrence into environment as emerging pollutants of these preservative compounds has been extensively studied in the last decades, and consequently, a rapid and reliable method for their quantitative quantification is required. In this study, methylparaben (MP) and propylparaben (PP) were chosen as representatives for paraben class. The individual electrochemical detection of each paraben has been successfully performed. Their electrochemical oxidation occurred at the same potential value. Their simultaneous quantification should be assessed electrochemically only as general index of paraben class as a cumulative signal corresponding to both MP and PP from solution. The influence of pH on the electrochemical signal was studied. pH ranged between 1.3 and 9.0 allowed shifting the detection potential value to smaller value, which is very desired for the electroanalysis. Also, the signal is better-defined and higher sensitivity is achieved. Differential-pulsed voltammetry and square-wave voltammetry were exploited under the optimum pH conditions to improve the electroanalytical performance for the paraben detection. Also, the operation conditions were selected, i.e., the step potential, modulation amplitude and the frequency. Chronomaprometry application as the easiest electrochemical detection method led to worse sensitivity, probably due to a possible fouling effect of the electrode surface. The best electroanalytical performance was achieved by pulsed voltammetric technique but the selection of the electrochemical technique is related to the concrete practical application. A good reproducibility of the voltammetric-based method using carbon nanofiber-epoxy composite electrode was determined and no interference effect was found for the cation and anion species that are common in the water matrix. Besides these characteristics, the long life-time of the electrode give to carbon nanofiber-epoxy composite electrode a great potential for practical applications.

Keywords: carbon nanofiber-epoxy composite electrode, electroanalysis, methylparaben, propylparaben

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Authors: Nia Mair Fry, Matthew Profit, Chenfeng Li

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This work focuses on the development and implementation of a fully implicit-implicit, coupled mechanical deformation and porous flow, finite element software tool. The fully implicit software accurately predicts classical fundamental analytical solutions such as the Terzaghi consolidation problem. Furthermore, it can capture other analytical solutions less well known in the literature, such as Gibson’s sedimentation rate problem and Coussy’s problems investigating wellbore stability for poroelastic rocks. The mechanical volume strains are transferred to the porous flow governing equation in an implicit framework. This will overcome some of the many current industrial issues, which use explicit solvers for the mechanical governing equations and only implicit solvers on the porous flow side. This can potentially lead to instability and non-convergence issues in the coupled system, plus giving results with an accountable degree of error. The specification of a fully monolithic implicit-implicit coupled porous media code sees the solution of both seepage-mechanical equations in one matrix system, under a unified time-stepping scheme, which makes the problem definition much easier. When using an explicit solver, additional input such as the damping coefficient and mass scaling factor is required, which are circumvented with a fully implicit solution. Further, improved accuracy is achieved as the solution is not dependent on predictor-corrector methods for the pore fluid pressure solution, but at the potential cost of reduced stability. In testing of this fully monolithic porous media code, there is the comparison of the fully implicit coupled scheme against an existing staggered explicit-implicit coupled scheme solution across a range of geotechnical problems. These cases include 1) Biot coefficient calculation, 2) consolidation theory with Terzaghi analytical solution, 3) sedimentation theory with Gibson analytical solution, and 4) Coussy well-bore poroelastic analytical solutions.

Keywords: coupled, implicit, monolithic, porous media

Procedia PDF Downloads 127

Authors: B. S Kaith, K. Sharma, V. Kumar, S. Kalia

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Superabsorbent are three-dimensional networks of linear or branched polymeric chains which can uptake large volume of biological fluids. The ability is due to the presence of functional groups like –NH2, -COOH and –OH. Such cross-linked products based on natural materials, such as cellulose, starch, dextran, gum and chitosan, because of their easy availability, low production cost, non-toxicity and biodegradability have attracted the attention of Scientists and Technologists all over the world. Since natural polymers have better biocompatibility and are non-toxic than most synthetic one, therefore, such materials can be applied in the preparation of controlled drug delivery devices, biosensors, tissue engineering, contact lenses, soil conditioning, removal of heavy metal ions and dyes. Gums are natural potential antioxidants and are used as food additives. They have excellent properties like high solubility, pH stability, non-toxicity and gelling characteristics. Till date lot of methods have been applied for the synthesis and modifications of cross-linked materials with improved properties suitable for different applications. It is well known that ion beam irradiation can play a crucial role to synthesize, modify, crosslink or degrade polymeric materials. High energetic heavy ions irradiation on polymer film induces significant changes like chain scission, cross-linking, structural changes, amorphization and degradation in bulk. Various researchers reported the effects of low and heavy ion irradiation on the properties of polymeric materials and observed significant improvement in optical, electrical, chemical, thermal and dielectric properties. Moreover, modifications induced in the materials mainly depend on the structure, the ion beam parameters like energy, linear energy transfer, fluence, mass, charge and the nature of the target material. Ion-beam irradiation is a useful technique for improving the surface properties of biodegradable polymers without missing the bulk properties. Therefore, a considerable interest has been grown to study the effects of SHIs irradiation on the properties of synthesized semi-IPNs and IPNs. The present work deals with the preparation of semi-IPNs and IPNs and impact of SHI like O7+ and Ni9+ irradiation on optical, chemical, structural, morphological and thermal properties along with impact on different applications. The results have been discussed on the basis of Linear Energy Transfer (LET) of the ions.

Keywords: adsorbent, gel, IPNs, semi-IPNs

Procedia PDF Downloads 360

Authors: Oluwabukola Oluwaseyi Oduntan

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The English Language plays a central and strategic role in the school system because almost all the school subjects are taught using the English language. However, students’ achievement in this subject at senior secondary school is not encouraging. Therefore, this study examined the effects of oral-written mode of assessment on senior secondary school students’ achievement in a descriptive essay. It also examined the moderating effects of students’ gender and class on students’ achievement in a descriptive essay. The study adopted a pretest-posttest, control group, quasi-experimental design with a 2x2x3 factorial matrix. The participant consisted of 140 Senior Secondary II students drawn from four intact classes from four schools randomly selected from four Local Government Areas randomly selected from Oyo town in Oyo State. Two schools were assigned each to the treatment group and the control group. The following instruments were used for the study: Descriptive Essay Achievement Test (r = 0.78); Descriptive Achievement Test Marking Scheme; Check List of Oral-Written Assessment and Teachers’ Instructional Guide on Descriptive Essay (r = 0.81). Seven null hypotheses guided the study and tested at 0.05 level of significance. Data were analyzed using Analysis of Covariance, Estimated Marginal Means and Scheffe post-hoc test. The result revealed that treatment had a significant main effect on students’ achievement in descriptive essay (F(1,127) = 25.407, P < .05, η2 = .167). Students exposed to oral-written assessment had a higher achievement scores ((x ) ̅= 36.15) than those exposed to written assessment ((x ) ̅= 28.55). There was no significant main effect of gender on students’ achievement in descriptive essay (F₍₁, ₁₂₇₎ = .349, P > .05, η2 = .003). The result also revealed that the effects of class was not significant on students’ students’ achievement in descriptive essay (F₍₁, ₁₂₇₎ = .679, P > .05, η2 = .006). Oral-written mode of assessment enhanced students’ achievement in a descriptive essay. It is, therefore, recommended that teachers and curriculum developers should adopt the use of oral-written assessment for better improvement of students’ achievement in a descriptive essay.

Keywords: class, gender, oral-written assessment, written assessment

Procedia PDF Downloads 308

Authors: Karolina Mazur, Stanislaw Kuciel

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Polylactides (PLA) and polyhydroxyalkanoates (PHA) are the two groups of biodegradable and biocompatible thermoplastic polymers most commonly utilised in medicine and rehabilitation. The aim of this work is to determine the changes in the strength properties and the microstructures taking place in biodegradable polymer composites during their long-term storage in a highly cooled environment (i.e. a freezer at -24ºC) and to initially assess the durability of such biocomposites when used as single-use elements of rehabilitation or medical equipment. It is difficult to find any information relating to the feasibility of long-term storage of technical products made of PLA or PHA, but nonetheless, when using these materials to make products such as casings of hair dryers, laptops or mobile phones, it is safe to assume that without storing in optimal conditions their degradation time might last even several years. SEM images and the assessment of the strength properties (tensile, bending and impact testing) were carried out and the density and water sorption of two polymers, PLA and PHA (NaturePlast PLE 001 and PHE 001), filled with cellulose fibres (corncob grain – Rehofix MK100, Rettenmaier&Sohne) up to 10 and 20% mass were determined. The biocomposites had been stored at a temperature of -24ºC for 4 years. In order to find out the changes in the strength properties and the microstructure taking place after such a long time of storage, the results of the assessment have been compared with the results of the same research carried out 4 years before. Results shows a significant change in the manner of fractures – from ductile with developed surface for the PHA composite with corncob grain when the tensile testing was performed directly after the injection into a more brittle state after 4 years of storage, which is confirmed by the strength tests, where a decrease of deformation is observed at point of fracture. The research showed that there is a way of storing medical devices made out of PLA or PHA for a reasonably long time, as long as the required temperature of storage is met. The decrease of mechanical properties found during tensile testing and bending for PLA was less than 10% of the tensile strength, while the modulus of elasticity and deformation at fracturing slightly rose, which may implicate the beginning of degradation processes. The strength properties of PHA are even higher after 4 years of storage, although in that case the decrease of deformation at fracturing is significant, reaching even 40%, which suggests its degradation rate is higher than that of PLA. The addition of natural particles in both cases only slightly increases the biodegradation.

Keywords: biocomposites, PLA, PHA, storage

Procedia PDF Downloads 254

Authors: Isiaka Oladele Oladipo, Olusegun Adewale Ajayi

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The blood pressure fitness of female college students has been implicated in sedentary lifestyles. This study was designed to determine the effects of the Aerobic Dance Circuit Training Programme (ADCT) on blood pressure variables (Diastolic Blood Pressure (DBP) and Systolic Blood Pressure (SBP). Participants’ Pretest-Posttest control group quasi-experimental design using a 2x2x4 factorial matrix was adopted, while one (1) research question and two (2) research hypotheses were formulated. Seventy (70) untrained obese students-volunteers age 21.10±2.46 years were purposively selected from Oyo town, Nigeria; Emmanuel Alayande College of Education (experimental group and Federal College of Education (special) control group. The participants’ BMI, weight (kg), height (m), systolic bp(mmHg), and diastolic bp (mmHg) were measured before and completion of ADCT. Data collected were analysed using a pie chart, graph, percentage, mean, frequency, and standard deviation, while a t-test was used to analyse the stated hypotheses set at the critical level of 0.05. There were significant mean differences in baseline and post-treatment values of blood pressure variables in terms of SBP among the experimental group 136.49mmHg and 131.66mmHg; control group 130.82mmHg and 130.56mmHg (crit-t=2.00, cal.t=3.02, df=69, p<.0, the hypothesis was rejected; while DBP experimental group 88.65mmHg and 82.21mmHg; control group 69.91mmHg and 72.66mmHg (crit-t=2.00, cal.t=1.437, df=69, p>.05) in which the hypothesis was accepted). It was revealed from the findings that participants’ SBP decrease from week 4 to week 12 of ADCT indicated an effective reduction in blood pressure variables of obese female students. Therefore, the study confirmed that the use of ADCT is safe and effective in the management of blood pressure for the healthy benefit of obesity.

Keywords: aerobic dance circuit training, fitness lifestyles, obese college female students, systolic blood pressure, diastolic blood pressure

Procedia PDF Downloads 62

Authors: Damian Stanislaw Nakonieczny, Grazyna Simha Martynkova, Marianna Hundakova, G. Kratosová, Karla Cech Barabaszova

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The main aim of the research was to functionalize the surface of spherical aluminum silicates in the form of so-called cenospheres. Cenospheres are light ceramic particles with a density between 0.45 and 0.85 kgm-3 hat can be obtained as a result of separation from fly ash from coal combustion. However, their occurrence is limited to about 1% by weight of dry ash mainly derived from anthracite. Hence they are very rare and desirable material. Cenospheres are characterized by complete chemical inertness. Mohs hardness in range of 6 and completely smooth surface. Main idea was to prepare the surface by chemical etching, among others hydrofluoric acid (HF) and hydrogen peroxide, caro acid, silanization using (3-aminopropyl) triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) to obtain the maximum development and functionalization of the surface to improve chemical and mechanical connection with biomedically used polymers, i.e., polyacrylic methacrylate (PMMA) and polyetheretherketone (PEEK). These polymers are used medically mainly as a material for fixed and removable dental prostheses and PEEK spinal implants. The problem with their use is the decrease in mechanical properties over time and bacterial infections fungal during implantation and use of dentures. Hence, the use of a ceramic filler that will significantly improve the mechanical properties, improve the fluidity of the polymer during shape formation, and in the future, will be able to support bacteriostatic substances such as silver and zinc ions seem promising. In order to evaluate our laboratory work, several instrumental studies were performed: chemical composition and morphology with scanning electron microscopy with Energy-Dispersive X-Ray Probe (SEM/EDX), determination of characteristic functional groups of Fourier Transform Infrared Spectroscopy (FTIR), phase composition of X-ray Diffraction (XRD) and thermal analysis of Thermo Gravimetric Analysis/differentia thermal analysis (TGA/DTA), as well as assessment of isotherm of adsorption with Brunauer-Emmett-Teller (BET) surface development. The surface was evaluated for the future application of additional bacteria and static fungus layers. Based on the experimental work, it was found that orated methods can be suitable for the functionalization of the surface of cenosphere ceramics, and in the future it can be suitable as a bacteriostatic filler for biomedical polymers, i.e., PEEK or PMMA.

Keywords: bioceramics, composites, functionalization, surface development

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Authors: Abdul Walusansa

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In this paper, paper notes and coins were collected from general public in Kampala City where ready-to-eat food can be served, in order to survey for bacterial contamination. The total bacterial number and potentially pathogenic organisms loading on currency were tested. All isolated potential pathogens were also tested for antibiotic resistance against four most commonly prescribed antibiotics. 1. The bacterial counts on one hundred paper notes sample were ranging between 6～10918/cm cm-2,the median was 141/ cm-2, according to the data it was much higher than credit cards and Australian notes which were made of polymer. The bacterial counts on sixty coin samples were ranging between 2～380/cm-2, much less than paper notes. 2. Coliform (65.6%), E. coli (45.9%), S. aureus (41.7%), B. cereus (67.7%), Salmonella (19.8%) were isolated on one hundred paper notes. Coliform (22.4%), E. coli (5.2%), S. aureus (24.1%), B. cereus (34.5%), Salmonella (10.3%) were isolated from sixty coin samples. These results suggested a high rate of potential pathogens contamination of paper notes than coins. 3. Antibiotic resistances are commonly in most of the pathogens isolated on currency. Ampicillin resistance was found in 60%of Staphylococcus aureus isolated on currency, as well as 76.6% of E. coil and 40% of Salmonella. Erythromycin resistance was detected in 56.6% of S. aureus and in 80.0% of E. coli. All the pathogens isolated were sensitive to Norfloxacin, Salmonella and S. aureus also sensitive to Cefaclor. In this paper, we also studied the antimicrobial capability of metal coins, coins collected from different countries were tested for the ability to inhibit the growth of E. sakazakii, S. aureus, E. coli, L. monocytogenes and S. typhimurium. 1) E. sakazakii appeared very sensitive to metal coins, the second is S. aureus, but E. coli, L. monocytogenes and S. typhimurium are more resistant to these metal coin samples. 2) Coins made of Nickel-brass alloy and Copper-nickel alloy showed a better effect in anti-microbe than other metal coins, especially the ability to inhibited the growth of E. sakazakii and S. aureus, all the inhibition zones produced on nutrient agar are more than 20.6 mm. Aluminium-bronze alloy revealed weak anti-microbe activity to S. aureus and no effect to kill other pathogens. Coins made of stainless steel also can’t resist bacteria growth. 3) Surprisingly, one cent coins of USA which were made of 97.5% Zinc and 2.5% Cu showed a significant antimicrobial capability, the average inhibition zone of these five pathogens is 45.5 mm.

Keywords: antibiotic sensitivity, bacteria, currency, coins, parasites

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Authors: Reza Eslami-Farsani, Hamed Khosravi, Saba Fayazzadeh

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Lightweight and efficient structures have the aim to enhance the efficiency of the components in various industries. Toward this end, composites are one of the most widely used materials because of durability, high strength and modulus, and low weight. One type of the advanced composites is grid-stiffened composite (GSC) structures which have been extensively considered in aerospace, automotive, and aircraft industries. They are one of the top candidates for replacing some of the traditional components which are used here. Although there are a good number of published surveys on the design aspects and fabrication of GSC structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Matrix modification using nanoparticles is an effective method to enhance the flexural properties of the fibrous composites. In the present study, a silane coupling agent (3-glycidoxypropyltrimethoxysilane/3-GPTS) was introduced onto the silica (SiO2) nanoparticle surface and its effects on the three-point flexural response of isogrid E-glass/epoxy composites were assessed. Based on the fourier transform infrared spectrometer (FTIR) spectra, it was inferred that the 3-GPTS coupling agent was successfully grafted onto the surface of SiO2 nanoparticles after modification. Flexural test revealed an improvement of 16%, 14%, and 36% in stiffness, maximum load and energy absorption of the isogrid specimen filled with 3 wt.% 3-GPTS/SiO2 compared to the neat one. It would be worth mentioning that in these structures, a considerable energy absorption was observed after the primary failure related to the load peak. Also, 3-GPTMS functionalization had a positive effect on the flexural behavior of the multiscale isogrid composites. In conclusion, this study suggests that the addition of modified silica nanoparticles is a promising method to improve the flexural properties of the grid-stiffened fibrous composite structures.

Keywords: isogrid-stiffened composite panels, silica nanoparticles, surface modification, flexural properties, energy absorption

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Authors: Sam Yurdakul, Nick Baverstock, Jim Mills

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TDT 064 (FLEXISEQ®) is a drug-free gel used to treat osteoarthritis (OA)-associated pain and joint stiffness. It contains ultra-deformable phospholipid Sequessome™ vesicles, which can pass through the skin barrier intact. In six randomized OA studies, topical TDT 064 was well tolerated and improved joint pain, physical function and stiffness. In the largest study, these TDT 064-mediated effects were statistically significantly greater than oral placebo and equivalent to celecoxib. To understand the therapeutic effects of TDT 064, we investigated the localisation of the drug-free vesicles within rat synovial joints. TDT 064 containing DiO-labelled Sequessome™ vesicles was applied to the knees of four 6-week-old CD® hairless rats (10 mg/kg/ joint), 2–3 times/day, for 3 days (representing the recommended clinical dose). Eighteen hours later, the animals and one untreated control were sacrificed, and the knee joints isolated, flash frozen and embedded in Acrytol Mounting Media™. Approximately 15 sections (10 µm) from each joint were analysed by fluorescence microscopy. To investigate whether the localisation of DiO fluorescence was associated with intact vesicles, an anti-PEG monoclonal antibody (mAb) was used to detect Tween, a constituent of Sequessome™ vesicles. Sections were visualized at 484 nm (DiO) and 647 nm (anti-PEG mAb) and analysed using inForm 1.4 (Perkin Elmer, Inc.). Significant fluorescence was observed at 484 nm in sections from TDT 064-treated animals. No non-specific fluorescence was observed in control sections. Fluorescence was detected as discrete vesicles on the cartilage surfaces, inside the cartilaginous matrix and within the synovial space. The number of DiO-labelled vesicles in multiple fields of view was consistent and >100 in sections from four different treated knees. DiO and anti-PEG mAb co-localised within the collagenous tissues in four different joint sections. Under higher magnification (40x), vesicles were seen in the intercellular spaces of the synovial joint tissue, but no fluorescence was seen inside cells. These data suggest that the phospholipid vesicles in TDT 064 localize at the surface of the joint cartilage; these vesicles may therefore be supplementing the phospholipid deficiency reported in OA and acting as a biolubricant within the synovial joint.

Keywords: joint pain, osteoarthritis, phospholipid vesicles, TDT 064

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Authors: Surendra Agrawal, Pravina Gurjar, Supriya Bhide, Ram Gaud

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Levamisole hydrochloride is a prominent anticancer drug in the treatment of colon cancer but resulted in toxic effects due poor bioavailability and poor cellular uptake by tumor cells. Levamisole is an unstable drug. Incorporation of this molecule in solid lipids may minimize their exposure to the aqueous environment and partly immobilize the drug molecules within the lipid matrix-both of which may protect the encapsulated drugs against degradation. The objectives of the study were to enhance bioavailability by sustaining drug release and to reduce the toxicities associated with the therapy. Solubility of the drug was determined in different lipids to select the components of Solid Lipid Nanoparticles (SLN). Pseudoternary phase diagrams were created using aqueous titration method. Formulations were subjected to particle size and stability evaluation to select the final test formulations which were characterized for average particle size, zeta potential, and in-vitro drug release and percentage transmittance to optimize the final formulation. SLN of Levamisole hydrochloride was prepared by Nanoprecipitation method. Glyceryl behenate (Compritol 888 ATO) was used as core comprising of Tween 80 as surfactant and Lecithin as co-surfactant in (1:1) ratio. Entrapment efficiency (EE) was found to be 45.89%. Particle size was found in the range of 100-600 nm. Zeta potential of the formulation was -17.0 mV revealing the stability of the product. In-vitro release study showed that 66 % drug released in 24 hours in pH 7.2 which represent that formulation can give controlled action at the intestinal environment. In pH 5.0 it showed 64% release indicating that it can even release drug in acidic environment of tumor cells. In conclusion, results revealed SLN to be a promising approach to sustain the drug release so as to increase bioavailability and cellular uptake of the drug with reduction in toxic effects as dose has been reduced with controlled delivery.

Keywords: SLN, nanoparticulate delivery of levamisole, pharmacy, pharmaceutical sciences

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Authors: B. Hammouti, H. Oudda, A. Benabdellah, A. Benayada, A. Aouniti

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Corrosion behaviour of carbon steel was studied in various concentrated HClO4 solutions. To explain the acid attack in relation of H+ activity, new sensor was realised: two carbon paste electrodes (CPE) were constructed by incorporating ferrocene (Fc) and orthoquinone into the carbon paste matrix and crossed by weak current to stabilize potential difference. The potentiometric method at imposed weak current between these two electrodes permits the in situ determination of both concentration and acidity level of various concentrated HClO4 solutions. The different factors affecting the potential at imposed current as current intensity, temperature and H+ ion concentration are studied. The potentials measured between ferrocene and chloranil electrodes are directly linked to the acid concentration. The acidity Ri(H) function defined represents the determination of the H+ activity and constitutes the extend of pH is concentrated acid solutions. Ri(H) has been determined and compared to Strehlow Ro(H), Janata HGF and Hammett Ho functions. The collected data permit to give a scale of strength of mineral concentrated acids at a given concentration. Ri(H) is numerically equal to the thermodynamic Ro(H), but deviated from Hammett functions based on indicator determination. The CPE electrode with inserted ferrocene in presence of ferricinium (Fc+) ion in concentrated HClO4 at various concentrations is realized without junction potential and may plays the role of a practical reference electrode (FRE) in concentrated acids. Fc+ was easily prepared in biphasic medium HClO4-acid by the quantitative oxidation of ferrocene by the ortho-chloranil (oQ). Potential of FRE is stable with time. The variation of equilibrium potential of the interface Fc/ Fc+ at various concentrations of Fc+ (10-4 - 2 10-2 M) obeyed to the Nernst equation with a slope 0.059 Volt per decade. Corrosion rates obtained by weight loss and electrochemical techniques were then easily linked to acidity level.

Keywords: ferrocene, strehlow, concentrated acid, corrosion, Generalised pH, sensor carbon paste electrode

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Authors: Chih-Jer Lin, Jian-Hong Hou

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Industry 4.0 is a vision of integrated industry implemented by artificial intelligent computing, software, and Internet technologies. The main goal of industry 4.0 is to deal with the difficulty owing to competitive pressures in the marketplace. For today’s manufacturing factories, the type of production is changed from mass production (high quantity production with low product variety) to medium quantity-high variety production. To offer flexibility, better quality control, and improved productivity, robot manipulators are used to combine material processing, material handling, and part positioning systems into an integrated manufacturing system. To implement the automated system for sheet metal bending operations, motion planning of a 7-degrees of freedom (DOF) robot is studied in this paper. A virtual reality (VR) environment of a bending cell, which consists of the robot and a bending machine, is established using the virtual robot experimentation platform (V-REP) simulator. For sheet metal bending operations, the robot only needs six DOFs for the pick-and-place or tracking tasks. Therefore, this 7 DOF robot has more DOFs than the required to execute a specified task; it can be called a redundant robot. Therefore, this robot has kinematic redundancies to deal with the task-priority problems. For redundant robots, Pseudo-inverse of the Jacobian is the most popular motion planning method, but the pseudo-inverse methods usually lead to a kind of chaotic motion with unpredictable arm configurations as the Jacobian matrix lose ranks. To overcome the above problem, we proposed a method to formulate the motion planning problems as optimization problem. Moreover, a genetic algorithm (GA) based method is proposed to deal with motion planning of the redundant robot. Simulation results validate the proposed method feasible for motion planning of the redundant robot in an automated sheet-metal bending operations.

Keywords: redundant robot, motion planning, genetic algorithm, obstacle avoidance

Procedia PDF Downloads 133

Authors: Han Zheng

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This research is being conducted to explore women's leadership in China's National Governing Bodies ( in order to identify the barriers to women's leadership and provide feasible solutions. Extensive research has been undertaken internationally, which has identified and acknowledged the underrepresentation of women in leadership positions across multiple industries and global contexts. According to these studies, leadership specifically within the sports industry was both historically and is still currently male-dominated. Within China, the underrepresentation of women in leadership positions is also evident, which women only occupy 16% of the leadership in business enterprises and 5.6% in scientific and technological research institutions, yet there is limited research that has looked to examine why this is the case regarding women's leadership in China, especially within in sports industry. Therefore, this research gap drives the purpose, which aims to explore the current situation of women's leadership in sports National Governing Bodies (NGBs) in China. By using both questionnaires and interviews, data from NGBs in China will be collected. This research will achieve the following three goals: 1, determine the representation level of women's leadership in the target organizations. 2, identify barriers to women's leadership and their causes. 3, provide feasible solutions. Based on the multi-level framework, this study develops a "barrier matrix" framework: according to the analysis of the previous literature, it concludes that there are eight main barriers that hinder the development of women's leadership. The research combines qualitative and quantitative analysis, using questionnaires and interviews. Key findings according to the analysis of the primary data collected: 1. The average proportion of female occupational leadership in China's sports NGBs is less than 17.5%. 2. 50.8% of China's sports NGBs have no equal employment opportunity policy. 3. According to the preliminary qualitative analysis of the interviews, it is found that the core barriers affecting women's leadership development are mainly in the following areas: male-dominated culture and gender stereotyping (macro-level), biased organizational policies and procedures (meso-level), work-family conflicts and self-limiting behaviors (micro-level).

Keywords: women leadership, sport management, gender equality, sport leadership, sport NGBs

Procedia PDF Downloads 168

Authors: S. Paszkiewicz, A. Zubkiewicz, A. Szymczyk, D. Pawlikowska, I. Irska, E. Piesowicz, A. Linares, T. A. Ezquerra

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Over the last century, the world has become increasingly dependent on oil as its main source of chemicals and energy. Driven largely by the strong economic growth of India and China, demand for oil is expected to increase significantly in the coming years. This growth in demand, combined with diminishing reserves, will require the development of new, sustainable sources for fuels and bulk chemicals. Biomass is an attractive alternative feedstock, as it is widely available carbon source apart from oil and coal. Nowadays, academic and industrial research in the field of polymer materials is strongly oriented towards bio-based alternatives to petroleum-derived plastics with enhanced properties for advanced applications. In this context, 2,5-furandicarboxylic acid (FDCA), a biomass-based chemical product derived from lignocellulose, is one of the most high-potential biobased building blocks for polymers and the first candidate to replace the petro-derived terephthalic acid. FDCA has been identified as one of the top 12 chemicals in the future, which may be used as a platform chemical for the synthesis of biomass-based polyester. The aim of this study is to synthesize and characterize the multiblock copolymers containing rigid segments of poly(trimethylene 2,5-furanoate) (PTF) and soft segments of poly(tetramethylene oxide) (PTMO) with excellent elastic properties or aliphatic polyesters of polycaprolactone (PCL). Two series of PTF based copolymers, i.e., PTF-block-PTMO-T and PTF-block-PCL-T, with different content of flexible segments were synthesized by means of a two-step melt polycondensation process and characterized by various methods. The rigid segments of PTF, as well as the flexible PTMO/or PCL ones, were randomly distributed along the chain. On the basis of 1H NMR, SAXS and WAXS, DSC an DMTA results, one can conclude that both phases were thermodynamically immiscible and the values of phase transition temperatures varied with the composition of the copolymer. The copolymers containing 25, 35 and 45wt.% of flexible segments (PTMO) exhibited elastomeric property characteristics. Moreover, with respect to the flexible segments content, the temperatures corresponding to 5%, 25%, 50% and 90% mass loss as well as the values of tensile modulus decrease with the increasing content of aliphatic polyether or aliphatic polyester in the composition.

Keywords: furan based polymers, multiblock copolymers, supramolecular structure, functional properties

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Authors: Reza Eslami-Farsani, Hamed Khosravi, Saba Fayazzadeh

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Lightweight and efficient structures have the aim to enhance the efficiency of the components in various industries. Toward this end, composites are one of the most widely used materials because of durability, high strength and modulus, and low weight. One type of the advanced composites is grid-stiffened composite (GSC) structures, which have been extensively considered in aerospace, automotive, and aircraft industries. They are one of the top candidates for replacing some of the traditional components, which are used here. Although there are a good number of published surveys on the design aspects and fabrication of GSC structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Matrix modification using nanoparticles is an effective method to enhance the flexural properties of the fibrous composites. In the present study, a silane-coupling agent (3-glycidoxypropyltrimethoxysilane/3-GPTS) was introduced onto the silica (SiO2) nanoparticle surface and its effects on the three-point flexural response of isogrid E-glass/epoxy composites were assessed. Based on the fourier transform infrared spectrometer (FTIR) spectra, it was inferred that the 3-GPTS coupling agent was successfully grafted onto the surface of SiO2 nanoparticles after modification. Flexural test revealed an improvement of 16%, 14%, and 36% in stiffness, maximum load and energy absorption of the isogrid specimen filled with 3 wt.% 3-GPTS/SiO2 compared to the neat one. It would be worth mentioning that in these structures, considerable energy absorption was observed after the primary failure related to the load peak. In addition, 3-GPTMS functionalization had a positive effect on the flexural behavior of the multiscale isogrid composites. In conclusion, this study suggests that the addition of modified silica nanoparticles is a promising method to improve the flexural properties of the grid-stiffened fibrous composite structures.

Keywords: isogrid-stiffened composite panels, silica nanoparticles, surface modification, flexural properties

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Authors: Azieva A. M., Yastremsky E. V., Kirillova D. A., Patsaev T. D., Sharikov R. V., Kamyshinsky R. A., Lukanina K. I., Sharikova N. A., Grigoriev T. E., Vasiliev A. L.

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Adhesive properties of scaffolds, which predominantly depend on the chemical and structural features of their surface, play the most important role in tissue engineering. The basic requirements for such scaffolds are biocompatibility, biodegradation, high cell adhesion, which promotes cell proliferation and differentiation. In many cases, synthetic polymers scaffolds have proven advantageous because they are easy to shape, they are tough, and they have high tensile properties. The regeneration of nerve tissue still remains a big challenge for medicine, and neural stem cells provide promising therapeutic potential for cell replacement therapy. However, experiments with stem cells have their limitations, such as low level of cell viability and poor control of cell differentiation. Whereas the study of already differentiated neuronal cell culture obtained from newborn mouse brain is limited only to cell adhesion. The growth and implantation of neuronal culture requires proper scaffolds. Moreover, the polymer scaffolds implants with neuronal cells could demand specific morphology. To date, it has been proposed to use numerous synthetic polymers for these purposes, including polystyrene, polylactic acid (PLA), polyglycolic acid, and polylactide-glycolic acid. Tissue regeneration experiments demonstrated good biocompatibility of PLA scaffolds, despite the hydrophobic nature of the compound. Problem with poor wettability of the PLA scaffold surface could be overcome in several ways: the surface can be pre-treated by poly-D-lysine or polyethyleneimine peptides; roughness and hydrophilicity of PLA surface could be increased by plasma treatment, or PLA could be combined with natural fibers, such as collagen or chitosan. This work presents a study of adhesion of both induced pluripotent stem cells (iPSCs) and mouse primary neuronal cell culture on the polylactide scaffolds of various types: oriented and non-oriented fibrous nonwoven materials and sponges – with and without the effect of plasma treatment and composites with collagen and chitosan. To evaluate the effect of different types of PLA scaffolds on the neuronal differentiation of iPSCs, we assess the expression of NeuN in differentiated cells through immunostaining. iPSCs more effectively differentiate into neurons on PLA scaffolds with high adhesive properties for primary neuronal cells.

Keywords: PLA scaffold, neurons, neuronal differentiation, stem cells, polylactid

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Authors: Faezeh Eslamian, Zhiming Qi, Michael J. Tate

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Phosphorus losses from agricultural fields through leaching is one of the main contributors to eutrophication of lakes in Quebec as well as North America. The main objective of this study is to evaluate the application of high calcium hydrated lime as a soil amendment in reducing the subsurface transport of phosphorus to water bodies by studying the interactions between phosphorus leaching and lime application in three common agricultural soil textures (sandy loam, loam and clay loam) in Quebec. For this purpose, 6 intact soil columns of 10 cm diameter and 20 cm deep were taken from each of the three different soil textured agricultural fields. Lime (high calcium hydrated lime) was applied to the top 5 cm of half of the intact soil columns while the rest were left as controls. The columns were leached with artificial rainwater in-consecutively at a rate of 3 mm h-1 over a 90-day period. The total amount of water added was equal to the average total rainfall of the region in fall. The leachate samples were collected daily and analyzed for dissolved reactive phosphorus, total dissolved phosphorus, total phosphorus, pH, electrical conductivity, calcium, magnesium, potassium and iron. The results showed that lime was able to significantly reduce dissolved reactive phosphorus concentrations in the leachates by 70 and 40 percent in sandy loam and loam soil columns, respectively, while phosphorus concentration in the clay loam soil leachates were increased by 40 percent. The calcium in lime has P-binding capabilities. Soil chemical properties in sandy and loamy soils can affect phosphorus leaching, whereas, transport mechanisms in clay soils with macropores dominate phosphorus leaching behaviors. The presence of preferential pathways and cracks in the clay soil columns has led to a quick transport of phosphorus through the soil and the less contact time with the soil matrix, therefore, causing less opportunity for P sorption and larger P release. Application of lime to agricultural fields can be considered as a promising measure in mitigating phosphorus loss from sandy loam and loam soils.

Keywords: leaching, lime, phosphorus, soil texture

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Authors: Yu-Wen Cheng, Jau-Der Ho, Liang-Huan Wu, Fan-Li Lin, Li-Huei Chen, Hung-Ming Chang, Yueh-Hsiung Kuo, George Hsiao

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Retina glial activation and neuroinflammation have been confirmed to cause devastating responses in retinodegenerative diseases. The expression and activation of matrix metalloproteinase (MMP)-9 and inducible nitric oxide synthase (iNOS) could be exerted as the crucial pathological factors in glaucoma- and blue light-induced retinal injuries. The present study aimed to investigate the retinoprotective effects and mechanisms of fungal ingredient 3,4-dihydroxybenzalacetone (DBL) isolated from Phellinus linteus in the retinal glial activation and retinodegenerative animal models. According to the cellular studies, DBL significantly and concentration-dependently abrogated MMP-9 activation and expression in TNFα-stimulated retinal Müller (rMC-1) cells. We found the inhibitory activities of DBL were strongly through the STAT- and ERK-dependent pathways. Furthermore, DBL dramatically attenuated MMP-9 activation in the stimulated Müller cells exposed to conditioned media from LPS-stimulated microglia BV-2 cells. On the other hand, DBL strongly suppressed LPS-induced production of NO and ROS and expression of iNOS in microglia BV-2 cells. Consistently, the phosphorylation of STAT was substantially blocked by DBL in LPS-stimulated microglia BV-2 cells. In the evaluation of retinoprotective functions, the high IOP-induced scotopic electroretinographic (ERG) deficit and blue light-induced abnormal pupillary light response (PLR) were assessed. The deficit scotopic ERG responses markedly recovered by DBL in a rat model of glaucoma-like ischemia/reperfusion (I/R)-injury. DBL also reduced the aqueous gelatinolytic activity and retinal MMP-9 expression in high IOP-injured conditions. Additionally, DBL could restore the abnormal PLR and reduce retinal MMP-9 activation. In summary, DBL could ameliorate retinal neuroinflammation and MMP-9 activation by predominantly inhibiting STAT3 activation in the retinal Müller cells and microglia, which exhibits therapeutic potential for glaucoma and other retinal degenerative diseases.

Keywords: glaucoma, blue light, DBL, retinal Müller cell, MMP-9, STAT, Microglia, iNOS, ERG, PLR

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Authors: Sadia H. Syeda, Zain H. Malik

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As systems continue to become more complex and the interdependencies of processes and sub-systems continue to grow and transform, the need for a comprehensive method of tracking and linking the lifecycle of the systems in a digital form becomes ever more critical. Digital Engineering (DE) provides an approach to managing an authoritative data source that links, tracks, and updates system data as it evolves and grows throughout the system development lifecycle. DE enables the developing, tracking, and sharing system data, models, and other related artifacts in a digital environment accessible to all necessary stakeholders. The DE environment provides an integrated electronic repository that enables traceability between design, engineering, and sustainment artifacts. The DE activities' primary objective is to develop a set of integrated, coherent, and consistent system models for the program. It is envisioned to provide a collaborative information-sharing environment for various stakeholders, including operational users, acquisition personnel, engineering personnel, and logistics and sustainment personnel. Examining the processes that DE can support in the systems engineering life cycle (SELC) is a primary step in the DE adoption and implementation journey. Through an analysis of the U.S Department of Defense’s (DoD) Office of the Secretary of Defense (OSD’s) Digital Engineering Strategy and their implementation, examples of DE implementation by the industry and technical organizations, this paper will provide descriptions of the current DE processes and best practices of implementing DE across an enterprise. This will help identify the capabilities, environment, and infrastructure needed to develop a potential roadmap for implementing DE practices consistent with its business strategy. A capability maturity matrix will be provided to assess the organization’s DE maturity emphasizing how all the SELC elements interlink to form a cohesive ecosystem. If implemented, DE can increase efficiency and improve the systems engineering processes' quality and outcomes.

Keywords: digital engineering, digital environment, digital maturity model, single source of truth, systems engineering life-cycle

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Authors: S. Y. Park, S. M. Lee, S. H. Lee, K. M. Lim

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In this research analyzed the effects that phase formation reaction change in the grey cast iron makes on characteristics of microstructures, liquidity, and mechanical properties through cooling curve when adding rare earth elements (R.E). This research was analyzed with comparison between the case of not adding the rare earth elements (R.E) into the grey cast iron with the standard composition (as 3.3%C-2.1%Si-0.7%Mn-0.1%S) and the case of adding 0.3% rare earth elements (R.E). The thermal analysis parameters have been drawn through eutectic temperature theoretically calculated, recalescence temperature, and undercooling temperature measured from start of eutectic reaction to end of solidification in the cooling curve obtained by thermal analysis to analyze formation behavior of graphite, and the effects by addition of rare earth elements on this have been reviewed. When adding rare earth elements (R.E), the cause of liquidity slowdown was analyzed trough the solidification starting temperature and change of solidification ending temperature. The strength and hardness have been measured to evaluate the mechanical properties, and the sound tensile strength has been evaluated through quality coefficient after measuring relative hardness and normality degree of tensile strength by calculating theoretical tensile strength and theoretical hardness. The change of Pearlite Inter-lamellar Spacing of matrix microstructure and eutectic cell count of macrostructure was measured to analyze the effects of the rare earth elements on the sound tensile strength. The change of eutectic cell count has been clarified through activation of the eutectic reaction, and the cause of pearlite inter-lamellar spacing clarified through eutectoid reaction temperature.

Keywords: cooling curve, element, grey cast iron, thermal analysis, rare earth element

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Authors: Fazl Ullah, Rahmat Ullah

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This paper shows a comprehensive learning focused on the optimization of gas production in shale gas reservoirs through hydraulic fracturing. Shale gas has emerged as an important unconventional vigor resource, necessitating innovative techniques to enhance its extraction. The key objective of this study is to examine the influence of fracture parameters on reservoir productivity and formulate strategies for production optimization. A sophisticated model integrating gas flow dynamics and real stress considerations is developed for hydraulic fracturing in multi-stage shale gas reservoirs. This model encompasses distinct zones: a single-porosity medium region, a dual-porosity average region, and a hydraulic fracture region. The apparent permeability of the matrix and fracture system is modeled using principles like effective stress mechanics, porous elastic medium theory, fractal dimension evolution, and fluid transport apparatuses. The developed model is then validated using field data from the Barnett and Marcellus formations, enhancing its reliability and accuracy. By solving the partial differential equation by means of COMSOL software, the research yields valuable insights into optimal fracture parameters. The findings reveal the influence of fracture length, diversion capacity, and width on gas production. For reservoirs with higher permeability, extending hydraulic fracture lengths proves beneficial, while complex fracture geometries offer potential for low-permeability reservoirs. Overall, this study contributes to a deeper understanding of hydraulic cracking dynamics in shale gas reservoirs and provides essential guidance for optimizing gas production. The research findings are instrumental for energy industry professionals, researchers, and policymakers alike, shaping the future of sustainable energy extraction from unconventional resources.

Keywords: fluid-solid coupling, apparent permeability, shale gas reservoir, fracture property, numerical simulation

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Authors: Mostafa Sefidgar, Sohrab Zendehboudi, Hossein Bazmara, Madjid Soltani

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Based on findings from clinical applications, most drug treatments fail to eliminate malignant tumors completely even though drug delivery through systemic administration may inhibit their growth. Therefore, better understanding of tumor formation is crucial in developing more effective therapeutics. For this purpose, nowadays, solid tumor modeling and simulation results are used to predict how therapeutic drugs are transported to tumor cells by blood flow through capillaries and tissues. A solid tumor is investigated as a porous media for fluid flow simulation. Most of the studies use Darcy model for porous media. In Darcy model, the fluid friction is neglected and a few simplified assumptions are implemented. In this study, the effect of these assumptions is studied by considering Brinkman model. A multi scale mathematical method which calculates fluid flow to a solid tumor is used in this study to investigate how neglecting fluid friction affects the solid tumor simulation. In this work, the mathematical model in our previous studies is developed by considering two model of momentum equation for porous media: Darcy and Brinkman. The mathematical method involves processes such as fluid flow through solid tumor as porous media, extravasation of blood flow from vessels, blood flow through vessels and solute diffusion, convective transport in extracellular matrix. The sprouting angiogenesis model is used for generating capillary network and then fluid flow governing equations are implemented to calculate blood flow through the tumor-induced capillary network. Finally, the two models of porous media are used for modeling fluid flow in normal and tumor tissues in three different shapes of tumors. Simulations of interstitial fluid transport in a solid tumor demonstrate that the simplifications used in Darcy model affect the interstitial velocity and Brinkman model predicts a lower value for interstitial velocity than the values that Darcy model does.

Keywords: solid tumor, porous media, Darcy model, Brinkman model, drug delivery

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Authors: K. Khouzami, J. Brassinne, C. Branca, E. Van Ruymbeke, B. Nysten, G. D’Angelo

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The development of hybrid organic-inorganic nanocomposites has recently attracted great interest. Typically, polymer silicates represent an emerging class of polymeric nanocomposites that offer superior material properties compared to each compound alone. Among these materials, complexes based on silicate clay and polysaccharides are one of the most promising nanocomposites. The strong electrostatic interaction between chitosan and montmorillonite can induce what is called physical hydrogel, where the coordination bonds or physical crosslinks may associate and dissociate reversibly and in a short time. These mechanisms could be the main origin of the uniqueness of their rheological behavior. However, owing to their structure intrinsically heterogeneous and/or the lack of dissipated energy, they are usually brittle, possess a poor toughness and may not have sufficient mechanical strength. Consequently, the properties of these nanocomposites cannot respond to some requirements of many applications in several fields. To address the issue of weak mechanical properties, covalent chemical crosslink bonds can be introduced to the physical hydrogel. In this way, quite homogeneous dually crosslinked microstructures with high dissipated energy and enhanced mechanical strength can be engineered. In this work, we have prepared a series of chitosan-montmorillonite nanocomposites chemically crosslinked by addition of poly (ethylene glycol) diglycidyl ether. This study aims to provide a better understanding of the mechanical behavior of dually crosslinked chitosan-based nanocomposites by relating it to their microstructures. In these systems, the variety of microstructures is obtained by modifying the number of cross-links. Subsequently, a superior uniqueness of the rheological properties of chemically crosslinked chitosan-montmorillonite nanocomposites is achieved, especially at the highest percentage of clay. Their rheological behaviors depend on the clay/chitosan ratio and the crosslinking. All specimens exhibit a viscous rheological behavior over the frequency range investigated. The flow curves of the nanocomposites show a Newtonian plateau at very low shear rates accompanied by a quite complicated nonlinear decrease with increasing the shear rate. Crosslinking induces a shear thinning behavior revealing the formation of network-like structures. Fitting shear viscosity curves via Ostward-De Waele equation disclosed that crosslinking and clay addition strongly affect the pseudoplasticity of the nanocomposites for shear rates γ ̇>20.

Keywords: chitosan, crossliking, nanocomposites, rheological properties

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Authors: Philip T. Broughton, Mark P. Bettney, Isla L. Smail

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Effective treatment of ground instability is essential when managing the impacts associated with historic mining. A field trial was undertaken by the Coal Authority to investigate the geotechnical performance and potential use of composite materials comprising resin and fill or stone to safely treat surface collapses, such as crown-holes, associated with shallow mining. Test pits were loosely filled with various granular fill materials. The fill material was injected with commercially available silicate and polyurethane resin foam products. In situ and laboratory testing was undertaken to assess the geotechnical properties of the resultant composite materials. The test pits were subsequently excavated to assess resin permeation. Drilling and resin injection was easiest through clean limestone fill materials. Recycled building waste fill material proved difficult to inject with resin; this material is thus considered unsuitable for use in resin composites. Incomplete resin permeation in several of the test pits created irregular ‘blocks’ of composite. Injected resin foams significantly improve the stiffness and resistance (strength) of the un-compacted fill material. The stiffness of the treated fill material appears to be a function of the stone particle size, its associated compaction characteristics (under loose tipping) and the proportion of resin foam matrix. The type of fill material is more critical than the type of resin to the geotechnical properties of the composite materials. Resin composites can effectively support typical design imposed loads. Compared to other traditional treatment options, such as cement grouting, the use of resin composites is potentially less disruptive, particularly for sites with limited access, and thus likely to achieve significant reinstatement cost savings. The use of resin composites is considered a suitable option for the future treatment of shallow mining collapses.

Keywords: composite material, ground improvement, mining legacy, resin

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