Search results for: nano gamma alumina

Authors: Mostafa Aminzadeh, Min Deng

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Modeling loss data is an important part of actuarial science. Actuaries use models to predict future losses and manage financial risk, which can be beneficial for marketing purposes. In the insurance industry, small claims happen frequently while large claims are rare. Traditional distributions such as Normal, Exponential, and inverse-Gaussian are not suitable for describing insurance data, which often show skewness and fat tails. Several authors have studied classical and Bayesian inference for parameters of composite distributions, such as Exponential-Pareto, Weibull-Pareto, and Inverse Gamma-Pareto. These models separate small to moderate losses from large losses using a threshold parameter. This research introduces a computational approach using a nonlinear regression model for loss data that relies on multiple predictors. Simulation studies were conducted to assess the accuracy of the proposed estimation method. The simulations confirmed that the proposed method provides precise estimates for regression parameters. It's important to note that this approach can be applied to datasets if goodness-of-fit tests confirm that the composite distribution under study fits the data well. To demonstrate the computations, a real data set from the insurance industry is analyzed. A Mathematica code uses the Fisher information algorithm as an iteration method to obtain the maximum likelihood estimation (MLE) of regression parameters.

Keywords: maximum likelihood estimation, fisher scoring method, non-linear regression models, composite distributions

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Authors: Emi Govorčin Bajsića, Vesna Ocelić Bulatović, Miroslav Slouf, Ana Šitum

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Composites based on a biodegradable polycaprolactone (PCL) containing 0.5, 1.0 and 2.0 wt % of titanium dioxide (TiO2) micro and nanoparticles were prepared by melt mixing and the effect of filler type and contents on the thermal properties, dynamic-mechanical behaviour and morphology were investigated. Measurements of storage modulus and loss modulus by dynamic mechanical analysis (DMA) showed better results for microfilled PCL/TiO2 composites than nanofilled composites, with the same filler content. DSC analysis showed that the Tg and Tc of micro and nanocomposites were slightly lower than those of neat PCL. The crystallinity of the PCL increased with the addition of TiO2 micro and nanoparticles; however, the c for the PCL was unchanged with micro TiO2 content. The thermal stability of PCL/TiO2 composites were characterized using thermogravimetric analysis (TGA). The initial weight loss (5 wt %) occurs at slightly higher temperature with micro and nano TiO2 addition and with increasing TiO2 content.

Keywords: polycaprolactone, titanium dioxide, thermal properties, morphology

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Authors: Prasanta Sutradhar, Mitali Saha

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With an increasing awareness of green and clean energy, zinc oxide based solar cells were found to be suitable candidates for cost-effective and environmentally friendly energy conversion devices. In this work, we have reported the green synthesis of zinc oxide nanoparticles (ZnO) by thermal method and under microwave irradiation using the aqueous extract of tomatoes as non-toxic and ecofriendly reducing material. The synthesized ZnO nanoparticles were characterised by UV-Visible spectroscopy (UV-Vis), infra-red spectroscopy (IR), particle size analyser (DLS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X- ray diffraction study (XRD). A series of ZnO nanocomposites with titanium dioxide nanoparticles (TiO2) and graphene oxide (GO) were prepared for photovoltaic application. Structural and morphological studies of these nanocomposites were carried out using UV-vis, SEM, XRD, and AFM. The current-voltage measurements of the nanocomposites demonstrated enhanced power conversion efficiency of 6.18% in case of ZnO/GO/TiO2 nanocomposite.

Keywords: ZnO, green synthesis, microwave, nanocomposites, I-V characteristics

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Authors: S. H. Rashmi, G. M. Madhu, A. A. Kittur, R. Suresh

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Polymer nanocomposites represent a new class of materials in which nanomaterials act as the reinforcing material in composites, wherein small additions of nanomaterials lead to large enhancements in thermal, optical, and mechanical properties. A boost in these properties is due to the large interfacial area per unit volume or weight of the nanoparticles and the interactions between the particle and the polymer. Micro-sized particles used as reinforcing agents scatter light, thus, reducing light transmittance and optical clarity. Efficient nanoparticle dispersion combined with good polymer–particle interfacial adhesion eliminates scattering and allows the exciting possibility of developing strong yet transparent films, coatings and membranes. This paper aims at synthesizing zinc oxide nanoparticles which are reinforced in poly vinyl alcohol (PVA) polymer. The mechanical properties showed that the tensile strength of the PVA nanocomposites increases with the increase in the amount of nanoparticles.

Keywords: glutaraldehyde, polymer nanocomposites, poly vinyl alcohol, zinc oxide

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Authors: Ajoy Kumar Das, Prasenjit Dey

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Heat transfer due to forced convection of copper water based nanofluid has been predicted by Artificial Neural network (ANN). The present nanofluid is formed by mixing copper nano particles in water and the volume fractions are considered here are 0% to 15% and the Reynolds number are kept constant at 100. The back propagation algorithm is used to train the network. The present ANN is trained by the input and output data which has been obtained from the numerical simulation, performed in finite volume based Computational Fluid Dynamics (CFD) commercial software Ansys Fluent. The numerical simulation based results are compared with the back propagation based ANN results. It is found that the forced convection heat transfer of water based nanofluid can be predicted correctly by ANN. It is also observed that the back propagation ANN can predict the heat transfer characteristics of nanofluid very quickly compared to standard CFD method.

Keywords: forced convection, square cylinder, nanofluid, neural network

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Authors: M. Jerold, V. Sivasubramanian

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In this study, nano zero valent iron Sargassum swartzii (nZVI-SS) biocomposite a marine algal based biosorbent was used for the removal of simulated crystal violet (CV) in batch and continuous fixed bed operation. The Box-Behnen design (BBD) experimental results revealed the biosoprtion was maximum at pH 7.5, biosorbent dosage 0.1 g/L and initial CV concentration of 100 mg/L. The effect of various column parameters like bed depth (3, 6 and 9 cm), flow rate (5, 10 and 15 mL/min) and influent CV concentration (5, 10 and 15 mg/L) were investigated. The exhaustion time increased with increase of bed depth, influent CV concentration and decrease of flow rate. Adam-Bohart, Thomas and Yoon-Nelson models were used to predict the breakthrough curve and to evaluate the model parameters. Out of these models, Thomas and Yoon-Nelson models well described the experimental data. Therefore, the result implies that nZVI-SS biocomposite is a cheap and most promising biosorbent for the removal of CV from wastewater.

Keywords: algae, biosorption, zero-valent, dye, wastewater

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Authors: Maryam Kiani, Abdul Basit Kiani

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At larger scales, the performance of cementitious materials is impacted by processes occurring at the nanometer scale. These materials boast intricate hierarchical structures with random features that span from the nanometer to millimeter scale. It is fascinating to observe how the nanoscale processes influence the overall behavior and characteristics of these materials. By delving into and manipulating these processes, scientists and engineers can unlock the potential to create more durable and sustainable infrastructure and construction materials. It's like unraveling a hidden tapestry of secrets that hold the key to building stronger and more resilient structures. The present work employs simulations as the computational modeling methodology to predict mechanical properties for carbon/silica based cementitious materials at the molecular/nano scale level. Studies focused on understanding the effect of higher mechanical properties of cementitious materials with carbon silica nanoparticles via Material Studio materials modeling.

Keywords: nanomaterials, SiO₂, carbon black, mechanical properties

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Authors: Aliyu Usman, Muhaammed Bello Ibrahim, Yusuf D. Amartey, Jibrin M. Kaura

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This research is aimed at investigating the effect of using amorphous silica ash (ASA) obtained from rice husk as a partial replacement of ordinary Portland cement (OPC) on the mechanical and microstructure properties of cement paste and mortar. ASA was used in partial replacement of ordinary Portland cement in the following percentages 3 percent, 5 percent, 8 percent and 10 percent. These partial replacements were used to produce Cement-ASA paste and Cement-ASA mortar. ASA was found to contain all the major chemical compounds found in cement with the exception of alumina, which are SiO2 (91.5%), CaO (2.84%), Fe2O3 (1.96%), and loss on ignition (LOI) was found to be 9.18%. It also contains other minor oxides found in cement. Consistency of Cement-ASA paste was found to increase with increase in ASA replacement. Likewise, the setting time and soundness of the Cement-ASA paste also increases with increase in ASA replacements. The test on hardened mortar were destructive in nature which include flexural strength test on prismatic beam (40mm x 40mm x 160mm) at 2, 7, 14 and 28 days curing and compressive strength test on the cube size (40mm x 40mm, by using the auxiliary steel platens) at 2,7,14 and 28 days curing. The Cement-ASA mortar flexural and compressive strengths were found to be increasing with curing time and decreases with cement replacement by ASA. It was observed that 5 percent replacement of cement with ASA attained the highest strength for all the curing ages and all the percentage replacements attained the targeted compressive strength of 6N/mm2 for 28 days. There is an increase in the drying shrinkage of Cement-ASA mortar with curing time, it was also observed that the drying shrinkages for all the curing ages were greater than the control specimen all of which were greater than the code recommendation of less than 0.03%. The scanning electron microscope (SEM) was used to study the Cement-ASA mortar microstructure and to also look for hydration product and morphology.

Keywords: amorphous silica ash, cement mortar, cement paste, scanning electron microscope

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Authors: Fatemeh Moradian, Razieh Ghorbani, Poria Biparva

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Growing resistance of microorganisms to potent antibiotics has renewed a great interest towards investigating bactericidal properties of nanoparticles and their Nano composites as an alternative. The use of metal nanoparticles to combat bacterial infections is one of the most wide spread applications of nanotechnology in the field of antibacterial. Nanomaterials have unique properties compared to their bulk counterparts. In this report, we demonstrate the antimicrobial activity of zerovalent Iron(ZVI) and Ag(silver) nanoparticles against Gram-negative bacteria E.coli(DH5α) and Pseudomonas aeruginosa. At first ZVI and Ag nanoparticles were synthesized by chemical reduction method and using scanning electron microscopy (SEM) the nanoparticle size determined. Different concentrations of Ag and ZVI nanoparticles were added to bacteria on nutrient agar medium. Minimum inhibitory concentration (MIC) of Ag and Fe nanoparticles for P. aeruginosa were 5µM and 1µg as well as for E.coli were 6µM. and 10 µg, respectively. Among the two nanoparticles, ZVI showed that the greatest antimicrobial activity against E.coli and Ag nanoparticle on P.aeruginosa. Results suggested that the bactericidal effect of metal nanoparticles has been attributed to their small size as well as high surface to volume ratio and NPs could be used as an effective antibacterial material.

Keywords: bactericidal properties, MIC, nanoparticle, SEM

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Authors: Moncef Balghouthi, Mahmoud Ben Amara, Abdessalem Ben Hadj Ali, Amenallah Guizani

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Concentrated solar power technology constitutes an interesting option to meet a part of future energy demand, especially when considering the high levels of solar radiation and clearness index that are available particularly in Tunisia. In this work, we present three experimental prototypes of solar concentrators installed in the research center of energy CRTEn in Tunisia. Two are medium temperature parabolic trough solar collector used to drive a cooling installation and for steam generation. The third is a parabolic dish concentrator used for hybrid generation of thermal and electric power. Optical and thermal evaluations were presented. Solutions and possibilities to construct locally the mirrors of the concentrator were discussed. In addition, the enhancement of the performances of the receivers by nano selective absorption coatings was studied. The improvement of heat transfer between the receiver and the heat transfer fluid was discussed for each application.

Keywords: solar concentrators, optical and thermal evaluations, cooling and process heat, hybrid thermal and electric generation

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Authors: Jihad Daba, Jean-Pierre Dubois

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Multi path fading noise degrades the performance of cellular communication, most notably in femto- and pico-cells in 3G and 4G systems. When the wireless channel consists of a small number of scattering paths, the statistics of fading noise is not analytically tractable and poses a serious challenge to developing closed canonical forms that can be analysed and used in the design of efficient and optimal receivers. In this context, noise is multiplicative and is referred to as stochastically local fading. In many analytical investigation of multiplicative noise, the exponential or Gamma statistics are invoked. More recent advances by the author of this paper have utilized a Poisson modulated and weighted generalized Laguerre polynomials with controlling parameters and uncorrelated noise assumptions. In this paper, we investigate the statistics of multi-diversity stochastically local area fading channel when the channel consists of randomly distributed Rayleigh and Rician scattering centers with a coherent specular Nakagami-distributed line of sight component and an underlying doubly stochastic Poisson process driven by a lognormal intensity. These combined statistics form a unifying triply stochastic filtered marked Poisson point process model.

Keywords: cellular communication, femto and pico-cells, stochastically local area fading channel, triply stochastic filtered marked Poisson point process

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Authors: K. Suresh, R. Arunkumar

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The objective of this study is to investigate the preparation of gramine nano suspension and protective effect of Gramine on the apoptosis of laryngeal cancer cells cell line (HEp-2 and KB). The growth inhibition rate of Hep-2 and KB cells in vitro were measured by MTT assay and apoptosis by, levels of reactive oxygen species, mitochondrial membrane potential, morphological changes and flowcytometry. Based on the results, we determined the effective doses of gramine as 127.23µm/ml for 24 hr and 119.81 µm/ml for 48hr in hep-2 cell line and 147.58 µm ml for 24 hr and 123.74µm µm/ml for 48hr in KB cell line. cytotoxicity effects of gramine were confirmed by treatment of HEp-2 cell and KB cell with IC50 concentration of gramine resulted in sequences of events marked by the enhance the apoptosis accompanied by loss of cell viability, modulation of reactive oxygen species and cell cycle arrest through the induction of G0/G1 phase arrest on HEp-2 cells. Our study suggests that the nanosuspension of gramine possesses the more cytotoxic effect of cancer cells and a novel candidate for cancer chemoprevention.

Keywords: apoptosis, HEp-2 cell line, KB cell line mitochondria, gramine, nanosuspension

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Authors: Mohamed F. Ahmed, Mabruka S. Elashheb, Fatma M. Ben Rabha

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This study aimed to determine the possible protective effects of L‐carnitine against gentamicin‐induced nephrotoxicity. Forty male albino rats were divided into 4 groups (10 rats each); Group 1: normal control, group 2: induced nephrotoxicity (gentamicin 50 mg/kg/day S.C; 8 days) , group 3: treated with L‐carnitine (40 mg/kg/d SC for 12 days) and group 4: treated with L‐carnitine 4 days before and for 8 days in concomitant with gentamicin. Gentamicin‐induced nephrotoxicity (group 2): caused significant increase in serum urea, creatinine, urinary N‐acetyl‐B‐D‐glucosaminidase (NAG), gamma glutamyl transpeptidase (GGT), urinary total protein and kidney tissue malondialdehyde (MDA) with significant decrease in serum superoxide dismutase (SOD), serum catalase and creatinine clearance and marked tubular necrosis in the proximal convoluted tubules with interruption in the basement membrane around the necrotic tubule compared to the normal control group. L‐carnitine 4 days before and for 8 days in concomitant with gentamicin (group 4) offered marked decrease in serum urea, serum creatinine, urinary NAG, urinary GGT, urinary proteins and kidney tissue MDA, with marked increase in serum SOD, serum catalase and creatinine clearance with marked improvement in the tubular damage compared to gentamicin‐induced nephrotoxicity group. L‐carnitine administered for 12 days produced no change in the above-mentioned parameters as compared to the normal control group. In conclusion: L‐carnitine could reduce most of the biochemical parameters and also improve the histopathological features of the kidney associated with gentamicin-induced nephrotoxicity.

Keywords: gentamicin, nephrotoxicity, L‐carnitine, kidney disease

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Authors: Rubina Shakya, Srijana Dangol, Dil Islam Mansur

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The exposure of constant stress stimuli in our daily lives is causing deterioration of neural connectivity in the brain. Interestingly, the improvement in larger-scale neural communication has been argued to rely on brain rhythms, which might be sensitive to binaural beats of particular frequency bands. The theoretical idea behind neural entrainment is that the rhythmic oscillatory activity within and between different brain regions can enhance cognitive function and mood state. So, we aimed to investigate whether the binaural beats of 40 Hz could enhance the cognition and the mood stability of the medical students at Kathmandu University of age 18-25 years old, which possibly, in the long run, might help to enhance their work productivity. The participants were asked to focus on the auditory stimuli of binaural beats with 200 Hz on the right side and 240 Hz on the left side of the headset for 15 minutes, every alternative day of three consecutive weeks. The Stroop’s test and the Brunel Mood Scale (BRUMS) were applied to assess the cognitive function and the mood state, respectively. The binaural beats significantly decreased the reaction time for the incoherent component of Stroop’s test in both male and female participants. For the mood state, scores of all positive emotions except ‘Calmness’ were significantly increased in the case of males. Whereas, scores of all positive emotions except ‘Vigor’ were significantly increased in the case of females. The results suggested that the meditation aided by binaural beats of 40 Hz helps in improving cognition and mood states to some extent.

Keywords: binaural beats, cognitive function, gamma neural oscillation, mood states

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Authors: Ghaleb Bin Huraib

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Atopic dermatitis (AD), also known as atopic eczema, is a chronic inflammatory skin disease characterized by severe itching and recurrent, relapsing eczema-like skin lesions, affecting up to 20% of children and 10% of adults in industrialized countries. AD is a complex multifactorial disease, and its exact etiology and pathogenesis have not been fully elucidated. The aim of this study was to investigate the impact of gene polymorphisms of T helper cell subtype Th1 and Th2 cytokines, interferon-gamma (IFN-γ), interleukin-6 (IL-6) and transforming growth factor (TGF)-β1on AD susceptibility in a Saudi cohort. One hundred four unrelated patients with AD and 195 healthy controls were genotyped for IFN-γ (874A/T), IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms using ARMS-PCR and PCR-RFLP technique. The frequency of genotypes AA and AT of IFN-γ (874A/T) differed significantly among patients and controls (P 0.001). The genotype AT was increased while genotype AA was decreased in AD patients as compared to controls. AD patients also had a higher frequency of T-containing genotypes (AT+TT) than controls (P = 0.001). The frequencies of alleles T and A were statistically different in patients and controls (P = 0.04). The frequencies of genotype GG and allele G of IL-6 (174G/C) were significantly higher, while genotype GC and allele C were lower in AD patients than in controls. There was no significant difference in the frequencies of alleles and genotypes of TGF-β1 (509C/T) polymorphism between the patient and control groups. These results showed that susceptibility to AD is influenced by the presence or absence of genotypes of IFN-γ (874A/T) and IL-6 (174G/C) polymorphisms. It is concluded T-allele and T-containing genotypes (AT+TT) of IFN-γ (874A/T) and G-allele and GG genotype ofIL-6 (174G/C) polymorphisms are susceptible to AD in Saudis. On the other hand, the TGF-β1 (509C/T) polymorphism may not be associated with AD risk in our population; however, further studies with large sample sizes are required to confirm these results.

Keywords: atopic dermatitis, Polymorphism, Interferon, IL-6

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Authors: Ammar Z. Alshemary, Zafer Evis

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In this study, nanorods of Cr³⁺/SiO₄⁴⁻ codoped hydroxyapatite (Cr³⁺/SiO₄⁴⁻-HA) were synthesized successfully and rapidly through microwave irradiation technique, using (Ca(NO₃)₂•4H₂O), ((NH₄)₂HPO₄), (SiC₈H₂₀O₄) and (Cr(NO₃)₃.9H₂O) as source materials for Ca²⁺, PO₄³⁻, SiO₄⁴⁻ and Cr³⁺ ions, respectively. The impact of dopants on the phase formation and microstructure of the powders were investigated by means of X-ray diffraction (XRD), Fourier transform infrared spectrum analysis (FT-IR) and Field emission electron microscopy (FESEM) techniques. XRD analysis showed that with an incorporation of Cr³⁺/SiO₄⁴⁻ ions into HA structure resulted in peak broadening and reduced peak height due to the amorphous nature and reduced crystallinity of the resulting HA powder. FTIR spectroscopy revealed the existence of the different vibrational modes matching to phosphates and hydroxyl groups. The FESEM analysis showed a change in the crystal shape from spherical to rod shaped particles upon Cr³⁺ doping into the crystal structure. Acknowledgments: This study was supported by Karabük University (Project no. KBÜBAP-17-YD-144). The authors would like to thank for support.

Keywords: nano-hydroxyapatite, microwave, dopants, characterization, microstructure

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Authors: R. Yuvakkumar, S. I. Hong

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Visible light driven monoclinic α-Bi2O3 photocatalyst was synthesized employing green synthesis method using rambutan peel wastes. 10 ml rambutan extract was added to 50 ml of 0.1M Bi(NO3)3 under stirring at about 80°C for 2 hours. The centrifuged and dried product was calcinated in a muffle furnace at 450°C to get pure α-Bi2O3. The characterized product photocatalytic activity was evaluated employing methyl orange (MeO) as model pollutant with 10 mg l-1 concentration at pH 7. The obtained product optical absorption edges located at 484 nm clearly revealed the photocatalyst excitation by visible light irradiation. The obtained yellow color photocatalyst accord with its strong absorption spectrum revealed the visible light absorption due to the band gap transition. The band gap energy of α-Bi2O3 was estimated to be 2.81 eV indicating the absorption of α-Bi2O3 in visible light region. The photocatalytic results of MeO degradation revealed that green synthesized Bi2O3 can effectively degrade 92% MeO within 240 min under visible light (>400 nm), which is slightly increased to that of chemically synthesized Bi2O3 (90%).

Keywords: green synthesis, bismuth oxide, photocatalytic activity, nano

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Authors: M. Fadlallah, G. Ghibaudo, C. G. Theodorou

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The dynamic variation in memory devices such as the Static Random Access Memory can give errors in read or write operations. In this paper, the effect of low-frequency and random telegraph noise on the dynamic variation of one SRAM cell is detailed. The effect on circuit noise, speed, and length of time of processing is examined, using the Supply Read Retention Voltage and the Read Static Noise Margin. New test run methods are also developed. The obtained results simulation shows the importance of noise caused by dynamic variation, and the impact of Random Telegraph noise on SRAM variability is examined by evaluating the statistical distributions of Random Telegraph noise amplitude in the pull-up, pull-down. The threshold voltage mismatch between neighboring cell transistors due to intrinsic fluctuations typically contributes to larger reductions in static noise margin. Also the contribution of each of the SRAM transistor to total dynamic variation has been identified.

Keywords: low-frequency noise, random telegraph noise, dynamic variation, SRRV

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Authors: Chaudhary Archana, Dhingra Poshika

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The architecture of the world is at a crossroads with the advent of new technology. The issues of energy efficiency and global warming are getting important with the coming times. New technologies are making their mark. For the architecture profession, nanotechnology will greatly impact construction materials and their properties. Nanotechnology, the understanding and control of matter at a scale of one to one hundred billions of a meter, is bringing incredible changes to the materials and processes of buildings. Materials will behave in many different ways as we are able to more precisely control their properties at the nanoscale. It is precisely called the next industrial revolution. We live in an age where scientific progress continues to transform human lifestyle. This is evermore true when it comes to the progress being made in the field of nanotechnology. This science stands to change and advance the practice of design in a multitude of ways – where architectural progress is being made at the molecular level. The nanotechnology has already been adopted in various buildings across the world. What an impact it shall have on the futuristic architecture in Chandigarh, India shall be discussed in the paper. But before we hurtle off toward a nano-utopia, we need to step back and ask ourselves whether this is a direction in which we really want to go.

Keywords: building materials, energy efficiency, nanotechnology, sustainability

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Authors: Mahmoud Elrouby

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Metal chalcogenide materials have wide spectrum of properties, for that these materials can be used in electronics, optics, magnetics, solar energy conversion, catalysis, passivation, ion sensing, batteries, and fuel cells. This work aims to, how can obtain these materials via electrochemical methods simply for further applications. The work regards in particular the systems relevant to the sulphur sub-group elements, i.e., sulphur, selenium, and tellurium. The role of electrochemistry in synthesis, development, and characterization of the metal chalcogenide materials and related devices is vital and important. Electrochemical methods as preparation tool offer the advantages of soft chemistry to access bulk, thin, nano film and epitaxial growth of a wide range of alloys and compounds, while as a characterization tool provides exceptional assistance in specifying the physicochemical properties of materials. Moreover, quite important applications and modern devices base their operation on electrochemical principles. Thereupon, our scope in the first place was to organize existing facts on the electrochemistry of metal chalcogenides regarding their synthesis, properties, and applications.

Keywords: electrodeposition, metal chacogenides, semiconductors, applications

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Authors: Wenliang Song, Yu Zhang, Hua Jin, Il Kim

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The self-assembly of the polypeptide (PP) into well-defined structures at different length scales is both biomimetic relevant and fundamentally interesting. Although there are various reports of nanostructures fabricated by the self-assembly of various PPs, directed self-assembly of PP into three-dimensional (3D) hierarchical structure has proven to be difficult, despite their importance for biological applications. Herein, an efficient method has been developed through living polymerization of phenylalanine N-Carboxy anhydride (NCA) towards the linear and cyclic polyphenylalanine, and the new invented swelling methodology can form diverse hierarchical polypeptide crystals. The solvent-dependent self-assembly behaviors of these homopolymers were characterized by high-resolution imaging tools such as atomic force microscopy, transmission electron microscopy, scanning electron microscope. The linear and cyclic polypeptide formed 3D nano hierarchical shapes, such as a sphere, cubic, stratiform and hexagonal star in different solvents. Notably, a crystalline packing model was proposed to explain the formation of 3D nanostructures based on the various diffraction patterns, looking forward to give an insight for their dissimilar shape inflection during the self-assembly process.

Keywords: self-assembly, polypeptide, bio-polymer, crystalline polymer

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Authors: Sleman Yahya Rasul

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Due to their transparency, various types of glass are utilized in numerous applications where clear visibility is essential. One such application involves environments where radiography, radiotherapy, and X-ray devices are used, all of which involve exposure to radiation. As is well-known, radiation can be lethal to humans. Consequently, there is a need for glass that can absorb and block these harmful rays in such settings. Effective protection from radiation typically requires materials with high atomic numbers and densities. Currently, lead oxide-infused glasses are commonly used for this purpose, but due to the toxicity of lead oxide, there is a demand for safer alternatives. HfO2 has been selected as an additive for boro-tellurite (M1-M2-M3) glasses intended for radiation shielding because it has a high atomic number, high density, and is non-toxic. In this study, new glasses will be developed as alternatives to leaded glasses by incorporating x mol% HfO2 into the boro-tellurite glass structure. The glass compositions will be melted and quenched using the traditional method in an alumina crucible at temperatures between 900–1100°C. The resulting glasses will be evaluated for their elastic properties (including elastic modulus, shear modulus, bulk modulus, and Poisson ratio), density, hardness, and fracture toughness. X-ray diffraction (XRD) will be used to examine the amorphous nature of the glasses, while Differential Thermal Analysis (DTA) will provide thermal analysis. Optical properties will be assessed through UV-Vis and Photoluminescence Spectroscopy, and structural properties will be studied using Raman spectroscopy and FTIR spectroscopy. Additionally, the radiation shielding capabilities will be investigated by measuring parameters such as mass attenuation coefficient, half-value thickness, mean free path, effective atomic number (Z_eff), and effective electron density (N_e). The aim of this study is to develop new, lead-free glasses with excellent optical properties and high mechanical strength to replace the leaded glasses currently used for radiation shielding.

Keywords: boro-tellurite glasses, hfo2, radiation shielding, mechanical properties, elastic properties, optical properties

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Authors: R. Tajau, R. Rohani, M. S. Alias, N. H. Mudri, K. A. Abdul Halim, M. H. Harun, N. Mat Isa, R. Che Ismail, S. Muhammad Faisal, M. Talib, M. R. Mohamed Zin

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Bio-based polymeric materials are increasingly used for a variety of applications, including surface coating, drug delivery systems, and tissue engineering. These polymeric materials are ideal for the aforementioned applications because they are derived from natural resources, non-toxic, low-cost, biocompatible, and biodegradable, and have promising thermal and mechanical properties. The nature of hydrocarbon chains, carbon double bonds, and ester bonds allows various sources of oil (edible), such as soy, sunflower, olive, and oil palm, to fine-tune their particular structures in the development of innovative materials. Palm oil can be the most eminent raw material used for manufacturing new and advanced natural polymeric materials involving radiation techniques, such as coating resins, nanoparticles, scaffold, nanotubes, nanocomposites, and lithography for different branches of the industry in countries where oil palm is abundant. The radiation technique is among the most versatile, cost-effective, simple, and effective methods. Crosslinking, reversible addition-fragmentation chain transfer (RAFT), polymerisation, grafting, and degradation are among the radiation mechanisms. Exposure to gamma, EB, UV, or laser irradiation, which are commonly used in the development of polymeric materials, is used in these mechanisms. Therefore, this review focuses on current radiation processing technologies for the development of various radiation-curable bio-based polymeric materials with a promising future in biomedical and industrial applications. The key focus of this review is on radiation curable palm oil-based products, which have been published frequently in recent studies.

Keywords: palm oil, radiation processing, surface coatings, VOC

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Authors: Nuray Güy, Mahmut Özacar

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Semiconductor nanoparticles such as TiO₂ and ZnO as photocatalysts are very efficient catalysts for wastewater treatment by the chemical utilization of light energy, which is capable of converting the toxic and nonbiodegradable organic compounds into carbon dioxide and mineral acids. ZnO semiconductor has a wide bandgap energy of 3.37 eV and a relatively large exciton binding Energy (60 meV), thus can absorb only UV light with the wavelength equal to or less than 385 nm. It exhibits low efficiency under visible light illumination due to its wide band gap energy. In order to improve photocatalytic activity of ZnO under visible light, band gap of ZnO may be narrowed by doping such as N, C, S nonmetal ions and coupled two separate semiconductors possessing different energy levels for their corresponding conduction and valence bands. ZnS has a wider band gap (Eg=3.7 eV) than ZnO and generates electron–hole pairs by photoexcitation rapidly. In the present work, N doped ZnO/ZnS nano photocatalysts with visible-light response were synthesized by microwave-hydrothermal method using thiourea as N source. The prepared photocatalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–visible (UV–vis). The photocatalytic activities samples and undoped ZnO have been studied for the degradation of dye, and have also been compared with together.

Keywords: photocatalyst, synthesis, visible light, ZnO/ZnS

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Authors: Krishnakant Bhole, Neerakallu D. Shivakumar, Shakti Singh Chauhan, Sanketh Tonannavar, Rajath S

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Synthesis of natural-based composite materials is state of the art. This work discusses the preparation and characterization of cellulose nanofibers (CNF) extracted from the bamboo pulp using TEMPO-oxidization and high-pressure homogenization methods. Bio-composites are prepared using synthesized CNF and bamboo particles. Nanocellulose prepared is characterized using SEM and XRD for morphological and crystallinity analysis, and the formation of fibers at the nano level is ensured. Composite specimens are fabricated using these natural sources and subjected to tensile and flexural tests to characterize the mechanical properties such as modulus of elasticity (MOE), modulus of rupture (MOR), and interfacial strength. Further, synthesized nanocellulose is used as a binding agent to prepare particleboards using various natural sources like bamboo, areca nut, and banana in the form of fibers. From the results, it can be inferred that nanocellulose prepared from bamboo pulp acts as a binding agent for making bio-composites. Hence, the concept of using matrix and reinforcement derived from natural sources can be used to prepare green composites that are highly degradable.

Keywords: nanocellulose, biocomposite, CNF, bamboo

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Authors: Chien Chon Chen, Chun Mei Chu, Chuan Ju Wang, Chih Yuan Chen, Ker Jer Huang

Abstract:

Cesiumiodide with Na doping (CsI(Na)) solution or melt is easily forming three- dimension dendrites on the free surface. The defects or bobbles form inside the CsI(Na) during the solution or melt solidification. The defects or bobbles can further effect the x-ray path in the CsI(Na) crystal and decrease the scintillation characteristics of CsI(Na). In order to enhance the CsI(Na) scintillated property we made single crystal of CsI(Na) column in the anodic aluminum oxide (AAO) template by hydraulic pressure injection method. It is interesting that when CsI(Na) melt is confined in the small AAO channels, the column grow as stable single column without any dendrites. The high aspect ratio (100~10000) of AAO and nano to sub-micron channel structure which is a suitable template for single of crystal CsI(Na) formation. In this work, a new low-cost approach to fabricate scintillator crystals using anodic aluminum oxide (AAO) rather than Si is reported, which can produce scintillator crystals with a wide range of controllable size to optimize their performance in X-ray detection.

Keywords: cesiumiodide, AAO, scintillator, crystal, X-ray

Procedia PDF Downloads 449

Authors: Soomal Hamza, Uzma Imran

Abstract:

Organochlorine pesticides bio-accumulate into the fat of fish, birds, and animals through which it enters the human food cycle. Due to their persistence and stability in the environment, many health impacts are associated with them, most of which are carcinogenic in nature. In this study, the level of organochlorine pesticides has been detected in Keenjhar Lake and remediated using Rhizoremediation technique. 14 OC pesticides namely, Aldrin, Deldrin, Heptachlor, Heptachlor epoxide, Endrin, Endosulfun I and II, DDT, DDE, DDD, Alpha, Beta, Gamma BHC and two plants namely, Water Hyacinth and Slvinia Molesta were used in the system using pot experiment which processed for 11 days. A consortium was inoculated in both plants to increase its efficiency. Water samples were processed using liquide-liquid extraction. Sediments and roots samples were processed using Soxhlet method followed by clean-up and Gas Chromatography. Delta-BHC was the predominantly found in all samples with mean concentration (ppb) and standard deviation of 0.02 ± 0.14, 0.52 ± 0.68, 0.61 ± 0.06, in Water, Sediments and Roots samples respectively. The highest levels were of Endosulfan II in the samples of water, sediments and roots. Water Hyacinth proved to be better bioaccumulaor as compared to Silvinia Molesta. The pattern of compounds reduction rate by the end of experiment was Delta-BHC>DDD > Alpha-BHC > DDT> Heptachlor> H.Epoxide> Deldrin> Aldrin> Endrin> DDE> Endosulfun I > Endosulfun II. Not much significant difference was observed between the pots with the consortium and pots without the consortium addition. Phytoremediation is a promising technique, but more studies are required to assess the bioremediation potential of different aquatic plants and plant-endophyte relationship.

Keywords: aquatic plant, bio remediation, gas chromatography, liquid liquid extraction

Procedia PDF Downloads 134

Authors: Marta Błażkiewicz-Mazurek, Adam Konefał

Abstract:

The project can be divided into three main parts: i. modeling the Cf-252 neutron source and conducting an experiment to verify the correctness of the obtained results, ii. design of the BNCT system infrastructure, iii. analysis of the results from the logical detector. Modeling of the Cf-252 source included designing the shape and size of the source as well as the energy and spatial distribution of emitted neutrons. Two options were considered: a point source and a cylindrical spatial source. The energy distribution corresponded to various spectra taken from specialized literature. Directionally isotropic neutron emission was simulated. The simulation results were compared with experimental values determined using the activation detector method using indium foils and cadmium shields. The relative fluence rate of thermal and resonance neutrons was compared in the chosen places in the vicinity of the source. The second part of the project related to the modeling of the BNCT infrastructure consisted of developing a simulation program taking into account all the essential components of this system. Materials with moderating, absorbing, and backscattering properties of neutrons were adopted into the project. Additionally, a gamma radiation filter was introduced into the beam output system. The analysis of the simulation results obtained using a logical detector located at the beam exit from the BNCT infrastructure included neutron energy and their spatial distribution. Optimization of the system involved changing the size and materials of the system to obtain a suitable collimated beam of thermal neutrons.

Keywords: BNCT, Monte Carlo, neutrons, simulation, modeling

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Authors: Chiagoziem A. Otuechere, Ebenezer O. Farombi

Abstract:

The protective effect of dichloromethane: methanol extract of Pterocarpus mildbraedii (PME), a widely consumed Nigerian leafy vegetable, on the toxicity of propanil was investigated in male rats. Animals were distributed into eight groups of five each. Group 1 served as control and received normal saline while rats in groups 2, 3, and 4 received 100 mg/kg, 200 mg/kg, and 400 mg/kg extract doses respectively. Group 5 rats were orally administered 200 mg/kg propanil while groups 6, 7, and 8 rats were given propanil plus extract. Oral administration of propanil elicited a 14.8%, 5%, 122%, and 78% increase in the activity of serum enzymes; alanine aminotransferase (AST), alanine aminotransferase(ALT), Alkaline phoshatase (ALP) and Gamma glutamyl transferase (ﻻGT). There were also increase in Lactate dehydrogenase (LDH) activity, direct bilirubin and lipid peroxidation levels. Furthermore, PME significantly attenuated the marked hepatic oxidative damage that accompanied propanil treatment. The extract significantly decreased LDH activity and bilirubin levels following propanil treatment. Furthermore, propanil-induced alterations in the activities of antioxidant enzymes: Superoxide dismutase (SOD), catalase (CAT) and glutathione s-transferase (GST) in these rats were modulated by the extract. The percentage DPPH Radical Scavenging Activity of the extract was determined as 55% and compared to those of Gallic acid (49%). Hepatic histology examination further confirmed the damage to the liver as it revealed severe periportal cellular infiltration of the hepatocytes. These biochemical and morphological alterations were attenuated in rats pre-treated with 100 mg/kg and 200 mg/kg doses of the extract. These results suggest that PME possesses protective effect against propanil-induced hepatotoxicity.

Keywords: antioxidant, hepatoprotection, Pterocarpus mildbraedii, propanil

Procedia PDF Downloads 407

Authors: Eun Ju Park, Wendy Rusli, He Tao, Alexander M. Van Herk, Sanggu Kim

Abstract:

Hollow micro-/nano- structured materials have proven to be promising in wide range of applications, such as catalysis, drug delivery and controlled release, biotechnology, and personal and consumer care. Hollow sphere structures can be obtained through various templating approaches; colloid templates, emulsion templates, multi-surfactant templates, and single crystal templates. Vesicles are generally the self-directed assemblies of amphiphilic molecules including cationic, anionic, and cationic surfactants in aqueous solutions. The directed silica capsule formations were performed at the surface of dioctadecyldimethylammoniumbromide(DODAB) bilayer vesicles as soft template. The size of DODAB bilayer vesicles could be tuned by extrusion of a preheated dispersion of DODAB. The synthesized hollow silica particles were characterized by conventional TEM, cryo-TEM and SEM to determine the morphology and structure of particles and dynamic light scattering (DLS) method to measure the particle size and particle size distribution.

Keywords: characterization, DODAB, hollow silica particle, synthesis, vesicle

Procedia PDF Downloads 298