Search results for: first derivative

Authors: Montasser Mohamed Abdelwahab Mahmoud, Abdelwahab Saber Esawi

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The language of the Qur’an has a wide range of understanding, reflection, and meanings. Therefore, translation of the Qur’an is inevitably nothing but a translation of the interpretation of the meanings of the Qur’an. It requires special competencies and skills for translators so that they can get close to the intended meaning of the verse of the Qur’an and convey it with precision. In the Arabic language, the verbal noun “AlMasdar” is a very important derivative that properly expresses the verbal idea in the form of a noun. It sounds the same as the base form of the verb with minor changes in the vowel pattern. It is one of the important topics in morphology. The morphologists divided verbal nouns into auditory and analogical, and they stated that that the verbal nouns (Masadars) originating from three-letter verbs are auditory, although they set controls for some of them in order to preserve them. As for the lexicographers, they mentioned the verbal nouns while talking about the lexical materials, and in some cases, their explanation of them exceeded that made by the morphologists, especially in their discussion of structures that the morphologists did not refer to in their books. The verb kafara (disbelief), for example, has three patterns, namely: al-kufْr, al-kufrān, and al-kufūr, and it was mentioned in the Holy Qur’an with different connotations. The verb ṣāma (fasted) with his two patterns (al-ṣaūm and al-ṣīām) was mentioned in the Holy Qur’an while their semantic meaning is different. The problem discussed in this research paper lied in the "linguistic loss" committed by translators when dealing with Islamic religious texts, especially the Qur'an. The study tried to identify the strategy adopted by translators of the Holy Qur'an in translating words that were classified as verbal nouns through analyzing the translation rendered by five translations of the Qur’an into English: Yusuf Ali, Pickthall, Mohsin Khan, Muhammad Sarwar, and Shakir. This study was limited to the verbal nouns in the Quraan that originate from three-letter verbs and have different semantic meanings.

Keywords: pattern, three-letter verbs, translation of the Quran, verbal nouns

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Authors: Faisal A. Salih

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Vinpocetine (Vin) is an ethyl ester of apovincamic acid and is a semisynthetic derivative of vincamine, an alkaloid from plants of the genus Periwinkle (plant) vinca minor. It was found that this compound stimulates cerebral metabolism: it increases the uptake of glucose and oxygen, as well as the consumption of these substances by the brain tissue. Vinpocetine enhances the flow of blood in the brain and has a vasodilating, antihypertensive, and antiplatelet effect. Vinpocetine seems to improve the human ability to acquire new memories and restore memories that have been lost. This drug has been clinically used for the treatment of cerebrovascular disorders such as stroke and dementia memory disorders, as well as in ophthalmology and otorhinolaryngology. It has no side effects, and no toxicity has been reported when using vinpocetine for a long time. For the quantitative determination of Vin in dosage forms, the HPLC methods are generally used. A promising alternative is potentiometry with Vin- selective electrode, which does not require expensive equipment and materials. Another advantage of the potentiometric method is that the pills and solutions for injections can be used directly without separation from matrix components, which reduces both analysis time and cost. In this study, it was found that the choice of a good plasticizer an electrode with the following membrane composition: PVC (32.8 wt.%), ortho-nitrophenyl octyl ether (66.6 wt.%), tetrakis-4-chlorophenyl borate (0.6 wt.%) exhibits excellent analytical performance: lower detection limit (LDL) 1.2•10⁻⁷ M, linear response range (LRR) 1∙10⁻³–3.9∙10⁻⁶ M, the slope of the electrode function 56.2±0.2 mV/decade). Vin masses per average tablet weight determined by direct potentiometry (DP) and potentiometric titration (PT) methods for the two different sets of 10 tablets were (100.35±0.2–100.36±0.1) mg for two sets of blister packs. The mass fraction of Vin in individual tablets, determined using DP, was (9.87 ± 0.02–10.16 ±0.02) mg, while the RSD was (0.13–0.35%). The procedure has very good reproducibility, and excellent compliance with the declared amounts was observed.

Keywords: vinpocetine, potentiometry, ion selective electrode, pharmaceutical analysis

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Authors: Sarekha Woranuch, Rangrong Yoksan

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Chitosan is a derivative of chitin, which is a second most naturally abundant polysaccharide found in crab shells, shrimp shells, and squid pens. The applications of chitosan in pharmaceutical, cosmetics, food and packaging industries have been reported owing to its general recognition as safe, excellent biodegradability and biocompatibility, as well as ability to form films, membranes, gels, beads, fibers and particles. Nevertheless, chitosan is an amino polysaccharide consisting of strong inter- and intramolecular hydrogen bonds which limit its solubility in neutral pH water resulting in restricted utilization. Chemical modification is an alternative way to impede hydrogen bond formation. The objective of the present research is to improve water solubility and antioxidant activity of chitosan by grafting with ferulic acid. Ferulic acid was grafted onto chitosan at the C-2 position via a carbodiimide-mediated coupling reaction. Different mole ratios of chitosan to ferulic acid (i.e. 1.0:0.0, 1.0:0.5, 1.0:1.0, 1.0:1.5, 1.0:2.0, and 1.0:2.5) and various reaction temperatures (i.e. 40, 60, and 80 °C) were used. The reaction was performed at different times (i.e. 1.5, 3.0, 4.5, and 6.0 h). The obtained ferulic acid-grafted chitosan was characterized by FTIR and 1H NMR technique. The influences of ferulic acid on crystallinity, solubility and radical scavenging activity of chitosan were also investigated. Ferulic acid grafted chitosan was successfully synthesized as confirmed from (i) the appearance of FTIR absorption band at 1517 cm-1 belonging to C=C aromatic ring of ferulic acid and the increased C–H stretching band intensity and (ii) the appearance of proton signals at δ = 6.31-7.67 ppm ascribing to methine protons of ferulic acid. The condition in which the reaction temperature of 60°C, reaction time of 3 h and the mole ratio of chitosan to ferulic acid of 1:1 gave the highest ferulic acid substitution degree, i.e. 0.37. The resulting ferulic acid grafted chitosan was soluble in water (1.3 mg/mL) due to its reduced crystallinity as compared with chitosan and also exhibited 90% greater radical scavenging activity than chitosan. The result suggested the utilization of ferulic acid grafted chitosan as an antioxidant material.

Keywords: antioxidant property, chitosan, ferulic acid, grafting

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Authors: Ahmed Khalil, Elhamy Tarabees, Svetlana Kovacikova

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The Red Sea Mountains have been famous for their ore deposits since ancient times. Also, petrographic analysis and previous potential field surveys indicated large unexplored accumulations of ore minerals in the area. Therefore, the main goal of the presented study is to contribute to the discovery of hitherto unknown ore mineral deposits in the Red Sea region. To achieve this goal, we used two geophysical techniques: land magnetic survey and magnetotelluric data. A high-resolution land magnetic survey has been acquired using two proton magnetometers, one instrument used as a base station for the diurnal correction and the other used to measure the magnetic field along the study area. Two hundred eighty land magnetic stations were measured over a mesh-like area with a 500m spacing interval. The necessary reductions concerning daily variation, regional gradient and time observation were applied. Then, the total intensity anomaly map was constructed and transformed into the reduced magnetic pole (RTP). The magnetic interpretation was carried out using the analytical signal as well as regional–residual separation is carried out using the power spectrum. Also, the tilt derivative method (TDR) technique is applied to delineate the structure and hidden anomalies. Data analysis has been performed using trend analysis and Euler deconvolution. The results indicate that magnetic contacts are not the dominant geological feature of the study area. The magnetotleruric survey consisted of two profiles with a total of 8 broadband measurement points with a duration of about 24 hours crossing a wadi um Gheig approximately 50 km south of El Quseir. Collected data have been inverted to the electrical resistivity model using the 3D modular 3D inversion technique ModEM. The model revealed a non-conductive body in its central part, probably corresponding to a dolerite dyke, with which possible ore mineralization could be related.

Keywords: magnetic survey, magnetotelluric, mineralization, 3d modeling

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Authors: Abhilash Sahu, Amit Priyadarshi

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In this paper, we will discuss the existence of weak solutions of the Kirchhoff type boundary value problem on the Sierpinski gasket. Where S denotes the Sierpinski gasket in R² and S₀ is the intrinsic boundary of the Sierpinski gasket. M: R → R is a positive function and h: S × R → R is a suitable function which is a part of our main equation. ∆p denotes the p-Laplacian, where p > 1. First of all, we will define a weak solution for our problem and then we will show the existence of at least two solutions for the above problem under suitable conditions. There is no well-known concept of a generalized derivative of a function on a fractal domain. Recently, the notion of differential operators such as the Laplacian and the p-Laplacian on fractal domains has been defined. We recall the result first then we will address the above problem. In view of literature, Laplacian and p-Laplacian equations are studied extensively on regular domains (open connected domains) in contrast to fractal domains. In fractal domains, people have studied Laplacian equations more than p-Laplacian probably because in that case, the corresponding function space is reflexive and many minimax theorems which work for regular domains is applicable there which is not the case for the p-Laplacian. This motivates us to study equations involving p-Laplacian on the Sierpinski gasket. Problems on fractal domains lead to nonlinear models such as reaction-diffusion equations on fractals, problems on elastic fractal media and fluid flow through fractal regions etc. We have studied the above p-Laplacian equations on the Sierpinski gasket using fibering map technique on the Nehari manifold. Many authors have studied the Laplacian and p-Laplacian equations on regular domains using this Nehari manifold technique. In general Euler functional associated with such a problem is Frechet or Gateaux differentiable. So, a critical point becomes a solution to the problem. Also, the function space they consider is reflexive and hence we can extract a weakly convergent subsequence from a bounded sequence. But in our case neither the Euler functional is differentiable nor the function space is known to be reflexive. Overcoming these issues we are still able to prove the existence of at least two solutions of the given equation.

Keywords: Euler functional, p-Laplacian, p-energy, Sierpinski gasket, weak solution

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Authors: Joseph F. Cabrera, Rachael Dela Cruz

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This study specifically examines patterns that define ethnoracially diverse neighborhoods. Ethnoracial diversity is important as it facilitates cross-racial interactions within neighborhoods which have been theorized to be associated with such outcomes as intergroup harmony, the reduction of racial and ethnic prejudice and discrimination, and increases in racial tolerance. Los Angeles (LA) is an ideal location to study ethnoracial spatial patterns as it is one of the most ethnoracially diverse cities in the world. A large influx of Latinos, as well as Asians, have contributed to LA’s urban landscape becoming increasingly diverse over several decades. Our dataset contains all census tracts in Los Angeles County in 2016 and incorporates Census and ACS demographic and spatial data. We quantify ethnoracial diversity using a derivative of Simpson’s Diversity Index and utilize this measure to test previous literature that suggests Latinos are one of the key drivers of changing ethnoracial spatial patterns in Los Angeles. Preliminary results suggest that there has been an overall increase in ethnoracial diversity in Los Angeles neighborhoods over the past sixteen years. Patterns associated with this trend include decreases in predominantly white and black neighborhoods, increases in predominantly Latino and Asian neighborhoods, and a general decrease in the white populations of the most diverse neighborhoods. A similar pattern is seen in neighborhoods with large Latino increases- a decrease in white population, but with an increase in Asian and black populations. We also found support for previous research that suggests increases in Latino and Asian populations act as a buffer, allowing for black population increases without a sizeable decrease in the white population. Future research is needed to understand the underlying causes involved in many of the patterns and trends highlighted in this study.

Keywords: race, race and interaction, racial harmony, social interaction

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Authors: Boitumelo Setlhare, Mduduzi P. Mokoena, Ademola O. Olaniran

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Agricultural and industrial activities have led to increasing production of xenobiotics such as 2,4-dichlorophenol (2,4-DCP), a derivative of 2,4-dichlorophenoxyacetic acid (2,4-D), which is a widely used herbicide. Bioremediation offers an efficient, cost-effective and environmentally friendly method for degradation of the compound through the activities of the various microbial enzymes involved in the catabolic pathway. The aim of this study was to isolate and characterize bacterial isolate indigenous to contaminated sites in Durban, South Africa for 2,4-DCP degradation. One bacterium capable of utilizing 2,4-DCP as sole carbon source was isolated using culture enrichment technique and identified as Pseudomonas chlororaphis strain UFB2 via PCR amplification and analysis of 16S rRNA gene sequence. This isolate was able to degrade up to 75.11% of 2,4-DCP in batch cultures within 10 days, with the degradation rate constant of 0.14 mg/l/d. Phylogenetic analysis revealed the relatedness of this bacterial isolate to other Pseudomonas sp. previously characterized for chlorophenol degradation. PCR amplification of the catabolic genes involved in 2,4-DCP degradation revealed the presence of the correct amplicons for phenol hydroxylase (600 bp), catechol 1,2-dioxygenase (214 bp), muconate isomerase (851 bp), cis-dienelactone hydrolase (577 bp), and trans-dienelactone hydrolase (491 bp) genes. Enzyme assays revealed activity as high as 21840 mU/mg, 15630 mU/mg, 2340 mU/mg and 1490 mU/mg obtained for phenol hydroxylase, catechol 1,2-dioxygenase, cis-dienelactone hydroxylase and trans-dienelactone hydroxylase, respectively. The absence of catechol 2,3-dioxygenase gene and the corresponding enzyme in this isolate suggests that the organism followed ortho-pathway for 2,4-DCP degradation. Furthermore, the absence of malaycetate reductase genes showed that the bacterium may not be able to completely mineralize 2,4-DCP. Further studies are required to optimize 2,4-DCP degradation by this isolate as well as to elucidate the mechanism of 2,4-DCP degradation.

Keywords: biodegradation, catechol 1, 2-dioxygenase, 2, 4-dichlorophenol, phenol hydroxylase, Pseudomonas chlororaphis

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Authors: Adamu Abubakar, Abdulganiyu Yunusa, Likkason Othniel Kamfani, Abdulrahman Idris Augie

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This research study is being carried out in accordance with the Gwandu formation's potential exploratory activities in the inland basin of northwest Nigeria.The present research aims to identify and characterize subsurface anomalies within Gwandu formation using electrical resistivity tomography (ERT) and magnetic surveys, providing valuable insights for mineral exploration. The study utilizes various data enhancement techniques like derivatives, upward continuation, and spectral analysis alongside 2D modeling of electrical imaging profiles to analyze subsurface structures and anomalies. Data was collected through ERT and magnetic surveys, with subsequent processing including derivatives, spectral analysis, and 2D modeling. The results indicate significant subsurface structures such as faults, folds, and sedimentary layers. The study area's geoelectric and magnetic sections illustrate the depth and distribution of sedimentary formations, enhancing understanding of the geological framework. Thus, showed that the entire formations of Eocene sediment of Gwandu are overprinted by the study area's Tertiary strata. The NE to SW and E to W cross-profile for the pseudo geoelectric sections beneath the study area were generated using a two-dimensional (2D) electrical resistivity imaging. 2D magnetic modelling, upward continuation, and derivative analysis are used to delineate the signatures of subsurface magnetic anomalies. The results also revealed The sediment thickness by surface depth ranges from ∼4.06 km and ∼23.31 km. The Moho interface, the lower and upper mantle crusts boundary, and magnetic crust are all located at depths of around ∼10.23 km. The vertical distance between the local models of the foundation rocks to the north and south of the Sokoto Group was approximately ∼6 to ∼8 km and ∼4.5 km, respectively.

Keywords: high-resolution aeromagnetic data, electrical resistivity imaging, subsurface anomalies, 2d dorward modeling

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Authors: Saman Khan, Imrana Naseem

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Copper is an essential trace element required for pro-angiogenic co-factors including vascular endothelial growth factor (VEGF). Elevated levels of copper are found in various types of cancer including prostrate, colon, breast, lung and liver for angiogensis and metastasis. Therefore, targeting copper via copper-specific chelators in cancer cells can be developed as effective anticancer treatment strategy. In continuation of our pursuit to design and synthesize copper chelators, herein we opted for a reaction to incorporate di-(2-picolyl) amine in 3-(bromoacetyl) coumarin (parent backbone) for the synthesis of complex 1. We evaluated lipid peroxidation, protein carbonylation, ROS generation, DNA damage and consequent apoptosis by complex 1 in exogenously added Cu(II) in human peripheral lymphocytes (simulate malignancy condition). Results showed that Cu(II)-complex 1 interaction leads to cell proliferation inhibition, apoptosis, ROS generation and DNA damage in human lymphocytes, and these effects were abrogated by cuprous chelator neocuproine and ROS scavengers (thiourea, catalase, SOD). This indicates that complex 1 cytotoxicity is due to redox cycling of copper to generate ROS which leads to pro-oxidant cell death in cancer cells. To further confirm our hypothesis, using the rat model of diethylnitrosamine (DEN) induced hepatocellular carcinoma; we showed that complex 1 mediates DNA breakage and cell death in isolated carcinoma cells. Membrane permeant copper chelator, neocuproine, and ROS scavengers inhibited the complex 1-mediated cellular DNA degradation and apoptosis. In summary, complex 1 anticancer activity is due to its copper chelation capability. These results will provide copper chelation as an effective targeted cancer treatment strategy for selective cytotoxic action against malignant cells without affecting normal cells.

Keywords: cancer treatment, copper chelation, ROS generation, DNA damage, redox cycling, apoptosis

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Authors: Nicholas C. Rose, Christopher D. Spicer

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The regeneration of damaged or diseased tissues would provide an invaluable therapeutic tool in biological research and medicine. Cells must be provided with a number of different biochemical signals in order to form mature tissue through complex signaling networks that are difficult to recreate in synthetic materials. The ability to attach and detach bioactive proteins from material in an iterative and dynamic manner would therefore present a powerful way to mimic natural biochemical signaling cascades for tissue growth. We propose to reversibly attach these bioactive proteins using ortho-boronoimine (oBI) linkages and related derivatives formed by the reaction of an ortho-boronobenzaldehyde with a nucleophilic amine derivative. To enable the use of oBIs for biomaterial modification, we have studied binding and cleavage processes with precise detail in the context of small molecule models. A panel of oBI complexes has been synthesized and screened using a novel Förster resonance energy transfer (FRET) assay, using a cyanine dye FRET pair (Cy3 and Cy5), to identify the most reactive boron-aldehyde/amine nucleophile pairs. Upon conjugation of the dyes, FRET occurs under Cy3 excitation and the resultant ratio of Cy3:Cy5 emission directly correlates to conversion. Reaction kinetics and equilibria can be accurately quantified for reactive pairs, with dissociation constants of oBI derivatives in water (KD) found to span 9-orders of magnitude (10⁻²-10⁻¹¹ M). These studies have provided us with a better understanding of oBI linkages that we hope to exploit to reversibly attach bioconjugates to materials. The long-term aim of the project is to develop a modular biomaterial platform that can be used to help combat chronic diseases such as osteoarthritis, heart disease, and chronic wounds by providing cells with potent biological stimuli for tissue engineering.

Keywords: dynamic, bioconjugation, bornoimine, rapid, physiological

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Authors: Kevin A. Droguett, Edwin G. Pérez, Denis Fuentealba, Margarita E. Aliaga, Angélica M. Fierro

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Supramolecular chemistry is a field of growing interest. Moreover, studying the formation of host-guest complexes between macrocycles and dyes is highly attractive due to their potential applications. Examples of the above are drug delivery, catalytic process, and sensing, among others. There are different dyes of interest in the literature; one example is the quinolinone derivatives. Those molecules have good optical properties and chemical and thermal stability, making them suitable for developing fluorescent probes. Secondly, several macrocycles can be seen in the literature. One example is the cucurbiturils. This water-soluble macromolecule family has a hydrophobic cavity and two identical carbonyl portals. Additionally, the thermodynamic analysis of those supramolecular systems could help understand the affinity between the host and guest, their interaction, and the main stabilization energy of the complex. In this work, two 7-(diethylamino) quinoline-2 (1H)-one derivative (QD1-2) and their interaction with cucurbit[7]uril (CB[7]) were studied from an experimental and in-silico point of view. For the experimental section, the complexes showed a 1:1 stoichiometry by HRMS-ESI and isothermal titration calorimetry (ITC). The inclusion of the derivatives on the macrocycle lends to an upward shift in the fluorescence intensity, and the pKa value of QD1-2 exhibits almost no variation after the formation of the complex. The thermodynamics of the inclusion complexes was investigated using ITC; the results demonstrate a non-classical hydrophobic effect with a minimum contribution from the entropy term and a constant binding on the order of 106 for both ligands. Additionally, dynamic molecular studies were carried out during 300 ns in an explicit solvent at NTP conditions. Our finding shows that the complex remains stable during the simulation (RMSD ~1 Å), and hydrogen bonds contribute to the stabilization of the systems. Finally, thermodynamic parameters from MMPBSA calculations were obtained to generate new computational insights to compare with experimental results.

Keywords: host-guest complexes, molecular dynamics, quinolin-2(1H)-one derivatives dyes, thermodynamics

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Authors: Alireza Naserpoor

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Derivatives are the most important innovation which has happened in the past decades. When it comes to financial markets, it has changed the whole way of operations of stock, commodities and currency market. Beside a lot of advantages, Conventional derivatives contracts have some disadvantages too. Some problems have been caused by derivatives contain raising Volatility, increasing Bankruptcies and causing financial crises. Standard Parallel Salam contract as an Islamic financial product meanwhile is a financing instrument can be used for risk management by investors. Standard Parallel Salam is a Shari’ah-Compliant contract. Furthermore, it is an alternative to conventional derivatives. Despite the fact that the unstructured types of that, has been used in several Islamic countries, This contract as a structured and standard financial instrument introduced in Iran Mercantile Exchange in 2014. In this paper after introducing parallel Salam, we intend to examine a collection of international experience and local measure regarding launching standard parallel Salam contract and proceed to describe standard scenarios for trading this instrument and practical experience in Iran Mercantile Exchange about this instrument. Afterwards, we make a comparison between SPS and Futures contracts as a conventional derivative. Standard parallel salam contract as an Islamic financial product, can be used for risk management by investors. SPS is a Shariah-Compliant contract. Furthermore it is an alternative to conventional derivatives. This contract as a structured and standard financial instrument introduced in Iran Mercantile Exchange in 2014. despite the fact that the unstructured types of that, has been used in several Islamic countries. In this article after introducing parallel salam, we intend to examine a collection of international experience and local measure regarding launching standard parallel salam contract and proceed to describe standard scenarios for trading this instrument containing two main approaches in SPS using, And practical experience in IME about this instrument Afterwards, a comparison between SPS and Futures contracts as a conventional derivatives.

Keywords: futures contracts, hedging, shari’ah compliant instruments, standard parallel salam

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Authors: Sunantha Teyarachakul

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We consider the worker-learning Newsvendor Model, under the case of lost-sales for unmet demand, with the research objective of proposing the cost-minimization order policy and lot size, scheduled to arrive at the beginning of the selling-period. In general, the New Vendor Model is used to find the optimal order quantity for the perishable items such as fashionable products or those with seasonal demand or short-life cycles. Technically, it is used when the product demand is stochastic and available for the single selling-season, and when there is only a one time opportunity for the vendor to purchase, with possibly of long ordering lead-times. Our work differs from the classical Newsvendor Model in that we incorporate the human factor (specifically worker learning) and its influence over the costs of processing units into the model. We describe this by using the well-known Wright’s Learning Curve. Most of the assumptions of the classical New Vendor Model are still maintained in our work, such as the constant per-unit cost of leftover and shortage, the zero initial inventory, as well as the continuous time. Our problem is challenging in the way that the best order quantity in the classical model, which is balancing the over-stocking and under-stocking costs, is no longer optimal. Specifically, when adding the cost-saving from worker learning to such expected total cost, the convexity of the cost function will likely not be maintained. This has called for a new way in determining the optimal order policy. In response to such challenges, we found a number of characteristics related to the expected cost function and its derivatives, which we then used in formulating the optimal ordering policy. Examples of such characteristics are; the optimal order quantity exists and is unique if the demand follows a Uniform Distribution; if the demand follows the Beta Distribution with some specific properties of its parameters, the second derivative of the expected cost function has at most two roots; and there exists the specific level of lot size that satisfies the first order condition. Our research results could be helpful for analysis of supply chain coordination and of the periodic review system for similar problems.

Keywords: inventory management, Newsvendor model, order policy, worker learning

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Authors: Aida Safiera, Andika Dwi Rubyantoro, Muhammad Bagus Prakasa

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Indonesia’s needs of diesel oil each year are increasing and getting urge. However, that problems are not supported by the amount of oil production that still low and also influenced by the fact of oil reserve is reduced. Because of that, the government prefers to import from other countries than fulfill the needs of diesel. To anticipate that problem, development of fuel based on renewable diesel is started. Renewable diesel is renewable alternative fuel that is hydrocarbon derivative from decarbonylation of non-edible oil. Indonesia is rich with natural resources, including nyamplung oil (Calophyllum inophyllum oil) and zeolite. Nyamplung oil (Calophyllum inophyllum oil) has many stearic acids which are useful on renewable diesel synthesis meanwhile zeolite is cheap. Zeolite is many used on high temperature reaction and cracking process on oil industry. Zeolite also has advantages which are a high crystallization, surface area and pores. In this research, the main focus that becomes our attention is on preparation and characterization of metal nanocrystal. Active site that used in this research is Nickel Molybdenum (NiMo). The advantage of nanocrystal with nano scale is having larger surface area. The synthesis of metal nanocrystal will be done with conventional preparation modification method that is called simple heating. Simple heating method is a metal nanocrystal synthesis method using continuous media which is polymer liquid. This method is a simple method and produces a small particles size in a short time. Influence of metal nanocrystal growth on this method is the heating profile. On the synthesis of nanocrystal, the manipulated variables are temperature and calcination time. Results to achieve from this research are diameter size on nano scale (< 100 nm) and uniform size without any agglomeration. Besides that, the conversion of synthesis of renewable diesel is high and has an equal specification with petroleum diesel. Catalyst activities are tested by FT-IR and GC-TCD on decarbonylation process with a pressure 15 bar and temperature 375 °C. The highest conversion from this reaction is 35% with selectivity around 43%.

Keywords: renewable diesel, simple heating, metal nanocrystal, NiMo, zeolite

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Authors: Adel Salem Bahakeem, Ahmad Jamal, Mir Md. Maruf Morshed, Elwaleed Awad Khidir

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Direct Current (DC) servo motors, or simply DC motors, play an important role in many industrial applications such as manufacturing of plastics, precise positioning of the equipment, and operating computer-controlled systems where speed of feed control, maintaining the position, and ensuring to have a constantly desired output is very critical. These parameters can be controlled with the help of control systems such as the Proportional Integral Derivative (PID) controller. The aim of the current work is to investigate the effects of Proportional (P) and Integral (I) controllers on the steady state and transient response of the DC motor. The controller gains are varied to observe their effects on the error, damping, and stability of the steady and transient motor response. The current investigation is conducted experimentally on a servo trainer CE 110 using analog PI controller CE 120 and theoretically using Simulink in MATLAB. Both experimental and theoretical work involves varying integral controller gain to obtain the response to a steady-state input, varying, individually, the proportional and integral controller gains to obtain the response to a step input function at a certain frequency, and theoretically obtaining the proportional and integral controller gains for desired values of damping ratio and response frequency. Results reveal that a proportional controller helps reduce the steady-state and transient error between the input signal and output response and makes the system more stable. In addition, it also speeds up the response of the system. On the other hand, the integral controller eliminates the error but tends to make the system unstable with induced oscillations and slow response to eliminate the error. From the current work, it is desired to achieve a stable response of the servo motor in terms of its angular velocity subjected to steady-state and transient input signals by utilizing the strengths of both P and I controllers.

Keywords: DC servo motor, proportional controller, integral controller, controller gain optimization, Simulink

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Authors: Leixuri Aguirre, Iñaki Milton-Laskibar, Elizabeth Hijona, Luis Bujanda, Agnes M. Rimando, Maria P. Portillo

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Introduction: In recent years great attention has been paid by scientific community to phenolic compounds as active biomolecules naturally present in foodstuffs due to their beneficial effects on health. Pterostilbene is a resveratrol dimethylether derivative which shows higher biodisponibility. Objective. To analyze the effects of two doses of pterostilbene on several markers of thermogenic capacity in a model of genetic obesity, which shows reduced thermogenesis. Methods: The experiment was conducted with thirty Zucker (fa/fa) rats that were distributed in 3 experimental groups, the control group and two groups orally administered with pterostilbene at 15 and 30 mg/kg body weight/day for 6 weeks. Gene expression of Ucp1, Pgc-1α, Cpt1b, Pparα, Nfr1, Tfam and Cox-2 were assessed by RT-PCR, protein expression of UCP1 and GLUT4 by western blot and enzyme activity of carnitine palmitoyl transferase 1b and citrate synthase by spectrophotometry in interscapular brown adipose tissue (iBAT). Statistical analysis was performed by using one way ANOVA and Newman-Keuls as post-hoc test. Results: Pterostilbene did not change gene expression of Pgc-1α. However, significant increases were found in the expression of Ucp1, Pparα, Nfr-1 and Cox-2. Protein expression of UCP1 and GLUT4 was increased in animals treated with pterostilbene, as well as the activities of CPT-1b and CS. These effects were observed with both doses of pterostilbene, without differences between them. Conclusions: These results show that pterostilbene increases thermogenic and oxidative capacity of brown adipose tissue in obese rats. Whether these effects effectively contribute to the anti-obesity properties of these compound needs further research. Acknowledgments: MINECO-FEDER (AGL2015-65719-R), Basque Government (IT-572-13), University of the Basque Country (ELDUNANOTEK UFI11/32), Institut of Health Carlos III (CIBERobn). Iñaki Milton is a fellowship from the Basque Government.

Keywords: brown adipose tissue, pterostilbene, thermogenesis, uncoupling protein 1

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Authors: Wadha Alqahtani

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In recent times, polymers have seen a great surge in interest in the field of medicine, particularly chemotherapeutics. One recent innovation is the conversion of polymeric materials into “polymeric nanoparticles”. These nanoparticles can be designed and modified to encapsulate and transport drugs selectively to cancer cells, minimizing collateral damage to surrounding healthy tissues, and improve patient quality of life. In this study, we have synthesized pseudo-branched polyester polymers from bio-based small molecules, including sorbitol, glutaric acid and a propargylic acid derivative to further modify the polymer to make it “click-able" with an azide-modified target ligand. Melt polymerization technique was used for this polymerization reaction, using lipase enzyme catalyst NOVO 435. This reaction was conducted between 90- 95 °C for 72 hours. The polymer samples were collected in 24-hour increments for characterization and to monitor reaction progress. The resulting polymer was purified with the help of methanol dissolving and filtering with filter paper then characterized via NMR, GPC, FTIR, DSC, TGA and MALDI-TOF. Following characterization, these polymers were converted to a polymeric nanoparticle drug delivery system using solvent diffusion method, wherein DiI optical dye and chemotherapeutic drug Taxol can be encapsulated simultaneously. The efficacy of the nanoparticle’s apoptotic effects were analyzed in-vitro by incubation with prostate cancer (LNCaP) and healthy (CHO) cells. MTT assays and fluorescence microscopy were used to assess the cellular uptake and viability of the cells after 24 hours at 37 °C and 5% CO2 atmosphere. Results of the assays and fluorescence imaging confirmed that the nanoparticles were successful in both selectively targeting and inducing apoptosis in 80% of the LNCaP cells within 24 hours without affecting the viability of the CHO cells. These results show the potential of using biodegradable polymers as a vehicle for receptor-specific drug delivery and a potential alternative for traditional systemic chemotherapy. Detailed experimental results will be discussed in the e-poster.

Keywords: chemotherapeutic drug, click chemistry, nanoparticle, prostat cancer

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Authors: Mamoon Masud, Suleman Mazhar

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Indus river basin’s irrigation system in Pakistan is extremely complex, spanning over 50,000 km. Maintenance and monitoring of this demands enormous resources. This paper describes the development of a streamlined and low-cost autonomous underwater vehicle (AUV) for the monitoring of irrigation canals including water quality monitoring and water theft detection. The vehicle is a hovering-type AUV, designed mainly for monitoring irrigation canals, with fully documented design and open source code. It has a length of 17 inches, and a radius of 3.5 inches with a depth rating of 5m. Multiple sensors are present onboard the AUV for monitoring water quality parameters including pH, turbidity, total dissolved solids (TDS) and dissolved oxygen. A 9-DOF Inertial Measurement Unit (IMU), GY-85, is used, which incorporates an Accelerometer (ADXL345), a Gyroscope (ITG-3200) and a Magnetometer (HMC5883L). The readings from these sensors are fused together using directional cosine matrix (DCM) algorithm, providing the AUV with the heading angle, while a pressure sensor gives the depth of the AUV. 2 sonar-based range sensors are used for obstacle detection, enabling the vehicle to align itself with the irrigation canals edges. 4 thrusters control the vehicle’s surge, heading and heave, providing 3 DOF. The thrusters are controlled using a proportional-integral-derivative (PID) feedback control system, with heading angle and depth being the controller’s input and the thruster motor speed as the output. A flow sensor has been incorporated to monitor canal water level to detect water-theft event in the irrigation system. In addition to water theft detection, the vehicle also provides information on water quality, providing us with the ability to identify the source(s) of water contamination. Detection of such events can provide useful policy inputs for improving irrigation efficiency and reducing water contamination. The AUV being low cost, small sized and suitable for autonomous maneuvering, water level and quality monitoring in the irrigation canals, can be used for irrigation network monitoring at a large scale.

Keywords: the autonomous underwater vehicle, irrigation canal monitoring, water quality monitoring, underwater line tracking

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Authors: Joel Bonales, Venecia Solorzano, Carlos Garcia

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A great percentage of the wastewater generated in developing countries don’t receive any treatment, which leads to numerous environmental impacts. In response to this, a paradigm change in the current wastewater treatment model based on large scale plants towards a small and medium scale based model has been proposed. Nevertheless, small scale wastewater treatment (SS-WTTP) with novel technologies such as anaerobic digesters, as well as the utilization of derivative co-products such as biogas, still presents diverse environmental impacts which must be assessed. This study consisted in a Life Cycle Assessment (LCA) performed to a SS-WWTP which treats wastewater from a small commercial block in the city of Morelia, Mexico. The treatment performed in the SS-WWTP consists in anaerobic and aerobic digesters with a daily capacity of 5,040 L. Two different scenarios were analyzed: the current plant conditions and a hypothetical energy use of biogas obtained in situ. Furthermore, two different allocation criteria were applied: full impact allocation to the system’s main product (treated water) and substitution credits for replacing Mexican grid electricity (biogas) and clean water pumping (treated water). The results showed that the analyzed plant had bigger impacts than what has been reported in the bibliography in the basis of wastewater volume treated, which may imply that this plant is currently operating inefficiently. The evaluated impacts appeared to be focused in the aerobic digestion and electric generation phases due to the plant’s particular configuration. Additional findings prove that the allocation criteria applied is crucial for the interpretation of impacts and that that the energy use of the biogas obtained in this plant can help mitigate associated climate change impacts. It is concluded that SS-WTTP is a environmentally sound alternative for wastewater treatment from a systemic perspective. However, this type of studies must be careful in the selection of the allocation criteria and replaced products, since these factors have a great influence in the results of the assessment.

Keywords: biogas, life cycle assessment, small scale treatment, wastewater treatment

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Authors: Nadia Chougui, Nawal Makhloufi, Farouk Rezgui, Elias Benramdane, Carmen S. R. Freire, Carla Vilela, Armando J. D. Silvestre

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Native to Mexico, Opuntia ficus-indica was introduced in southern Spain, and thereafter, it was spread throughout the Mediterranean Basin by the Spanish conquerors in the 16th and 17th centuries. O. ficus-indica is a tropical and subtropical plant able to grow in arid and semi-arid regions, such as the Mediterranean and Central America regions. The culture of Opuntia covers about 200,000 ha in North Africa. This tree is used against soil erosion and desertification for fruit production and is encouraged to promote the livestock sector. It has recently received ever-increasing attention from researchers worldwide for the multivalent pharmaceutical and cosmetical potential of its different compartments (fruits, seeds, cladodes). The present study investigated the elaboration by casting method and characterization of new biodegradable films composed of cladodes powder (CP) of the plant raw material mentioned above, and a marine seaweed derivative, namely agar (A). The effect of glycerol concentration on the properties of the films was evaluated at four different contents (30, 40, 50 and 60 wt.%). The films present UV-blocking properties, thermal stability as well as moderate mechanical performance and water vapor transmission rate (WVTR). The results point to an increase in thickness, elongation at break, moisture content, water solubility, and WVTR with increasing glycerol content. On the contrary, Young’s modulus, tensile strength and contact angle decreased as glycerol concentration increased. The best combination is obtained for the film with 30% glycerol, based on an intermediate compromise between physical, mechanical, thermal and barrier properties. All these outcomes express the potentiality of the powder obtained from grinding the OFI cladodes as raw material to produce low-cost films for the development of sustainable packaging materials.

Keywords: Opuntia ficus-indica cladodes powder, agar, biobased films, effect of plasticizer, sustainable packaging

Procedia PDF Downloads 75

Authors: Narayan Moger, Divya B., Preethi Jambagi, Krishnaveni C. K., Apsana M. R., B. R. Patil, Basvaraj Bagewadi

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Salinity is one of the major threats to world food security. Considering the requirement for salt tolerant crop plants in the present study was undertaken to clone and transferred the salt tolerant ectA gene from marine ecosystem into agriculture crop system to impart salinity tolerance. Ectoine is the compatible solute which accumulates in the cell membrane, is known to be involved in salt tolerance activity in most of the Halophiles. The present situation is insisting to development of salt tolerant transgenic lines to combat abiotic stress. In this background, the investigation was conducted to develop transgenic tomato lines by cloning and transferring of ectA gene is an ectoine derivative capable of enzymatic action for the production of acetyl-diaminobutyric acid. The gene ectA is involved in maintaining the osmotic balance of plants. The PCR amplified ectA gene (579bp) was cloned into T/A cloning vector (pTZ57R/T). The construct pDBJ26 containing ectA gene was sequenced by using gene specific forward and reverse primers. Sequence was analyzed using BLAST algorithm to check similarity of ectA gene with other isolates. Highest homology of 99.66 per cent was found with ectA gene sequences of isolates Halomonas elongata with the available sequence information in NCBI database. The ectA gene was further sub cloned into pRI101-AN plant expression vector and transferred into E. coli DH5α for its maintenance. Further pDNM27 was mobilized into A. tumefaciens LBA4404 through tri-parental mating system. The recombinant Agrobacterium containing pDNM27 was transferred into tomato plants through In planta plant transformation method. Out of 300 seedlings, co-cultivated only twenty-seven plants were able to well establish under the greenhouse condition. Among twenty-seven transformants only twelve plants showed amplification with gene specific primers. Further work must be extended to evaluate the transformants at T1 and T2 generations for ectoine accumulation, salinity tolerance, plant growth and development and yield.

Keywords: salinity, computable solutes, ectA, transgenic, in planta transformation

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Authors: Song Hung Chi, Lee Chun Benn

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Follow by the “A Research on Types of Settlement Housing Alterations of Chinese New Village in Malaysia- A Study in Ampang New Village, Selangor” preliminary informed that the main factors for expansion and enlargement suitably due to the needs of user's life and restoration purpose. The alterations behavior generally derived at the rear position of main house with different types of derivatives, the averages expansion area are not exceeding of 100㎡, while building materials used were wooden, wooden structure, and zinc which are non-permanent building materials. Therefore, a subsequent studies taken in this paper, further to analyze the drawing with summarize method, to explore the derived forms and the constituted rules of housing alterations in Ampang Village, as a more complete presentation of housing alterations in New Village. Firstly, classified the existing housing alterations into three types by using summarize method, which are Type 1, Additional of Prototype House; Type 2, Expansion of Prototype House; and Type 3, Diffusion of Additional. The results shows that the derivative mode of alterations can be divided into the use of "continuous wall" or "non-continuous wall," this will affects the structural systems and roof styles of alterations, and formed the different layers of interior space with "stages" and "continuity". On the aspects of spatial distribution, sacrificial area as a prescriptive function of space, it was mostly remains in the original location which in the center of living area after alterations. It is an important characteristic in a New Village house, reflecting the traditional Ethics of Hakka Chinese communities in the settlement. In addition, wooden as the main building materials of constituted rules for the prototype house, although there were appeared other building materials, such as cement, brick, glass, metal and zinc after alterations, but still mostly as "wooden house" pattern. Result show because of the economy of village does not significantly improve, and also forming the similarity types in alterations and constructions of the additional building with the existing. It did not significantly improve on the quality of living, but only increased the area of usage space.

Keywords: Ampang new village, derived forms, constituted rules, alterations

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Authors: Meltem Karatepe Kaya

Abstract:

The concept of corporate governance is not new but, due to the recent international financial crisis, it has become prominent in contemporary business, accounting and legal debates. There is a wealth of anecdotal evidence which shows that protection of minority shareholders is an important issue in the corporate governance literature. Minority shareholders typically hold low amounts of stocks, so the benefits gained from their participation in shareholder meetings are very asymmetric to the cost. Therefore, the presence of a good corporate governance structure is the proper protection of and respect for the rights and interests of shareholders, particularly those of minority shareholders. The research will attempt to find answers to the following questions: Why minority shareholders’ rights should be protected? How minority shareholders’ rights could be improved? Does the legal framework in the United Kingdom provide adequate protection for minority shareholders? This study will assess regulations about the legal protections of minority shareholders and try to find answer this question: ’Why is it inevitable for company law to treat in a successful way the problems arising from minority shareholders' conflict with other shareholders of a company?’The protection of minority shareholders is not only a corporate governance objective in its own right but also has added importance particularly in developing countries. In the United Kingdom(UK) and the United States of America(USA), there are diffused ownership structures so that any shareholders do not influence the management of the company. This is in stark contrast to companies in developing countries such as Turkey where controlling shareholders and related insiders are a well-known feature of ownership structures, and where companies are often governed and managed by controlling shareholders such as family firms and associated companies through cross-shareholdings and pyramiding ownership structures. In Turkey, the agency problem is not between shareholders and management. Rather it gives rise to another dimension of the agency problem – a conflict of interest between majority shareholders (controlling) and minority shareholders. This research will make a particularly useful contribution to knowledge-based information and understanding of company law in the UK, particularly minority shareholders' remedies. It will not only give information about law and regulations of minority shareholders' remedies but also it will provide some knowledge about doctrinal discussions and relevant cases. The major contribution to study will be in the knowledge of law and regulation in the legal protections of minority shareholders in the United Kingdom and Turkey. In this study, the recommendations will be given for the development of the legal framework and practices of protections for minority shareholders and small investors.

Keywords: controlling shareholders, corporate governance, derivative actions, minority shareholders

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Authors: M. Mirmohammadi, S. Taghdisi, F. Anali

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Gossypol is a yellow anti-nutritional compound found in the cotton plant. This substance exists in the cottonseed and other parts of the cotton plant, such as bark, leaves, and stems. Chemically, gossypol is a very active polyphenolic aldehyde compound, and due to this polyphenolic structure, it has antioxidant and therapeutic properties. On the other hand, this compound, especially in free form, has many toxic effects, that its excessive consumption can be very dangerous for humans and animals. In this study, gossypol was extracted as a derivative compound of gossypol acetic acid from cottonseed using the n-hexane solvent with an efficiency of 0.84 ± 0.04, which compared to the Gossypol extracted from cottonseed oil with the same method (cold press) showed a significant difference with its efficiency of 1.14 ± 0.06. Therefore, it can be suggested to use cottonseed oil to extract this valuable compound. In the other part of this research, cottonseed extracts and cotton bolls extracts were obtained by two methods of soaking and Soxhlet with hydroalcoholic solvent taken with a ratio of (25:75), then by using extracts and corn starch powder, four herbal medicine code was created and after receiving the code of ethics (IR.SSU.REC.1398.136) the therapeutic effect of each one on the Cutaneous leishmaniasis resistant to drugs (caused by the leishmaniasis parasite) was investigated in real patients and its results was compared with the common drug glucantime (local ampoule) (n = 36). Statistical studies showed that the use of herbal medicines prepared with cottonseed extract and cotton bolls extract has a significant positive effect on the treatment of the disease’s wounds (p-value > 0.05) compared to the control group (only ethanol). Also, by comparing the average diameter of the wounds after a two-month treatment period, no significant difference was found between the use of ointment containing extracts and local glucantime ampoules (p-value < 0.05). Bolls extract extracted with the Soxhlet method showed the best therapeutic effects, although there was no significant difference between them (p-value < 0.05). Therefore, there is acceptable reliability to recommend this medicine for the treatment of Cutaneous leishmaniasis resistant to drugs without the side effects of the chemical drug glucantime and the pain of injecting the ampoule.

Keywords: cottonseed oil, gossypol, cotton boll, cutaneous leishmaniasis

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Authors: Umar Hayatu Sidik

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Application of liquid base petroleum fuel (petrol and diesel) for transportation fuel causes emissions of greenhouse gases (GHGs), while natural gas (NG) reduces the emissions of greenhouse gases (GHGs). At present, compression and liquefaction are the most matured technology used for transportation system. For transportation use, compression requires high pressure (200–300 bar) while liquefaction is impractical. A relatively low pressure of 30-40 bar is achievable by adsorbed natural gas (ANG) to store nearly compressed natural gas (CNG). In this study, adsorbents for high-pressure adsorption of methane (CH4) was prepared from coconut shells and polyetheretherketone (PEEK) using potassium hydroxide (KOH) and microwave-assisted activation. Design expert software version 7.1.6 was used for optimization and prediction of preparation conditions of the adsorbents for CH₄ adsorption. Effects of microwave power, activation time and quantity of PEEK on the adsorbents performance toward CH₄ adsorption was investigated. The adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric (TG) and derivative thermogravimetric (DTG) and scanning electron microscopy (SEM). The ideal CH4 adsorption capacities of adsorbents were determined using volumetric method at pressures of 5, 17, and 35 bar at an ambient temperature and 5 oC respectively. Isotherm and kinetics models were used to validate the experimental results. The optimum preparation conditions were found to be 15 wt% amount of PEEK, 3 minutes activation time and 300 W microwave power. The highest CH4 uptake of 9.7045 mmol CH4 adsorbed/g adsorbent was recorded by M33P15 (300 W of microwave power, 3 min activation time and 15 wt% amount of PEEK) among the sorbents at an ambient temperature and 35 bar. The CH4 equilibrium data is well correlated with Sips, Toth, Freundlich and Langmuir. Isotherms revealed that the Sips isotherm has the best fit, while the kinetics studies revealed that the pseudo-second-order kinetic model best describes the adsorption process. In all scenarios studied, a decrease in temperature led to an increase in adsorption of both gases. The adsorbent (M33P15) maintained its stability even after seven adsorption/desorption cycles. The findings revealed the potential of coconut shell-PEEK as CH₄ adsorbents.

Keywords: adsorption, desorption, activated carbon, coconut shells, polyetheretherketone

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Authors: Lee Yujin, Han Jiye, Oh Jin-Woo

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The adverse effects of endocrine disrupting chemicals (EDCs) has attracted considerable public interests. The benzene-like EDCs structure mimics the mechanisms of hormones naturally occurring in vivo, and alters physiological function of the endocrine system. Although, some of the most representative EDCs such as polychlorinated biphenyls (PCBs) and phthalates compounds already have been prohibited to produce and use in many countries, however, PCBs and phthalates in plastic products as flame retardant and plasticizer are still circulated nowadays. EDCs can be released from products while using and discarding, and it causes serious environmental and health issues. Here, we developed virus-based structurally coloured nanostructure that can detect minute EDCs concentration sensitively and selectively. These structurally coloured nanostructure exhibits characteristic angel-independent colors due to the regular virus bundle structure formation through simple pulling technique. The designed number of different colour bands can be formed through controlling concentration of virus solution and pulling speed. The virus, M-13 bacteriophage, was genetically engineered to react with specific ECDs, typically PCBs and phthalates. M-13 bacteriophage surface (pVIII major coat protein) was decorated with benzene derivative binding peptides (WHW) through phage library method. In the initial assessment, virus-based color sensor was exposed to several organic chemicals including benzene, toluene, phenol, chlorobenzene, and phthalic anhydride. Along with the selectivity evaluation of virus-based colour sensor, it also been tested for sensitivity. 10 to 300 ppm of phthalic anhydride and chlorobenzene were detected by colour sensor, and showed the significant sensitivity with about 90 of dissociation constant. Noteworthy, all measurements were analyzed through principal component analysis (PCA) and linear discrimination analysis (LDA), and exhibited clear discrimination ability upon exposure to 2 categories of EDCs (PCBs and phthalates). Because of its easy fabrication, high sensitivity, and the superior selectivity, M-13 bacteriophage-based color sensor could be a simple and reliable portable sensing system for environmental monitoring, healthcare, social security, and so on.

Keywords: M-13 bacteriophage, colour sensor, genetic engineering, EDCs

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Authors: Sourav Biswas, Goutam Prasanna Kar, Suryasarathi Bose

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In order to obtain better materials, control in the precise location of nanoparticles is indispensable. It was shown here that ordered arrangement of nanoparticles, possessing different characteristics (electrical/magnetic dipoles), in the blend structure can result in excellent microwave absorption. This is manifested from a high reflection loss of ca. -67 dB for the best blend structure designed here. To attenuate electromagnetic radiations, the key parameters i.e. high electrical conductivity and large dielectric/magnetic loss are targeted here using a conducting inclusion [multiwall carbon nanotubes, MWNTs]; ferroelectric nanostructured material with associated relaxations in the GHz frequency [barium titanate, BT]; and a loss ferromagnetic nanoparticles [nickel ferrite, NF]. In this study, bi-continuous structures were designed using 50/50 (by wt) blends of polycarbonate (PC) and polyvinylidene fluoride (PVDF). The MWNTs was modified using an electron acceptor molecule; a derivative of perylenediimide, which facilitates π-π stacking with the nanotubes and stimulates efficient charge transport in the blends. The nanoscopic materials have specific affinity towards the PVDF phase. Hence, by introducing surface-active groups, ordered arrangement can be tailored. To accomplish this, both BT and NF was first hydroxylated followed by introducing amine-terminal groups on the surface. The latter facilitated in nucleophilic substitution reaction with PC and resulted in their precise location. In this study, we have shown for the first time that by compartmentalized approach, superior EM attenuation can be achieved. For instance, when the nanoparticles were localized exclusively in the PVDF phase or in both the phases, the minimum reflection loss was ca. -18 dB (for MWNT/BT mixture) and -29 dB (for MWNT/NF mixture), and the shielding was primarily through reflection. Interestingly, by adopting the compartmentalized approach where in, the lossy materials were in the PC phase and the conducting inclusion (MWNT) in PVDF, an outstanding reflection loss of ca. -57 dB (for BT and MWNT combination) and -67 dB (for NF and MWNT combination) was noted and the shielding was primarily through absorption. Thus, the approach demonstrates that nanoscopic structuring in the blends can be achieved under macroscopic processing conditions and this strategy can further be explored to design microwave absorbers.

Keywords: barium titanate, EMI shielding, MWNTs, nickel ferrite

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Authors: Habtamu Garoma Debela, Gemechis File Duressa

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In this work, our primary interest is to provide ε-uniformly convergent numerical techniques for solving singularly perturbed semilinear boundary value problems with non-local boundary condition. These singular perturbation problems are described by differential equations in which the highest-order derivative is multiplied by an arbitrarily small parameter ε (say) known as singular perturbation parameter. This leads to the existence of boundary layers, which are basically narrow regions in the neighborhood of the boundary of the domain, where the gradient of the solution becomes steep as the perturbation parameter tends to zero. Due to the appearance of the layer phenomena, it is a challenging task to provide ε-uniform numerical methods. The term 'ε-uniform' refers to identify those numerical methods in which the approximate solution converges to the corresponding exact solution (measured to the supremum norm) independently with respect to the perturbation parameter ε. Thus, the purpose of this work is to develop, analyze, and improve the ε-uniform numerical methods for solving singularly perturbed problems. These methods are based on nonstandard fitted finite difference method. The basic idea behind the fitted operator, finite difference method, is to replace the denominator functions of the classical derivatives with positive functions derived in such a way that they capture some notable properties of the governing differential equation. A uniformly convergent numerical method is constructed via nonstandard fitted operator numerical method and numerical integration methods to solve the problem. The non-local boundary condition is treated using numerical integration techniques. Additionally, Richardson extrapolation technique, which improves the first-order accuracy of the standard scheme to second-order convergence, is applied for singularly perturbed convection-diffusion problems using the proposed numerical method. Maximum absolute errors and rates of convergence for different values of perturbation parameter and mesh sizes are tabulated for the numerical example considered. The method is shown to be ε-uniformly convergent. Finally, extensive numerical experiments are conducted which support all of our theoretical findings. A concise conclusion is provided at the end of this work.

Keywords: nonlocal boundary condition, nonstandard fitted operator, semilinear problem, singular perturbation, uniformly convergent

Procedia PDF Downloads 143

Authors: Brahim Sow

Abstract:

Background: Throughout West Africa, Balanites aegyptiaca (BA), or Zygophyllaceae, is widely used in traditional medicine to treat diabetes, hypertension, inflammation, malaria and liver disorders. In our recent research, we found that BA has nephroprotective potential against diabetes mellitus, hypertension and kidney disorders. However, to our knowledge, no systematic studies have been carried out on its derivative (toxicity) profile. Aim of the study: The study was conducted to assess the potential potency of the hydroalcoholic extract of BA bark in rats by the acute and sub-acute oral route. Materials and methods: Male and female rats in the acute depression study received BA extract orally at single doses of 500 mg/kg, 2000 mg/kg, 3000 mg/kg and 5000 mg/kg (n = 6 per group/sex). To assess acute depression, abnormal behaviour, toxic symptoms, weight and death were observed for 14 consecutive days. For the subacute impairment study, Wistar rats received the extract orally at doses of 125, 250 and 500 mg/kg (n=6 per group/sex) per day for 28 days. Behaviour and body weight were monitored daily. At the end of the treatment period, biochemical, haematological and histopathological examinations were performed, and gross and histopathological examinations of several organs were carried out. To determine the presence or absence of phytochemicals, the BA extract was subjected to gage phage chromatographic examination. Results: The absence of absorption chromatography of BA indicates the absence of cyanide groups. This suggests that the BA extract does not contain toxic substances. No mortality or adverse effects were observed at 5000 mg/kg in the acute depression test. With regard to body weight, general behaviour, relative organ weights, haematological and biochemical parameters, BA extract did not induce any mortality or potentially treatment-related effects in the sub-acute study. The normal architecture of the vital organs was revealed by histopathological examination, indicating the absence of morphological alterations. Conclusion: BA extract administered orally for 28 days at doses up to 500 mg/kg did not cause toxicological damage in rats in the present study. The median lethal dose (LD50) of the extract was estimated to be over 5000 mg/kg in an acute hyperglycaemia study.

Keywords: Balanites aegyptiaca L Delile, haematology, biochemistry, rat

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Authors: A. Kouloumpis, P. Zygouri, G. Potsi, K. Spyrou, D. Gournis

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Much of the research effort on graphene focuses on its use as building block for the development of new hybrid nanostructures with well-defined dimensions and behavior suitable for applications among else in gas storage, heterogeneous catalysis, gas/liquid separations, nanosensing and biology. Towards this aim, here we describe a new bottom-up approach, which combines the self-assembly with the Langmuir Schaefer technique, for the production of fullerene-intercalated graphene hybrid materials. This new method uses graphene nanosheets as a template for the grafting of various fullerene C60 molecules (pure C60, bromo-fullerenes, C60Br24, and fullerols, C60(OH)24) in a bi-dimensional array, and allows for perfect layer-by-layer growth with control at the molecular level. Our film preparation approach involves a bottom-up layer-by-layer process that includes the formation of a hybrid organo-graphene Langmuir film hosting fullerene molecules within its interlayer spacing. A dilute water solution of chemically oxidized graphene (GO) was used as subphase on the Langmuir-Blodgett deposition system while an appropriate amino surfactant (that binds covalently with the GO) was applied for the formation of hybridized organo-GO. After the horizontal lift of a hydrophobic substrate, a surface modification of the GO platelets was performed by bringing the surface of the transferred Langmuir film in contact with a second amino surfactant solution (capable to interact strongly with the fullerene derivatives). In the final step, the hybrid organo-graphene film was lowered in the solution of the appropriate fullerene derivative. Multilayer films were constructed by repeating this procedure. Hybrid fullerene-based thin films deposited on various hydrophobic substrates were characterized by X-ray diffraction (XRD) and X-ray reflectivity (XRR), FTIR, and Raman spectroscopies, Atomic Force Microscopy, and optical measurements. Acknowledgments. This research has been co‐financed by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF)‐Research Funding Program: THALES. Investing in knowledge society through the European Social Fund (no. 377285).

Keywords: hybrids, graphene oxide, fullerenes, langmuir-blodgett, intercalated structures

Procedia PDF Downloads 327