421 research outputs found

    An analytical model of trilateration localization error

    Get PDF
    Trilateration and multilateration are important location estimation techniques used in a diverse range of networks and applications. The system of equations yielded by multilateration can be reduced to simpler linear equations which can be solved to arrive at a closed form analytic solution. Exploiting this solution technique, we develop a novel and unique analytical model for the localization error resulting from trilateration. The analytical model can be used for the analysis of the localization error in all applications wherever multilateration is used for position estimation including internet of things, wireless sensor networks and global navigation satellite system thereby increasing reliability and quality of localization. As an example, we use the analytical model to corroborate the fact that localization error is a function of topology of reference positions in addition to distance estimation errors. The analytical model is verified using simulation experiments

    Lithium-Ion Supercapacitor Using Vertically-Aligned Carbon Nanotubes From Direct Growth Technique, And Its Electrochemical Characteristics

    Get PDF
    This paper reports the fabrication of a lithium ion supercapacitor from vertically-aligned carbon nanotubes (VACNTs) directly grown on a conductive substrate (SUS 310S alloy), using alcohol catalytic chemical vapour deposition technique. CNTs direct growth technique on an electrically conducting foil simplifies the electrode assembly, thus reducing the fabrication process, because the foil can directly act as a current collector. With the VACNT direct growth technique, the supercapacitor electrode was easily prepared and assembled with a non-aqueous 1 M LiPF6 electrolyte. Experimental results show that CNTs (multi-walled type structures of good quality) were perpendicularly grown to the substrate. This device demonstrates a specific capacitance of up to 101 F g-1 (at a scan rate of 1 mVs-1), and a high-rate capability, up to a scan rate of 1000 mVs-1. The VACNT electrode electrochemical performance was also measured by galvanostatic charge-discharge and electrochemical impedance spectroscopy. The effect of free standing CNTs direct growth on the current collector makes insulating binder material unnecessary, thus producing better ion accessibilities to its surface. This also contributes to the good and reliable electrochemical supercapacitor performance

    Effect of Dodecylbenzene Sulfonic Acid Dopant Concentrations on the Synthesis of Polyaniline

    Get PDF
    Modified physicochemical properties of polyaniline (PANI) colloids in response to various polymerization conditions are being made to enhance the electrical conductivity of PANI that can be used in supercapacitor purpose. In this paper, an attempt has been made to improve the mechanical stability of PANI by synthesizing with different concentrations (0.8, 1.65, 2.0, and 2.5 mmol) of dodecylbenzenesulfonic acid (DBSA). The DBSA doped PANI colloids were characterized by using XRD, Raman spectra and SEM. PANI containing 2.0 mmol of DBSA has the highest percentage of crystallinity (Xc %) as analyzed from XRD spectrum. Scanning electron microscopy (SEM) has been used to investigate the influence of the feed concentration of DBSA on the morphology of the polymer.  A detailed study on the  Raman spectroscopies of PANI-DBSA colloids has been carried out  which shows that intensity of RAMAN spectra are directly proportional to the increased crystallized region of doped PANI samples; higher intensity may attribute due to the large change in polarization associated with the formation of covalent bond in PANI

    Effect of Dodecylbenzene Sulfonic Acid Dopant Concentrations on the Synthesis of Polyaniline

    Get PDF
    Modified physicochemical properties of polyaniline (PANI) colloids in response to various polymerization conditions are being made to enhance the electrical conductivity of PANI that can be used in supercapacitor purpose. In this paper, an attempt has been made to improve the mechanical stability of PANI by synthesizing with different concentrations (0.8, 1.65, 2.0, and 2.5 mmol) of dodecylbenzenesulfonic acid (DBSA). The DBSA doped PANI colloids were characterized by using XRD, Raman spectra and SEM. PANI containing 2.0 mmol of DBSA has the highest percentage of crystallinity (Xc %) as analyzed from XRD spectrum. Scanning electron microscopy (SEM) has been used to investigate the influence of the feed concentration of DBSA on the morphology of the polymer.  A detailed study on the  Raman spectroscopies of PANI-DBSA colloids has been carried out  which shows that intensity of RAMAN spectra are directly proportional to the increased crystallized region of doped PANI samples; higher intensity may attribute due to the large change in polarization associated with the formation of covalent bond in PANI

    A screen to identify drug resistant variants to target-directed anti-cancer agents

    Get PDF
    The discovery of oncogenes and signal transduction pathways important for mitogenesis has triggered the development of target-specific small molecule anti-cancer compounds. As exemplified by imatinib (Gleevec), a specific inhibitor of the Chronic Myeloid Leukemia (CML)-associated Bcr-Abl kinase, these agents promise impressive activity in clinical trials, with low levels of clinical toxicity. However, such therapy is susceptible to the emergence of drug resistance due to amino acid substitutions in the target protein. Defining the spectrum of such mutations is important for patient monitoring and the design of next-generation inhibitors. Using imatinib and BCR/ABL as a paradigm for a drug-target pair, we recently reported a retroviral vector-based screening strategy to identify the spectrum of resistance-conferring mutations. Here we provide a detailed methodology for the screen, which can be generally applied to any drug-target pair

    Spray behaviour of hydro-treated ester fatty acids fuel made from used cooking oil at low injection pressures

    Get PDF
    The spray characteristics significantly affected the combustion performance. The injection pressure and fuel properties are factors that affect the spray cone angle, penetration, and droplet distribution. Although substantial research has been conducted on spray attributes, understanding the complex biofuel spray dynamics in real nozzles and injectors is crucial. This study examines hydro-processed esters and fatty acid (HEFA) spray characteristics of used cooking oil and palm oil biodiesel in a constant-volume chamber. The study was performed by varying the injection pressures ranging from 30 to 120psi for pure fuels and Jet A-1 blends. Experiments were conducted at standard sea-level atmospheric pressure and an ambient temperature of ±297K using an airblast fuel injector. The initial fuel temperature was set at ±302K. Jet A-1 was used as the baseline fuel for the comparative analysis. Particle image velocimetry (PIV) was employed to visualise the microscopic and macroscopic characteristics of the fuel spray. The results revealed a progressive increase in the penetration length corresponding to an increase in the injection pressure. Lower pressures yielded non-uniform particle distributions across the spray area, whereas cone angle augmentation stabilised at elevated pressures. A blend of 60% Jet A-1 and 40% HEFA closely matched Jet A-1 characteristics, indicating alternative aviation fuel potential. These real-time insights into spray behaviour are critical for enhancing the fuel efficiency and mitigating the generation of particulate emissions resulting from spray combustion

    Supplementing a-Linolenic acid in the in vitro maturation media improves nuclear maturation rate of oocytes and early embryonic development in the Nili Ravi buffalo

    Get PDF
    The present study was conducted to investigate the effect of omega-3 poly unsaturated fatty acid (PUFA), α-linolenic acid (ALA; 18:3 n-3) on the in vitro maturation (IVM) of buffalo oocytes and subsequent embryonic development. Buffalo cumulusoocyte complexes (COCs; n = 2282) were in vitro matured in TCM-199 (0.6% fatty acid free bovine serum albumin, 0.02 Units/ml FSH, 1 µg/ml 17-β-estradiol, 10 µg/ml epidermal growth factor, 50 µg/ml gentamicin) supplemented with 0 (control), 25, 50, 100, 150 or 300 µm ALA under an atmosphere of 5% CO2 in air at 38.5ºC for 22-24 h. The matured oocytes were then fertilized in Tyrode’s Albumin Lactate Pyruvate (TALP) medium and cultured in synthetic oviductal fluid (SOF) medium. Concentrations up to 100 μm ALA improves (P ≤ 0.05) the cumulus expansion compared to control. Higher percentage of oocytes reaching MII stage was observed at 50 μm and 100 μm of ALA compared to control (P ≤ 0.05). Concentrations of 150 and 300 µm ALA were detrimental both for cumulus expansion and nuclear maturation rate of buffalo oocytes. Moreover, supplementation with 100 μm ALA improved (P ≤ 0.05) cleavage rate compared to control and treatment with 50 and 100 μm ALA yielded significantly higher morulae compared to control. The results of present study indicate that the supplementation with 100 μm ALA to the IVM medium improves nuclear maturation rate of buffalo oocytes and subsequent early embryonic development

    Location Assisted Subcarrier and Power Allocation in Underlay Mobile Cognitive Radio Networks

    Get PDF
    In this paper we perform subcarrier and power allocation for the downlink transmission in a cognitive radio network by exploiting the location information of mobile secondary users. A mixed integer nonlinear problem is formulated which maximizes the aggregate capacity of the secondary network, subject to the constrained interference at the primary user and the maximum transmit power limit of the secondary base station. To solve the formulated problem, an optimal subcarrier allocation is first obtained based on a practical assumption, followed by an optimal power allocation achieved using standard optimization methods. The proposed solution can facilitate to reduce latency and provide high speed communication of big data for mobile secondary users since speed, direction and location are all taken into account for effective allocation of resources. Simulation results verify our design intentions and confirm the efficiency of the proposed resource allocation strategy. © 2018 IEEE

    TAT-peptide conjugated repurposing drug against SARS-CoV-2 main protease (3CLpro): potential therapeutic intervention to combat COVID-19

    Get PDF
    The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that originated in Chinese city of Wuhan has caused around 906,092 deaths and 28,040,853 confirmed cases worldwide (WHO, 11 September, 2020). In a life-threatening situation, where there is no specific and licensed anti-COVID-19 vaccine or medicine available; the repurposed drug might act as a silver bullet. Currently, more than 211 vaccines, 80 antibodies, 31 antiviral drugs, 35 cell-based, 6 RNA-based and 131 other drugs are in clinical trials. It is therefore utter need of the hour to develop an effective drug that can be used for the treatment of COVID-19 before a vaccine can be developed. One of the best-characterized and attractive drug targets among coronaviruses is the main protease (3CL^{pro}). Therefore, the current study focuses on the molecular docking analysis of TAT-peptide^{47–57} (GRKKRRQRRRP)-conjugated repurposed drugs (i.e., lopinavir, ritonavir, favipiravir, and hydroxychloroquine) with SARS-CoV-2 main protease (3CL^{pro} to discover potential efficacy of TAT-peptide (TP) - conjugated repurposing drugs against SARS-CoV-2. The molecular docking results validated that TP-conjugated ritonavir, lopinavir, favipiravir, and hydroxychloroquine have superior and significantly enhanced interactions with the target SARS-CoV-2 main protease. In-silico approach employed in this study suggests that the combination of the drug with TP is an excelling alternative to develop a novel drug for the treatment of SARS-CoV-2 infected patients. The development of TP based delivery of repurposing drugs might be an excellent approach to enhance the efficacy of the existing drugs for the treatment of COVID-19. The predictions from the results obtained provide invaluable information that can be utilized for the choice of candidate drugs for in vitro, in vivo and clinical trials. The outcome from this work prove crucial for exploring and developing novel cost-effective and biocompatible TP conjugated anti-SARS-CoV-2 therapeutic agents in immediate future
    corecore