Experimental Characterization of Electrical Discharge Machining of Aluminum 6061 T6 Alloy using Different Dielectrics

Electrical discharge machining is a non-traditional machining method broadly employed in industries for machining of parts that have typical profiles and require great accuracy. This paper investigates the effects of electrical parameters: pulse-on-time and current on three performance measures (material removal rate, microstructures and electrode wear rate), using distilled water and kerosene as dielectrics. A comparison between dielectrics for the machining of aluminum 6061 T6 alloy material in terms of performance measures was performed. Aluminum 6061 T6 alloy material was selected, because of its growing use in the automotive and aerospace industrial sectors. The experimental sequence was designed using Taguchi technique of L9 orthogonal array by changing three levels of pulse-on-time and current, and test runs were performed separately for each dielectric. The results obtained show that greater electrode wear rate (EWR) and higher material removal rate (MRR) were achieved with distilled water when compared with kerosene. These greater EWR and MRR responses can be attributed to the early breakage of the weak oxide and carbide layers formed on the tool and alloy material surfaces, respectively. The innovative contributions of this study include, but are not limited to, the possibility of machining of aluminum 6061 T6 alloy with graphite electrode to enhance machinability and fast cutting rate employing two different dielectrics.Peer reviewe

Synthesis, Characterization and DNA Cleavage of Copper(II) Complex with D,L-Dithiothreitol

Purpose: To study deoxyribonucleic acid (DNA) shearing capability of copper(II) complex of dithiothreitol (DTT) and to fevaluate its potential application in cancer therapy.Methods: A parrot green complex was synthesized by grinding copper acetate monohydrate and DTT in 1:2 molar ratio in a mortar until no fumes of acetic acid were observed. The complex was characterized using attenuated total reflectance-Fourier transform infra-red (ATR-FTIR), and x-ray diffraction (XRD) techniques. Further information was also collected through Karl Fischer titration, thermogravimetric analysis (TGA) and (magnetic moment. Cleavage of DNA was determined by agarose gel electrophoresis. The gel was then stained, analyzed and photographed under ultraviolet (UV) light.Results: ATR-FTIR confirmed the formation of copper(II) complex with DTT by binding through thiol group based on the disappearance of the thiol (-SH) stretching peak at 2545 cm-1. The crystalline structure was elucidated by a sharp intense peak at 38.520 in XRD spectrum while the octahedral geometry of complex was inferred from a magnetic moment of 1.72 B.M. The results for water content obtained by Karl Fischer titration and TGA revealed that water molecules are not part of the coordination sphere of the complex. Cleavage study of DNA showed that the complex completely sheared the circular DNA compared to pure DTT.Conclusion: Solvent free synthesis of Copper(II)-DTT complex has been successfully achieved, and an anhydrous complex with octahedral geometry obtained. The complex has a greater potential to shear DNA molecule than pure DTT.Keywords: DNA shearing, Copper(II) complex, Dithiothreitol, Attenuated total reflectance-Fourier transform infra-red, Karl Fischer titration, Magnetic momen

An Approach for Adaptive Automatic Threat Recognition Within 3D Computed Tomography Images for Baggage Security Screening

BACKGROUND: The screening of baggage using X-ray scanners is now routine in aviation security with automatic threat detection approaches, based on 3D X-ray computed tomography (CT) images, known as Automatic Threat Recognition (ATR) within the aviation security industry. These current strategies use pre-defined threat material signatures in contrast to adaptability towards new and emerging threat signatures. To address this issue, the concept of adaptive automatic threat recognition (AATR) was proposed in previous work. OBJECTIVE: In this paper, we present a solution to AATR based on such X-ray CT baggage scan imagery. This aims to address the issues of rapidly evolving threat signatures within the screening requirements. Ideally, the detection algorithms deployed within the security scanners should be readily adaptable to different situations with varying requirements of threat characteristics (e.g., threat material, physical properties of objects). METHODS: We tackle this issue using a novel adaptive machine learning methodology with our solution consisting of a multi-scale 3D CT image segmentation algorithm, a multi-class support vector machine (SVM) classifier for object material recognition and a strategy to enable the adaptability of our approach. Experiments are conducted on both open and sequestered 3D CT baggage image datasets specifically collected for the AATR study. RESULTS: Our proposed approach performs well on both recognition and adaptation. Overall our approach can achieve the probability of detection around 90% with a probability of false alarm below 20%. CONCLUSIONS: Our AATR shows the capabilities of adapting to varying types of materials, even the unknown materials which are not available in the training data, adapting to varying required probability of detection and adapting to varying scales of the threat object

Enhanced Inter-Cell Interference Coordination Challenges in Heterogeneous Networks

3GPP LTE-Advanced has started a new study item to investigate Heterogeneous Network (HetNet) deployments as a cost effective way to deal with the unrelenting traffic demand. HetNets consist of a mix of macrocells, remote radio heads, and low-power nodes such as picocells, femtocells, and relays. Leveraging network topology, increasing the proximity between the access network and the end-users, has the potential to provide the next significant performance leap in wireless networks, improving spatial spectrum reuse and enhancing indoor coverage. Nevertheless, deployment of a large number of small cells overlaying the macrocells is not without new technical challenges. In this article, we present the concept of heterogeneous networks and also describe the major technical challenges associated with such network architecture. We focus in particular on the standardization activities within the 3GPP related to enhanced inter-cell interference coordination.Comment: 12 pages, 4 figures, 2 table

Pemodelan Stokastik Curah Hujan Dari Beberapa Stasiun Curah Hujan Wilayah Tanggamus

This research is to study the periodic and stochastic models in the series of daily rainfall data. The study was conducted using daily rainfall data with a data length of 25 years (1977-2001) from the station of Banjar Agung, Gisting and Gunung Batu. This research used secondary rainfall data from Tanggamus, This study change the series of daily rainfall data into the sepektrum rainfall using FFT (Fast Fourier Transform). Periodicity of daily rainfall data were presented by using 512 rainfall. Stochastic series of rainfall data are assumed as the difference (error) between the rainfall data with periodic rainfall model. Results of this study is the correlation coefficient from three rainfall stations In this study, the correlation coefficient (R) between the data and the periodic model is 0,9974, between stochastic data series and stochastic models is 0,9996, and between data and periodic stochastic models is 0,99997. From these results it can be concluded that the periodic stochastic models of rainfall from Tanggamus periodic models using 512 rainfall data, the approach provides a very significant

Exploring Aluminum Tolerance at Seedling Stage in Rice (Oryza Sativa, Linn) by Using Modified Magnavaca Nutrient Solution

Aluminum (Al) toxicity is considered as one of the main constraints for crop production in acidic soil. This study was subjected to observe the response of root and shoot growth of eight rice varieties under Al stress in hydrophonic solution. A modified Magnavaca's solution was used to compare the effect of Al stress using different variables which were relative root elongation (RRE), relative shoot length (RSL) and relative root weight (RRW). The experiment was conducted in split-plot experimental design. Eight rice varieties were screened in four Al levels (0 μM, 540 μM, 750 μM, and 1,300 μM). Root length, shoot length,and root dry weight were measured after 7 days of treatment, then the RRE, RSL, and RRW were calculated. The results showed that Al significantly reduced RRE and RSL but increased RRW. RSL was reduced as the Al concentration increased while RRE reduction started only at 750 μM Al concentration. It was observed that RRW was significantly higher under 540 and 750 μM Al concentration. However, no significant difference was observed in 1,300 μM Al concentration. The increase in root weight is partly attributed by the thickening of the root wall, but this effect was diminished due to root hair inhibition under 1,300 μM Al concentration. Among these three variables observed, root and shoot lengths indicated better variables in determining Al tolerance in rice, compared to root weight. However, these variables were not sufficient to represent root and shoot growth inhibition, and not sufficient to be used solely for Al toxicity screenin

Data of chemical analysis and electrical properties of SnO2-TiO2 composite nanofibers

In this data article, we provide energy dispersive X-ray spectroscopy (EDX) spectra of the electrospun composite (SnO2-TiO2) nanowires with the elemental values measured in atomic and weight%. The linear sweep voltammetry data of composite and its component nanofibers are provided. The data collected in this article is directly related to our research article “Synergistic combination of electronic and electrical properties of SnO2 and TiO2 in a single SnO2-TiO2 composite nanowire for dye-sensitized solar cells

THE IN VITRO AND EX VIVO EFFECT OF PHYLLANTHUS NIRURI METHANOL EXTRACT ON HEPATIC GLUTATHIONE S-TRANSFERASE ACTIVITY IN STZ-INDUCED DIABETIC SPRAGUE DAWLEY RATS

ABSTRACTObjective: The aim of this study was to investigate the in vitro and ex vivo (acute and sub-chronic doses) effect of Phyllanthus niruri methanol extract (PNME) on the activity of cytosolic glutathione S-transferase (GST) in streptozotocin (STZ)-induced diabetic young female Sprague Dawley (SD) rats.Methods: Young female SD rats were induced type I diabetes mellitus using STZ (60 mg/kg i.v.). The in vitro study was performed on cytosolic fraction of diabetic rat livers using PNME in concentrations of 0.01, 1 and 10 µg/ml. Meanwhile, ex vivo studies were performed on diabetic rats using PNME in doses of 500, 1000, 2000 and 5000 mg/kg p.o. for acute study (1 day) and 100, 500 and 2000 mg/kg/day p.o. for sub-chronic study (14 days). The GST activity in the cytosolic liver fraction was measured using spectrophotometric analysis.Results: The in vitro study showed that, there is no significant effect of the three concentrations of PNME versus control on GST activity in cytosolic fraction of diabetic young female SD rat livers, while for ex vivo study, there is a significant dose independent induction effect on GST enzyme activity at all doses used in acute study. Meanwhile, sub-chronic study showed significant dose-independent induction effect at doses 500 and 2000 mg/kg.Conclusion: This study suggests that Phyllanthus niruri may increase the clearance of drugs that are metabolized by GST enzyme in phase II metabolism when given concomitantly with this plant extract.Key words: Phyllanthus niruri, GST, diabetic rats, cytosolic liver fraction, phase II metabolismÂ

Role Enhancement of ZnO nanoparticles and ZnO/Ag composite for Medical Applications

ZnO nanoparticles assisted with ethanol and 2propanol as capping agent investigated the medical activities of ZnO nanoparticles and ZnO/Ag composite. ZnO nanoparticles were prepared using zinc acetate and silver nitrate as a source of zinc and silver. ZnO/Ag composite also prepared and studied the medical activities. XRD pattern indicates that the structure of ZnO was hexagonal wurtzite with average size 5 nm according to Scherre's formula. The optical band gap of ZnO nanoparticle showed very sensitive for using different capping agent as shown in UV-VIS spectra and also showed blue shift in wavelength corresponding to capping agent. Finally, the antibacterial properties of ZnO and ZnO/Ag composite against Gram-negative and Gram-positive bacteria have been demonstrated using well diffusion method and indentify their antibacterial effects compared with organic antibacterial agents. Keywords: ZnO nanoparticles, ZnO/Ag composite, antibacterial

Isolation of Lactobacillus salivarius from Children and Purification of Bacteriocin to Inhibition Cancer Cell in Vitro

Bacteria being used to make anticancer agents could provide an extra source of lead compounds for the pharmaceutical industry.  Bacterium Lactobacillus salivarius produce compounds that selectively inhibit growth of human cancer cells Lactobacillus salivarius naturally produces a compound called Bacteriocins.  Bacteriocins are bacterial proteins produced to prevent the growth of competing microorganisms in a particular biological niche and we can use it as antineoplastic. The aim of this study was to isolate bacteriocin produced by lactic acid bacteria. A preparation of bacteriocin from a strain Lactobacillus salivarius has long been shown to have antineoplastic activity against a variety of human tumor and animal tumor cell lines in vitro. A total of 60 LAB  were isolated from children stool 45 isolate showed a clear antimicrobial activity against indicator strain Streptococcus aureus and by used sodium phosphate buffer (pH8) from an 80% ammonium sulfate precipitate. The inhibition  activity was determent by well diffusion assay method technique, Bacteriocin purification processes were carried out by using ion-exchange (Trisacryl SP) and gel filtration chromatography (Sephacryl – S300). The apparent molecular mass of partially purified bacteriocin was 15. 848 kDa,  Cell Culture was maintained in RPMI 1640 medium supplemented with 10% (vol/vol) fetal calf serum,  Cytotoxicity of bacteriocin was assessed on human cell line (RD) and animal cell line (MDCK) cell viability after incubation for 48 h in medium containing 500AU/ml (1.15 mg/ml). Both cell types used in this study were sensitive to bacteriocin and the bacteriocin appeared to inhibit proliferation of tumor cell line. The animal cell line was more sensitivity than human cell line