Compact ultra-wideband planar serrated antenna with notch band ON/OFF control

The design and analysis of a compact planar UWB antenna with notch band ON/OFF control is presented. The UWB response is achieved by a microstrip fed staircase patch with an identical inverted ground plane. The notch band is switched ON or OFF by integrating a pin diode across a lambda/2 inverted `U' slot embedded in the patch     

Survival of Staphylococcus aureus and Listeria monocytogenes on vacuum-packaged beef jerky and related products stored at 21 degrees C

In the manufacture of beef jerky, a thermal lethality step is followed by drying to prevent growth of pathogenic bacterial postprocessing contaminants on the finished product. Recent guidelines from the U.S. Department of Agriculture have raised the question of the maximum water activity (a(w)) in jerky products that will inhibit growth of pathogenic bacteria. The survival of the potential postprocessing contaminants Staphylococcus aureus and Listeria monocytogenes was evaluated on 15 vacuum-packaged beef jerky and related products with a(w) values ranging from 0.47 to 0.87, just below the 0.88 limit reported for anaerobic growth of S. aureus. Small individual product pieces were inoculated on the outer surface with five strains each of S. aureus and L. monocytogenes, repackaged under vacuum, and stored at room temperature (21 degrees C) for 4 weeks. Pathogen numbers were determined before storage and after 1 and 4 weeks. None of the 15 jerky products supported growth of either pathogen. Counts of S. aureus fell by 0.2 to 1.8 log CFU after 1 week of storage and by 0.6 to 5.3 log CFU after 4 weeks of storage. Numbers of L. monocytogenes fell by 0.6 to 4.7 log CFU and by 2.3 to 5.6 log CFU after 1 and 4 weeks of storage, respectively. Although factors other than a(w) may have some effect on pathogen survival, the results of the present study clearly support drying beef jerky to an a(w) of < or = 0.87 to ensure that bacterial pathogens cannot grow on vacuum-packaged product stored at room temperature.     

Preparation and microwave characterization of PTFE/PEEK blends

Present paper describes the preparation and characterization of the PTFE / PEEK blends. The surface morphology of different volume percentage of PTFE/PEEK blends is investigated using Scanning Electron Microscopy. The permittivity and loss tangent of the blends up to 40 MHz are studied using a Precision Impedance Analyzer. The variation of permittivity with respect to temperature (τ_εr) of the composite blends are also measured in the 0–100°C temperature region using a microprocessor controlled hot and cold chamber. The microwave dielectric properties of the polymer blends are studied in the X‐band (8.2–12.4 GHz) region by waveguide cavity perturbation technique using a Vector Network Analyzer. Rectangular cavity resonator is used to measure the complex permittivity of the PTFE/PEEK blends. Different modeling approaches are used to predict the theoretical permittivity of the blends and the results are compared with the experimental values. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Residual deposits in green tea shoots and black tea after individual and combined application of propiconazole and copper oxychloride

BACKGROUND: A combination of propiconazole and copper oxychloride is commonly used for controlling blister blight disease caused by the fungus Exobasidium vexans Massee of tea in south India. Field trials were conducted in wet and dry seasons to determine the rate of dissipation of propiconazole and copper oxychloride (COC) in green tea shoots and black tea. High‐performance liquid chromatography was used to quantify propiconazole residues in these matrices. Copper was analysed using atomic absorption spectrometry. RESULTS: The rate of dissipation of propiconazole in both seasons followed first‐order kinetics. Dissipation was faster in the wet than in the dry season. Factors such as rainfall elution and leaf growth dilution lead to faster residual decline in the wet season. However, even in wet season 0.10 mg kg^?1 of propiconazole residues were noted in black tea on the seventh day after fungicide application because of its systemic nature. Thus good control over the disease could be achieved. CONCLUSION: The recommended safe harvest interval and half‐life for the combined application of propiconazole and COC from this study is 5.39 and 2.43 days respectively in green tea shoots during the dry season. Moreover, the residues of propiconazole in green tea shoots on the seventh day is the same as the maximum residue limit (MRL) proposed by the European Union (EU), indicating that combined application of the two chemicals does not leave significant residues on seventh day or thereafter. Hence, upon harvest, which is usually between 8 and 10 days after fungicide application, the green tea shoots are safer from fungicide residues and pose less risk to human consumption. Copyright © 2009 Society of Chemical Industry     

Ultra-wideband slot antenna for wireless USB dongle applications

An ultra-wideband (UWB) printed slot antenna, suitable for integration with the printed circuit board (PCB) of a wireless universal serial-bus (WUSB) dongle is presented. The design comprises a near-rectangular slot fed by a coplanar waveguide printed on a PCB of width 20 mm. The proposed design has a large bandwidth covering the 3.1? 10.6 GHz UWB band, unaffected by the ground length, and omnidirectional radiation patterns. A linear phase response throughout the band further confirms its suitability for high-speed wireless connectivity.     

Compact uniplanar antenna for WLAN applications

A compact dual-band uniplanar antenna for operation in the 2.4/5.2/5.8 GHz WLAN/HIPERLAN2 communication bands is presented. The dual-band antenna is obtained by modifying one of the lateral strips of a slot line, thereby producing two different current paths. The antenna occupies a very small area of 14.5times16.6 mm² including the ground plane on a substrate having dielectric constant 4.4 and thickness 1.6 mm at 2.2 GHz. The antenna resonates with two bands from 2.2 to 2.52 GHz and from 5 to 10 GHz with good matching, good radiation characteristics and moderate gain     

A mosaic glass reflector solar furnace

A mosaic solar furnace has been fabricated with locally available materials at a cost of about 5000 rupees. The concentrator has a power input of about 6 kW. The efficiency is upto 40% at low temperatures but drops at elevated temperatures. The reflecting surface is made of about 10,000 2.5-cm² commercial back-silvered, plane glass pieces and is approximately contoured to a paraboloid. The furnace recorded a maximum temperature of 520 °C at the focus and had a sharp temperature distribution at the focal region. Suitability and economic viability of this furnace for energy uses are discussed.     

Cytotoxic potential of the preparations from Solanum trilobatum and the effect of sobatum on tumour reduction in mice

Madin Darby canine kidney cells transformed by alkaline stress (MDCK-F cells) constitutively migrate at a rate of about 1 microm.min-1. Migration depends on the intermittent activity of a Ca2+-stimulated, 53-pS K+ channel (KCa channel) that is inhibitable by charybdotoxin. In the present study we examined whether this intermittent KCa channel activity results in a significant K+ loss across the plasma membrane. K+ efflux from MDCK-F cells should result in a transient increase of extracellular K+ ([K+]e) in the close vicinity of a migrating cell. However, due to the rapid diffusion of K+ ions into the virtually infinite extracellular space, such a transient increase in [K+]e was too small to be detected by conventional K+-selective electrodes. Therefore, we developed a "shielded ion-sensitive microelectrode" (SIM) that limited diffusion to a small compartment, formed by a shielding pipette which surrounded the tip of the K+-sensitive microelectrode. The SIM improved the signal to noise ratio by a factor of at least three, thus transient increases of [K+]e in the vicinity of MDCK-F cells became detectable. They occurred at a rate of 1.3 min-1. The cell releases 40 fmol K+ during each burst of intermittent KCa channel activity, which corresponds to about 15% of the total cellular K+ content. Since transmembrane K+ loss must be accompanied by anion loss and therefore leads to a decrease of cell volume, these findings support the hypothesis that intermittent volume changes are a prerequisite for the migration of MDCK-F cells.     

Phish Block: A Blockchain Framework for Phish Detection in Cloud

The data in the cloud is protected by various mechanisms to ensure security aspects and user’s privacy. But, deceptive attacks like phishing might obtain the user’s data and use it for malicious purposes. In Spite of much technological advancement, phishing acts as the first step in a series of attacks. With technological advancements, availability and access to the phishing kits has improved drastically, thus making it an ideal tool for the hackers to execute the attacks. The phishing cases indicate use of foreign characters to disguise the original Uniform Resource Locator (URL), typosquatting the popular domain names, using reserved characters for re directions and multi-chain phishing. Such phishing URLs can be stored as a part of the document and uploaded in the cloud, providing a nudge to hackers in cloud storage. The cloud servers are becoming the trusted tool for executing these attacks. The prevailing software for blacklisting phishing URLs lacks the security for multi-level phishing and expects security from the client’s end (browser). At the same time, the avalanche effect and immutability of block-chain proves to be a strong source of security. Considering these trends in technology, a block-chain based filtering implementation for preserving the integrity of user data stored in the cloud is proposed. The proposed Phish Block detects the homographic phishing URLs with accuracy of 91% which assures the security in cloud storage.