A compact uniplanar ACS fed multi band low cost printed antenna for modern 2.4/3.5/5 GHz applications

Microsystem Technologies - A uniplanar compact triple operating band asymmetric coplanar strip (ACS) fed printed antenna loaded with multiple L-shaped branches and the asymmetric rectangular ground...     

Analysis of Frequency,Intensity, and Interference of Discomfort in Computerized Numeric Control Machine Operations

The introduction of Computerized Numeric Control (CNC) technology in manufacturing industries revolutionized the production process a few decades back. There are some health and safety problems associated with these machine operations, however. The main objectives of the present work is to study the health and safety issues associated with the CNC machines with respect to control and display, specifically to determine the frequency, intensity of discomfort, and its interference in operating different CNC machines as reported by the workers operating them. The postural discomfort associated with CNC machines was studied, and the frequency, intensity of discomfort, and interference of the level of discomfort with the participants' ability to work were recorded and analyzed. The study revealed that 20.5% of the operators reported discomfort 1 or 2 times, 25.4% experienced discomfort 3 to 4 times in a week, 37.7% had discomfort daily, and 16.4% reported discomfort several times a day. Discomfort was reported in all the body parts involved (lower back, neck, upper back, shoulder, and leg), but the highest discomfort scores were associated with the shoulder and arm region. Workers reporting discomfort several times a day also reported high mean discomfort scores. The study established that the frequency and intensity of the discomfort in all body parts is related to the position of the control panel and display. © 2012 Wiley Periodicals, Inc.     

Regularized nonnegative shared subspace learning

Joint modeling of related data sources has the potential to improve various data mining tasks such as transfer learning, multitask clustering, information retrieval etc. However, diversity among various data sources might outweigh the advantages of the joint modeling, and thus may result in performance degradations. To this end, we propose a regularized shared subspace learning framework, which can exploit the mutual strengths of related data sources while being immune to the effects of the variabilities of each source. This is achieved by further imposing a mutual orthogonality constraint on the constituent subspaces which segregates the common patterns from the source specific patterns, and thus, avoids performance degradations. Our approach is rooted in nonnegative matrix factorization and extends it further to enable joint analysis of related data sources. Experiments performed using three real world data sets for both retrieval and clustering applications demonstrate the benefits of regularization and validate the effectiveness of the model. Our proposed solution provides a formal framework appropriate for jointly analyzing related data sources and therefore, it is applicable to a wider context in data mining.     

Metallurgical Studies of Austenitic Stainless Steel 304 under Warm Deep Drawing

Austenitic stainless steel 304 was deep drawn with different blank diameters under warm conditions using 20 t hydraulic press. A number of deep drawing experiments both at room temperature and at 150 ℃ were conducted to study the metallography. Also, tensile test experiments were conducted on a universal testing machine up to 700 ℃ and the broken specimens were used to study the fractography of the material using scanning electron microscopy in various regions. The microstructure changes were observed at limiting draw ratio （LDR） when the cup is drawn at different temperatures. In austenitic stainless steel, martensite formation takes place that is not only affected by temperature, hut also influenced by the rate at which the material is deformed. In austenitic stainless steel 304, dynamic strain regime appears above 300 ℃ and it decreases the formability of material due to brittle fracture as studied in its fractography. From the metallographic studies, the maximum LDR of the material is observed at 150 ℃ before dynamic strain regime. It is also observed that at 150 ℃, grains are coarse in the drawn cups at LDR.     

Ultrathin PFPE Film Systems Fabricated by Covalent Assembly: An Application to Tribology

In this study, we have employed covalent molecular assembly to fabricate robust thin film structures comprising molecular layers and have demonstrated its application in tribology. An anhydride-functionalized polymer (gantrez) was deposited over an amine-functionalized silicon surface through covalent binding and employed as an intermediate layer between derivatized silicon and perfluoropolyether (PFPE). X-ray photoelectron spectroscopy, atomic force microscopy, and ellipsometry were employed to study the interfacial chemistry, morphology, and thickness of the assembled films. The films show excellent stability and strength against sonication, which can be attributed to the covalent interlayer linkage. Such films showed wear life of >100,000 cycles in ball-on-disk sliding tests at a normal load of 0.5 N and a sliding rotation of 200 rpm at a track radius of 3.2 mm. The performance was superior compared to that of PFPE-coated self assembled monolayers used as the lubricating layer. The film systems and assembly technique can be employed as nano-lubrication in several technological applications, such as information storage devices and micro-electro-mechanical systems.     

Ion-Exchange Behavior of New and Novel Zirconium(IV)-Based Composite Cation-Exchangers

The synthesized polyaniline-Zr(IV) selenoiodate and polyaniline-Zr(IV) selenomolybdate composite ion exchangers were characterized by Fourier transform infrared spectroscopy, UV spectra, X-ray diffraction, scanning electron microscope, thermogravimetric analysis, and conductivity studies. The ion-exchange capacities, effect of eluent concentration, elution time, elution behavior, and pH on ion-exchange capacity were also studied to exploit the ion-exchange capability of the composites. The study revealed that polyaniline-Zr(IV) selenoiodate and polyaniline-Zr(IV) selenomolybdate ion exchangers are having excellent ion-exchange capacity values for K⁺ ion 1.36 and 1.44?meq?g^?1, respectively. The organic polymeric part of the composites provides mechanical and chemical stability, whereas the inorganic part supports the ion-exchange behavior and thermal stability. The increase in electrical conductivity is due to the inorganic and organic parts. A mechanism for the formation of the polyaniline-Zr(IV) selenoiodate and polyaniline-Zr(IV) selenomolybdate composite ion exchangers is discussed, which may also be applied for the preparation of other composite ion exchangers. Sorption behavior of metal ions on the composites was studied in different solvent systems. On the basis of distribution coefficient values (K_d), it has been found that the cation-exchange materials are highly selective for Pb(II)-ions. Such modified composite materials can be applied as an electrochemically switchable ion exchanger for water treatment, especially water softening.     

Periodic nano/micro-hole array silicon solar cell

In this study, we applied a metal catalyst etching method to fabricate a nano/microhole array on a Si substrate for application in solar cells. In addition, the surface of an undesigned area was etched because of the attachment of metal nanoparticles that is dissociated in a solution. The nano/microhole array exhibited low specular reflectance (<1%) without antireflection coating because of its rough surface. The solar spectrum related total reflection was approximately 9%. A fabricated solar cell with a 40-μm hole spacing exhibited an efficiency of 9.02%. Comparing to the solar cell made by polished Si, the external quantum efficiency for solar cell with 30 s etching time was increased by 16.7%.