Manipulability Based Hierarchical Control of Perturbed Walking

International Journal of Control, Automation and Systems - In this paper, a novel manipulability based three-level hierarchical approach is suggested for control of perturbed bipedal walking. An...     

Value stream mapping approach and analytical network process to identify and prioritize production system’s Mudas (case study: natural fibre clothing manufacturing company)

The current research has been done to identify and prioritize the Mudas of the production line of a natural fibre clothing manufacturing company; in this way, value stream mapping has been used to identify the Mudas, then analytical hierarchy method has been used to screen the Mudas. In the first step, necessary information to design value stream of production process has been obtained by observation, measurement and interview; afterward, according to the obtained information and by forming a focus group, Mudas in the production line have been identified and prioritized according to seven categories of Mudas. In order to prioritizing the Mudas by the usage of analytical hierarchy method, the Super Decision software has been applied. Then, according to the obtained priorities, suggested map of the future value system has been drawn and some suggestions have been presented to eliminate Mudas and move towards the lean manufacturing.     

Surface and structure characteristics of commercial K-Feldspar powders: Effects of temperature and leaching media

This study presents morphological and structural variations of K-Feldspar mineral after acid treatment. Both organic and inorganic acids such as C₂H₂O₄, HCl, HNO₃ and H₂SO₄ were employed for this purpose. Another aim of this study was to find an optimum experimental condition for iron (Fe) removal with a minimum damage on the structure of K-Feldspar in which high whiteness index is obtained. The effect of different parameters such as concentration, pH and temperature on the final structure of this mineral was investigated. To find out the chemical composition of powder, XRF was utilized. FTIR, XRD and SEM were employed to study the structure of mineral. Spectrophotometry was chosen to analyze whiteness index of powder after acid treatment. It was found that O—Al—O bond at 647 cm^-1 for H₂SO₄ and HNO₃ treated sample disappeared. However, HCl and C₂H₂O₄ were ineffective at this band. In addition, the results revealed an increase in K-Feldspar content, a decrease in Fe content, an increase in whiteness index and no significant structural change for C₂H₂O₄ leached sample. Whiteness index of 91% was obtained for C₂H₂O₄ leached sample with the pH of 2.5 to 3 at temperature of 50℃ and during 1 h.     

Fuzzy kernel K-medoids clustering algorithm for uncertain data objects

Pattern Analysis and Applications - Most data mining algorithms are designed for traditional type of data objects which are referred to as certain data objects. Certain data objects contain no...     

Polymer adhesion in heat‐treated nonwovens

Polymer adhesion and sintering in compound nonwovens was studied. Nonwovens containing a mixture of binding bi‐component (BICO) fibers embedded in a fibrous matrix were heated to melt the outer shell of BICO fibers and interlock the matrix to create stiff load‐bearing surfaces. It was found that stiffness depends on heat‐treatment regimes. In low‐temperature regimes, BICO fibers melt, but do not fully flow and encase the surrounding filler matrix. At sufficiently high temperatures, the shells of BICO fibers melt and flow which results in encasing the neighboring filler fibers. This results in an abrupt increase in the nonwoven stiffness which is independent of heat‐treatment temperature. At significantly high temperatures, the filler matrix fibers sinter to each other leading to a further increase in stiffness. The experiments were conducted with co‐polymers frequently used in the shells of BICO to demonstrate the interlocking mechanism characteristic of these compound nonwovens. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46165.     

Zein nanoparticle‐embedded electrospun PVA nanofibers as wound dressing for topical delivery of anti‐inflammatory diclofenac

Bioactive wound dressings from poly(vinyl alcohol) (PVA) and zein nanoparticles (NPs) loaded with diclofenac (DLF) were prepared successfully by the single jet electrospinning method. DLF‐loaded zein NPs with an average diameter of ～228 nm were prepared using anti‐solvent precipitation method. The formulation of zein:DLF 1:1 exhibited optimum encapsulation efficiency of 47.80%. The NPs were characterized by dynamic light scattering, zeta‐potential measurement, and differential scanning calorimetry. In vitro, drug release profiles of the DLF‐loaded zein NPs, and PVA–zein NPs were also studied within 120 h and showed the release efficiency of nearly 80% from zein NPs. A more controlled release of DLF was achieved by embedding the zein NPs in the PVA nanofibers. Fourier transform infrared spectroscopy was used to analyze possible interactions between different components of the fabricated dressings. The mechanical properties of the developed dressings were also evaluated using uniaxial tensile testing. Young's modulus (E) of the dressings decreased after inclusion of zein NPs within the PVA nanofibers. Moreover, fibroblast culturing experiments proved that the composite dressings supported better cell attachment and proliferation compared to PVA nanofibers, by exhibiting moderate hydrophilicity. The results suggested that the electrospun composite dressing of PVA nanofibers and zein NPs is a promising topical drug‐delivery system and have a great potential for wound healing application. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46643.     

A New Method Modifying Single Miller Feedforward Frequency Compensation to Drive Large Capacitive Loads: Putting an Attenuator in the Path

A new method to compensate three-stage amplifier to drive large capacitive loads is proposed in this paper. Gain Bandwidth Product is increased due to use an attenuator in the path of miller compensation capacitor. Analysis demonstrates that the gain bandwidth product will be improved significantly without using large compensation capacitor. Using a feedforward path is deployed to control a left half plane zero which is able to cancel out first non-dominant pole. A three stage amplifier is simulated in a 0.18 μm CMOS technology. The purpose of the design is to compensate three-stage amplifier loading 1000 pF capacitive load. The simulated amplifier with a 1000 pF capacitive load is performed in 3.3 MHz gain bandwidth product, and phase margin of 50. The compensation capacitor is reduced extremely compared to conventional nested miller compensation methods. Since transconductance of each stage is not distinct, and it is close to one another; as a result, this method is suitable low power design methodology.     

Improved Message Forwarding for Multi-Hop HaRTES Real-Time Ethernet Networks

Nowadays, switched Ethernet networks are used in complex systems that encompass tens to hundreds of nodes and thousands of signals. Such scenarios require multi-switch architectures where communications frequently occur in multiple hops. In this paper we investigate techniques to allow efficient multi-hop communication using HaRTES switches. These are modified Ethernet switches that provide real-time traffic scheduling, dynamic bandwidth management and temporal isolation between real-time and non-real-time traffic. This paper addresses the problem of forwarding traffic in HaRTES networks. Two methods have been recently proposed, namely Distributed Global Scheduling (DGS) that buffers traffic between switches, and Reduced Buffering Scheme (RBS), that uses immediate forwarding. In this paper, we discuss the design and implementation of RBS within HaRTES and we carry out an experimental validation with a prototype implementation. Then, we carry out a comparison between RBS and DGS using worst-case response time analysis and simulation. The comparison clearly establishes the superiority of RBS concerning end-to-end response times. In fact, with sample message sets, we achieved reductions in end-to-end delay that were as high as 80 %.     

Catalytic performance of Samaria-promoted Ni and Co/SBA-15 catalysts for dry reforming of methane

Methane reforming with CO₂ over Samaria-promoted Ni and Co/SBA-15 was comparatively investigated. The Co, Ni (10%wt) and Sm (0.5, 1 and 1.5%wt) ions were introduced by two-solvent impregnation method. The Ni and Co catalysts with/without promoter, were examined by N2 adsorption-desorption, x-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), temperature programmed reduction (TPR) and thermogravimetric analysis (TGA) methods, and then evaluated in CO₂ reforming of methane. The XRD and TEM results indicated that Ni and Co/SBA-15 promoted by 1%wt of Samaria, had the smallest NiO and Co₃O₄ particles size and the highest dispersion; as a result, they would rather studying dry reforming of methane test. Catalytic results indicated that Samaria promoted Ni/SBA-15 had the highest conversion (CH₄ conversion～58% at 700 °C), while a remarkable decrease of catalytic activity was observed over Samaria-promoted Co/SBA-15 (CH₄ conversion～25% at 700 °C). The positive effect of Samaria on Ni/SBA-15 catalyst activity is probably due to smaller NiO particles, higher NiO dispersion and lower trend to carbon deposition. On the contrary, the negative effect of Samaria on Co/SBA-15 catalyst activity is maybe due to Co oxidation to inactive phase and sintering of Co particles in high temperatures.