A survey on IP‐based wireless sensor network solutions

Wireless sensor networks (WSNs) are composed of thousands of smart‐sensing nodes, which capture environment data for a sink node. Such networks present new challenges when compared with traditional computer networks, namely in terms of smart node hardware constraints and very limited energy resources. Ubiquitous computing can benefit from WSNs from the perspective that sensed data can be used instead of the user without explicit intervention, turning ubiquitous computing into a reality. Internet connectivity in WSNs is highly desirable, featuring sensing services at a global scale. Two main approaches are considered: proxy based or sensor node stack based. This second approach turns sensors into data‐producing hosts also known as ‘The Internet of Things’. For years, the TCP/IP (Transmission Control Protocol/Internet Protocol) suite was considered inappropriate for WSNs, mainly due to the inherent complexity and protocol overhead for such limited hardware. However, recent studies made connecting WSNs to the Internet possible, namely using sensor node stack based approaches, enabling integration into the future Internet. This paper surveys the current state‐of‐the‐art on the connection of WSNs to the Internet, presents related achievements, and provides insights on how to develop IP‐based communication solutions for WSNs today. Copyright © 2010 John Wiley & Sons, Ltd.     

Tannins, peptic ulcers and related mechanisms

This review of the current literature aims to study correlations between the chemical structure and gastric anti-ulcer activity of tannins. Tannins are used in medicine primarily because of their astringent properties. These properties are due to the fact that tannins react with the tissue proteins with which they come into contact. In gastric ulcers, this tannin-protein complex layer protects the stomach by promoting greater resistance to chemical and mechanical injury or irritation. Moreover, in several experimental models of gastric ulcer, tannins have been shown to present antioxidant activity, promote tissue repair, exhibit anti Helicobacter pylori effects, and they are involved in gastrointestinal tract anti-inflammatory processes. The presence of tannins explains the anti-ulcer effects of many natural products.     

Effects of 3β-Acethyl Tormentic Acid (3ATA) on ABCC Proteins Activity

Multidrug resistance (MDR) is considered the main cause of cancer chemotherapy failure and patient relapse. The active drug efflux mediated by transporter proteins of the ABC (ATP-binding cassette) family is the most investigated mechanism leading to MDR. With the aim of inhibiting this transport and circumventing MDR, a great amount of work has been dedicated to identifying pharmacological inhibitors of specific ABC transporters. We recently showed that 3β-acetyl tormentic acid (3ATA) had no effect on P-gp/ABCB1 activity. Herein, we show that 3ATA strongly inhibited the activity of MRP1/ABCC1. In the B16/F10 and Ma104 cell lines, this effect was either 20X higher or similar to that observed with MK571, respectively. Nevertheless, the low inhibitory effect of 3ATA on A549, a cell line that expresses MRP1-5, suggests that it may not inhibit other MRPs. The use of cells transfected with ABCC2, ABCC3 or ABCC4 showed that 3ATA was also able to modulate these transporters, though with an inhibition ratio lower than that observed for MRP1/ABCC1. These data point to 3ATA as a new ABCC inhibitor and call attention to its potential use as a tool to investigate the function of MRP/ABCC proteins or as a co-adjuvant in the treatment of MDR tumors.     

Mesoporous nitrogen-doped carbon-glass ceramic cathodes for solid-state lithium-oxygen batteries

The composite of nitrogen-doped carbon (N-C) blend with lithium aluminum germanium phosphate (LAGP) was studied as cathode material in a solid-state lithium-oxygen cell. Composite electrodes exhibit high electrochemical activity toward oxygen reduction. Compared to the cell capacity of N-C blend cathode, N-C/LAGP composite cathode exhibits six times higher discharge cell capacity. A significant enhancement in cell capacity is attributed to higher electrocatalytic activity and fast lithium ion conduction ability of LAGP in the cathode.     

Mechanistic approach to predict real machining time for milling free-form geometries applying high feed rate

An accurate estimate of machining time is very important for predicting delivery time, manufacturing costs, and also to help production process planning. Most commercial CAM software systems estimate the machining time in milling operations simply by dividing the entire tool path length by the programmed feed rate. This time estimate differs drastically from the real process time because the feed rate is not always constant due to machine and computer numerical controlled (CNC) limitations. This study presents a practical mechanistic method for milling time estimation when machining free-form geometries. The method considers a variable called machine response time (MRT) which characterizes the real CNC machine’s capacity to move in high feed rates in free-form geometries. MRT is a global performance feature which can be obtained for any type of CNC machine configuration by carrying out a simple test. For validating the methodology, a workpiece was used to generate NC programs for five different types of CNC machines. A practical industrial case study was also carried out to validate the method. The results indicated that MRT, and consequently, the real machining time, depends on the CNC machine’s potential: furthermore, the greater MRT, the larger the difference between predicted milling time and real milling time. The proposed method achieved an error range from 0.3% to 12% of the real machining time, whereas the CAM estimation achieved from 211% to 1244% error. The MRT-based process is also suggested as an instrument for helping in machine tool benchmarking.     

Characterization of cellular ceramics for high-temperature applications

Polymeric sponge replication technique is the most used process to obtain ceramic foams with a cellular structure for filtration applications. This technique is based on an impregnation of a polymeric sponge with ceramic slurry, removal by squeezing, followed by burning out polymer and high temperature sintering. Ceramic filters must present high permeability and strength. However, these parameters are influenced in different ways by the processing method and the consequent cellular structure. In this work the relationship between permeability and strength has been investigated for 10- and 40-ppi (pores per linear inch) Al₂O₃–ZrO₂ filter materials. Characterization included the evaluation of the permeability and strength as well as the microstructural analyses of the fracture surface.     

Synthesis and molding of niobium oxynitrides with macropores generation Reactivity and stability in cyclohexane dehydrogenation

The main objective of this work is to prepare extruded niobium oxynitrides with macropores generation from niobium oxides varying: (i) the pore size distribution, burning polymeric molecules mixed with the precursor oxide before peptization; (ii) the final temperature of nitridation; (iii) the nitridation heating rate. The samples were characterized at different preparation stages. The specific pore volume increased up to five times without any loss of the total specific area. Some of these materials were employed in the cyclohexane dehydrogenation reaction. It was observed that they are active but they are less stable than molybdenum and tungsten oxynitrides when exposed to air. This behavior may be due to a faster superficial oxidation process.     

Mathematical modeling of thin-layer drying of fermented and non-fermented sugarcane bagasse

This work reports hot-air convective drying of thin-layer fermented and non-fermented sugarcane bagasse. For this purpose, experiments were carried out in a laboratory-scale dryer assessing the effects of solid-state fermentation (SSF) on the drying kinetics of the processing material. The fermented sugarcane bagasse in SSF was obtained with the use of Kluyveromyces marxianus NRRL Y-7571. Drying experiments were carried out at 30, 35, 40 and 45 °C, at volumetric air flow rates of 2 and 3 m³ h^?1. The ability of ten different thin-layer mathematical models was evaluated towards representing the experimental drying profiles obtained. Results showed that the fermented sugarcane bagasse presents a distinct, faster drying, behavior from that verified for the non-fermented material at the same conditions of temperature and volumetric air flow rate. It is shown that the fermented sugarcane bagasse presented effective diffusion coefficient values of about 1.3 times higher than the non-fermented material. A satisfactory agreement between experimental data and model results of the thin-layer drying of fermented and non-fermented sugarcane bagasse was achieved at the evaluated experimental conditions.     

Influence of Design Parameters on Linear Induction Motor End Effect

In this paper, a factor referred to as k_f for linear induction motor end effect analysis is presented. The mathematical model takes into account the longitudinal entry end effect. The entry end effect produces considerable distortion in magnetic field distribution. It is shown how this influence is derived from the machine-developed force that is calculated through the application of the 1-D theory. The k_f factor establishes the relationship between the longitudinal end effect and machine parameters, mainly the number of magnetic poles, secondary resistivity, and frequency.     

Validation of the alkane technique to estimate diet selection of goats grazing heather–gorse vegetation communities

The effect of n‐alkane faecal recovery on the accuracy of diet composition estimates, when increasing the number of diet components, was studied. Seven dietary treatments, composed of different proportions of herbaceous (Lolium perenne and Trifolium repens) and woody species (Erica umbellata, Erica cinerea, Calluna vulgaris, Erica arborea and Ulex gallii) were offered to 28 goats housed in metabolism crates. Diet composition was estimated from alkane concentrations in diet and faeces, with and without correction for incomplete faecal recoveries, using least‐squares procedures and was compared with the known diet proportions. There were no significant differences between measured proportions of dietary components and those estimated with alkanes when applying the faecal recovery corrections. In contrast, the proportions calculated without faecal recovery correction differed significantly (p < 0.05) from the actual proportions, overestimating feeds with higher content of long‐chain n‐alkanes. The diet composition affected significantly the faecal recovery of alkanes if there were significant differences on in vivo digestibility. The n‐alkane faecal recoveries decreased as the diet digestibility increased. The results obtained show that the application of the alkane methodology for grazing animals should be preceded by calculation of the actual alkane faecal recoveries for each type of vegetation community and experimental conditions. Copyright © 2005 Society of Chemical Industry