Control of a Teleoperation System by State Convergence with Variable Time Delay

In this paper, we propose a novel control scheme for bilateral teleoperation of n degree-of-freedom (DOF) nonlinear robotic systems with time-varying communication delay. We consider that the human operator contains a constant force on the local manipulator. The local and remote manipulators are coupled using state convergence control scheme. By choosing a Lyapunov-Krasovskii functional, we show that the local-remote teleoperation system is asymptotically stable. It is also shown that, in the case of reliable communication protocols, the proposed scheme guarantees that the remote manipulator tracks the delayed trajectory of the local manipulator. The time delay of communication channel is assumed to be unknown and randomly time varying, but the upper bounds of the delay interval and the derivative of the delay are assumed to be known.

Improved high-speed de-excitation system for brushless synchronous machines tested on a 20 MVA hydro-generator

Synchronous machines with brushless excitation have the disadvantage that the field winding is not accessible for the de-excitation of the machine. This means that, despite the proper operation of the protection system, the slow de-excitation time constant may produce severe damage in the event of an internal short circuit. A high-speed de-excitation system for these machines was developed, and this study presents the continuation of a previously published study. This study presents the design by computer simulation and the results of the first commissioning of this de-excitation system in a commercial 20 MVA hydro-generator. The de-excitation is achieved by inserting resistance in the field circuit, obtaining a dynamic response similar to that achieved in machines with static excitation. In this case, a non-linear discharge resistor was used, making the dynamic response even better.

PartsList: a web-based system for dynamically ranking protein folds based on disparate attributes, including whole-genome expression and interaction information

As the number of protein folds is quite limited, a mode of analysis that will be increasingly common in the future, especially with the advent of structural genomics, is to survey and re-survey the finite parts list of folds from an expanding number of perspectives. We have developed a new resource, called PartsList, that lets one dynamically perform these comparative fold surveys. It is available on the web at http://bioinfo.mbb.yale.edu/partslist and http://www.partslist.org. The system is based on the existing fold classifications and functions as a form of companion annotation for them, providing ‘global views’ of many already completed fold surveys. The central idea in the system is that of comparison through ranking; PartsList will rank the approximately 420 folds based on more than 180 attributes. These include: (i) occurrence in a number of completely sequenced genomes (e.g. it will show the most common folds in the worm versus yeast); (ii) occurrence in the structure databank (e.g. most common folds in the PDB); (iii) both absolute and relative gene expression information (e.g. most changing folds in expression over the cell cycle); (iv) protein–protein interactions, based on experimental data in yeast and comprehensive PDB surveys (e.g. most interacting fold); (v) sensitivity to inserted transposons; (vi) the number of functions associated with the fold (e.g. most multi-functional folds); (vii) amino acid composition (e.g. most Cys-rich folds); (viii) protein motions (e.g. most mobile folds); and (ix) the level of similarity based on a comprehensive set of structural alignments (e.g. most structurally variable folds). The integration of whole-genome expression and protein–protein interaction data with structural information is a particularly novel feature of our system. We provide three ways of visualizing the rankings: a profiler emphasizing the progression of high and low ranks across many pre-selected attributes, a dynamic comparer for custom comparisons and a numerical rankings correlator. These allow one to directly compare very different attributes of a fold (e.g. expression level, genome occurrence and maximum motion) in the uniform numerical format of ranks. This uniform framework, in turn, highlights the way that the frequency of many of the attributes falls off with approximate power-law behavior (i.e. according to V–b, for attribute value V and constant exponent b), with a few folds having large values and most having small values.

Persistent confusion of total entropy and chemical system entropy in chemical thermodynamics.

The change in free energy with temperature at constant pressure of a chemical reaction is determined by the sum (dS) of changes in entropy of the system of reagents, dS(i), and the additional entropy change of the surroundings, dS(H), that results from the enthalpy change, W. A faulty identification of the total entropy change on reaction with dS(i) has been responsible for the attribution of general validity to the expressions (d deltaG/dT)p = -deltaS(i) and d(deltaG/T)/d(1/T)= deltaH, which are found in most textbooks and in innumerable papers.

The vertebrate alcohol dehydrogenase system: variable class II type form elucidates separate stages of enzymogenesis.

A mixed-class alcohol dehydrogenase has been characterized from avian liver. Its functional properties resemble the classical class I type enzyme in livers of humans and animals by exhibiting low Km and kcat values with alcohols (Km = 0.7 mM with ethanol) and low Ki values with 4-methylpyrazole (4 microM). These values are markedly different from corresponding parameters of class II and III enzymes. In contrast, the primary structure of this avian liver alcohol dehydrogenase reveals an overall relationship closer to class II and to some extent class III (69 and 65% residue identities, respectively) than to class I or the other classes of the human alcohol dehydrogenases (52-61%), the presence of an insertion (four positions in a segment close to position 120) as in class II but in no other class of the human enzymes, and the presence of several active site residues considered typical of the class II enzyme. Hence, the avian enzyme has mixed-class properties, being functionally similar to class I, yet structurally similar to class II, with which it also clusters in phylogenetic trees of characterized vertebrate alcohol dehydrogenases. Comparisons reveal that the class II enzyme is approximately 25% more variable than the "variable" class I enzyme, which itself is more variable than the "constant" class III enzyme. The overall extreme, and the unusual chromatographic behavior may explain why the class II enzyme has previously not been found outside mammals. The properties define a consistent pattern with apparently repeated generation of novel enzyme activities after separate gene duplications.

Liquid–Liquid, Vapor–Liquid, and Vapor–Liquid–Liquid Equilibrium Data for the Water–n-Butanol–Cyclohexane System at Atmospheric Pressure: Experimental Determination and Correlation

The temperature and the composition of the vapor–liquid–liquid equilibrium (VLLE) and the vapor–liquid equilibrium (VLE) of a ternary mixture of water–n-butanol–cyclohexane were measured at atmospheric pressure (101.32 kPa) in a modified dynamic recirculating still. As found in the literature, the experimental data obtained reveal a ternary azeotrope at 341.86 K with a mole fraction composition of 0.281, 0.034, and 0.685 water, n-butanol, and cyclohexane, respectively. The liquid–liquid equilibrium (LLE) compositions were measured at a constant temperature of 313.15 K and compared with data in the literature collected at other temperatures. Thermodynamic consistency of all the experimental data was demonstrated. The universal quasichemical (UNIQUAC) and the nonrandom two-liquid (NRTL) thermodynamic models were used to correlate the VLE and LLE data, while the original universal functional (UNIFAC) model was used to compare the predicted data.

Smart Sentinel: Monitoring and Prevention System in the Smart Cities

Today, faced with the constant rise of the Smart cities around the world, there is an exponential increase of the use and deployment of information technologies in the cities. The intensive use of Information Technology (IT) in these ecosystems facilitates and improves the quality of life of citizens, but in these digital communities coexist individuals whose health is affected developing or increasing diseases such as electromagnetic hypersensitivity. In this paper we present a monitoring, detection and prevention system to help this group, through which it is reported the rates of electromagnetic radiation in certain areas, based on the information that the own Smart City gives us. This work provides a perfect platform for the generation of predictive models for detection of future states of risk for humans.

Isobaric vapor–liquid–liquid–solid equilibrium of the water + NaCl + 1-butanol system at 101.3 kPa

A mixture of water + NaCl + 1-butanol at 101.3 kPa is studied in order to determine the influence of salt on its experimental vapor–liquid–liquid–solid equilibrium. A detailed analysis of the evolution with temperature of the different equilibrium regions is carried out. The study is conducted at a constant pressure of 101.3 kPa in a recirculating still that has been modified by our research group. The changes in the 1-butanol/water composition ratio in the vapor phase that are provoked by the salt are studied as a function of equilibrium region. In addition, the mutual solubility of 1-butanol and water is assessed in the liquid–liquid and solid–liquid regions.

Profitability analysis of a femtosecond laser system for cataract surgery using a fuzzy logic approach

AIM: To define the financial and management conditions required to introduce a femtosecond laser system for cataract surgery in a clinic using a fuzzy logic approach. METHODS: In the simulation performed in the current study, the costs associated to the acquisition and use of a commercially available femtosecond laser platform for cataract surgery (VICTUS, TECHNOLAS Perfect Vision GmbH, Bausch & Lomb, Munich, Germany) during a period of 5y were considered. A sensitivity analysis was performed considering such costs and the countable amortization of the system during this 5y period. Furthermore, a fuzzy logic analysis was used to obtain an estimation of the money income associated to each femtosecond laser-assisted cataract surgery (G). RESULTS: According to the sensitivity analysis, the femtosecond laser system under evaluation can be profitable if 1400 cataract surgeries are performed per year and if each surgery can be invoiced more than $500. In contrast, the fuzzy logic analysis confirmed that the patient had to pay more per surgery, between $661.8 and $667.4 per surgery, without considering the cost of the intraocular lens (IOL). CONCLUSION: A profitability of femtosecond laser systems for cataract surgery can be obtained after a detailed financial analysis, especially in those centers with large volumes of patients. The cost of the surgery for patients should be adapted to the real flow of patients with the ability of paying a reasonable range of cost.

The Emission Trading Scheme reform: will the Commission's proposal save the system? EPC Policy Brief, 29 May 2015

The European Union’s Emission Trading Scheme (ETS), proposed by the Commission in 2001, entered into force in 2005. It was the flagship instrument of an ambitious policy aiming to reduce the emission of greenhouse gasses in the EU by making emission allowances a freely tradable ‘financial commodity’. However, in recent years, the cracks in the system have begun to show as the price of these CO2 emission allowances has dropped. In this Policy Brief, Jørgen Knud Henningsen argues that the envisaged ETS reform may not be enough to address the system’s shortcomings, and that there should be a more open discussion about its potential if it is to contribute to the EU’s goal of a largely de-carbonised economy by 2050.

Planktonic foraminiferal faunas and stable isotope ratios of sediments from the Benguela Upwelling System

Two sediment cores retrieved from the continental slope in the Benguela Upwelling System, GeoB 1706 (19°33.7'S 11°10.5'E) and GeoB 1711 (23°18.9'S, 12°22.6'E), reveal striking variations in planktonic foraminiferal abundances during the last 160,000 years. These fluctuations are investigated to assess changes in the intensity and position of the upwelling centres off Namibia. Four species make up over 95% of the variation within the core, and enable the record to be divided into episodes characterized by particular planktonic foraminiferal assemblages. The fossil assemblages have meaningful ecological significance when compared to those of the modern day and the relationship to their environment. The cold-water planktonic foraminifer, Neogloboquadrina pachyderma sinistral [N. pachyderma (s)], dominates the modern-day, coastal upwelling centres, and Neogloboquadrina pachyderma dextral and Globigerina bulloides characterize the fringes of the upwelling cells. Globorotalia inflata is representative of the offshore boundary between newly upwelled waters and the transitional, reduced nutrient levels of the subtropical waters. In the fossil record, episodes of high N. pachyderma (s) abundances are interpreted as evidence of increased upwelling intensity, and the associated increase in nutrients. The N. pachyderma (s) record suggests temporal shifts in the intensity of upwelling, and corresponding trophic domains, that do not follow the typical glacial-interglacial pattern. Periods of high N. pachyderma (s) abundance describe rapid, discrete events dominating isotope stages 3 and 2. The timing of these events correlates to the temporal shifts of the Angola-Benguela Front (Jansen et al., 1997) situated to the north of the Walvis Ridge. Absence of high abundances of N. pachyderma (s) from the continental slope of the southern Cape Basin indicates that Southern Ocean surface water advection has not exerted a major influence on the Benguela Current System. The coincidence of increased upwelling intensity with the movement of the Angola-Benguela Front can be interpreted mainly by changes in strength and zonality of the trade wind system.

The Newtonian system of philosophy : adapted to the capacities of young ladies and gentlemen, and familiarized and made entertaining, by objects with which they are intimately acquainted : being the substance of six letters, read to a select company of friends /

Cf. Roscoe, S. Newbery, J348(8)

Chronic shallow seawater circulation driven by subsurface gas dynamics, at the Southern Hydrate Ridge seep system, Cascadia

Senior thesis written for Oceanography 445

Nervous and muscle system development in Phascolion strombus (Sipuncula)

Recent interpretations of developmental gene expression patterns propose that the last common metazoan ancestor was segmented, although most animal phyla show no obvious signs of segmentation. Developmental studies of non-model system trochozoan taxa may shed light on this hypothesis by assessing possible cryptic segmentation patterns. In this paper, we present the first immunocytochemical data on the ontogeny of the nervous system and the musculature in the sipunculan Phascolion strombus. Myogenesis of the first anlagen of the body wall ring muscles occurs synchronously and not subsequently from anterior to posterior as in segmented spiralian taxa (i.e. annelids). The number of ring muscles remains constant during the initial stages of body axis elongation. In the anterior-posteriorly elongated larva, newly formed ring muscles originate along the entire body axis between existing myocytes, indicating that repeated muscle bands do not form from a posterior growth zone. During neurogenesis, the Phascolion larva expresses a non-metameric, paired, ventral nerve cord that fuses in the mid-body region in the late-stage elongated larva. Contrary to other trochozoans, Phascolion lacks any larval serotonergic structures. However, two to three FMRFamide-positive cells are found in the apical organ. In addition, late larvae show commissure-like neurones interconnecting the two ventral nerve cords, while early juveniles exhibit a third, medially placed FMRFamidergic ventral nerve. Although we did not find any indications for cryptic segmentation, certain neuro-developmental traits in Phascolion resemble the conditions found in polychaetes (including echiurans) and myzostomids and support a close relationship of Sipuncula and Annelida.

Modelling tribology of slider and disk in a computer hard drive system

Issues of wear and tribology are increasingly important in computer hard drives as slider flying heights are becoming lower and disk protective coatings thinner to minimise spacing loss and allow higher areal density. Friction, stiction and wear between the slider and disk in a hard drive were studied using Accelerated Friction Test (AFT) apparatus. Contact Start Stop (CSS) and constant speed drag tests were performed using commercial rigid disks and two different air bearing slider types. Friction and stiction were captured during testing by a set of strain gauges. System parameters were varied to investigate their effect on tribology at the head/disk interface. Chosen parameters were disk spinning velocity, slider fly height, temperature, humidity and intercycle pause. The effect of different disk texturing methods was also studied. Models were proposed to explain the influence of these parameters on tribology. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were used to study head and disk topography at various test stages and to provide physical parameters to verify the models. X-ray Photoelectron Spectroscopy (XPS) was employed to identify surface composition and determine if any chemical changes had occurred as a result of testing. The parameters most likely to influence the interface were identified for both CSS and drag testing. Neural Network modelling was used to substantiate results. Topographical AFM scans of disk and slider were exported numerically to file and explored extensively. Techniques were developed which improved line and area analysis. A method for detecting surface contacts was also deduced, results supported and explained observed AFT behaviour. Finally surfaces were computer generated to simulate real disk scans, this allowed contact analysis of many types of surface to be performed. Conclusions were drawn about what disk characteristics most affected contacts and hence friction, stiction and wear.