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In a novel process, CO2 and CH4 from the off‐gases of the coke oven and blast furnace are used in homogeneous reforming of those greenhouse gases to valuable syngas, a mixture of H2 and CO. Synthetic mixtures of the off‐gases from those large apparatuses of steel industry are fed to a high‐temperature, high‐pressure flow reactor at varying temperature, pressure, residence time, and mixing ratio of coke oven gas (COG) to blast furnace gas (BFG). In this study, a maximal reduction of 78.5 % CO2 and a CH4 conversion of 95 % could be achieved at 1350 °C, 5.5 bar, and a COG/BFG ratio of 0.6. Significant carbonaceous deposits were formed but did not block the reactor tube in the operational time window allowing cyclic operation of the process. These measurements were based on prior thermodynamic analysis and kinetic predictions using an elementary‐step reaction mechanism., A new concept and proof‐of‐principle of a novel process is presented for the reduction of CO2 emissions occurring in the steel industry. The potential of using off‐gases of the coke oven and blast furnace for the dry reforming of the CH4 to valuable syngas is investigated theoretically and experimentally. A maximal reduction of 78.5 % CO2 and a CH4 conversion of 95 % was achieved at conditions relevant for the steel industry.

Low temperature steam reforming in combination with hydrogen selective membranes presents great potential of intensifying the classical industrial hydrogen production process via natural gas. This concept can lead to significant environmental and process benefits, such as reduced energy needs, milder material stability requirements and considerably simplified process layouts via e.g. avoiding the use of downstream WGS reactors. Ni and Rh based catalysts supported on La 2 O 3 -CeO 2 -ZrO 2 , already identified as active and stable at these conditions, are further investigated in the current work aiming at the elucidation of reaction kinetics. Temperature programmed experiments of methane conversion in steam reforming and decomposition modes in conjunction with isotopic investigations using CD 4 are carried out, showing that cleavage of a C H bond participates in the rate determine step, whereas steam derived intermediates do not. A thermodynamically consistent microkinetic model considering a comprehensive set of surface pathways is also developed. The model describes correctly experimental trends, predicting surface CH 3 dehydrogenation to be rate limiting. Estimated model parameters further help elucidate the different catalysts’ activities. The combined approach presented shows potential to accelerate catalyst and process design efforts for the promising low temperature steam reforming hydrogen production process.

A comprehensive knowledge of the loads applied during activities of daily living to the femur shaft is necessary to the design of direct attachments of relevant prostheses. A motion analysis system was used together with an established protocol with skin markers to estimate the three components of the forces and moments acting on ten equidistant points along the full femur shaft. Twenty healthy young volunteers were analyzed while performing three repetitions of the following tasks: level walking at three different speeds, straight-line and with sudden changes of direction to the right and to the left, stairs ascending and descending, squat, rising from a chair and sitting down. Average load patterns, after normalisation for body weight and height, were calculated over subjects for each point, about the three anatomical axes, and for each motor task. These patterns were found consistent over subjects, but different among the anatomical axes and tasks. In general, the moments were observed limitedly influenced by the progression speed, and higher for more proximal points. The moments were also higher in abd/adduction (8.1% body weight*height on average), nearly three times larger than those in flex/extension (2.6) during stair descending. The largest value over all moments was 164.8. N. m, abd/adduction in level walking at high speed. The present results should be of value also for a most suitable level for amputation in transfemoral amputation, for in-vitro mechanical tests and for finite element models of the femur.

Steam reforming of natural gas for the production of hydrogen at low operation temperature offers significant financial and environmental advantages. However, the presence of higher hydrocarbons as minor components of natural gas can significantly affect the formation of coke and thus the effectiveness of the catalyst. In this study, the effect of the presence of C2–C3 alkanes in the feedstock on the carbon accumulation during low temperature steam reforming of methane is investigated over Ni and Rh catalysts supported on lanthanum doped ceria–zirconia mixed oxide. Both catalysts showed high resistance to coke formation and especially in the case of Rh/La/CeO 2 –ZrO 2 , the carbon accumulation detected was low even after 10 h on stream in steam reforming of all mixtures of hydrocarbons tested. The presence of higher alkanes in methane increased the amount of carbon on Ni(10)CeZrLa compared to pure methane as well as the nature of the carbonaceous species. Increase in the C-number of the additive alkane had almost no influence on the total amount of carbon formed (C/H feed ratio = constant) but favored the formation of filamentous carbon.

Selective seed consumption by harvester ants may be affected by several seed attributes, amongst which seed size and environmental availability play a prominent role. In the present study, we considered the effects of seed size and seed availability on the coexistence and diet preference of two Messor species (Messor wasmanni and Messor minor). M. wasmanni colonies collected the most abundant resource in the environment, grass seeds (Poaceae), according to their availability whilst M. minor showed a nonselective process. In addition, the two ant species showed a different seed size preference, with M. wasmanni adopting a selective strategy and M. minor a generalist strategy. However, competition for foraging resources between the two ant species (assessed by null model algorithms) seems not to affect their foraging behaviour. The lack of a competitive structure within the ant assemblage suggests, in fact, that resources are not a limiting factor for species coexistence.

One of the most promising technologies for CO 2 capture is the Calcium Looping Cycle, which is based on the reversible carbonation reaction of CaO. The main challenge for CaL technology is the deterioration of CO 2 capture capacity during multicyclic operation. In this work, the triethanolamine (TEA) was used as a complexing agent in a modified sol–gel method for the preparation of sintering resistant CaO–Ca 3 Al 2 O 6 . The sorbent showed high capture capacity (0.45 g/g sorb. or 84% carbonation conversion) which was retained after 45 cycles. Parametric study of sorption was realized by varying the carbonation and calcination conditions (temperature and CO 2 concentration). Under severe conditions of calcination temperature at 950 °C in pure CO 2 flow after 100 cycles the sorbent still retained almost 40% of the initial sorption capacity corresponding to 30% carbonation conversion.

In this paper we survey the Tychono. property for discrete groups. General results and relations with amenability, with discrete potential theory (random walks), and with the theory of weights and of characters are discussed. We then present a characterization of Tychonoff property for virtually abelian groups, for polycyclic groups, and for linear groups. We also consider the case of metabelian groups, and several examples are given.

Low temperature steam reforming (400-550°C) for the production of hydrogen offers significant advantages compared to the conventional process. The milder operating conditions lead to lower operation costs and cost of construction materials. Additionally, no CO shift reactor is required due to favorable temperature for the WGS reaction. In this work, we report the catalytic performance of Ni and Rh catalysts supported on La2O3-ZrO2 and La2O3-CeO2-ZrO2 for their application in a multifuel membrane reformer operating at low temperature. The performance of the catalysts is assessed in different operating conditions in methane steam reforming (GHSV, temperature, H2O/CH4ratio) as well as in reforming of model biogas. Stability tests were conducted up to 90h on stream (1bar and 7bar) and the tendency toward carbon formation was investigated. All catalysts were active in the reforming reactions at 400-550°C and the catalysts supported on La2O3-CeO2-ZrO2 showed superiority in activity and stability probably due to the presence of ceria in the support which contributes to the reforming rate and the resistance to carbonaceous deposits. Ni(10)CeZrLa exhibited remarkably stable performance with minimum amount of carbon formed after 90h (ca. 0.05wt%). TPO and TPH analysis of the carbonaceous deposits showed that the dominating type of carbon is highly reactive and can be easily removed by oxidation or hydrogenation at 500°C. This fact makes the catalyst even more promising for the proposed low temperature process, since the catalyst can be hydrogenated by using part of the H2 production stream without further heating of the reactor. © 2015 Elsevier B.V..

The reaction rate of low-temperature steam reforming was studied over two Ni-based catalysts. Experimental tests were carried out for temperatures between 400 and 550 °C and pressures between 1 and 7 bar, using methane and simulated biogas (1:1 methane-carbon dioxide mixture) as carbonaceous feed. The results were analyzed with a simplified reaction rate expression. The parameters of such expression were optimized in order to provide a tool for the design of an industrial scale reactor using the catalysts considered. © 2016 Hydrogen Energy Publications LLC

Background:The tensor tympani muscle is the largest muscle within the middle ear. Its voluntary contraction is a very unusual event. Only a few papers have documented its audiometric effects.Objective:To report an unusual case of voluntary tensor tympani muscle contraction and describe its audiometric effects.Case report:A 27-year-old man, who presented complaining of voluntarily evoked bilateral tinnitus, was found to be able to voluntarily contract the tensor tympani muscle in both ears simultaneously. Audiograms were performed under conditions of rest and maximal contraction of the tensor tympani muscle. The most remarkable effects were conductive hearing loss at lower frequencies and an increase in middle-ear impedance.Conclusion:The importance of the tensor tympani muscle in middle-ear physiology remains unclear. It has been related to the attenuation of sounds produced during the mastication process. Voluntary control over the tensor tympani muscle is an extremely rare event. However, an understanding of the potential audiometric effects of its contraction could aid the diagnosis of hearing disorders.

The catalytic performance on steam reforming and carbonaceous deposits was examined over Ni/La/CeO2-ZrO2 and Rh/La/CeO2-ZrO2 catalysts, prepared via wet impregnation. The catalytic performance tests were conducted using mixtures of C2–C4 alkanes and CH4 as steam reforming feedstock for 4 h at the temperature range of 400–550 °C and for 10 h at 500 °C, with S/C = 3 and GHSV = 70,000 h−1. Analysis on the used catalysts was carried out via temperature-programmed oxidation (TPO). Both catalysts showed high activity towards the alkane feedstock achieving product distribution close to that predicted by thermodynamics with no significant deactivation during the experiments. TPO of the used catalysts after 10 h on stream showed increased carbon depositions compared to the pure methane reforming but still at very low levels, even though the concentration of the second alkane used was much higher than the real concentration in natural gas.

Two integral versions of input to state stability are considered: integral input-to-state stability (iISS) and integral input-to-integral-state stability (iIiSS). We present sufficient conditions that guarantee that if a controller achieves semiglobal practical iISS (respectively, iIiSS) of an ap- proximate discrete-time model of a nonlinear sampled-data system, then the same controller achieves semiglobal practical iISS (respectively, iIiSS) of the exact discrete-time model by reducing the sampling period. Recent results on numerical methods for systems with measurable disturbances can be used to generate approximate models that we consider. Results are presented for arbitrary dynamic controllers that can be discontinuous in general.

El estudio explora simbolizaciones afectivas que estructuran las relaciones de los estudiantes en la experiencia de practicas. Con el fin de detectar las principales representaciones de 213 estudiantes universitarios de Psicologia Clinica sobre su papel como pasantes, las actividades profesionales, las funciones que tienen que cumplir y la integracion entre la educacion universitaria y los contextos reales de trabajo, se aplico un cuestionario para el analisis de la dinamica y las expectativas generadas por la imaginacion de su futuro. A traves de tecnicas estadisticas multivariantes, analisis de correspondencia multiple (ACM) y analisis de conglomerados (AC), se identificaron cuatro grupos. Los resultados fueron los siguientes: falta de poder en general, desconfianza y desmotivacion hacia practicas (17.7%); afiliacion a organismos de alojamiento con el fin de obtener el aumento de la aceptacion y poder (33.8%); alto pragmatismo, orientacion a la tarea y el cumplimiento de lo que los cuerpos de alojamiento proponen (30.8%) y demanda de reconocimiento sin ninguna negociacion (17.7%). No se detecto ninguna relacion entre los clusteres y algunas variables ilustrativas relacionadas con el sexo y los indicadores de exito academico, los problemas y la participacion. Estas agrupaciones se conciben como dimensiones latentes que explican el 57.9% de la varianza total y se refieren a: la desconexion/implicacion hacia la experiencia de practicas; impotencia/omnipotencia sobre el uso de las competencias y la devaluacion/idealizacion del cuerpo de alojamiento en relacion con la formacion universitaria. Surgen dos cuestiones fundamentales: la brecha entre la formacion universitaria y las practicas, la segunda se ocupa de la discontinuidad entre las practicas y el mercado laboral. Se discuten algunas reflexiones e implicaciones para la practica.

A method is described for set-point tracking in nonlinear systems when pointwise-in-time input and/or state inequality constraints are to be enforced. It consists of adding to a primal compensated system a nonlinear device called command governor (CG) whose action is based on the current state, set-point, and prescribed constraints. The CG selects at any time the system input via a receding-horizon strategy from a virtual sequence amongst all possible command sequences by solving a constrained quadratic optimization problem. Provided that the initial state is admissible, the overall system is proved to fulfil the constraints and have desirable performance stability properties.

In this paper, we deal with the problem of stabilization of uncertain systems in the presence of input constraint. First algebraic conditions are derived for input-to-state stability of linear system with saturated linear feedback of low dimension. Then a recursive design procedure is derived for robust stabilization of block upper triangular nonlinear systems with feedforward structure.

The methane steam reforming (MSR) technology is the oldest and the most vital route to convert CH4 into H2. The conventional process usually operates in a high temperature range of 973-1173 K due to the highly endothermic nature of the reforming reaction. Necessity to increase the energy efficiency leads to the development of processes operating at low temperature and of highly active and coke resistant catalysts. An active catalyst which can provide high reforming reaction rates at low temperature (

In this paper we present new results on asymptotic consensus for continuous-time nonlinear time varying cooperative networks. We endow the well known assumption of integral connectivity proposed by Moreau with a remarkable additional feature of being frozen in state variables, making its direct verification more straightforward. Moreover, we give an estimate of the exponential rate of convergence towards the agreement manifold.

Objective To describe and analyze the main outcomes achieved in a series of patients with sporadic vestibular schwannoma (VS) larger than 40 mm in extrameatal diameter, defined as giant VS, submitted to microsurgery by the enlarged translabyrinthine approach with transapical extension. Study design Retrospective chart review. Setting Tertiary referral center. Patients A retrospective chart review was conducted on 2,133 patients who underwent surgery for VS from April 1987 to July 2009. One hundred ten cases of giant VS were elected for analysis. Main outcome measures Extent of removal, residual or recurrent disease, facial nerve integrity during surgery, long-term facial nerve function, and postoperative complications. Results Total removal was accomplished in 91.8% of cases. In 5 patients (4.5%), total removal was accomplished in 2 stages. Near-total removal was performed in 7 patients (6.3%). The facial nerve was anatomically preserved in 76.4% of cases. Intraoperative facial nerve reconstruction was performed in 8 cases. Facial nerve function after 1 year of follow-up was House-Brackmann grades I to III in 75% of cases. There were no deaths in this series. Neurovascular life-threatening complications occurred in 2 patients. Cerebrospinal fluid leak was present in 1.8% of cases. Conclusion Results indicate the enlarged translabyrinthine approach with transapical extension as an elective approach for removal of giant VS. The method permits achievement of a high rate of total removal with low incidence of complications.

The cytopathology of a Potato virus X (PVX) recombinant variant (encoding as fusion of an epitope of immunological interest with the N-terminus of the coat protein, PVX Sma P18DD) has been compared with that induced by the wild-type virus (PVX wt) in Nicotiana benthamiana plants. Both PVX wt and PVX Sma P18DD caused similar ultrastructural alterations, characterized by the presence of laminated inclusion components and bulk virus accumulations in mesophyll cells. However, some striking differences were observed not only in the morphology of these accumulations (typically ordered in PVX wt infection and disordered in PVX Sma P18DD infection) but also because the chimeric virus caused peculiar alterations in chloroplasts structure.

This paper is a collection of general results in geometric group theory, concerning, in particular, amenability and its relation with growth of groups, cohomology and weights.

Results for estimating the convergence rate of non-stationary distributed consensus algorithms are provided, on the basis of qualitative (mainly topological) as well as basic quantitative information (lower-bounds on the matrix entries). The results appear to be tight in a number of instances and are illustrated through simple as well as more sophisticated examples. The main idea is to follow propagation of information along certain spanning trees which arise in the communication graph.

New results on the structure of density functions for almost global stability analysis of nonlinear systems are discussed. In particular, it is shown how the smoothness constraint poses, under certain technical assumptions, a serious challenge in the construction of density functions which are almost everywhere expanding along the flow.

This paper provides a solution to the problem of controlling the orientation of a geostationary spacecraft, subject to actuator failures. The proposed scheme is based on a two levels Supervisory Switching Logic. It selects the most appropriate controller from a bank of candidate control laws, depending on the state of the actuators. In order to establish the working conditions of the satellite, techniques of fault detection and fault diagnosis are adopted.

A new input-output qualitative notion, closely related to passivity, is introduced for general nonlinear systems with inputs and outputs and its usefulness in proving convergence in positive feedback interconnections is investigated. This property, roughly speaking, plays for positive feedback the natural counter-part of what passivity is for negative feedback interconnections.

International audience; In this paper we deal with the problem of stabilization of uncertain systems in the presence of input constraint. First algebraic conditions are derived for input-to-state stability of linear system with saturated linear feedback of low dimension. Then a recursive design procedure is derived for robust stabilization of block upper triangular nonlinear systems with feedforward structure.

Two different adaptive controllers for systems with backlash acting on the input are discussed: one in continuous time and one in discrete time. Both schemes are based on a backlash inverse and a linear controller. The unknown plant parameters and the backlash width are estimated. The estimated parameters are used for pole placement design of the controller and for backlash compensation in the backlash inverse. Some analysis of the estimator convergence is done. Simulations of a second order plant show that both schemes give a nice behavior.

The pathogenetic mechanism underlying glucose intolerance in pancreatic cancer is still unclear. We studied the pattern of three glucose regulating hormones (C-peptide, glucagon and GH) in pancreatic cancer patients with (N = 34) and without (N = 8) hyperglycemia, and compared the findings made with those from subjects with other hyperglycemic conditions of well-known origin [type I diabetes mellitus (8 cases) and diabetes mellitus secondary to chronic pancreatitis (13 cases) or liver cirrhosis (4 cases)]. In hyperglycemic pancreatic cancer patients, C-peptide was absent in 26% of the cases, reduced in 24%, elevated in 29% and within the normal range in the remaining 21%. In normoglycemic pancreatic cancer this hormone was reduced in two cases (25%) and within the normal range in all the others. GH was within the normal range in all cases: glucagon was below the normal range in some hyperglycemic pancreatic cancer patients (41%) or within the normal range in all the remaining patients. No correlations were found between the three hormones when findings from subjects were considered all together. However, in pancreatic cancer C-peptide and glucagon presented consensual variations. C-peptide, glucagon and GH levels were not related to tumor volume; glucagon was found to be associated with liver metastases. C-peptide was correlated with serum ALT and ALP. We may conclude that hyperglycemia associated with pancreatic cancer may be caused by different mechanisms. In some cases a reduced secretion of both insulin and glucagon was observed, as occurs in chronic pancreatitis. In the majority of patients, beta cell function appears normal, and the hyperglycemic state may depend on an altered peripheral sensitivity to insulin due to the pancreatic pathology itself or to consensual liver involvement.

Systems with counter-clockwise input-output (I-O) dynamics were recently introduced in order to study the convergence of positive feedback loops (possibly to many different equilibrium states). The author shows how this notion can be used to perform bifurcation analysis and globally predict multistability of a closed-loop feedback interconnection just by using the knowledge of steady-state I-O responses of the systems. To illustrate the theory, this method is then applied to a recently published model of mitogen activated protein kinase (MAPK) cascade. Furthermore, some examples (mainly motivated by molecular biology) of systems that enjoy the property are presented and discussed.

Equilibrium hydration of p-methoxy-α-α-α-trifluoroacetophenone (MTFA) in water and anionic micelles of sodium dodecyl sulfate (SDS) has been followed by 19F NMR and UV spectrometry, and is strongly disfavored by the micelles. The effects can be separated into those due to the different transfer equilibria of the carbonyl and hydrate forms and to a decrease in water activity in the micelles. The transfer equilibria of the carbonyl and hydrate forms of MTFA between water and micelles have been followed by NMR spectrometry and an activity of water at the micellar surface of 0.6 has been determined. Attainment of hydration equilibrium in water, aqueous acetonitrile, and micelles has been followed by UV spectrometry and rate constants for forward and reverse reactions have been calculated. The overall equilibrium of the p-octyloxy derivative has been examined in aqueous acetonitrile and SDS micelles. The hydrophobic octyl group reduces the rate and equilibrium constants of hydration.