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ABSTRACTIn this paper, region reaching controller is designed for fully actuated ocean surface vessels to reach a desired target region instead of a point. There are not the requirements for both the pre-specified trajectory outside the desired region and the desired pinpoint position inside the desired region. The controller design is based on the potential energy function, backstepping recursive design methodology, and the Lyapnov stability analysis theory. If the target region is specified arbitrarily small, the target region reduces to a point, and hence the region reaching control can be a generalisation of the setpoint control. Simulation results are presented to illustrate the performance of the proposed controller.

The Raton Basin had the highest number of earthquakes in Colorado and New Mexico from 2008 to 2010. The rate of both wastewater injection and earthquakes in the basin increased dramatically starting in 1999 and 2001, respectively. We compare seismicity (ML0.0–4.3) in the Raton Basin from 2008 to 2010 with the location of modeled pore pressure increases, estimated from cumulative wastewater injection volume beginning at the onset of well injection to present for all 28 injection wells in the basin. We find that modeled pore pressures in the New Mexico portion of the basin (above 0.08 MPa) reached that necessary to induce seismicity (0.01–0.1 MPa). We simulate a fault plane, 20 km long, inferred from seismicity in Vermejo Park (1355 of 1881 total earthquakes), in our model. We find that the relatively permeable fault allows pressures to migrate deeper into the basin at the onset of our study in 2008, providing an explanation for the observed seismicity in the basement. The Tercio lineament of earthquakes is similar to Vermejo Park fault in strike, but has fewer earthquakes (129) and is shorter in length (9 km). Seismicity in Vermejo Park occurs continuously, but earthquakes occur episodically in the remainder of the basin. The number of earthquakes we observe in seven seismic clusters increases as the cumulative injected volume from wells within 5 km increases. The modeled pore pressures, earthquake locations, and relationship between cumulative volume and number of earthquakes indicate that seismicity in the Raton Basin is likely induced. We infer a 20 km long Vermejo Park fault from seismicity that shows pore pressure changes of 0.08 MPa by 2008Pore pressure modeling shows changes up to 0.50 MPa, despite an underpressured disposal interval not in direct contact with the basementThe number of earthquakes and cumulative volume of wastewater injected are correlated for wells within 5, 10, and 15 km of seismicity

The self-incompatibility (SI) gene that is specifically expressed in pistils encodes the SI-associated ribonuclease (S-RNase), functioning as the female-specificity determinant of a gametophytic SI system. Despite extensive surveys in Malus domestica, the S-alleles have not been fully investigated for Malus sieversii, the primary wild ancestor of the domesticated apple. Here we screened the M. sieversii S-alleles via PCR amplification and sequencing, and identified 14 distinct alleles in this species. By contrast, nearly 40 are present in its close wild relative, Malus sylvestris. We further sequenced 8 nuclear genes to provide a neutral reference, and investigated the evolution of S-alleles via genealogical and population genetic analyses. Both shared ancestral polymorphism and an excess of non-synonymous substitution were detected in the S-RNases of the tribe Maleae in Rosaceae, indicating the action of long-term balancing selection. Approximate Bayesian Computations based on the reference neutral loci revealed a severe bottleneck in four of the six studied M. sieversii populations, suggesting that the low number of S-alleles found in this species is mainly the result of diversity loss due to a drastic population contraction. Such a bottleneck may lead to ambiguous footprints of ongoing balancing selection detected at the S-locus. This study not only elucidates the constituents and number of S-alleles in M. sieversii but also illustrates the potential utility of S-allele number shifts in demographic inference for self-incompatible plant species.

Circular RNAs (circRNAs) represent a class of non-coding RNAs that are widely expressed in mammals. However, it is largely unknown about the function of human circRNAs and the roles of circRNAs in human oral squamous cell carcinomas (OSCC). Here we performed a comprehensive study of circRNAs in human OSCC using circRNA and mRNA microarrays, and identified many circRNAs that are differentially expressed between OSCC tissue and paired non-cancerous matched tissue. We further found a circRNA termed circRNA_100290 that served as a critical regulator in OSCC development. We discovered that circRNA_100290 was upregulated and co-expressed with CDK6 in OSCC tissue. Knockdown of circRNA_100290 decreased expression of CDK6 and inhibited proliferation of OSCC cell lines in vitro and in vivo. Via luciferase reporter assays, circRNA_100290 was observed to directly bind to miR-29 family members. Further EGFP/RFP reporter assays showed that CDK6 was the direct target of miR-29b. Taken together, we conclude that circRNA_100290 may function as a competing endogenous RNA to regulate CDK6 expression through sponging up miR-29b family members. Taken together, it indicates that circRNAs may exert regulatory functions in OSCC and may be a potential target for OSCC therapy.

This study aimed to describe the burden of community-acquired acute kidney injury (AKI) in China based on a nationwide survey about AKI.

Ionospheric anomalies before earthquakes during geomagnetic quiet conditions have been extensively discussed due to the importance of earthquake prediction. However, because of the high variability of ionosphere, a real caution should be adopted before attributing the observations to seismo‐ionospheric precursors. In an investigation of contradictory results in ionospheric variation before the 2013 Lushan earthquake, we examine the ionospheric variation versus solar activity. In order to assess the influence of solar activity of 27 day periodicity on ionospheric variation, a quadratic regression model is developed by using the data of F2layer critical frequency (foF2) in April of 2008–2014. Using the model, ionospheric variation before the 2013 Lushan earthquake is analyzed. The results show that foF2was strongly correlated with solar activity index, F10.7, and had a low correlation with the remaining by eliminating the contribution of solar radiation, which indicates that the gradual reduction in foF2before the earthquake was contributed to the variation of solar radiation rather than the forthcoming earthquake. Reduction in foF2before the 2013 Lushan earthquake was observed under a geomagnetic quiet conditionSynchronous variation in foF2and F10.7before the earthquake was obtainedThe reduction in foF2was related to solar activity

In order to improve the corrosion resistance of Al2O3-SiC-C castables, super-fine TiO2(SFT) powder was added directly to the castable with the aim of synthesizing TiC/TiN through in situ reactions. Thermodynamic calculations carried out by FactSage suggested that it was possible to synthesize TiC/TiN through in situ reactions. Analysis performed by X-ray diffraction (XRD) and a scanning electronic microscope equipped with an energy diffraction spectrum analyzer (SEM-EDS) indicated that TiC/TiN was synthesized in the Al2O3-SiC-C castable. The corrosion resistance of Al2O3-SiC-C castables with and without 2 mass-% SFT was compared after a static crucible corrosion test with the assistance of SEM-EDS and XRD. It was clear that the corrosion resistance of Al2O3-SiC-C castables with added SFT was much better then that without added SFT. This might be associated with the location of the in situ-formed TiC/TiN solid particles in the liquid slag, which would prevent the penetration of molten slag into the structure through their effect on the viscosity increment of liquid slag.

Rational multiple-field coupling, component control, and microarchitectures design for utilization of multiform driving forces as well as benefiting charge-carrier separation and migration is considered to be an outstanding approach to improve water splitting efficiency for alleviating increasing environmental problems. Herein, a novel piezo-photoelectric catalyst, coaxial TiO2-BaTiO3-CuInS2heterostructures, was designed for efficient hydrogen production, synergistically driven by mechanical force, electricity, and light. The vertical growth of TiO2nanorods guarantees sufficient generation of photoinduced charges and their fast migration. Electric field generated by the piezoelectric BaTiO3shell under a mechanical driving force will promote the separation and transfer of photogenerated charge carriers, thereby minimizing the probability of charge recombination. The further incorporation of the outermost layer of CuInS2is beneficial to broaden light harvesting. Of particular importance is the cascade band arrangement of the three different functional components, which greatly enhances the transfer of photo- and piezoelectrically induced charges. With the synergy of enhanced light harvesting, energy band engineering, and nanostructure interfacial design, the fabricated TiO2-BaTiO3-CuInS2photoelectrode has achieved significant enhancement of piezo-photoelectric hydrogen evolution efficiency and could be expanded for pollutant decomposition. This simple yet general strategy provides valuable guidance for cooperatively capitalizing on piezoelectricity to engineer high-performing energy conversion and environmental protection.

Monoclonal antibodies that disrupt CD40–CD40 ligand (CD40L) interactions are likely to have use in human transplantation. However, the extent of the immunosuppressive effects of CD40–CD40L blockade in humans is unknown. Hyper‐IgM syndrome (HIGM) is a rare primary immunodeficiency syndrome characterized by defects in the CD40–CD40L pathway, severe immune deficiency (IgG), and high or normal IgM levels. However, the effects of CD40L deficiency on T‐ and natural killer (NK)‐cell function is not established. Here, we present a patient with HIGM syndrome who underwent liver transplantation for hepatitis C virus infection. Posttransplantation, NK‐cell antibody‐dependent cytokine release (γ‐interferon) to alloantigens and T cell responses to viral antigens and mitogens were assessed and showed normal CD4+, CD8+, and NK‐cell responses. We also examined antibody‐dependent cellular cytotoxicity against a CD40+and HLA‐expressing cell line. These experiments confirmed that the patient's NK cells were equivalent to those of normal subjects in mediating antibody‐dependent cellular cytotoxicity despite the absence of CD40–CD40L interactions. Mitogenic stimulation of the patient's peripheral blood mononuclear cells showed no expression of CD40L on T and NK cells compared with increased expression in normal subjects. Taken together, these data suggest that absence of CD40L expression is responsible for aberrant B cell immunity but had little impact on NK‐ and T cell immune responses in vitro. In this case report, immunologic analyses propose that the genetic absence of CD40 ligand expression alone in a hyper IgM syndrome patient may not be sufficient to obliterate NK cell and memory T cell immune responses after liver transplantation and may still pose a risk for transplant rejection.

In order to evaluate the movement performance of a human hip joint, a novel parallel manipulator called 3SPS+1PS bionic parallel test platform is proposed in this article. SPS denotes the spherical-prismatic-spherical leg, and PS the prismatic-spherical leg where only the prismatic joint is actuated and hence underlined. For the 3SPS+1PS bionic parallel test platform with four degrees of freedom including three rotations and one translation, the formulae for solving the inverse kinematics equations are derived based on the quaternion method. Unit quaternion is used to represent the position and orientation of a moving platform, and singularities caused by Euler angles are avoided. Combining the topological structure characteristics of the parallel manipulator, the orientation workspace of the moving platform at a given translation position is constructed. Moreover, the procedures to solve and evaluate the orientation workspace of the parallel manipulator are obtained. In order to ensure dexterity and obtain more workspace, the condition index is studied by the condition number and singular values analysis of the dimensionally homogeneous Jacobi matrix. The parallel manipulator has three rotations about the Z-axis, the Y-axis, and the X-axis applied to represent three rotation motions (flexion/extension (FE), abduction/adduction (AA), and internal/external (IE) rotation motion) of a human hip joint, respectively. The numerical results illustrate that the 3SPS + 1PS bionic parallel test platform generates ±25° to ±108° in FE, −20° to 20° in AA, and −21° to 21° in IE rotation where the maximum permissible condition numbers of Jacobi matrix are set within the range 15–20 and the parallel manipulator can provide full-scale friction motion for hip joint simulator. In the dexterous orientation workspace, the slide track on the friction counterface of hip joint prostheses can be varied consistently. By verifying the lengths of the SPS-type active legs, the parallel manipulator can provide cross-path multidirectional slide motion for hip joint prostheses. The three-dimensional model and kinematics simulation of the manipulator are established and analysed. The simulation results prove that the 3SPS + 1PS bionic parallel test platform can accurately represent human hip joint motion and provide more reliable experimental data for hip joint prostheses in clinical application. The research builds the theoretical basis for its bionic motion simulation in practical application.

Hemiarthroplasty is an attractive alternative to total joint replacement for the young active patient, when only one side of the synovial joint is damaged. In the development of a hemiarthroplasty prosthesis, a comprehensive understanding of the tribology of both the natural joint and the hemireplaced joint is necessary. The objectives of this study were to investigate the tribological response of polyurethane (PU) as a potential hemiarthroplasty material. Bovine medial compartmental knees were tested in a Prosim pendulum friction simulator, which applied physiologically relevant loading and motion. The healthy medial compartment was investigated as a negative control; a stainless steel hemiarthroplasty was investigated as a positive control; and three PU hemiarthroplasty plates of different moduli (1.4 MPa, 6.5 MPa, and 22 MPa) were also investigated. Using the lower-modulus PU caused reduced levels of contact stress and friction shear stress, which resulted in reduced levels of opposing cartilage wear. The two PU bearings with the lowest moduli demonstrated a similar tribological performance to the negative control. The higher-modulus PU (22 MPa) did demonstrate higher levels of friction shear stress, and wear resulted on the opposing cartilage, although not as severe as the wear from the stainless steel group. This study supports the use of compliant PU designs in future tribological experiments and hemiarthroplasty design applications.

Nitrogen ion implantation and carburization technology were chosen to modify the surface properties of titanium alloys. The surface components and element concentration distribution profile of the modified titanium alloy were characterized with X-ray photoelectron spectroscopy (XPS). The surface hardness and contact angle of the modified titanium alloys were measured to analyse the improvement of the mechanical properties and wettability. Friction and wear tests were performed between the modified titanium alloy plate against a ZrO2ball on a universal multi-functional tester. Then the tribological behaviours of the modified titanium alloys were investigated by means of scanning electron microscopy and a laser granularity ana-lyser. The XPS analysis results indicated that titanium nitride and titanium carbide were formed on the titanium alloy surface. In addition, the surface hardness of nitrogen-ion-implanted titanium increased from 335±7.4 HV (n=6) to 357±9.8 HV (n=6), whereas the surface hardness of carburized titanium increased to 750±25.3 HV (n=6). The contact angles of nitrogen-ion-implanted and carburized titanium alloys were decreased from 83 to 80 and 71.5°, respectively, indicating an improvement of surface wettability. In addition, the wear results indicated that both nitrogen ion implantation and carburization greatly improved the wear resistance of the titanium alloys and decreased the size of the wear debris. Finally, an attempt was made to explain the wear mechanisms of the modified titanium alloys.

Violence towards professionals within the emergency department (ED) occurs at a concerning rate. We hypothesized that increased violence may be associated with the number of patients on mental health holds (MHHs) boarding in the ED.

In this note, we investigate the controllability of linear hybrid systems via bumpless transfer input and constrained switching. By bump. less transfer input, we mean that the control input signals are as close as possible at switching times. By constrained switching, we mean that the switching index sequence is cyclic and the switching time sequence is possibly with pre-assigned duration intervals. While the problem is well motivated in several practical situations, it is also theoretically interesting. A complete criterion for controllability is presented, and a computational procedure is developed for finding a switching signal and a control input to achieve the controllability. [ABSTRACT FROM AUTHOR]

Extracellular matrix (ECM) proteins play an essential role during biomineralization in bone and engineered tissues. In a previous study [1], we showed that calcite preferentially nucleated on pure elastin fibers. However, the actual cellular ECM fibers are composed of a combination of proteins, primarily collagen, fibronectin and some elastin. Here we follow the calcium carbonate- and calcium phosphate- mineralization process in vitro when these ECM proteins are combined and determine the differences between these proteins in the biomineralization process. The surface morphology and mechanical properties of the protein fibers during the early stages were probed by atomic force microscopy (AFM) and shear modulation force microscopy (SMFM). The nucleation of the mineral crystals on the protein matrices was investigated by scanning electron microscopy (SEM). Preliminary data showed that the moduli of all protein fibers increased at the early stages, with collagen having the largest increase in supersaturated calcium bicarbonate solution. In metastable calcium phosphate solutions the modulus of the mixed elastin-fibronectin fibres increased to a greater extent than the moduli of the fibers composed of the single proteins. Longer exposure in the mineral solutions led to the formation of crystals templated along the self-assembled fiber structures.

Decreased serotonergic facilitation of upper-airway motor neurons during sleep has been postulated as an important mechanism rendering the upper airway vulnerable to obstruction in patients with obstructive sleep apnea syndrome (OSA). Although serotonin reuptake inhibitors have been shown to produce modest reductions in the apnea-hypopnea index (AHI) during non-rapid eye movement (NREM) sleep, they have not been proven to be generally effective as treatments for OSA. Conversely, antagonists of type 3 (5-HT3) serotonin receptors effectively have been shown to reduce the frequency of central apneas during rapid eye movement (REM) sleep in a rodent model of sleep-related breathing disorder. We sought to determine whether mirtazapine, a mixed 5-HT2/5-HT3 antagonist that also promotes serotonin release in the brain would effectively reduce AHI during both NREM and REM sleep in patients with OSA.

Real-time 3-dimensional echocardiography is increasingly used in clinical cardiology. Studies have been shown that this technique can be accurately used to assess both cardiac mass and chamber volumes. We review the work showing that real-time 3-dimensional Doppler echocardiography can be used to accurately calculate intracardiac flow volumes that can potentially be used to assess cardiac function, intracardiac shunt, and valve regurgitation.

Parameter setting is a critical step in the Hopfield networks solution of the traveling salesman problem (TSP), which is often prone to extraneous solutions. This paper presents some stability criteria that ensure the convergence of valid solutions and suppression of infeasible solutions. Our theory is based on an enhanced parametric formulation that maps TSP onto a continuouse-time Hopfield network (CHN), which is more advantageous than the Hopfield-Tank (H-T) formulation. A set of analytical conditions for optimal parameter settings of the CHN is then derived, and the resulting performance is validated by simulations. [ABSTRACT FROM AUTHOR]

Objective: We sought to assess the feasibility, accuracy, and reproducibility of a rapid full volume acquisition strategy using real-time (RT) 3-dimensional (3D) echocardiography (3DE) for measurement of left ventricular (LV) volumes, mass, stroke volume (SV), and ejection fraction (EF) in children. Methods: A total of 19 healthy children (mean 10.6 +/- 2.8 years, 11 male and 9 female) were prospectively enrolled in this study. RT 3DE was performed using an ultrasound system to acquire full volume 3D dataset from the apical window with electrocardiographic triggering in 8 s/dataset. The images were processed offline using software. The LV endocardial and epicardial borders were traced manually to derive LV end-systolic volume, end-diastolic volume, mass, SV, and EF. Magnetic resonance imaging (MRI) studies were performed on a 1.5-T scanner using a breath hold 2-dimensional cine-FIESTA (fast imaging employing steady-state acquisition) sequence. Results: All RT 3DE and MRI data were acquired successfully for analysis. Measurements of LV end-systolic volume, end-diastolic volume, mass, SV, and EF by RT 3DE correlated well by Pearson regression (r = 0.86-0.97, P < .001) and agreed well by Bland-Altman analysis with MRI. The interobserver and intraobserver variability of RT 3DE measurements were less than 5%. Conclusions: This prospective study demonstrated that RT 3DE measurements of LV end-systolic volume, end-diastolic volume, mass, SV, and EF in children using rapid full volume acquisition strategy are feasible, accurate, and reproducible and are comparable with MRI measurements.

In this paper, a neuro-fuzzy-based model is used to describe the nonlinearity of the Hammerstein process without any prior process knowledge, thus avoiding the inevitable restrictions on static nonlinear function encountered by using the polynominal approach. In doing so, a clustering algorithm is presented in order to identify the centers and widths of the neuro-fuzzy-based Hammerstein model, and an updating algorithm guaranteeing the global convergence of the weights of the model is developed based on the Lyapunov approach. As a result, the proposed method can avoid the problems of initialization and convergence of the model parameters, which are usually resorted to a trial and error procedure in the existing iterative algorithms used for the identification of Hammerstein model. Examples are used to illustrate the performance and applicability of the proposed neuro-fuzzy-based Hammerstein model.

We developed and assessed a real-time 3-dimensional (3D) digital Doppler method for measurement of flow volumes through the mitral valve in children. A total of 13 children (aged 10.46 +/- 2.5 years; 8 boys/5 girls) were enrolled. An ultrasound system (Sonos 7500, Philips, Andover, Mass) was used to acquire raw 3D velocity data for flow measurement based on Gaussian control surface theorem [flow (mL/s) = mean velocity x flow area]. Stroke volume (SV) measured by real-time 3D digital Doppler with the control surface at the mitral valve annulus or orifice was compared with the SV by phase velocity cine magnetic resonance imaging (MRI) at the ascending aorta and by left ventricular volumetric MRI measurement. The best correlation and agreement were seen at the mitral valve orifice by real-time 3D digital Doppler compared with SV by phase velocity cine MRI at the ascending aorta (r = 0.92, mean difference = -5.2 +/- 12.0 mL) and SV by left ventricular volumetric MRI measurement (r = 0.94, mean difference = -0.2 +/- 10.3 mL).

In this note, direct adaptive neural network (NN) control is studied for a class of multiple-input-multiple-output nonlinear systems based On input-output discrete-time model with unknown interconnections between subsystems. By finding an orthogonal matrix to tune the NN weights, the closed-loop system Is proven to be semiglobally uniformly ultimately bounded. The control performance of the closed-loop system is guaranteed by suitably choosing the design parameters. [ABSTRACT FROM AUTHOR]

The crystallization of poly(ethylene−vinyl acetate) and linear low-density polyethylene (LLDPE) films spun-cast from the polymer/toluene solutions with as-cast thickness from 460 to 10 nm was studied. The lamellar thickness was measured using small-angle X-ray scattering (SAXS) and found to increase from 14 to 21 nm for films thinner than 100 nm. The morphology of LLDPE measured by scanning probe microscopy (SPM) showed an edge-on lamellae for the films thicker than 30 nm and flat-on lamellae for the films thinner than 15 nm. A pseudo-“shish-kebab” tiny crystal structure was observed in between the larger lamellae. Crystallinity was confirmed using attenuated total reflectance−Fourier transformed infrared spectroscopy (ATR-FTIR) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The shear modulation force microscopy technique (SMFM) was used to measure the melting point, Tm, which was found to decrease for films thinner than 100 nm. The rate of decrease was a function of the annealing protocol, but in all cases for films approximately 20 nm thick Tm was depressed by 35−40 °C. This large value cannot be predicted from the classical Gibbs−Thomson relation, unless a change in the effective heat of fusion is assumed due to surface interactions.

This paper presents the state-of-the-art of recent investigations on the friction and wear behavior of some solid interfaces in a magnetic field or electric current environment. The tribometers used for study of electromagnetic effect on friction and wear are introduced. The experimental results of the variation of coefficient of friction and wear rate for magnetic and nonmagnetic materials and materials with varying electrical conductivities are summarized. It is found that both magnetic field and electric current have significant influence on the friction and wear of these materials. The magnetic and electrical properties of sliding couples control the friction and wear in response to applied magnetic field and electric current, respectively. Relevant mechanisms and observations are also reported in the paper.

Abstract.:  The genus Hippophae comprises 7 species and 8 subspecies according to the latest classification, and has shown enormous ecological, nutrient and medicinal values. Here we analyzed the phylogenetic relationships among 15 taxa of the genus by comparing sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA). ITS sequences in Hippophae varied in length from 651 bp to 666 bp. The aligned sequences were 690 bp in length and 269 (39.0%) were variable sites with 150 being parsimony-informative. The amount of polymorphism observed within a taxon was extremely low in most taxa except for two putative hybrid species. The aligned sequences were analyzed by maximum parsimony (MP) and neighbor-joining (NJ) methods. In the strict consensus trees of parsimony analysis, the monophyly of Hippophae was supported by 100% bootstrap value. H. tibetana was at the basal position of the genus, and the remaining taxa formed two clades with high bootstrap support. The first clade included subspecies of H.␣rhamnoides and the other one consisted of remaining species. Parsimony analysis also suggested that the species H. tibetana, H. neurocarpa and H.␣salicifolia were all distinct. Although the sequence divergence among subspecies of H. rhamnoides was also remarkably high, the molecular data supported the monophyly of H. rhamnoides when H. rhamnoides subsp. gyantsensis Rousi was excxluded. The NJ trees showed essentially the same topology. The taxonomical arrangement that divided the genus into two sections was not supported based on the ITS sequences. However, the hybrid origin of H. goniocarpa and H. litangensis proposed previously was supported by the present ITS data.

The bispectral index (BIS) and the rapidly extracted auditory evoked potentials index (A-line ARX Index or AAI) have been proposed as methods to measure the depth of sedation. A prospective study was designed to assess the performance of both these methods for measuring the depth of sedation induced by propofol or midazolam under epidural block.

In this paper; a new robust adaptive neural network controller (RANNC) is presented for a class of non-affine nonlinear systems in the presence of unknown nonlinearities and disturbances. Firstly, the existence of an ideal implicit feedback linearisation control (IFLC) is established based on implicit function theory. Using Taylor series expansion, it is shown that the control of non-affine nonlinear systems is equivalent to the control ofaffine nonlinear systems in the neighbourhood of the operating trajectory under mild conditions. Then, a robust adaptive neural network control scheme is presented for the transformed nonlinear systems by using neural networks as universal approximators for the unknown system nonlinearities. The proposed RANNC can guarantee that all the signals in the closed-loop system are bounded and the tracking error asymptotically converges to zero. Simulation studies on the control of a continuously stirred tank reactor (CSTR) system are used to show the effectiveness of the scheme.

The interfacial properties of a homopolymer (polybutadiene (PB)) and a terpolymer (brominated poly(isobutylene-co-p-methylstyrene) (BIMS)) are reported. Neutron reflectivity was used to study the interfacial structure. The results were complemented by scanning transmission X-ray microscopy and atomic force microscopy, which were used to probe the morphology of these binary blends. Our results show that the interfacial behavior of these elastomeric blends is a direct function of the BIMS chemical composition. The interfacial width decreased with increasing bromide functionality. At levels below 8mol%, the para-methylstyrene concentration had a less pronounced effect on the compatibility and interfacial characteristics. We also studied the effect of styrene butadiene random copolymers on the miscibility of the PB/BIMS blends. The results showed that styrene-butadiene rubber (SBR) was not fully miscible with BIMS and PB on an individual basis, but addition of relatively small amount of SBR enhances the compatibilization of the PB/BIMS interface. Self-consistent field (SCF) modeling was used to determine the optimum copolymer composition. The calculations are consistent with the experimental results.

With the increasing importance of thin film in various applications, there is a need for new techniques with high surface sensitivity to measure physical properties. In this paper, we report results using a recently developed technique based on atomic force microscopy, temperature-dependent shear modulation force microscopy (SMFM), to investigate the surface glass transition. We test the effects of pressure under the tip, modulation frequency, and driving amplitude, which have been the subject of some controversy. The glass transition measurements on polystyrene and poly(methyl methacrylate) with different sample geometries demonstrate that the active volume probed by this technique has lateral dimensions on the order of the tip−sample contact radius. Applications to thin film glass transition measurements and surface segregation in long-chain/short-chain blends demonstrate the general utility of this technique.

The effects of carbon black and pyrogeneous silica fillers on the interfacial properties of a homopolymer [polybutadiene, (PB)] and a terpolymer [brominated poly(isobutylene-co-p-methylstyrene), (BIMS)] are reported. Neutron reflectivity (NR) was used to study the interfacial structure. The results are complemented by scanning transmission X-ray microscopy (STXM) and lateral force microscopy (LFM), which were used to probe the morphology and surface lateral force. Small-angle neutron scattering (SANS) was used to characterize the size and surface properties of the filler aggregates in elastomers. Our results show that the interfacial behavior of PB/BIMS is more sensitive to carbon black than to silica. The interfacial broadening is significantly slowed down with addition of merely φCB = 0.01 (volume fraction) carbon black fillers. This volume level is much lower than that used in bulk rubbers (φCB ≥ 0.1). Pyrogeneous silica has a less pronounced effect on the interfacial characteristics. When both carbon and silica are incorporated into the PB layer, the effect of carbon black is offset by silica fillers.

The effects of an interacting, hydrophobic silicon surface on the interfacial properties of the immiscible polymer blend polybutadiene (PB) and brominated poly(isobutylene-co-p-methylstyrene) (BIMS) were studied using neutron reflectivity (NR). The results show that an adsorbed polymer layer, approximately 2Rg (Rg is the radius of gyration) thick, is always present at the silicon interface. This observation confirms the existence of an immobile gel-like layer which was invoked by numerous authors to explain the reduced dynamics and anomalous rheological properties of polymers at long distances from interactive substrates. The attractive substrate was also shown to affect the equilibrium interfacial width between the immiscible polymers. Narrowing of the interfacial width was observed only when the layer adjacent to the silicon substrate was less than 3Rg thick, indicating that only chains in direct contact with the interface were affected.

The wetting behavior of deuterated poly(ethyl acrylate) (dPEA) and polystyrene (PS) homopolymers on the substrates of dPEA−PS graft copolymers with different graft chains (dPEA-g-xPS, x = 1, 3, 5, average number of graft chains) was investigated utilizing scanning force microscopy (SFM). The lateral force and adhesion force measurements of dPEA-g-xPS substrates show that the surface molecular mobility of the dPEA-g-xPS substrate with the dPEA outermost layer decreases with the number of graft chains because of their different aggregation structure. As the number of PS grafts increases, the wetting behavior of dPEA on graft copolymer substrates changes from wetting to partially wetting. The contact angle measurement at the dPEA homopolymer/dPEA-g-xPS substrate interface indicates that the substrate with more PS grafts has a higher interfacial tension with the dPEA homopolymer. The wetting behavior of PS homopolymer on the dPEA-g-xPS substrates depends on the viscosity of the substrate, which is expected to be lower than that of the PS homopolymer. The dewetting velocities of the PS homopolymer increase with the increase of PS grafts in the dPEA-g-xPS graft copolymers.