Characterisation of unbound aggregate materials considering physical and morphological properties

The objective of this paper is to evaluate the factors affecting resilient and permanent deformation behaviour of unbound granular materials, with a focus on the aggregate physical and morphological characteristics. To evaluate the behaviour of base course, repeated load triaxial testing is commonly used to establish the stress-dependent resilient modulus properties of unbound aggregate base and subbase materials. Although resilient modulus of aggregates is a critical input into mechanistic-empirical pavement design methods, the resilient modulus of unbound base material is often estimated from empirical correlations with index properties in the AASHTOWare Pavement ME design procedure for its simplicity. Since actual field stress conditions and resilient modulus stress states are generally quite different from those generated in the empirical test methods, use of an empirical correlation could lead to an unreliable prediction of resilient modulus and permanent deformation. In order to properly assess the stability of an unbound aggregate layer, it is necessary to establish a proper process to understand the factors affecting fundamental and performance-related properties of unbound granular materials. In this study, aggregate samples from four different sources were tested for resilient modulus and Poisson’s ratio measurements using the Precision Unbound Material Analyzer equipment. Morphological or shape properties of aggregate samples were also measured using an image analysis device. The results demonstrate that aggregate physical and morphological properties affect aggregate resilient and permanent deformation. Further, it is suggested that the resilient modulus of the aggregate should not be used as the sole indicator of rutting performance of aggregate base.     

Boron doped titaniumdioxide nanotube arrays: production,characterization and photocatalytic properties

In numerous studies, regularly oriented anatase titanium dioxide nanotube arrays (TNTAs), obtained through electrochemical anodization, have been employed as catalyst surfaces for photocatalytical applications. However, in many practical applications the phocatalytical activities are restricted due to their wide band gaps. This work shows that photocatalytical activity of TNTAs can be improved by a novel approach which provides boron incorporation into TiO₂ structure during anodization process without any further treatment. Anodization was performed in an aqueous solution containing hydrofluoric acid, oxalic acid and sodium fluoroborate (NaBF₄) at room temperature on titanium (Gr2) substrates. The anodized samples were annealed at 480?°C for 2 h in air in order to obtain anatase transformation and intended crystalline structure. As-prepared B-doped TNT structure was characterized by field emission scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction, atomic force microscopy and ultraviolet–visible light diffuse absorbance spectroscopy. The photocatalytic kinetics of B-doped TNTAs for the degradation of methylene blue (MB) under visible light irradiation were evaluated in details.     

Construction of an amperometric pyruvate oxidase enzyme electrode for determination of pyruvate and phosphate

In this study an amperometric biosensor based on pyruvate oxidase was developed for the determination of pyruvate and phosphate. For construction of the biosensor pyruvate oxidase was immobilized with gelatin and insolubilized in film by forming cross-linked bonds with glutaraldehyde. The film was fixed on a YSI type dissolved oxygen (DO) probe, covered with a teflon membrane which is high-sensitive for oxygen. The working principle of the biosensor depends on detection of consumed DO concentration related to pyruvate concentration which is used in enzymatic reaction catalyzed by pyruvate oxidase. The biosensor response shows a linearity with pyruvate concentration between 0.0025 and 0.05 μM and also response time of the biosensor is 3 min. In the optimization studies of the biosensor the most suitable enzyme activity was found as 2.5 U/cm² for pyruvate oxidase, and also phosphate buffer (pH 7.0; 50 mM) and 35 °C were established as providing the optimum working conditions. In the characterization studies of the biosensor some parameters such as reproducibility, substrate specificity, operational stability, determination of phosphate, and interference effects of some compounds on the pyruvate determination were investigated. Finally, the concentration of pyruvate was determined by using spectrophotometric method and the results obtained were compared to results obtained by the biosensor.     

Viscoelastic and Processing Effects on the Fiber-Matrix Interphase Strength. Part II. The Effects of Cure Temperature Time and Curing Agent Content

The effects of curing agent content, cure temperature and time on the adhesion strength between carbon fibers (treated with epoxy sizing) and a thermosetting epoxy (Epon 815) are studied using the single fiber fragmentation test procedure. Theoretical equations describing a majority of the phenomena affecting the adhesion process are also reviewed. The possibility of superposition between percent curing agent content, cure temperature and time is illustrated based on the analytical models presented. Experimental data are presented in the form of percent relative frequency histograms for the fiber fragments in a collective fashion. Such presentation of the data allows for interpretation of the skewness in the data population. Optimum curing agent, cure temperature and time values resulting in highest interfacial strength are also determined.     

Goal emulation and planning in perceptual space using learned affordances

In this paper, we show that through self-interaction and self-observation, an anthropomorphic robot equipped with a range camera can learn object affordances and use this knowledge for planning. In the first step of learning, the robot discovers commonalities in its action-effect experiences by discovering effect categories. Once the effect categories are discovered, in the second step, affordance predictors for each behavior are obtained by learning the mapping from the object features to the effect categories. After learning, the robot can make plans to achieve desired goals, emulate end states of demonstrated actions, monitor the plan execution and take corrective actions using the perceptual structures employed or discovered during learning. We argue that the learning system proposed shares crucial elements with the development of infants of 7–10 months age, who explore the environment and learn the dynamics of the objects through goal-free exploration. In addition, we discuss goal emulation and planning in relation to older infants with no symbolic inference capability and non-linguistic animals which utilize object affordances to make action plans.     

Seismic based strengthening of steel and RC telecommunication poles based on fem analysis

This study describes a numerical projection of pre- and post-retrofitted conditions of telecommunication poles subjected to seismic hazards. The absence of explicit guidelines for the rehabilitation of existing poles motivated the investigation of the effectiveness of steel jacketing for the retrofitting of self-supporting steel and reinforced concrete (RC) telecommunication poles. Effects of mast flexibility, variable damping on dynamic response, and significance of period on base shear amplification were investigated. The overall effectiveness of retrofitting against base excitation was assessed for RC and steel poles through the application of modal analyses and response spectrum approach based on a set of strong motion accelerograms recorded during the 1994 Northridge earthquake. Based on a serviceability approach, the analysis of results shows effectiveness of the steel jacketing in increasing load carrying capacity of the poles by enabling stress redistribution.     

PLOD2 Is a Prognostic Marker in Glioblastoma That Modulates the Immune Microenvironment and Tumor Progression

This study aimed to investigate the role of Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase 2 (PLOD2) in glioblastoma (GBM) pathophysiology. To this end, PLOD2 protein expression was assessed by immunohistochemistry in two independent cohorts of patients with primary GBM (n₁ = 204 and n₂ = 203, respectively). Association with the outcome was tested by Kaplan–Meier, log-rank and multivariate Cox regression analysis in patients with confirmed IDH wild-type status. The biological effects and downstream mechanisms of PLOD2 were assessed in stable PLOD2 knock-down GBM cell lines. High levels of PLOD2 significantly associated with (p₁ = 0.020; p₂ < 0.001; log-rank) and predicted (cohort 1: HR = 1.401, CI [95%] = 1.009–1.946, p₁ = 0.044; cohort 2: HR = 1.493; CI [95%] = 1.042–2.140, p₂ = 0.029; Cox regression) the poor overall survival of GBM patients. PLOD2 knock-down inhibited tumor proliferation, invasion and anchorage-independent growth. MT1-MMP, CD44, CD99, Catenin D1 and MMP2 were downstream of PLOD2 in GBM cells. GBM cells produced soluble factors via PLOD2, which subsequently induced neutrophils to acquire a pro-tumor phenotype characterized by prolonged survival and the release of MMP9. Importantly, GBM patients with synchronous high levels of PLOD2 and neutrophil infiltration had significantly worse overall survival (p < 0.001; log-rank) compared to the other groups of GBM patients. These findings indicate that PLOD2 promotes GBM progression and might be a useful therapeutic target in this type of cancer.     

The Examination of Afyonkarahisar’s Geothermal System Corrosion

Corrosion and scaling of metal surfaces are the major problems caused by geothermal fluids when metallic structures are used. This article describes a study of corrosion and scaling problems in the Afyonkarahisar Geothermal Heating System (AFJET) in Afyonkarahisar, Turkey. Water analysis, XRD, SEM, EDX, IC, ICP-OES analyses, and electrochemical methods were used in this study. Pentasodium triphosphate (Na₅P₃O₁₀), maleic anhydride (C₄H₂O₃), and 1,3-benzendisulfonic acid disodium salt (C₆H₄Na₂O₆S₂) were used as corrosion inhibitors. Tests were carried out using geothermal water from AF11 well. The experimental temperatures were chosen as 298, 333, and 358 K. Inhibitor concentrations were chosen as 1 × 10^?1, 1 × 10^?2, 1 × 10^?3, and 1 × 10^?4 mol/dm³. Moreover, mixed inhibitor solutions were prepared using the inhibitor concentrations that showed the best inhibition. The first mixed inhibitor solution showed 96% inhibition. The second mixed inhibitor solution showed 90% inhibition. The tested inhibitors act as anodic inhibitors. XRD analysis shows that there is CaCO₃ aragonite scaling in the system. Increasing TDS, alkalinity, and hardness all promote scale formation. The photomicrographs from SEM-EDX and the metallographic microscope show that the tested inhibitors form a protective film on the surface. IC and ICP-OES analyses show that the concentration of Ca²⁺ is very high, which supports scale formation.     

Performance modelling of serial production lines with inspection/repair stations

The authors derived a set of analytical models for serial production lines with multiple operation stations and multiple inspection/repair stations. Multiple defect types may be acquired by the production units from the raw stock as well as during processing at operation stations. The analytical models are steady-state equations for outgoing quality level, throughput rate and scrap rates. The analytical models are based on (1) traffic rate equations of the flow through a production line when represented as a directed flow network and (2) probabilistic models of changes in defect attributes of the production units as they flow. The formulas may be used for evaluating inspection configuration designs including the formulation of optimal cost models.