Development of degradation model for urban asphalt pavement

There is a lack of a profound understanding of urban pavement deterioration pattern. This is due to the complexity of traffic conditions and the variety of pavement structures in urban roads. The lack of a suitable deterioration model for the urban pavements limits the possibility of making any scientific and cost-effective repair and maintenance strategy. There is a need for a better understanding of the long-term behaviour of urban pavements by which predictive pavement condition models can be derived and consequently a suitable maintenance management system can be built. In response to this need, a comprehensive field study was performed in three Iranian cosmopolitan cities. Pervasive pavement damages were defined and an urban pavement condition index was established. A deterioration model was developed by monitoring and analysing the conditions of road pavements in a period of four years. This model varies as the structural and loading conditions of the pavement change. The efficiency and practicability of the model in predicting the conditions of the pavements were illustrated.     

A Novel Energy-Aware Clustering Method via Lion Pride Optimizer Algorithm (LPO) and Fuzzy Logic in Wireless Sensor Networks (WSNs)

Wireless Personal Communications - Recent technological advances and developments in the field of communication information systems, especially in microelectro mechanical systems have provided the...     

Regeneration of catalyst clay soils (Tonsil CO 610 G) by supercritical carbon dioxide

Extraction of deactivatived materials from contaminated clay soils (Tonsil CO 610 G) by supercritical carbon dioxide was investigated. Effect of different conditions including extraction temperature (308.15–338.15 K) and pressure (100–330 bar) (thermodynamic conditions), flow rate (4.2–42.6 cc/min), and static time (45–85 min) were investigated to find the optimum conditions for extraction of deactivatived materials. Based on the different experiments, optimum conditions for flow rate (4.2 cc/min), static time (85 min) and extraction pressure and temperature (330 bar and 313.15 K) were obtained. In addition, the GC-MS analysis and Bromine index (BI) analysis were revealing that the clay soil is activated and could be used as catalyst again.     

Analyzing soft tissue stiffness of human upper arms during physical dynamic and quasi-static impacts in human–machine interaction

Knowledge of the changes in the behavior of human soft tissue stiffness during physical impact in human–machine interaction (HMI) plays a vital role in the development of biofidelity testing devices such as a human dummy. These testing devices are widely applied as an effective means to validate the safety of machinery during dynamic or static contact with humans in HMI. In this study, we assess changes in soft tissue stiffness in the upper arm of individuals under both dynamic (0.7 and 0.25 m/s) and quasi-static (QS) impacts under a constrained contact condition. Three impactor shapes (cylindrical, cubic, and spherical) are used in this study. Impact experiments are conducted using impactors attached to a pendulum. The soft-tissue displacement is determined using an ultrasound device. The impact force-displacement curves illustrate the nonlinear behavior of the soft tissue stiffness under both dynamic and QS impacts. By utilizing the “Linear Mixed Model” statistical analysis, we found that changes in the impact velocity significantly influenced the changes in the nonlinear behavior of soft tissue stiffness while there was no significant effect of the changes in the impactor shape on the nonlinear behavior of the soft tissue stiffness. Additionally, we revealed that the changes in the soft tissue stiffness are influenced by the size of the contact area. Moreover, we demonstrated a range of changes in soft tissue stiffness for different impact velocities, which provide valuable information for developing future validation test devices in HMI, such as the design and evaluation of dummy skin.     

Design issues in parallel simulation languages

The authors address several key issues in designing languages for parallel discrete-event simulation and survey the state-of-the-art techniques aimed at solving these problems. Attention is given to issues that are specific to parallel simulation, e.g., the parallel synchronization schemes, or issues that have not previously been a problem for sequential simulation, e.g., termination. Various specialized PSLs (parallel simulation languages) may also have quite different design issues. The problem of achieving transparency is addressed. In particular it is observed that a major difficulty in achieving the design criteria is the overhead introduced by the methods for solving the problems considered. In some cases making the design criteria less constrained appears to be unavoidable. The authors also propose several useful high-level language constructs to facilitate modeling in order to have the simulation system deal with the low-level details transparently. They show that extending the capability of an existing programming language is the simplest available technique for designing a PSL     

Parallel simulation based on conservative time windows: A performance study

The paper presents a Conservative Time Window (CTW) algorithm for parallel simulation of discrete event systems. The physical system to be simulated is partitioned into n disjoint sub-systems, each of which is represented by an object The CTW algorithm identifies a time window for each object, such that events occurring in each window are independent of events in other windows and thus they can be processed concurrently. The CTW algorithm was implemented on a shared memory multiprocessor, a Sequent Symmetry S81 with 16 processors. We measured performance of the CTW algorithm on two types of network topologies: feed-forward networks and networks with feedback loops. We used three metrics to measure performance: speed-up, average number of independent windows detected by the algorithm, and average number of events occurring in each window. We also investigated the impact of various event scheduling policies on performance. The results obtained show that the CTW algorithm produces good performance in many cases.     

Integral sliding mode control for nonlinear damped model of arch microbeams

Microsystem Technologies - In this paper, a second order integral sliding mode controller (SMC) and a two-dimensional integral sliding mode controller are designed for a nonlinear damped model of...     

Evaluation of Ni‐Mo and Ni‐Mo‐P Electroplated Coatings on Stainless Steel for PEM Fuel Cells Bipolar Plates

Stainless steel bipolar plates (BPPs) are the preferred choice for proton exchange membrane fuel cells (PEMFCs); however, a surface coating is needed to minimize contact resistance and corrosion. In this paper, Ni–Mo and Ni–Mo–P coatings were electroplated on stainless steel BPPs and investigated by XRD, SEM/EDX, AFM and contact angle measurements. The performance of the BPPs was studied by corrosion and conduction tests and by measuring their interfacial contact resistances (ICRs) ex situ in a PEMFC set‐up at varying clamping pressure, applied current and temperature. The results revealed that the applied coatings significantly reduce the ICR and corrosion rate of stainless steel BPP. All the coatings presented stable performance and the coatings electroplated at 100 mA cm⁻² showed even lower ICR than graphite. The excellent properties of the coatings compared to native oxide film of the bare stainless steel are due to their higher contact angle, crystallinity and roughness, improving hydrophobicity and electrical conductivity. Hence, the electroplated coatings investigated in this study have promising properties for stainless steel BPPs and are potentially good alternatives for the graphite BPP in PEMFC.