Engineering

An Investigation of the Effect of Sand Content on Geotechnical Properties of Fibrous Peat
In this study, the effect of sand content on compaction, shear strength, and compressibility of fibrous peat was investigated. The sand used for the study is rounded and poorly graded passing 2-mm sieve and retaining on 1-mm sieve. Samples were prepared by adding 10, 20, 30, 40, and 50 % sand by weight, respectively. Standard Proctor tests were carried out for each mixture to determine the opt...


Computational Aerodynamic Interaction of Hypersonic Flow with Pin-Protuberance on Blunted Cones
Computational study of the aerodynamic behavior of blunt nose bodies like conic geometries with lateral pin-protuberance in hypersonic flow was investigated. The pressure distribution along the cone’s longitudinal axis in the presence of the cylindrical pin was studied using numerical simulations. Static aerodynamic coefficients in the Mach range of 5–9.7 at an angle of incidence of zero a...
Establishment of the optimal time interval between periodic inspections for redundant systems
For redundant systems with periodic inspections, the establishment of the optimal time interval between inspections that maximize availability and minimize costs is a challenging issue. This paper develops a model to analyze the reliability and determine the optimal interval between inspections of redundant systems subjected to periodic inspections. It uses discrete time Markov Chains to define...


Explicit and implicit methods for probabilistic common-cause failure analysis
The occurrence of a probabilistic common-cause failure (PCCF) in a system results in failures of multiple system components with different probabilities. A PCCF can be caused by external shocks or propagated failures originating from some components within the system. This paper proposes an explicit method and an implicit method to analyze the reliability of systems subject to internal or exter...
A copula-based sampling method for data-driven prognostics
This paper develops a Copula-based sampling method for data-driven prognostics. The method essentially consists of an offline training process and an online prediction process: (i) the offline training process builds a statistical relationship between the failure time and the time realizations at specified degradation levels on the basis of off-line training data sets; and (ii) the online predi...


Development and application of a living probabilistic safety Assessment tool: Multi-objective multi-dimensional optimization of surveillance requirements in NPP considering their ageing
The benefits of utilizing the probabilistic safety assessment towards improvement of nuclear power plant safety are presented in this paper. Namely, a nuclear power plant risk reduction can be achieved by risk-informed optimization of the deterministically-determined surveillance requirements. A Living Probabilistic Safety Assessment tool for time-dependent risk analysis on component, system an...
Choosing a heuristic and root node for edge ordering in BDD-based network reliability analysis
In the binary decision diagram (BDD)-based network reliability analysis, heuristics have been widely used to obtain a reasonably good ordering of edge variables. Orderings generated using different heuristics can lead to dramatically different sizes of BDDs, and thus dramatically different running times and memory usages for the analysis of the same network. Unfortunately, due to the nature of ...

Joint optimal inspection and inventory for a k-out-of-n system
The objective of this paper is to develop a model, which optimizes jointly the inspection frequency and the inventory level for a k-out-of-n system with repairable components whose failures are hidden. The system is periodically inspected to detect failed components, and the components are either minimally repaired or replaced with spares from the inventory. The system fails between periodic in...
Effect of Sliding Speed and Applied Load on Dry Sliding Tribological Performance of TiAl Matrix Self-lubricating Composites
More durable, low-friction self-lubricating materials in modern industry are greatly needed for tribological systems. The current paper presents the tribological performance of TiAl matrix self-lubricating composites (TSC) containing MoS2, hexagonal BN and Ti3SiC2 designated as MhT against GCr15 steel counterface under several sliding speeds from 0.2 to 0.8 m s−1 and applied loads from 6 to...

Charge Distribution View: Large Difference in Friction Performance Between Graphene and Hydrogenated Graphene Systems
Density functional theory calculations including dispersion correction (DFT-D2) were used to investigate the relationship between charge distribution and nanofriction characteristics of graphene-based material systems. In our calculations, the single-side-hydrogenated graphene (SSHGraphene) system exhibits lower coefficient of friction, whereas the graphane system exhibits larger one compared w...
Recurring patterns in stationary intervals of abdominal uterine electromyograms during gestation
Abdominal uterine electromyograms (uEMG) studies have focused on uterine contractions to describe the evolution of uterine activity and preterm birth (PTB) prediction. Stationary, non-contracting uEMG has not been studied. The aim of the study was to investigate the recurring patterns in stationary uEMG, their relationship with gestation age and PTB, and PTB predictivity. A public database of 3...

Binary optimization for source localization in the inverse problem of ECG
The goal of ECG-imaging (ECGI) is to reconstruct heart electrical activity from body surface potential maps. The problem is ill-posed, which means that it is extremely sensitive to measurement and modeling errors. The most commonly used method to tackle this obstacle is Tikhonov regularization, which consists in converting the original problem into a well-posed one by adding a penalty term. The...
Mechanical vibrations of carbon nanotube-based mass sensors: an analytical approach
The purpose of this paper is to examine the potential of single-walled carbon nanotubes as mass sensors by developing analytical expressions and then comparing the outcome with structural mechanics corresponding predictions. – The carbon nanotube (CNT) resonators are assumed to be either single or double clamped. Analytical formulas capable of describing the vibrational behavior of such CNT-b...
Light-sensitive biosensors based on photoactive marine cultivated strains
The purpose of this study is to construct imaging pixels using novel bioactive films. Despite the notable progress in electronic imaging devices, these sensors still cannot compete with biological vision counterparts such as the human eye. Light sensitive biolayers and pigments in living organisms show superior performance in terms of low noise operation and speed. Although photoactive biolayer...
Concentration estimation of formaldehyde using metal oxide semiconductor gas sensor array-based e-noses
The purpose of this paper is to present a novel concentration estimation model for improving the accuracy and robustness of low-cost electronic noses (e-noses) with metal oxide semiconductor sensors in indoor air contaminant monitoring and overcome the potential sensor drift. – In the quantification model, a piecewise linearly weighted artificial neural network ensemble model (PLWE-ANN) with ...