Hybrid Coding Technique for Pulse Detection in an Optical Time Domain Reflectometer

The paper introduces a novel hybrid coding technique for improved pulse detection in an optical time domain reflectometer. The hybrid schemes combines Simplex codes with signal averaging to articulate a very sophisticated coding technique that considerably reduces the processing time to extract specified coding gains in comparison to the existing techniques. The paper quantifies the coding gain of the hybrid scheme mathematically and provide simulative results in direct agreement with the theoretical performance. Furthermore, the hybrid scheme has been tested on our self-developed OTDR

Pathogenic mutations in TULP1 responsible for retinitis pigmentosa identified in consanguineous familial cases.

PurposeTo identify pathogenic mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in consanguineous familial cases.MethodsSeven large familial cases with multiple individuals diagnosed with retinitis pigmentosa were included in the study. Affected individuals in these families underwent ophthalmic examinations to document the symptoms and confirm the initial diagnosis. Blood samples were collected from all participating members, and genomic DNA was extracted. An exclusion analysis with microsatellite markers spanning the TULP1 locus on chromosome 6p was performed, and two-point logarithm of odds (LOD) scores were calculated. All coding exons along with the exon-intron boundaries of TULP1 were sequenced bidirectionally. We constructed a single nucleotide polymorphism (SNP) haplotype for the four familial cases harboring the K489R allele and estimated the likelihood of a founder effect.ResultsThe ophthalmic examinations of the affected individuals in these familial cases were suggestive of RP. Exclusion analyses confirmed linkage to chromosome 6p harboring TULP1 with positive two-point LOD scores. Subsequent Sanger sequencing identified the single base pair substitution in exon14, c.1466A>G (p.K489R), in four families. Additionally, we identified a two-base deletion in exon 4, c.286_287delGA (p.E96Gfs77*); a homozygous splice site variant in intron 14, c.1495+4A>C; and a novel missense variation in exon 15, c.1561C>T (p.P521S). All mutations segregated with the disease phenotype in the respective families and were absent in ethnically matched control chromosomes. Haplotype analysis suggested (p<10(-6)) that affected individuals inherited the causal mutation from a common ancestor.ConclusionsPathogenic mutations in TULP1 are responsible for the RP phenotype in seven familial cases with a common ancestral mutation responsible for the disease phenotype in four of the seven families

Axial load-axial deformation behaviour of circular concrete columns reinforced with GFRP bars and helices

Fibre Reinforced Polymer (FRP) bars has attracted a significant amount of research attention in the last three decades to overcome the problems associated with the corrosion of steel reinforcing bars in reinforced concrete members. A limited number of studies, however, have investigated the behaviour of concrete columns reinforced with FRP bars. Also, available design standards either ignore the contribution of or do not recommend the use of GFRP bars in compression members. This study reports the results of experimental investigations of concrete specimens reinforced with GFRP bars and GFRP helices as longitudinal and transverse reinforcement, respectively. A total of five circular concrete columns of 205 mm in diameter and 800 mm in height were cast and tested under axial compression. The experimental results showed that reducing the spacing of the GFRP helices or confining the specimens with CFRP sheet led to improvements in the strength and ductility of the specimens. Also, an analytical model has been developed for the axial load-axial deformation behaviour of the circular concrete columns reinforced with GFRP bars and helices. The model has been validated with the experimental results

Axial compressive behaviour of circular CFFT: Experimental database and design-oriented model

Concrete Filled Fibre Reinforced Polymer Tube (CFFT) for new columns construction has attracted significant research attention in recent years. The CFFT acts as a formwork for new columns and a barrier to corrosion accelerating agents. It significantly increases both the strength capacity (Strength enhancement ratio) and the ductility (Strain enhancement ratio) of reinforced concrete columns. In this study, based on predefined selection criteria, experimental investigation results of 134 circular CFFT columns under axial compression have been compiled and analysed from 599 CFFT specimens available in the literature. It has been observed that actual confinement ratio (expressed as a function of material properties of fibres, diameter of CFFT and compressive strength of concrete) has significant influence on the strength and ductility of circular CFFT columns. Design oriented models have been proposed to compute the strength and strain enhancement ratios of circular CFFT columns. The proposed strength and strain enhancement ratio models have significantly reduced Average Absolute Error (AAE), Mean Square Error (MSE), Relative Standard Error of Estimate (RSEE) and Standard Deviation (SD) as compared to other available strength and strain enhancement ratios of circular CFFT column models. The predictions of the proposed strength and strain enhancement ratio models match well with the experimental strength and strain enhancement ratios investigation results in the compiled database

Axial Load and Bending Moment Behaviour of Square High Strength Concrete (HSC) Columns Reinforced with Steel Equal Angle (SEA) Sections

This paper presents the behaviour of square high-strength concrete (HSC) specimens reinforced longitudinally with steel equal angle (SEA) sections under different loading conditions. For the same cross-sectional area, a SEA section has a higher second moment of area than a steel bar, which results in a greater bending stiffness of the concrete member reinforced with SEA sections. Also, the area of confined concrete is greater in concrete members reinforced with SEA sections compared to members reinforced with steel bars, which results in higher strength and ductility. A total of 8 specimens of 210 mm square cross-section and 800 mm height were constructed and tested. The specimens were divided into two groups with four specimens in each group. Group R-S50 specimens serve as the reference group and were reinforced longitudinally with four N12 (12 mm diameter) deformed steel bars. Group A30-S50 specimens were reinforced longitudinally with four A30 (29.1 mm x 29.1 mm x 2.25 mm) SEA sections. All specimens were reinforced laterally with R10 (10 mm diameter) plain steel bars and spaced at 50 mm centres. The main variables considered in the study included the type of longitudinal reinforcement and the magnitude of load eccentricity. It was obtained from the experimental results that specimens reinforced longitudinally with SEA sections showed greater ductility compared to specimens reinforced longitudinally with steel bars under different loading conditions

Behavior of High-Strength Concrete Columns Reinforced with Galvanized Steel Equal-Angle Sections under Different Loading Conditions

Experimental results are presented for a new method of reinforcing concrete columns with galvanized steel equal-angle (GSEA) sections. For the same cross-sectional area, a GSEA section has a higher second moment of area than a conventional steel bar, which leads to a higher bending stiffness of the GSEA reinforced concrete member. In addition, the area of confined concrete is higher in GSEA reinforced concrete members than in steel bar reinforced members, which results in higher strength and ductility. The experimental program involved testing of 20 square, high-strength concrete (HSC) specimens under concentric axial load, eccentric axial load, and four-point loading. The specimens were reinforced longitudinally with either four N12 (12-mm-diameter deformed steel) bars or four GSEA sections and transversely with R10 (10-mm-diameter plain steel) bars. The specimens were 800 mm high with a 210 x 210 mm square cross section. Fifteen specimens were tested under either a concentric or eccentric axial load. The remaining five specimens were tested under four-point loading. Effects of the type of longitudinal reinforcement, spacing of transverse reinforcement, and loading conditions on the behavior of HSC specimens were investigated and discussed. Experimental results showed that, in general, specimens reinforced with GSEA sections had higher load-carrying capacities than the specimens reinforced with steel bars. In addition, the postpeak load-deformation behavior was observed to be more pronounced in specimens reinforced with GSEA sections than in specimens reinforced with steel bars

Investigation of engineering properties of normal and high strength fly ash based geopolymer and alkali-activated slag concrete compared to ordinary Portland cement concrete

Fly ash-based geopolymer (FAGP) and alkali-activated slag (AAS) concrete are produced by mixing alkaline solutions with aluminosilicate materials. As the FAGP and AAS concrete are free of Portland cement, they have a low carbon footprint and consume low energy during the production process. This paper compares the engineering properties of normal strength and high strength FAGP and AAS concrete with OPC concrete. The engineering properties considered in this study included workability, dry density, ultrasonic pulse velocity (UPV), compressive strength, indirect tensile strength, flexural strength, direct tensile strength, and stress-strain behaviour in compression and direct tension. Microstructural observations using scanning electronic microscopy (SEM) are also presented. It was found that the dry density and UPV of FAGP and AAS concrete were lower than those of OPC concrete of similar compressive strength. The tensile strength of FAGP and AAS concrete was comparable to the tensile strength of OPC concrete when the compressive strength of the concrete was about 35 MPa (normal strength concrete). However, the tensile strength of FAGP and AAS concrete was higher than the tensile strength of OPC concrete when the compressive strength of concrete was about 65 MPa (high strength concrete). The modulus of elasticity of FAGP and AAS concrete in compression and direct tension was lower than the modulus of elasticity of OPC concrete of similar compressive strength. The SEM results indicated that the microstructures of FAGP and AAS concrete were more compact and homogeneous than the microstructures of OPC concrete at 7 days, but less compact and homogeneous than the microstructures of OPC concrete at 28 days for the concrete of similar compressive strength

An Assessment on the Non-Invasive Methods for Condition Monitoring of Induction Motors

The ability to forecast motor mechanical faults at incipient stages is vital to reducing maintenance costs, operation downtime and safety hazards. This paper synthesized the progress in the research and development in condition monitoring and fault diagnosis of induction motors. The motor condition monitoring techniques are mainly classified into two categories that are invasive and non-invasive techniques. The invasive techniques are very basic, but they have some implementation difficulties and high cost. The non-invasive methods, namely MCSA, PVA and IPA, overcome the disadvantages associated to invasive methods. This book chapter reviews the various non-invasive condition monitoring methods for diagnosis of mechanical faults in induction motor and concludes that the instantaneous power analysis (IPA) and Park vector analysis (PVA) methods are best suitable for the diagnosis of small fault signatures associated to mechanical faults. Recommendations for the future research in these areas are also presented

Current optical technologies for wireless access

The objective of this paper is to describe recent activities and investigations on free-space optics (FSO) or optical wireless and the excellent results achieved within SatNEx an EU-framework 6th programme and IC 0802 a COST action. In a first part, the FSO technology is briefly discussed. In a second part, we mention some performance evaluation criterions for the FSO. In third part, we briefly discuss some optical signal propagation experiments through the atmosphere by mentioning network architectures for FSO and then discuss the recent investigations in airborne and satellite application experiments for FSO. In part four, we mention some recent investigation results on modelling the FSO channel under fog conditions and atmospheric turbulence. Additionally, some recent major performance improvement results obtained by employing hybrid systems and using some specific modulation and coding schemes are presented

Experimental Investigation of Circular High-Strength Concrete Columns Reinforced with Glass Fiber-Reinforced Polymer Bars and Helices under Different Loading Conditions

Existing design codes and guidelines do not adequately address the design of concrete columns reinforced with fiber-reinforced polymer (FRP) bars. Accordingly, a number of research studies investigated the behavior of FRP bar-reinforced concrete columns. However, the previous studies were limited to FRP bar-reinforced normal-strength concrete (NSC) columns. In this study, the behavior of glass fiber-reinforced polymer (GFRP) bar-reinforced high-strength concrete (HSC) specimens under different loading conditions was investigated in terms of axial load-carrying capacity, confinement efficiency of the GFRP helices, as well as the ductility and post-peak axial load-axial deformation response. The effects of the key parameters such as the type of the reinforcement (steel and GFRP), the pitch of the transverse helices, and the loading condition (concentric, eccentric, and four-point loading) on the performance of the specimens were investigated. It was observed that the GFRP bar-reinforced HSC specimen sustained similar axial load under concentric axial compression compared to its steel counterpart, but the efficiency of GFRP bar-reinforced HSC specimens in sustaining axial loads decreased with an increase in the axial load eccentricity. Direct replacement of steel reinforcement by the same amount of GFRP reinforcement in HSC specimens resulted in about 30% less ductility under concentric axial load. However, it was found that the ductility and post-peak axial load-axial deformation behavior of the GFRP bar-reinforced HSC specimens can be significantly improved by providing closely spaced helices