An overview of burst, buckling, durability and corrosion analysis of lightweight FRP composite pipes and their applicability

© 2019 Elsevier Ltd. All rights reserved.The main aim of this review article was to address the performance of filament wound fibre reinforced polymer (FRP) composite pipes and their critical properties, such as burst, buckling, durability and corrosion. The importance of process parameters concerning merits and demerits of the manufacturing methods was discussed for the better-quality performance. Burst analysis revealed that the winding angle of ±55° was observed to be optimum with minimum failure mechanisms, such as matrix cracking, whitening, leakage and fracture. The reduction of buckling effect was reported in case of lower hoop stress value in the hoop to axial stress ratio against axial, compression and torsion. A significant improvement in energy absorption was observed in the hybrid composite pipes with the effect of thermal treatment. However, the varying winding angle in FRP pipe fabrication was reported as an influencing factor affecting all the aforementioned properties. Almost 90% of the reviewed studies was done using E-glass/epoxy materials for the composite pipe production. By overcoming associated limitations, such as replacing synthetic materials, designing new material combinations and cost-benefit analysis, the production cost of the lightweight FRP composite pipes can be decreased for the real-time applications.Peer reviewe

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Effieciency Limiting Processes in Novel Laser Materials For Optical Computing and Communications Applications.

The novel Ga(NAsP)-based semiconductors have recently grown in popularity due to applications such as development of energy efficient long-term stable semiconductor lasers on silicon substrates for optical computing applications. GaAsSb-based active materials have also recently been extensively investigated for the development of temperature stable uncooled semiconductor lasers for 1.3 &mu;m optical communications applications. Electrical injection lasing operation at room temperature (RT) is demonstrated in Ga(NAsP)/GaP quantum well (QW) lasers with a threshold current density, Jth of 4 kA/cm2 at the lasing wavelength of 981 nm. From temperature dependence measurements we find that the threshold current is dominated by non-radiative recombination process(es), which account for at least 92% of Jth at RT. The characteristic temperature, T0 (T1 is measured to be ~104K (~99K) around 200K, which drops to ~58K (~37K) around RT. Hydrostatic pressure measurements reveal a strong increase in threshold current with increasing pressure. This implies that current leakage dominates carrier recombination, which is also responsible for their low characteristic temperatures, T0 and T1 at RT. The band-structure properties of novel BxGa1-xP alloys are also investigated. These layers are utilized as strain-compensating layers for the lattice-matched integration of Ga(NAsP) quantum well lasers on an exact (001) silicon substrate. Experimental and theoretical studies reveal the dependence of the direct and indirect band gaps for strained BxGa1-x P layers grown on silicon as a function of Boron composition from which we derive the properties of freestanding BxGa1-xP. For Boron fractions up to 6%. We find that the bowing parameter for the lowest (indirect) band gap is -6.2+-0.2 eV. High crystalline quality and promising optical material properties are demonstrated and applied to monolithically integrated Ga(NAsP)/(BGa)P multi-quantum well heterostructures on (001) silicon substrates. Electrical injection lasing operation is demonstrated for the first time up to 165K in Ga(NAsP)/(BGa)P QW lasers monolithically integrated on a (001) silicon substrate. The devices show a Jth of 1.6 kA/cm2 at the lasing wavelength of 860 nm at 165 K. The T0 (T1) in the devices is ~198K (~99K) at 100 K, decreasing to ~73K (~35 K) at 165 K. Temperature dependence of the “Z” analysis shows that Zth increases from 1.7 at 40 K to 2.3 at 165 K. The value of Zth < 2 at low temperatures signifies that the monomolecular (defect) current contribution at threshold in these devices is significant. The non-radiative contribution accounts for ~ 83% (of which at least ~40% is monomolecular recombination) of even at a low temperature of 165K. It is proposed that defects originate due to the non-optimized miscut angle of the silicon substrate and due to diffusion of Nitrogen from active region to the barrier regions. A strong increase in Jth with increasing pressure at 165K suggests the presence of carrier leakage. The temperature and pressure dependence of Jth for GaAsSb/GaAs QW lasers with different device characteristics are investigated. Thermally activated carrier leakage via defects is observed in the GaAsSb/GaAs QW devices. Devices grown under optimal conditions reduce the nonradiative recombination mechanism from 93% to. 76% at RT, compared with a device grown under non-optimized conditions. This improvement in carrier recombination mechanisms leads to a large improvement in the Jth from 533 Acm-2/QW to 138 Acm-2/QW and the characteristic temperature, T0 (T1) from ~51K (~104K) to ~62K (~138K) near RT

Modeling Of Hybrid EDFA/DRA For Long Haul Optical Fiber Communication System

This research work focuses on the modeling of hybrid EDFA/DRA for long haul optical fiber communication system (OFCS). The mathematical model of hybrid EDFA/DRA is represented by two separate models. The first model deals with the modeling of double pass (DP) Erbium doped fiber amplifier (EDFA) and the second model deals with the modeling of distributed Raman amplifier (DRA). These two models are integrated in order to model the hybrid EDFA/DRA

Efficiency limiting processes in novel laser materials for optical computing and communications applications

The novel Ga(NAsP)-based semiconductors have recently grown in popularity due to applications such as development of energy efficient long-term stable semiconductor lasers on silicon substrates for optical computing applications. GaAsSb-based active materials have also recently been extensively investigated for the development of temperature stable uncooled semiconductor lasers for 1.3 !-lm optical communications applications. Electrical injection lasing operation at room temperature (RT) is demonstrated in Ga(NAsP) / GaP quantum well (QW) lasers with a threshold current density, J th of 4 kA/ cm2 at the lasing wavelength of 981 nm: From temperature dependence measurements we find that the threshold current is dominated by non-radiative recombination process(es), which account for at least 92% of Jth at RT. The characteristic temp_erature, To (TI) is measured to be ~104K (~99K) around 200K, which drops to ~58K (~37K) aroundRT. Hydrostatic pressure measurements reveal a strong increase in threshold current with increasing pressure. This . implies that current leakage dominates carrier recombination, which is also responsible for their low characteristic temperatures, To and TI at RT. The band-structure properties of novel BxGal_xP alloys are also investigated. These layers are utilized as strain-compensating layers for the lattice-matched integration of Ga(NAsP) . quantum well lasers on an exact (001) silicon substrate. Experimental and-theoretical studies reveal the dependence of the direct and indirect band gaps for strained BxGal_xP layers grown on silicon as a function of Boron composition from which we derive the properties of free- standing BxGal_xP' For Boron fractions up to 6%. We find that the bowing parameter for the lowest (indirect) band gap is -6.2±0.2 eV. High crystalline quality and promising optical material properties are demonstrated and applied to monolithically integrated Ga(NAsP) / (BGa)P multi-quantum well heterostructures on (001) silicon substrates. Electrical injection lasing operation is demonstrated for the first time up to 165K in Ga(NAsP) / (BGa)P QW lasers monolithically integrated on a (001) silicon substrate. The devices show aJth of 1.6 kA/ cm' at the lasing wavelength of 860 nm at 165 K. The To (TI) in the devices is ~198K (~99K) at 100 K;decreasing to ~73K (~35 K) at 165 K. Temperature dependence of the "Z" analysis shows that Zth increases from 1.7 at 40 K to 2.3 at 165 K. The value of Zth < 2 at low temperatures signifies that the monomolecular (defect) current contribution at threshold in these devices is significant. The non-radiative contribution accounts for ~ 83% (of which at least ~40% is monomolecular recombination) of Jth even at a low temperature of 165K. It is proposed that defects originate due to the non-optimized miscut angle of the silicon substrate and due to diffusion of Nitrogen from active region to the barrier regions. A strong increase in Jth with increasing pressure at 165K suggests the presence of, carrier leakage. The temperature and press~e dependence of Jth for GaAsSb/GaAs QW lasers with different device characteristics are investigated. Thermally activated carrier leakage via defects is observed in the GaAsSb/GaAs QW devices. Devices grown under optimal conditions reduce the nonradiative recombination mechanism from 93% to 76% at RT, compared with a device grown under non-optimized conditions. This improvement in carrier recombination mechanisms leads to a large improvement in the Jth from 533 Acm-2/QW to 138 Acm-2/QW and the characteristic temperature, To (TI) from ~51K (~104K) to ~62K (~138K) near RT.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Modeling of hybrid EDFA/DRA : theory, numerical simulation and experimental evaluation

This book focuses on the modeling of hybrid EDFA/ DRA for long haul optical fiber communication system. The mathematical model of hybrid EDFA/DRA is represented by two separate models. The first model deals with the modeling of double pass Erbium doped fiber amplifier (EDFA) and the second model deals with the modeling of distributed Raman amplifier (DRA). These two models are integrated in order to model the hybrid EDFA / DRA. A mathematical model of DP EDFA is developed. A combination of Runge-Kutta method and relaxation method is used to numerically solve the developed DP EDFA mathematical model. The numerical results are used to describe the design process of an optimized DP EDFA. The DP EDFA mathematical model is validated with the help of previously published experimental results. A mathematical model of DRA is developed. An approach to numerically solve the developed DRA mathematical model is described. Numerical results are used to characterize the DRA. The DRA mathematical model is validated with the help of previously published experimental results

Physical Properties and Characteristics of III-V Lasers on Silicon

The development of laser technology based on silicon continues to be of key importance for the advancement of electronic-photonic integration offering the potential for high data rates and reduced energy consumption. Progress was initially hindered due to the inherent indirect band gap of silicon. However, there has been considerable progress in developing ways of incorporating high gain III-V based direct band gap materials onto silicon, bringing about the advantages of both materials. In this paper, we introduce the need for lasers on silicon and review some of the main approaches for the integration of III-V active regions, including direct epitaxial growth, hybrid integration, defect blocking layers and quantum dots. We then discuss the roles of different carrier recombination processes on the performance of devices formed using both wafer fusion and direct epitaxial approaches

Band structure properties of novel BxGa1-xP alloys for silicon integration

We have grown and investigated the band-structure properties of novel III-V alloys based upon BxGa1-xP. These layers are utilized as strain-compensating layers for the lattice-matched integration of novel direct bandgap Ga(NAsP) quantum well lasers on silicon. Experimental and theoretical studies reveal the dependence of the direct and indirect band gaps for strained BxGa1-xP layers grown on silicon as a function of Boron composition from which we derive the properties of free-standing BxGa1-xP. For Boron fractions up to 6%, we find that the bowing parameter for the lowest (indirect) band gap is -6.2±0.2 eV. High crystalline quality and promising optical material properties are demonstrated and applied to monolithically integrated Ga(NAsP)/(BGa)P multi-quantum well heterostructures on (001) silicon substrates. Our results show that novel (BGa)P layers are suitable for strain compensation purposes, which pave the way towards a commercial solution for the monolithic integration of long term stable laser diodes on silicon substrates