Correlation of index changes with stress changes in fibers containing UV-written Bragg gratings

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The development of soft electronic and optoelectronic systems is essential for the growth and industrial deployment of research fields such as smart textiles and wearables. However, it remains challenging to identify materials that reconcile the required mechanical attributes (e.g. softness and stretchability) with functional metrics essential to develop high-performance devices (e.g. electrical conductivity or photoconductivity). Moreover, it is equally important to find processing routes that can produce

Pulsed fiber laser at 2-µm band has important applications in fields including material processing, environmental monitoring, and surgery. Mode-locking and Q-switching are two common working mechanisms of pulsed lasers, while the control of their existence and conversion in the same laser proves difficult. In this work, the theoretical model used in ultrafast laser optics is adapted for the conversion between mode-locked and Q-switched pulses. We proposed a method which introduces a feedback loop to control

This study compares implicit stochastic optimization (ISO) and explicit stochastic optimization (ESO) for deriving operational rules for conjunctive use of surface water and groundwater, and proposes an improved ISO formulation that accounts for capturing interdependence among sequential decisions. In the present formulation, previously determined decision variables are introduced as additional inputs to the rule model. The analysis is carried out using the example of the conjunctive use system of the Qazvi

Ultra-low noise lasers are essential tools in various applications, including data communication, light detection and ranging (LiDAR), quantum computing and sensing, and optical metrology. Recent advances in integrated photonics, specifically the development of the ultra-low loss silicon nitride (

Si3N4

) platform, have allowed attaining performance that exceeds conventional legacy laser systems, including the phase noise of fiber lasers. This platform can be combined with the monolithic integration of piez

When making predictions, a language model must trade off how much it relies on its context versus its prior knowledge. Choosing how sensitive the model is to its context is a fundamental functionality, as it enables the model to excel at tasks like retrieval-augmented generation and question-answering. In this paper, we search for a knob that controls this sensitivity, determining whether language models answer from the context or their prior knowledge. To guide this search, we first design a task for contr

Since the first demonstration of the process in 1995, fused silica is a widely used material for direct femtosecond waveguide writing. However, the high exposure dose requirement requires a low writing speed, which limits potential applications. By using ultraviolet light at 343 nm with yet, comparably longer pulses (450 fs) than normally used, we demonstrate high-speed low-loss waveguide writing, at a rate, approximately 1,000 times faster than typically used writing parameters. The fabricated waveguides a

The conventional way of generating optical waveforms relies on in-phase and quadrature (IQ) modulation of a continuous-wave (CW) laser tone. In this case, the bandwidth of the resulting optical waveform is limited by the underlying electronic components, in particular by the digital-to-analog converters (DACs) generating the drive signals for the IQ modulator. This bandwidth bottleneck can be overcome by using a concept known as optical arbitrary waveform generation (OAWG), where multiple IQ modulators and

Efficient and robust free-space light coupling in integrated systems is a challenging task for photonic devices. Here we propose a femtosecond laser process combined with CW laser thermal reflow for manufacturing a fiber-to-fiber free-space light-coupling device in fused silica. The monolithic free-space coupler design consists of two fiber holders and two ball lenses, used to achieve both, fiber-output collimation and fiber-injection. The device proved to efficiently work at 633 nm for single mode fiber co

Crack propagation is critical for the assessment of the strength of rocks. Linear Elastic Fracture Mechanics (LEFM) theory is commonly used to describe its propagation. However, the variation of the fracture energy, its key parameter, is generally poorly understood as its experimental measurements are influenced by temperature, stress biaxiality, and rupture velocity. This indicates other dissipative processes may occur in the vicinity of the crack. We conduct Modified Ring Tests (MRT) on Carrara marble to

An analytical model based on global load sharing (GLS) theory is developed to guide design of fiber-reinforced hybrid composites with superior mechanical properties to single-fiber-type composites. The hybrid is assumed to comprise two types of fibers-low- ...

A novel mode II fracture test setup based on a simple tensile loading scenario with a discontinuous ply specimen is proposed in the paper as the first step towards determination of the cohesive law of composite layer interfaces. Key outputs of the procedur ...

Glass fiber-reinforced polymer (GFRP) materials are increasingly used in building construction for the design of multifunctional structures. These composite materials allow the integration of structural functions, building physics functions (mainly thermal insulation) and architectural functions (complex forms and color) in single large-scale building components. GFRP materials also allow the fabrication of translucent structural components with high degree of transparency when optically aligned resins and

Reverse total shoulder arthroplasty (rTSA) is recommended in case of severe muscle deficiency, along with important joint wear. Although having a correct placement of the prosthesis after the operation and a recovery of the mobility, several cases of scapula fracture are reported, in the region of the scapular spine or the acromion. Complication occurs 3 to 9 months after the surgery and may necessitate a second intervention. Such fractures are likely to be provoked by important stresses in the scapula, due

Direction reversals of intrinsic toroidal rotation have been observed in diverted Alcator C-Mod Ohmic L-mode plasmas following electron density ramps. For low density discharges, the core rotation is directed cocurrent, and reverses to countercurrent follo ...

Dramatic growth of urban populations in the developing countries is being a challenging issue in the upcoming decades. Tabriz is one of those megacities in the northwest of Iran with a rapid rate of development and modernization. As a consequence an urban-social segregation is being formed in the southeast of the city. To hinder such segregation a mix program that combines the traditional aspects of the urban development and modern life styles is proposed. Within this respect a residential complex built in

Structural stability issues in planar solid oxide fuel cells (SOFC) arise from the mismatch between the coefficients of thermal expansion (CTE) of the components. The stress state at operating temperature is the superposition of several contributions, which differ depending on the component. First, the cells undergo residual stresses due to the sintering phase during the manufacturing process. Furthermore, the load applied during the assembly of the stack to ensure the electric contact and flatten the cells

This paper examines the mechanisms by which a polymer is dispersed in a co-rotating twin-screw extruder. An experimental investigation of the morphological evolution has been carried out on a 45-mm co-rotating twin-screw extruder. Polyethylene/polystyrene (PE/PS) blends in the low concentration range (i.e., 5-15 wt% of PE) were used as a model system. The following general trends were observed. First, the minor phase right after melting is predominantly in a fibrillar form. Secondly, droplet and fiber diame

The effect of the presence of metabolism-induced concentration correlations in the calibration samples on the prediction performance of partial least-squares regression (PLSR) models and mid-infrared spectra from Chinese hamster ovary cell cultures was investigated. Samples collected from batch cultures contained highly correlated metabolite concentrations as a result of metabolic relations. Calibrations based on such samples could only be used to predict concentrations in new samples if a similar correlati

The parameters affecting the packing stress of fiber mats for melt impregnation, resin transfer molding and compression molding are systematically investigated. An analytical equation based on local bending of fibers, which was previously derived for non-impregnated networks, is applied to composite mats of dispersed planar bundles impregnated with molten polypropylene. It is shown that many simultaneous mechanisms interact during packing of impregnated bundle mats, in particular when the mats are needled.

What is the meaning' of a single spike? Spike-triggered averaging (reverse correlations') yields the typical input just before a spike. Similarly, cross-correlations describe the probability of firing an output spike given (one additional) presynaptic input spike. In this paper we analytically calculate reverse and cross-correlations for a spiking neuron model with escape noise. The influence of neuronal parameters (such as the membrane time constant, the noise level, and the mean firing rate) on the form

Correlation of index changes with stress changes in fibers containing UV-written Bragg gratings

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Development of soft electronic and optoelectronic fiber-based devices via the thermal drawing process

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