Real-time Ultraviolet Radiation Sensor Based on Modified Cladding Optical Fibers Technology

In this work, the performance of single-mode optical fibers (SMFs) for ultraviolet (UV) radiation monitoring and dosimetry applications is presented. In particular, this work will focus on the Radiation-Induced Absorption (RIA) phenomena in the Near-Infrared domain (NIR). Such phenomena play a very important role in the sensing mechanism for SMF. Single mode fibers with a diameter of 50 µm were used for this purpose. These fibers were dipped into germanium (Ge) solution with different concentrations (1, 3, and 5 wt%) to produce the sensing part of the sensor. For all optical fiber sensors under investigation, the results indicated the dependence of the RIA on the applied UV radiation energy. Also, a redshift in peak wavelength was obtained. The influence of Ge concentration on sensing efficiency was studied and the best results were obtained with 3 wt% concentration as compared to 1 wt % and 5 wt % concentrations. The presented sensor shows good sensitivity to UV radiation which makes it possible to be applied in medical applications.

Efficiency of food egg production used for keeping layers of monochrome light with different wavelengths

Artificial light, as an environmental factor, is crucial for the release of hormones that play a key role in a bird's life, growth, immunity and reproduction. For laying hens, light plays an important role in the development and functioning of the reproductive system, significantly affecting the age of laying the first egg, egg-laying and productivity in general. The source of artificial light of the latest generation in poultry farming is LED lamps. Compared to incandescent and fluorescent lamps, LEDs have a longer service life, specific spectrum, lower heat output, higher energy efficiency and reliability, as well as lower maintenance costs, so they are increasingly used by manufacturers. LEDs are a special type of semiconductor diode that can give monochrome light. However, information on the effect of monochrome light with different wavelengths of light on the physiological state of the hens’ body is quite contradictory. Therefore, the aim of the work was to study the efficiency of egg production using monochrome light with different wavelengths. For this purpose, in the conditions of a modern complex for production of food eggs in a poultry house with an area of 2915 m2, 4 groups of hens of the industrial herd "Hy-Line W-36" were formed, each of which was kept in a separate poultry house similar in area and cage equipment. Each poultry house was equipped with cage batteries "Big Dutchman" (Germany), consisting of 1176 cages with an area of 40544 cm2 (362 × 112 cm). The differences between the poultry houses applied only to LED lamps. Thus, hens of the 1st group were kept using LED lamps with a peak light wavelength of 458 nm (blue color of the spectrum), the 2nd group – 603 nm (yellow color of the spectrum), the 3rd group – 632 nm (orange color of the spectrum) and the 4th group – 653 nm (red color of the spectrum). Every day, for 44 weeks of the productive period, the number of eggs laid by the laying hens of each group and the intensity of their laying were determined. The number of hatched hens (due to death and culling) was also counted daily and the number of livestock was determined. Once a week, the weight of eggs and live weight of laying hens were measured from certain labeled cages according to a sample. The European egg production rate on the basis of productivity was determined. It was found that for the maintenance of laying hens of modern white-egg crosses in 12-tier cage batteries of classical designs, it is advisable to use lighting with a peak wavelength of 653 nm, that is with red light. This makes it possible for the 44-week egg-laying period to receive an additional 4.8–18.8 million eggs from each poultry house (0.4–1.6 thousand eggs per 1 m2 of its area) at the highest level of the European egg production rate at 1.0–3.8 units The decrease in the peak wavelength from 653 to 632 nm, which was manifested by a change in light from red to orange, was accompanied by a decrease in the preservation of livestock by 0.7% (3.8% ˂ normal), body weight – by 0.6% within physiological norms, egg-laying per initial laying hen – by 2.9% (5.3% ˂ norm), which caused a decrease in the gross yield of eggs by 4.5 million eggs and egg mass – by 3273 tons from each poultry house, including 1.6 thousand eggs and 112.3 kg per 1 m2 of its area, with a decrease in the level of European egg production rate by 1.0 units. The decrease in the peak wavelength to 603 nm, that is the change in the color of light from red and orange to yellow, was accompanied by a decrease in the preservation of livestock by 6.0–6.7% (9.8% ˂ normal), body weight – by 1.0 –1.7% within the physiological norm, egg-laying per initial laying hen – by 6.6–10.3% (11.6% ˂ of the norm) and feed consumption – by 0.6–0.7% (7.5%) > norms), which led to a decrease in gross egg yield by 7.8–12.6 million eggs and egg mass – by 505.7–833.0 tons from each poultry house, including 2.7–4.3 thousand eggs and 173.5–285.8 kg per 1 m2 of its area, with a decrease in the level of the European egg production rate by 1.6–2.6 units. The decrease in the peak wavelength to 458 nm, that is the change in light color from red, orange and yellow to blue, is accompanied by a decrease in the preservation of livestock by 4.2–10.9% (14.0% ˂ normal), body weight – by 2,3–4.0% (0.2% ˂ of the norm), egg-laying per initial laying hen – by 5.6–15.3% (16.5% ˂ of the norm) and feed costs – by 2.0–2.7 % (5.3%> norms), which led to a decrease in gross egg yield by 6.1–18.8 million eggs and egg mass – by 365.3–1198.3 tons from each poultry house, including 2.1–6.4 thousand eggs and 125.3–288.9 kg per 1 m2 of its area, with a decrease in the level of the European egg production rate by 1.2–3.8 units.

Influence of light wavelength on viability and reproductive function of hens

The article presents the results of influence of monochrome light with different light wavelengths on the hens’ viability and productivity. For this purpose, in the conditions of a modern complex for production of food eggs in a poultry house with an area of 2915 m2, 4 groups of hens of the industrial herd “Hy-Line W-36” were formed, each of which was kept in a separate poultry house similar in area and cage equipment. Each poultry house was equipped with “Big Dutchman” cage batteries, consisting of 1176 cages with an area of 40544 cm2. The differences between the poultry houses applied only to LED lamps. Hens of the 1st group were kept using LED lamps with a peak light wavelength of 458 nm (blue color of the spectrum), the 2nd group – 603 nm (yellow color of the spectrum), the 3rd group – 632 nm (orange color of the spectrum) and 4 groups – 653 nm (red color of the spectrum). Every day, for 34 weeks of the productive period (up to 52 weeks of age), the number of eggs laid by the laying hens of each group was determined. The number of hatched hens (due to death and culling) was also counted daily and the number of livestock was determined. Once a week, the weight of eggs and live weight of laying hens were measured from certain labeled cages. It was found that the reduction of the wavelength of light during the keeping of hens in the cages of multi-tiered batteries affects their viability and reproductive function. The decrease in the peak wavelength from 653 to 632 nm, which was manifested by a change in the color of light from red to orange, was accompanied by a decrease in the preservation by 0.3 %, body weight – by 0.8 %, egg laying on the initial laying – by 3.1 %, egg-laying per average laying hen – by 2.8 % and feed costs – by 0.2 %. The decrease in the peak wavelength to 603 nm, that is the change in the color of light from red and orange to yellow, was accompanied by a decrease in the preservation by 6.4–6.7 %, body weight – by 0.5–1.3 %, egg production by initial laying hen – by 7.1–10.0 %, laying hens on the average laying hen – by 0.4–3.2 % and feed costs – by 2.0–2.1 %. The decrease in the peak wavelength to 458 nm, that is the change in light color from red, orange and yellow to blue, was accompanied by a decrease in the preservation by 3.2–9.9 %, body weight – by 5.2–6.5 %, laying hens per initial laying hen – by 6.4–15.8 %, laying hens per middle laying hen – by 2.9–6.0 % and feed costs – by 1.0–3.1 %.

Emergence of Solitons from Irregular Waves in Deep Water

Numerical simulations were performed to study the long-distance evolution of irregular waves in deep water. It was observed that some solitons, which are the theoretical solutions of the nonlinear Schrödinger equation, emerged spontaneously as irregular wave trains propagated in deep water. The solitons propagated approximately at a speed of the linear group velocity. All the solitons had a relatively large amplitude and one detected soliton’s height was two times larger than the significant wave height of the wave train, therefore satisfying the rogue wave definition. The numerical results showed that solitons can persist for a long distance, reaching about 65 times the peak wavelength. By analyzing the spatial variations of these solitons in both time and spectral domains, it is found that the third-and higher-order resonant interactions and dispersion effects played significant roles in the formation of solitons.

Cortex Thickness Is Key for the Colors of Iridescent Starling Feather Barbules With a Single, Organized Melanosome Layer

The iridescent plumage of many birds is structurally colored due to an orderly arrangement of melanosomes in their feather barbules. Here, we investigated the blue- to purple-colored feathers of the European starling (Sturnus vulgaris) and the blue and green feathers of the Cape starling (Lamprotornis nitens). In both cases, the barbules contain essentially a single layer of melanosomes, but in S. vulgaris they are solid and rod-shaped, and in L. nitens they are hollow and rod- as well as platelet-shaped. We analyzed the coloration of the feathers by applying imaging scatterometry, bifurcated-probe- and micro-spectrophotometry. The reflectance spectra of the feathers of the European starling showed multiple peaks and a distinct, single peak for the Cape starling feathers. Assuming that the barbules of the two starling species contain a simple multilayer, consisting locally only of a cortex plus a single layer of melanosomes, we interpret the experimental data by applying effective-medium-multilayer modeling. The optical modeling provides quantitative insight into the function of the keratin cortex thickness, being the principal factor to determine the peak wavelength of the reflectance bands; the melanosome layer only plays a minor role. The air cavity in the hollow melanosomes of the Cape starling creates a strongly enhanced refractive index contrast, thus very effectively causing a high reflectance.

Understanding the Luminescence Characteristics of Ultraviolet InGaN/AlGaN Multiple Quantum Wells with Different In Gradients

The electroluminescence (EL) properties of InGaN/AlGaN ultraviolet light-emitting multiple quantum wells (MQWs) with identical average In content but different In gradients (In content increases linearly, along the growth direction) are investigated numerically. It is found that the luminescence efficiency is improved, and the EL spectral peak wavelength becomes longer for the MQW sample with a larger In gradient. Since the influence of In gradient is different for the conduction and valence bands in InGaN layers, the distribution of electrons and holes in QWs may be changed, leading to a redshift of EL spectra. In particular, when the In gradient increases, the overlap integral of electron-hole wavefunction in InGaN QWs increases, resulting in a higher radiative recombination rate and an enhanced EL intensity.

Statistical Modelling of Photonic Crystal Fibre Based Surface Plasmon Resonance Sensors Resonant Peak Wavelength for Tolerance Studies

We report a statistical approach to model the resonant peak wavelength (RPW) equation(s) of a photonic crystal fibre (PCF)-based surface plasmon resonance (SPR) sensors in terms of the PCF structural parameters (air-hole diameter, pitch, core diameter and gold layer thickness) at various tolerance levels. Design of experiments (statistical tool) is used to investigate the role played by the PCF structural parameters for sensing performance evaluation—RPW, across three tolerance levels (±2%, ±5% and ±10%). Pitch of the hollow-core PCF was discovered to be the major influencing parameter for the sensing performance (RPW) of the PCF-based SPR sensor while the inner metal (gold) layer thickness and core diameter are the least contributing parameters. This novel statistical method to derive the sensing performance parameter(s) of the PCF-based SPR sensors can be applied effectively and efficiently in the designing, characterisation, tolerance analysis not only at the research level, but also in optical fibre sensor fabrication industry to improve efficiency and lower cost.

Characteristics of Dye-doped Silica Nanoparticles- Based Random Lasers in the Air and Water

Random lasers based on dye-doped silica nanoparticles are attracted for biomedical applications due to their biocompatibility and high brightness. Several laser structures including silica powder and film have been reported. However, the dependence of lasing characteristics including lasing threshold and emission wavelength on the laser size and working environment have not been explored. Here, we demonstrate and compare the lasing characteristics of dye-doped silica random lasers in air and water. These lasers present in thin structures, the so-called microslices, with a thickness of 1 µm and various dimensions from 30 to 300 µm. It is found that the lasing threshold (Ith) decreases with increasing laser size such as for sample in the air and for sample in water, where A the sample surface area. For a similar size, the lasing threshold of the sample in water is about 3-8 times higher than that of the sample in the air. In addition, the lasing peak wavelength exhibits a red-shift with increasing laser size. In the air, a shift of 8 nm is recorded when the sample surface area increases from 21×103 to 169×103 µm2. Furthermore, for a similar size, the lasing wavelength of the sample in the air is also red-shifted (13 nm in average ) compared with that of the sample in water. Our finding provides useful information for the use of silica-based random lasers in bioimaging and biosensing applications.