13,724 research outputs found
UV-filter pollution: current concerns and future prospects.
UV-filters are widely used in cosmetics and personal care products to protect users' skin from redamage caused by ultraviolet (UV) radiation from the sun. Globally, an estimated 16,000 to 25,000 tonnes of products containing UV-filters were used in 2014 with modern consumption likely to be much higher. Beyond this use in cosmetics and personal care products, UV-filters are also widely used to provide UV-stability in industrial products such as paints and plastics. This review discusses the main routes by which UV-filters enter aquatic environments and summarises the conclusions of studies from the past 10 years that have investigated the effects of UV-filters on environmentally relevant species including corals, microalgae, fish, and marine mammals. Safety data regarding the potential impact of UV-filters on human health are also discussed. Finally, we explore the challenges surrounding UV-filter removal and research on more environmentally friendly alternatives to current UV-filters. [Abstract copyright: © 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.
Millimeter wave surface resistance of RBa2Cu3O(7-delta) (R=Y,Eu,Dy,Sm,Er) superconductors
The measurements are reported of the millimeter wave surface resistance R(sub s) at 58.6 GHz of bulk samples of RBa2Cu3O(7-delta) (R = Y,Eu,Dy,Sm,Er) and of YBa2Cu3O(7-delta) superconducting films, in the temperature range from 20 to 300 K. The bulk samples were prepared by cold pressing the powders of RBa2Cu3O(7-delta) into one in. disks. The powders were prepared by several sinterings in one atmosphere of oxygen at 925 C, with grindings between sinterings, to obtain the superconducting phase. The thin films were deposited on SrTiO3 and LaGaO3 substrates by pulsed laser ablation. Each sample was measured by replacing the end wall of a gold-plated Te sub 013 circular mode copper cavity with the sample and determining the cavity quality factor . From the difference in the Q-factor of the cavity, with and without the sample, the R(sub s) of the sample was determined
Determination of surface resistance and magnetic penetration depth of superconducting YBa2Cu3O(7-delta) thin films by microwave power transmission measurements
A novel waveguide power transmission measurement technique was developed to extract the complex conductivity of superconducting thin films at microwave frequencies. The microwave conductivity was taken of two laser ablated YBa2Cu3O(7-delta) thin films on LaAlO3 with transition temperatures of approx. 86.3 and 82 K, respectively, in the temperature range 25 to 300 K. From the conductivity values, the penetration depth was found to be approx. 0.54 and 0.43 micron, and the surface resistance (R sub s) to be approx. 24 and 36 micro-Ohms at 36 GHz and 76 K for the two films under consideration. The R sub s values were compared with those obtained from the change in the Q-factor of a 36 GHz Te sub 011-mode (OFHC) copper cavity by replacing one of its end walls with the superconducting sample. This technique allows noninvasive characterization of high transition temperature superconducting thin films at microwave frequencies
Arrival directions of large air showers, low-mu showers and old-age low-mu air showers observed at St. Chacaltaya
Arrival directions of air showers with primary energies in the range 10 to the 16.5 power eV to 10 to the 18th power eV show the first harmonic in right ascension (RA) with amplitude of 2.7 + or - 1.0% and phase of 13-16h. However, the second harmonic in RA slightly seen for showers in the range 10 to the 18th power eV to 10 to the 19th power eV disappeared by accumulation of observed showers. The distribution of arrival directions of low-mu air showers with primary energies around 10 to the 15th power eV observed at Chacaltaya from 1962 to 1967 is referred to, relating to the above-mentioned first harmonic. Also presented in this paper are arrival directions of old-age low-mu air showers observed at Chacaltaya from 1962 to 1967, for recent interest in gamma-ray air showers
Energetic delayed hadrons in large air showers observed at 5200m above sea level
Energetic delayed hadrons in air showers with electron sizes in the range 10 to the 6th power to 10 to the 9th power were studied by observing the delayed bursts produced in the shield of nine square meter scintillation detectors in the Chacaltaya air-shower array. The frequency of such delayed burst is presented as a function of electron size, core distance and sec theta
Millimeter wave transmission studies of YBa2Cu3O7-delta thin films in the 26.5 to 40.0 GHz frequency range
Millimeter wave transmission measurements through YBa2Cu3O(7-delta) thin films on MgO, ZrO2 and LaAlO3 substrates, are reported. The films (approx. 1 micron) were deposited by sequential evaporation and laser ablation techniques. Transition temperatures T sub c, ranging from 89.7 K for the Laser Ablated film on LaAlO3 to approximately 72 K for the sequentially evaporated film on MgO, were obtained. The values of the real and imaginary parts of the complex conductivity, sigma 1 and sigma 2, are obtained from the transmission data, assuming a two fluid model. The BCS approach is used to calculate values for an effective energy gap from the obtained values of sigma sub 1. A range of gap values from 2 DELTA o/K sub B T sub c = 4.19 to 4.35 was obtained. The magnetic penetration depth is evaluated from the deduced values of sigma 2. These results are discussed together with the frequency dependence of the normalized transmission amplitude, P/P sub c, below and above T sub c
Analisis Pengelolaan Area Bermain Outdoor Pada Anak Usia 4-5 Tahun Di Tk Lkia Pontianak
ANALISIS PENGELOLAAN AREA BERMAIN OUTDOOR PADA ANAK USIA 4-5 TAHUN DI TK LKIA PONTIANAK Abstrak: Penelitian ini bertujuan untuk mendeskripsikan pengelolaan area bermain outdoor pada anak usia 4-5 tahun di TK LKIA Pontianak. Metode penelitian yang digunakan adalah deskriptif dan menggunakan pendekatan kualitatif. Teknik yang digunakan dalam penelitian ini adalah teknik observasi, wawancara, dokumentasi dengan alat pengumpul data yaitu panduan wawancara, observasi, dokumentasi dan catatan lapangan. Dari hasil penelitian diperoleh bahwa perencanaan pengelolaan dilakukan pihak lembaga, pelaksanaan kegiatan melibatkan anak, guru, dan kepala TK, pengaturan dilakukan pihak lembaga dan kepala TK, pengawasan dan pengendalian dilakukan guru dengan berada langsung di area bermain outdoor guna mengawasi anak, kendala yang dihadapi guru dan kepala TK adalah kendala area bermain yang sempit,mengatur ulang alat permainan,waktu pengerjaan dari pihak lembaga,dan orang tua, sedangkan cara yang digunakan guru untuk mengatasi kendala tersebut dengan selalu mengawasi dan mengendalikan area bermain outdoor dengan baik. Kata Kunci : Pengelolaan, Area Bermain Outdoor, Prinsip Pengelolaan Abstract: This study aimed to describe the management of outdoor play areas for children aged 4-5 years in kindergarten LKIA Pontianak. The method used is descriptive and qualitative approach. The technique used in this research is observation, interview, documentation of the data collection tool that interview, observation, documentation and field notes. The result showed that the management planning conducted by agencies, the implementation of activities involving children, teachers, and heads of kindergartens, setting conducted by the institute and head of the kindergarten, supervision and control of teachers do with being directly in the play area outdoor to monitor children, the obstacles faced by teachers and the head of the kindergarten is a narrow constraints play area, reset the game equipment, the processing time of the institution, and the elderly, while the way that teachers use to overcome these obstacles by always supervising and controlling the outdoor play area well
Update to the Neutrino-Electron Scattering in Left-Right Symmetric Models
In a previous paper we study the neutrino-electron scattering in the
framework of a left-right symmetric model (LRSM). Constraints on the LRSM
parameters and were obtained. Based on new measurements we
present an update to these constraints and also include in the calculation the
radiative corrections.Comment: LaTex file, 4 pages and 3 uuencoded postscript figure
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