Photonuclear reactions with Zinc: A case for clinical linacs

The use of bremsstrahlung photons produced by a linac to induce photonuclear reactions is wide spread. However, using a clinical linac to produce the photons is a new concept. We aimed to induce photonuclear reactions on zinc isotopes and measure the subsequent transition energies and half-lives. For this purpose, a bremsstrahlung photon beam of 18 MeV endpoint energy produced by the Philips SLI-25 linac has been used. The subsequent decay has been measured with a well-shielded single HPGe detector. The results obtained for transition energies are in good agreement with the literature data and in many cases surpass these in accuracy. For the half-lives, we are in agreement with the literature data, but do not achieve their precision. The obtained accuracy for the transition energies show what is achievable in an experiment such as ours. We demonstrate the usefulness and benefits of employing clinical linacs for nuclear physics experiments

The community ecology perspective of omics data

The measurement of uncharacterized pools of biological molecules through techniques such as metabarcoding, metagenomics, metatranscriptomics, metabolomics, and metaproteomics produces large, multivariate datasets. Analyses of these datasets have successfully been borrowed from community ecology to characterize the molecular diversity of samples (ɑ-diversity) and to assess how these profiles change in response to experimental treatments or across gradients (β-diversity). However, sample preparation and data collection methods generate biases and noise which confound molecular diversity estimates and require special attention. Here, we examine how technical biases and noise that are introduced into multivariate molecular data affect the estimation of the components of diversity (i.e., total number of different molecular species, or entities; total number of molecules; and the abundance distribution of molecular entities). We then explore under which conditions these biases affect the measurement of ɑ- and β-diversity and highlight how novel methods commonly used in community ecology can be adopted to improve the interpretation and integration of multivariate molecular data. Video Abstract

A MAC Mode for Lightweight Block Ciphers

status: accepte

Relationships of temperature and biodiversity with stability of natural aquatic food webs

Temperature and biodiversity changes occur in concert, but their joint effects on ecological stability of natural food webs are unknown. Here, we assess these relationships in 19 planktonic food webs. We estimate stability as structural stability (using the volume contraction rate) and temporal stability (using the temporal variation of species abundances). Warmer temperatures were associated with lower structural and temporal stability, while biodiversity had no consistent effects on either stability property. While species richness was associated with lower structural stability and higher temporal stability, Simpson diversity was associated with higher temporal stability. The responses of structural stability were linked to disproportionate contributions from two trophic groups (predators and consumers), while the responses of temporal stability were linked both to synchrony of all species within the food web and distinctive contributions from three trophic groups (predators, consumers, and producers). Our results suggest that, in natural ecosystems, warmer temperatures can erode ecosystem stability, while biodiversity changes may not have consistent effects

Oscillation of second order nonlinear impulsive difference equations with continuous variables

This paper is concerned with a second order nonlinear impulsive difference equation with continuous variable. By using a nonimpulsive inequality sufficient conditions for the oscillation of impulsive difference equation are obtained.Розглянуто нелiнiйнi iмпульснi рiзницевi рiвняння другого порядку з неперервним аргументом. Використовуючи неiмпульсну нерiвнiсть, отримано достатнi умови осциляцiї iмпульсних рiзницевих рiвнянь

Accumulaton of metal and metal mixture in the spleen, brain and muscle tissues of Tilapia nilotica [Tilapia nilotica'da metal ve metal karişiminin dalak, beyin ve kas dokularindaki birikimi]

Accumulation of zinc and copper in the spleen, brain and muscle tisses of Tilapia nilotica was investigated by using copper (0.1, 0.5 and 1.0 ppm) and zinc (1.0, 5.0 and 10.0 ppm) and copper-zinc mixture (0.1+1.0, 0.5+5.0 and 1.0+10.0 ppm) in the medium for the periods of 30 and 60 days. No mortality was observed during the exposure to of copper, zinc and copper-zinc mixtures over 60 days In both cases (alone and mixture) the highest levels of zinc and copper were accumulated in the spleen, whereas accumulation was the lowest in the brain. Accumulation of a metal in the tissues decreased in the presence of the other metal

Saptırmalı ve saptırmasız dizilmiş kesik konik pimlerde ısı transfer katsayısı ve basınç kaybının bulunması

Bu çalışmada dikdörtgen kesitli bir kanal içersine yerleştirilmiş saptırmalı ve saptırmasız dizilmiş kesik konik pimlerde ısı transfer katsayısı ve basınç kaybı incelendi. Pimler arasındaki akışa dik ve paralel mesafeler değiştirilerek deneyler tekrarlandı.Reynolds sayısına bağlı olarak Nu sayısı ve basınç kayıp katsayısı f için saptırmalı ve saptırmasız dizilişler için en küçük kareler metodu kullanılarak yeni korelasyonlar geliştirildi. Geliştirilen korelasyonlar deneysel datalarla ve literatürdeki korelasyonlarla karşılaştırıldı. Isı transfer korelasyon katsayısı saptırmalı ve saptırmasız dizilişler için 690$\leq Re\leq$ 3110 aralığında L/D oranı 4.4 için sırasıyla 0.9742 ve 0.87988 olarak bulundu. Basınç kayıp katsayısı korelasyon katsayısı aynı yüzeylerde sırasıyla 0.96410 ve 0.99334 olarak bulundu. Isı transferi, saptırmalı yüzeylerde saptırmasız yüzeylerdekine göre % 22 daha fazla bulundu.In this study, the heat transfer and the pressure drop are experimentally examined on truncated short conic pins with staggered and in line arrays. Pins are inserted into the channel having rectangular cross-section. The axis intervals of the pins, which are perpendicular to the direction of flow and parallel to the direction of flow, are changed for the each experiment. Correlations are developed for Nu number and pressure drop coefficient depending on Re number by using the least-squares method. The correlations are compared with experimental data and other correlation in the literature. It is found that the correlations agree satisfactorily with experimental data. The correlation coefficient of heat transfer for staggered and in-line arrays are found to be 0.9742 and 0.87988 respectively in a Re number range of 690$\leq Re\leq$ 3110 with a L/D ratio, of 4.4. The correlation coefficients of pressure drop for same arrays are 0.96410 and 0.99334 respectively, The heat transfer rate is enhanced % 22 in staggered array of the pins with respect to in-line arrays

Calculation of heat transfer coefficient in staggered arrays of rectangular pin fins

Bu çalışmada, dikdörtgen kesitli bir kanal içine yerleştirilmiş dikdörtgen geometriye sahip pim kanatlardan ısı geçişi deneysel olarak incelenmiştir. Çalışmanın amacı, fan yardımıyla emilen havanın dikdörtgen kesitli bir kanal içine yerleştirilen ve kanalı tamamen dolduran dikdörtgen kanatlı yüzeylerde ısı geçişi deneysel olarak tespit edilerek elde edilen deneysel verilerden bir korelasyon denklemi elde etmektir. Deneysel çalışmada, kanalın sadece bir yüzeyinden sabit ısı akısı olduğu durumdaki çeşitli dizilişler denenmiştir. Yapılan çalışmada dikdörtgen kanat ölçüleri sabit tutulmuştur. Saptamalı dizilişler için akışa paralel yöndeki kanat eksenleri arasındaki mesafeler değiştirilerek toplam 3 adet farklı levha denenmiştir. Farklı dizilişlere sahip her levha için laminer ve türbülansu akıştaki çeşitli Re sayılarında ölçmeler yapılmış, Nu sayısı ve ısı taşınım katsayısı belirlenmiş, en küçük kareler metoduyla deney sonuçlarına uyan bir korelasyon geliştirilmiştir.In this study, the heat transfer in rectangular pin fins which placed in a channel of rectangular cross section is experimentally investigated. The purpose of the study is to obtain a correlation from the experimental data for heat transfer in rectangular pin,fin surfaces placed in a rectangular channel. Various arrays in a position where there is constant heat flux on only one side of the channel are tested in the experimental study. Rectangular pin fin dimensions are kept constant during the study. Three different plates are tested by chancing the distances between the pin fin axes parallel to the flow direction for the staggered arrays. Measurements are taken from different Re numbers in laminar and turbulent flow for each plate having different arrays. Nu number and heat transfer coefficient are determined and a correlation which agrees with experimental data is developed using the least-squaies method