The engineering performance of eco-friendly concretes containing diatomite fly ash and ground granulated blast furnace slag

Approximately 10 % of CO2 is emitted from an ordinary Portland cement production. In cement and concrete production, CO2 emissions can be greatly reduced by using Supplementary Cementitious Materials (SCMs). In addition, the microstructure and durability properties of concrete are greatly improved when silica-rich SCMs are used. In this study, Eco-Friendly concrete design was carried out using three different SCMs. Diatomite, ground granulated blast furnace (GGBFS) and fly ash (FA) were used as the SCM in the concrete mixtures. SCMs were used instead of cement at ratios of 5, 10, 15, and 20 wt %. When diatomite was used at the rate of 20 %, the standard consistency water increased 1.7 times as compared to the reference mixture. With the increase in the replacement ratio, the final setting times of the pastes increased. The high active SiO2 content of diatomite shortened the initial setting time and increased the compressive strength. The use of 5 % diatomite reduced the slump value by 57 % as compared to the reference mixture. The slump and Ve-Be tests of GGBFS and FA mixtures showed similar properties to the reference mixture. The 28-day compressive strength of concrete varied between 29.2–34.6 MPa. With the increase in the curing time of the concrete mixtures, up to 50 % improvements were observed in the compressive strength. Especially on the 180th day, a compressive strength of 44.1 MPa was obtained in concrete mixtures with a 10 % replacement ratio. While using the FA in the mixtures improved the abrasion properties, the opposite result was observed in the case of the GGBFS. It was observed that the mixtures with 5 % FA showed the closest properties to the reference mixture. As a result, it was determined that SCMs with different properties could be used in environmentally friendly concrete mixtures by up to a 20 % replacement ratio

Optical properties of SiGe single crystals grown by liquid phase diffusion

In this article, we present measurements for the pseudo-optical functions of germanium-rich SixGe1-x (0.000<x<0.100) single-crystals(grown by Liquid Phase Diffusion; LPD) using spectroscopic ellipsometry and photo reflectance techniques in the energy range of 1.72–3.20 eV. The E1 interband transition energies are obtained from numerically differentiated optical spectra for various crystal compositions. It was shown that the values of E1 interband transition energy determined by both the ellipsometric and photo reflectance measurements for germanium-rich SixGe1-x single-crystals are in agreement with those of bulk SiGe crystals reported in the literature[21–24].The interband transition energies are found to be in the range of 2.100 and 2.215 eV for the composition values of 0.000<x0.100. The surface morphology of the crystals assayed via atomic force microscopy shows fibrous surfaces with the average grain size of 250 nm. The measured root-mean-square (rms) roughness and maximum height are in the range of 3.78–5.40 and 32.42–67.84 nm, respectively, with increasing germanium composition

Social norms regarding alcohol use and associated factors among university students in Turkey

Background: Misperceptions on the higher rates of peer alcohol use are predictive of increased personal use among university students. Objectives: This study aims to assess the prevalence, perceived peers’ social norms and other predictors of alcohol use in a sample of Turkish university students. Methods: This study is established upon the baseline Turkish data on alcohol use of the project Social Norms Intervention for the prevention of Polydrug usE (SNIPE). The data was obtained by a self-reported, online questionnaire from 858 students of Marmara University who were registered to the study web page. Results: Alcohol use and drunkenness rates were 62.6%, and 40.9%, respectively. Twenty point two percent of students reported drinking alcohol at least once a week in the last two months. Majority of students (70.4%) reported that religion has an important or very important role in their lives. Perceived higher frequency of peer alcohol use (p&lt;0.000) and drunkenness (p&lt;0.000) were significantly associated with personal alcohol use frequency. Tobacco use rate was 60.2% and positively associated with alcohol use frequency (p&lt;0.000). In all participants, male gender (OR: 1.56; 95% CI: 1.07-2.28), giving less importance to religion (OR: 20.91; 95% CI: 10.95-39.95), tobacco use everyday/almost everyday (OR: 17.88; 95% CI: 9.33-34.29), perceived positive peer attitude towards alcohol use (OR: 2.192; 95% CI: 1.25-3.82) and perceived higher frequency of peer alcohol use (OR: 3.487; 95% CI: 1.66-7.31) were found to be associated risk factors for alcohol use. Age (OR: 1.186, CI 95%: 1.03-1.36) and perceived positive peer attitude towards alcohol use (OR: 3.86, CI 95%: 1.84-8.09) were the additional risk factors among female student whereas perceived positive peer alcohol use frequency (OR: 8.08, CI 95%: 2.40-27.10) among male students. Discussion: As the first study conducted in Turkey applying social norms theory, our results indicate the noticeable misperceptions of students regarding their peers’ alcohol use. Based on our results, targeting both tobacco and alcohol use, and a gender-sensitive approach employing social norms interventions may enhance the preventive strategies for risky alcohol use among university students

Determination of Serum Adenosine Deaminase and Xanthine Oxidase Levels in Patients with Crimean–Congo Hemorrhagic Fever

OBJECTIVE: Crimean-Congo hemorrhagic fever is an acute viral hemorrhagic fever with a high mortality rate. Despite increasing knowledge about hemorrhagic fever viruses, little is known about the pathogenesis of Crimean-Congo hemorrhagic fever. In this study, we measured serum adenosine deaminase and xanthine oxidase levels in Crimean-Congo hemorrhagic fever patients. METHODS: Serum adenosine deaminase levels were measured with a sensitive colorimetric method described by Giusti and xanthine oxidase levels by the method of Worthington in 30 consecutive hospitalized patients (mean age 42.6 ± 21.0). Laboratory tests confirmed their diagnoses of Crimean-Congo hemorrhagic fever. Thirty-five subjects (mean age 42.9 ± 19.1) served as the control group. RESULTS: There was a significant difference in adenosine deaminase and xanthine oxidase levels between cases and controls (p<0.05). However, neither adenosine deaminase nor xanthine oxidase levels varied with the severity of disease in the cases assessed (p>0.05). CONCLUSION: Adenosine deaminase and xanthine oxidase levels were increased in patients with Crimean-Congo hemorrhagic fever. Elevated serum xanthine oxidase activity in patients with Crimean-Congo hemorrhagic fever may be associated with reactive oxygen species generated by the xanthine/xanthine oxidase system during inflammatory responses. In addition, elevated lipid peroxidation may contribute to cell damage and hemorrhage. The association of cell damage and hemorrhage with xanthine oxidase activity should be further investigated in large-scale studies

Trap-integrated fluorescence detection based on silicon photomultipliers in a cryogenic Penning trap

We present a fluorescence-detection system for laser-cooled 9Be+ ions based on silicon photomultipliers (SiPM) operated at 4 K and integrated into our cryogenic 1.9 T multi-Penning-trap system. Our approach enables fluorescence detection in a hermetically-sealed cryogenic Penning-trap chamber with limited optical access, where state-of-the-art detection using a telescope and photomultipliers at room temperature would be extremely difficult. We characterize the properties of the SiPM in a cryocooler at 4 K, where we measure a dark count rate below 1/s and a detection efficiency of 2.5(3) %. We further discuss the design of our cryogenic fluorescence-detection trap, and analyze the performance of our detection system by fluorescence spectroscopy of 9Be+ ion clouds during several runs of our experiment.Comment: 12 pages, 11 figure

Design and simulation of 2DOF coil based asynchronous actuator

Spherical asynchronous motors (or actuators) have been one of the more popular subjects recently. The rotor body with a spherical shape is able to rotate around any axis within the stator; furthermore, the spherical actuators are expected to be well-suited to micro robotic applications due to their compact structures and fast response times. In the present study, a model of a two-degree-of-freedom spherical induction motor consisting of several (2 rotors 3 stators) multi-winding coils has been proposed. The parameters to be used in the motor model, basically inductances and mutual inductances, have been determined by analytical solutions of Maxwell's equations. These inductance values have been compared with finite element results obtained by a commercial package and good agreement has been observed. Nonlinear equations of motion of the two coils (in the rotor) have been developed and simulations were carried out by applying 0-24 Volts to the five stator windings. The motor model was shown to produce a torque of 0.028 Nm at 150 rpm