Effect of Granular Waste Compact Disc on Bond Strength between Steel Bars and Surrounding Concrete

In recent decades, researchers have tried to use waste materials as a partial or complete replacement of the gravel ingredients of concrete to reduce environmental impact. One of these materials is electronic waste. The problem of this disposal material, particularly outdated CDs and DVDs, has turned out to be serious. In this study, 36 pull-out cylindrical shape test specimens were used to conduct an ASTM C234-91A-compliant pull-out test to measure the bonding behavior and strength between three sizes of steel bars and concrete with different embedded lengths, including waste disc shreds (CD and DVD) as a partial substitute for fine aggregate. Four groups of modified concrete specimens with different percentages of disc shreds as partial replacements for sand were prepared. The ratio of cement:sand+disc:coarse aggregate:water was 1:2:2.5:0.4. The disc shreds were utilized to substitute partially for fine aggregate in four different weight percentages: 0%, 4%, 8%, and 12%; nevertheless, the cement-to-sand ratio was consistently 2. Results demonstrated that the bond strength is considerably influenced by the bar diameter and the disc shreds (CDs and DVDs) used as a partial replacement for fine aggregate. The bond strength behavior of the modified concrete with disc fibers is comparable with that of traditional concrete. The ACI-318 Code for the bond strength of ordinary Portland cement concrete was modified to calculate the bond strength of this new kind of disc concrete

Experimental and numerical investigation of the effect of water cooling on the temperature distribution of photovoltaic modules using copper pipes

In hot climates, PV efficiency drops dramatically if the surface temperature of the panels rises over a specific limit. Consequently, a cooling system is required to preserve PV modules as close to their operating temperature as feasible. For this purpose, the influence of an increase in PV surface temperature on PV performance was studied experimentally and numerically at the Research Institute of Petroleum Industry (RIPI) in July. The current study uses a cooling system consisting of rows of copper pipes connected to the PV backside. The experiments are conducted for four distinct scenarios, each with a different input fluid temperature ranging from 19.5 to 61 °C. The parametric analysis focuses on three influential factors: ambient temperature, solar radiation, and fluid inlet temperatures. In addition, other inputs are configured in accordance with the experimental conditions. The results showed that installing a cooling water system decreased the PV surface temperature from 60.20 °C to 40.24 °C at 9:00 am and from 73.98 °C to 73.33 °C at 1:30 pm. Furthermore, the electrical, thermal, overall, and exergy efficiencies drop as radiation intensity and water inlet temperature increase. In addition, the numerical results are validated with the experimental ones, and it shows high degrees of concordance

Terabit indoor laser-based wireless communications : LiFi 2.0 for 6G

This paper provides a summary of available technologies required for implementing indoor laser-based wireless networks capable of achieving aggregate data-rates of terabits per second as widely accepted as a sixth generation (6G) key performance indicator. The main focus of this paper is on the technologies supporting the near infrared region of the optical spectrum. The main challenges in the design of the transmitter and receiver systems and communication/networking schemes are identified and new insights are provided. This paper also covers the previous and recent standards as well as industrial applications for optical wireless communications (OWC) and LiFi

Effect of gold nanoparticles on the optical properties of Rhodamine 6G

Gold nanoparticles are synthesized by the laser ablation method and characterized by transmission electron microscopy and UV-visible absorption spectroscopy. The absorption and emission spectra and powers of Rhodamine 6G in the absence and presence of 27 nm diameter gold nanoparticles were studied. Empirical measurements represented that presence of gold nanoparticles lead to decrease the fluorescence power and fluorescence quantum yield, and increase the absorbance and absorbed power of Rhodamine 6G. Also, Stern-Volmer quenching constant of dye in proximity of nanoparticles shows high value which implies efficient quenching of the dye fluorescence by gold nanoparticles. Fluorescence quantum yield, radiative and nonradiative decay rate of Rhodamine 6G-gold nanoparticles assembly, in parallel orientation, as a function of dye’s dipole moment distance from gold nanoparticle’s surface, based on Gersten-Nitzan model, are calculated. Calculations show variations of the fluorescence quenching is strongly depended on the distance between the dye molecules and the Nps’ surface. Also, calculated radiative decay rate indicates good agreement with the experimental value, and results of the ratio of the nonradiative to the radiative decay rate of Rhodamine 6G-gold nanoparticles mixture show nonradiative energy transfer is better explained in terms of NSET rather than FRET mechanism

Habitat suitability prediction for Salamandra infraimmaculata (Caudata: Amphibia) in western Iran based on species distribution modeling

Salamandra infraimmaculata is a member of family Salamandridae that is distributed in Iran, Turkey, and Lebanon. We surveyed habitat suitability predictions for the species in Kurdistan province, Western Iran. Distribution prediction showed excellent performance (area under the curve = 0.962), with temperature seasonality (47.8%) and precipitation of coldest quarter (38.4%) being two main bioclimatic variables predicting species presence. Temperature and precipitation are two dependent variables on which vegetation and habitat type depend. Slopes of the western Zagros Mountains have moist and temperate oak forests that contain many springs. The presence of both oak forests and water resources may allow the establishment of populations of fire salamanders in the region. As the forests are decreasing because of human activities, the amount of suitable habitats for this species is also decreasing. It is necessary to develop and implement conservation programs to protect the oak forests on the western slopes of the Zagros

Immunolocalization of Insulin-Like Growth Factor-I and its Immunoreactivity during Ovary Developmental Stages of Persian Sturgeon Acipenser Persicus

Objective: Immunohistochemical localization and immunoreactivity of insulin-like growthfactor-I (IGF-I) were investigated during the ovarian developmental stages in Persian sturgeon.In addition, the effects of growth hormone and thyroxine were investigated on IGF-Iimmunoreactivity in vitro.Materials and Methods: Ovarian samples were taken from two brood stocks (caughtfrom the sea and from a river) during their reproductive migration and at three different developmentalstages based on their polarization index (PI). The effects of two hormones onIGF-I immunoreactivity were studied at two ovarian developmental stages (PI > 0.1 andPI < 0.07). In both experiments the immunoperoxidase method was performed in order todetect immunohistochemical localization and immunoreactivity of IGF-I.Results: Immunohistochemical localizations of IGFI were detected in the follicular layers.There was no significant immunoreactivity difference between the two brood stocks,however in the river brood stock IGF-I immunoreactivity was more intense in the ovarieswith PI < 0.07 than of PI > 0.1 (p < 0.05). Growth hormone (10 ng/ml) increased IGF-I immunoreactivityin ovarian samples from the river brood stock when their PI was less than0.07, however thyroxine had not such effect (p < 0.05).Conclusion: Our results showed that IGF-I is present in the ovaries of Persian sturgeonand its reactivity is different among their gonadal development stages. This may supporta role for IGF-I during reproductive physiology in female brood stocks of the Persian sturgeon.Moreover, growth hormone is a potential hormone to increase IGF-I immunoreactivityin the ovaries of this species

Automated Video-Based Analysis of Contractility and Calcium Flux in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes Cultured over Different Spatial Scales

Contractile motion is the simplest metric of cardiomyocyte health in vitro, but unbiased quantification is challenging. We describe a rapid automated method, requiring only standard video microscopy, to analyze the contractility of human-induced pluripotent stem cell-derived cardiomyocytes (iPS-CM). New algorithms for generating and filtering motion vectors combined with a newly developed isogenic iPSC line harboring genetically encoded calcium indicator, GCaMP6f, allow simultaneous user-independent measurement and analysis of the coupling between calcium flux and contractility. The relative performance of these algorithms, in terms of improving signal to noise, was tested. Applying these algorithms allowed analysis of contractility in iPS-CM cultured over multiple spatial scales from single cells to three-dimensional constructs. This open source software was validated with analysis of isoproterenol response in these cells, and can be applied in future studies comparing the drug responsiveness of iPS-CM cultured in different microenvironments in the context of tissue engineering

Terabit Indoor Laser-Based Wireless Communications: Lifi 2.0 For 6G

International audienceThis article introduces the general concepts of light fidelity (LiFi) 2.0 for sixth generation (6G) of wireless networks that will be based on indoor laser-based wireless networks capable of achieving aggregate data-rates of terabits per second as widely accepted as a 6G key performance indicator. The main focus of this article is on the technologies supporting the near infrared region of the optical spectrum. The main challenges in the design of the transmitter and receiver systems and communication/networking schemes are identified and new insights are provided. This article also covers the previous and recent standards as well as industrial applications for optical wireless communications (OWC) and LiFi