A New Technique for Measuring Laser Pulse Energy Using PZT/SiO2

This paper presents a novel laser pulse energy measurement method based on photoacoustic converters. The concept of paper design and built energy meters using PZT as three specimens have a diameter of (20, 24, and 25) mm, and coating SiO2 was chosen in this test because it has special properties, is affordable, and is compact in size. Genetic energy meters are expensive. Comparing the genetic meter (used in this study that is manufactured of pyroelectric material and PZT/SiO2). The outcomes demonstrated that within the laser pulse's energy (100-400mJ). Peak voltage values for PZT composites range from 0.48 to 0.84 volts at the voltage output as their diameter increases (PZT-S with a diameter of 20 mm). The output voltage ranges for PZT-M (diameter 24 mm) and PZT-B (diameter 25 mm) are 0.18 to 0.68 volts and 0.08 to 0.56 volts, respectively. The design has been built and characterized by measured voltage and energy meter sources. A piezoelectric actuator had been fabricated on silicon sand wafer composites by converting the light waves (the laser pulse) into shock waves. Unlike the energy meter type (pyroelectric) for genetic-, the energy meter created in (PZT/SiO2) is unaffected by Damage caused by high temperatures from laser Nd:YAG pulse energy

The Influence of Ablation Speed on the Synthesis of Carbon Nanostructures Via Pulsed Laser Ablation of Asphalt in Ethanol

Pulsed liquid laser ablation is considered a green method for the synthesis of nanostructures because there are no byproducts formed after the ablation. In this paper, a fiber laser of wavelength 1.064 µm, peak power of 1 mJ, pulse duration of 120 ns, and repetition rate of 20 kHz, was used to produce carbon nanostructures including carbon nanospheres and carbon nanorods from the ablation of asphalt in ethanol at ablation speeds of (100, 75, 50, 10 mm/s).  The morphology, composition and optical properties of the synthesized samples were studied experimentally using FESEM, HRTEM, EDS, and UV-vis spectrophotometer. Results showed that the band gap energy decreased with decreasing the ablation speed (increasing the ablation time), the minimum mean particle size of the synthesized samples was 76 nm at an ablation speed of 100mm/s, while the maximum mean particle size was 98 nm at ablation speed of 50 mm/s, the nanospheres were agglomerated to form larger spherical nanoshapes. All the synthesized carbon nano colloids exhibited a blue-green PL emission. It was concluded that the presence of carbon nanorods has an effect on the optical properties of the synthesized nanospheres

Development of NDIR CO2 Gas Sensing System Based on U-Shaped Optical Cavity

In this paper, a proposed carbon dioxide Gas Sensing System of high precision, rapid reaction, compact size and low power consumption rate is presented based on the non-dispersive infrared (NDIR) measurement. This system used to determine CO2 gas concentration in air; it consists of the single broadband light source, U-shape tube optical path cavity as gas cell, thermopile detector, and microcontroller circuit. This study investigates the efficiency of the U-tube optical path cavity at CO2 gas concentrations ranging from (0-5000) ppm. The obtained results show that it has the better thermal response compare to the linear tube and exhibits high sensitivity by change the transmitted light intensity into analog voltage. The proposed system design can be used as an environmental monitoring sensor

Effect of Adding Styrene-Butadiene Rubber (SBR) on Corrosion Resistance for Reinforced Concrete Columns

Corrosion in steel bars has the biggest effect on the concrete strength as well as its durability. Problems, such as increasing the crack widths, deflections, increasing stresses and decreasing concrete strength, are some subsequences of steel corrosion. Therefore, preventing these undesirable consequences, needs to address by researchers. Some additive materials which can be used in concrete might be the most effective cheap solution. In this research, Styrene Butadiene Rubber (SBR) was utilized in the concrete mixture to reduce water permeability in concrete. In order to test the effect of SBR on steel corrosion in structural members, seven reinforced concrete columns of circular cross section were casted with different contents of SBR, from one percent to six percent of water content. Using accelerated corrosion cells, major tests were done after twenty days.  Results show that SBR improved the compressive strength of the concrete up to thirty – one percent with using one percent of SBR. Moreover, the compression strength of the reinforced concrete columns increased about thirty – two percent with using six percent of SBR. Not only the concrete strength improved with adding SBR, but also the steel corrosion resistance increased and steel weight losing decreased

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population