Evaluating Service Characteristics of Working Surfaces of Car Parts by Microgeometric Quality Parameters

The correlation between the service characteristics of the working surfaces of car parts belonging to the rotary body class, and quality parameters—in particular, the height-related roughness parameter Ra—was estimated. Low values of Ra were found to be unable to guarantee an optimal microrelief geometry and, accordingly, high-performance characteristics of the working surface. The oil-accumulation power of the parts was investigated as a primary characteristic of sliding friction using the group of Rk parameters in the Abbott–Firestone diagram, based on the profilogram of the test specimen’s surfaces. The oil-absorption power of the surfaces formed by different technological operations was compared with different microgeometric quality parameter values.

Design and Analysis of a Graphene Based Slotted Bowtie Optical Plasmonic Nanoantenna

A graphene-based modified bowtie plasmonic nanoantenna resonating in the optical frequency spectrum with the periodic directors created by the slots on top of the radiating structure has been proposed in this paper. In the field of nanophotonics, a few optical nanoantennas have been reported to construct multipath wireless nanolinks. At the telecommunication wavelength of 1550 nm (193.5 THz), the maximum directivity of 9.67 dBi has been reached due to the maximum absorption power of graphene sheet by selecting the chemical potential of 0.5 eV. Since graphene supports surface plasmon polariton waves and acts either as an absorptive or transparent medium for distinct chemical potentials, the proposed graphene-based slotted bowtie optical nanoantenna has been optimized to obtain a dynamically controlled triple-directional radiation beam. With this distinctive nature, a multipath intra or inter on-chip wireless nanolink for secure optical data transfer can be realized by integrating a set of our proposed optical plasmonic nanoantennas.

Absorption Power and Cooling Combined Cycle with an Aqueous Salt Solution as a Working Fluid and a Technically Feasible Configuration

Combined systems for power production and thermally activated cooling have a high potential for improving the efficiency and utilisation of thermal systems. In this regard, various configurations have been proposed and are comprehensively reviewed. They are primarily based on absorption systems and the implementation of multiple levels of complexity and flexibility. The configuration of the absorption power and cooling combined cycle proposed herein has wide commercial applicability owing to its simplicity. The configuration of the components is not new. However, the utilisation of aqueous salt solutions, the comparison with ammonia chiller and with absorption power cycles, the focus on parameters that are important for real-life applications, and the comparison of the performances for constant heat input and waste heat recovery are novel. The proposed cycle is also compared with a system based on the organic Rankine cycle and vapour compression cycle. An investigation of its performance proves that the system is suitable for a given range of boundary conditions from a thermodynamic standpoint, as well as in terms of system complexity and technical feasibility. New possibilities with regard to added power production have the potential to improve the economics and promote the use of absorption chiller systems.

Comprehensive Thermal Analysis of Diamond in a High-Power Raman Cavity Based on FVM-FEM Coupled Method

Despite their extremely high thermal conductivity and low thermal expansion coefficients, thermal effects in diamond are still observed in high-power diamond Raman lasers, which proposes a challenge to their power scaling. Here, the dynamics of temperature gradient and stress distribution in the diamond are numerically simulated under different pump conditions. With a pump radius of 100 μm and an absorption power of up to 200 W (corresponding to the output power in kilowatt level), the establishment period of thermal steady-state in a millimeter diamond is only 50 μs, with the overall thermal-induced deformation of the diamond being less than 2.5 μm. The relationship between the deformation of diamond and the stability of the Raman cavity is also studied. These results provide a method to better optimize the diamond Raman laser performance at output powers up to kilowatt-level.

Mathematic Learning Material Capabilities on Special Needs

The purpose of this study was to see the application of students with special needs in inclusive schools and their absorption of Mathematics subject matter in the SMA National Examination 2018/2019 academic year. Although, the National Examination has legally abolished, the results of the last National Examination 2018/2019 can still be used to capture students' minimum academic abilities and also for reflection in order to improve the quality of education better. The ability of students can be seen from the results of the national exam, while the absorption of mathematics can be seen from the proportion of students with special needs in inclusive schools who can correctly answer questions on the National Mathematics Exam. The population of this study were all high school level students who took the National Examination for the 2018/2019 academic year, while the research sample was all inclusive high school students who took the National Examination for the 2018/2019 academic year. The data used is secondary data, namely the SMA National Exam data for the 2018/2019 academic year. Data analysis used Excel software, and then descriptive statistical analysis was carried out. The results showed the highest score of the National Mathematics Examination for students with special needs in inclusive schools was 54.02 and the lowest was 22.69 with an average score of 39.43. The average score of Mathematics for the Science Department is 45.66 (included in the poor category), the Language Department is 40.04 (including the poor category), while the Social Science Department is 29.28 (including the low category). The highest average absorption power of Mathematics in the Science department is 30%, in the scope of Algebra material, the lowest absorption is 23% in the scope of calculus material. In the social studies department, the highest average absorption power in mathematics is 29% each for algebra and statistics, the lowest absorption rate is 18% in the scope of Geometry and Trigonometry. Meanwhile, in the Language Department, the highest average absorption is algebra 38%, the lowest is 30% in the scope of Geometry and Trigonometry. The range of values for participants with special needs is very large so it needs assistance to improve the abilities of students. The weakness of special needs students in Mathematics is the material scope of Geometry and Trigonometry.

Absorption Power and Cooling Combined Cycle with an Aqueous Salt Solution as a Working Fluid and a Technically Feasible Configuration

Combined systems for power production and thermally activated cooling have a high potential for improving the efficiency and utilisation of thermal systems. In this regard, various configurations have been proposed and are comprehensively reviewed. They are primarily based on absorption systems and the implementation of multiple levels of complexity and flexibility. The configuration of the absorption power and cooling combined cycle proposed herein has wide commercial applicability owing to its simplicity. The configuration of the components is not new. However, the utilisation of aqueous salt solutions, the comparison with ammonia chiller and with absorption power cycles, the focus on parameters that are important for real-life applications, and the comparison of the performances for constant heat input and waste heat recovery are novel. The proposed cycle is also compared with a system based on the organic Rankine cycle and vapour compression cycle. An investigation of its performance proves that the system is suitable for a given range of boundary conditions from a thermodynamic standpoint, as well as in terms of system complexity and technical feasibility. New possibilities with regard to added power production have the potential to improve the economics and promote the use of absorption chiller systems.

Kapasitas Bioadsorpsi Bakteri Simbiosis Spons Laut Terhadap Kontaminan Logam Berat

Heavy metal pollution in the marine environment is quite high. Arsenic and Mercury are two types of dangerous heavy metals because they are toxic and are often found as components of pollution. The research objective was to determine the bio-absorption capacity and efficiency of sponge symbiotic bacteria against arsenic and mercury contaminants. The bio-absorbent material was used by two bacterial isolates, namely Bacillus licheniformis strain ATCC 9789 (Bl.6), the sponge symbiont Auletta Sp and Acinetobacter calcoaceticus strain PHCDB14 (Ac.8), the sponge symbiont Callyspongia aerizusa. The isolates were prepared through culture, then incubated 2 x 24 hours, suspension Bl.6 and Ac.8 were made, then adapted for 24 hours. Interaction with As3 + and Hg2 + contaminants with a concentration of 100 ppm in vials with time variations 0, 4, 8, 12, 16 days. The resulting interactions are extracted, concentrated, and acidified. The bio-absorption capacity and efficiency were determined based on absorption data using Atomic Absorption Spectrometry (AAS). The average efficiency of the bio-absorption of isolate Bl.6 against As3+ = 99.95%, Hg2+ = 88.49%, while isolate Ac.8 against As3+ = 99.95% and Hg2+ = 85.73%. Based on efficiency data, capacity and bio-absorption power relative to Bl.6 = Ac.8 against As3+ and Bl.6 ≥ Ac.8 contaminants to Hg2+. Isolates Bl.6 and Ac.8 adsorbed more strongly against As3+ contaminants than Hg2+.