Numerical Study on the Impact of Gap between Sheets on the Quality of Riveted Single-Strap Butt Joints

Some controllable process parameters in the riveting process such as the gap between sheets, have an important impact on the quality of a riveted butt joint. In this paper, the finite element model of a riveted single-strap butt joint is established with the help of ABAQUS analysis software, and the riveting process is simulated under five kinds of gaps between sheets. From the perspectives of rivet upsetting size, rivet interference, radial deformation of sheet, and analysis of residual stress around the hole of sheet, the influence of the gap between sheets on the connection quality of the riveted butt joint is summarized. The results show that the left and right sheets will contact each other and there is extrusion stress between the sheets when the gap is zero. When the applied tensile load continues to increase, due to the influence of the secondary bending, the strap sheet responsible for the connection produces warping deformation, and there will be no further contact between the sheets. When the gap between sheets increases from 0 to 2 mm, the maximum deformation of strap sheets increases from 0.876 to 0.927 mm, which proves that the gap between sheets have no significant effect on the deformation of the strap sheet.

Development of the Digital Site for Chemical Processes in the Manufacturing of Printed Circuit Boards

The article defines digital methods for controlling the quality of chemical processes. An architecture of a digital production line, which ensures the distribution of the computational load between the system components, is proposed. We considered the process of developing a prototype of a digital production site for servicing the etching operation during which controllable process parameters are determined; both hardware and software structures of the digital site are proposed. Studying the site operability, we determined the relationships between the process parameters, which made it possible to determine the boundaries of the designed system.

Electrospinning of Nanofibrous Membrane and Its Applications in Air Filtration: A Review

Air pollution caused by particulate matter and toxic gases is violating individual’s health and safety. Nanofibrous membrane, being a reliable filter medium for particulate matter, has been extensively studied and applied in the field of air purification. Among the different fabrication approaches of nanofibrous membrane, electrospinning is considered as the most favorable and effective due to its advantages of controllable process, high production efficiency, and low cost. The electrospun membranes, made of different materials and unique structures, exhibit good PM2.5 filtration performance and multi-functions, and are used as masks and filters against PM2.5. This review presents a brief overview of electrospinning techniques, different structures of electrospun nanofibrous membranes, unique characteristics and functions of the fabricated membranes, and summarization of the outdoor and indoor applications in PM filtration.

FACTORS ENHANCING THE ACCUMULATION OF BETA-CAROTENE IN RHODOTORULA TAIWANENSIS CT1

β-carotene known as an antioxidant, immunostimulant, provitamin A and natural colour is a popular additive used in food, cosmetics, and animal feed. Microbial β -carotene currently attracts attention thanks to its short production time and controllable process in comparing to the plant source. This study investigates the influences of the factors that enhance the accumulation of b-carotene in yeast strain Rhodotorula taiwanensis CT1. The addition of stressors including ethanol (0.2%), hydrogen peroxide (10mM) and NaCl (1M) to the 48h CT1 cultures improved the intracellular b-carotene to 2.2; 2.05 and 1.35 folds, respectively. Volumetric productivity of CT1 increased respectively 2.1; 2.0 and 1.1 folds. As a metabolism regulator, citric acid (1%) added into 48h CT1 culture had a positive effect on intracellular b-carotene in CT1, resulted in its increase 1.78 folds. The highest β-carotene in CT1 was obtained when 1% Tween 80 was added in the culture: The intracellular b-carotene reached 337.56 ± 1.30 µg/g dry biomass, increased 2.84 folds; volumetric productivity achieved 15.38 ± 0.30 mg/L, increased 2.64 folds. However, the influence of addition time and appropriate concentration of study factors remained undetermined and need to be deeply investigated in further study.

Metal Deposition Induced by the Step Region of Si (111)-(7 × 7) Surface

Scanning tunneling microscope results showed that Au and Fe atoms were steamed on the Si (111)-(7 × 7) substrate surface, with or without the step region. The experimental comparison proved that the induced effect of the step region is a controllable process, which CH3OH can adjust. In this paper, the latest progress on the dynamic phenomenon on the step region is discussed, including three deposition types: strong deposition, weak deposition, and the new quasi deposition. With a relatively weak interaction between Au and Si atoms, the linearity of the weak deposition is present in the step region. In contrast, Fe atoms tend to form a strong deposition along the boundary line between the flat and step regions. Different depositions correspond to different surface potential energy: a newly formed surface is stabilized by a quasi-potential made by breaking, and a metal atomic structure can be stabilized by forming several quasi depositions. After discussing the good adsorption properties, CH3OH can be used as an intermediate layer on the step region. As an important result of quasi deposition, a regular linear Fe cluster structure is created, which is perpendicular to the boundary line.

Simultaneous parametric optimization of micro-EDM drilling of brass C360 using Taguchi based grey relation analysis

Micro-EDM (Electro Discharge Machining) is widely used for precision manufacturing and drilling micro-holes in materials used in fuel nozzles, micro sensors and robots, surgical instruments, turbines etc. Present paper deals with drilling common C360 brass components by micro-machining and optimizing the process parameter using a hybrid approach of design of experiments (DoE) and grey relation analysis (GRA) concept. The three process responses considered are material removal rate (MRR), tool wear rate (TWR) and taper in drilled hole while the four selected controllable process parameters are capacitance(C), voltage(V), feed rate(f) and rotational speed of electrode (N). Significance of input factors on each response is analyzed with the help of a 24 full factorial by conducting 16 experiments at two levels for factors. Optimum levels of robustness for each process response are established through Taguchi’s S/N ratio. A combined grey relation grade is applied to find the process levels conducive for optimizing MRR and TWR simultaneously.

Hydrothermal combined with electrodeposition construction of a stable Co9S8/Ni3S2@NiFe-LDH heterostructure electrocatalyst for overall water splitting

This paper provides a controllable process to prepare stable and efficient water splitting electrocatalysts which can be applied to renewable energy storage and conversion.

Ultrathin amorphous iron-doped cobalt-molybdenum hydroxide nanosheets for advanced oxygen evolution reactions

Amorphous iron-doped cobalt-molybdenum ultrathin hydroxide (Fe-CoMo UH) nanosheets are fabricated by a controllable process, and exhibit excellent an OER catalytic performance.