Chronic Kidney Disease Among Workers Exposed To Perfluorooctanoic Acid (PFOA)

Background: Perfluorooctanoic acid (PFOA), a class of perfluorocarbons, are synthetic environmental contaminants. Their long biological half-lives and their poor ability to metabolize likely add to any chronic health effects they may pose, such as chronic kidney disease (CKD). The causal relationship between PFOA and CKD is still unclear, so it is necessary to look for some evidence regarding this relationship. The search for evidence is also complemented by a seven-step occupational disease assessment to establish occupational diseases. Aim: This study aims to justify chronic kidney disease of workers exposed to perfluorooctanoic acid can be diagnosed as occupational diseases.Methods: Searching literature for the evidence-based has been conducted with a clinical question through “PICO” method. Then continued with literature searching using the electronic database “PubMed”, “JSTOR”, and “Scopus” search engine. The keyword is “PFOA” “perfluoroalkyl substances” “perfluorooctanoic acid” “chronic kidney” “chronic kidney disease” “CKD” and combined with MeSH terms and Boolean operation. The inclusion criteria are research on humans, English language, and the exclusion is retracted articles.Result: From the five literatures obtained, there are differences in results. A study of workers exposed to perfluorooctanoic acid in a DuPont chemical plant with chronic kidney disease was (Standardized Mortality Ratios (SMR) = 3.11, 95% CI: 1.66, 5.32). Study in China found that perfluorooctanoic acid is not associated with renal function and higher risk of CKD (OR = 0.73, 95% CI: 0.57, 0.95; p=0.019).Conclusion: There are insignificant associations between perfluorooctanoic acid and chronic kidney disease.

Additive remanufacturing of coupler knuckle based on robotic gas metal arc welding

Take the wear parts of coupler knuckle as an example, the “Modeling—Slicing — Stacking” mode remanufacturing process is studied. First, the 3D model of the of the worn coupler knuckle surface is acquired by structured light 3D detection. The remanufacturing model of the failure part is built by Boolean operation between the original model and the acquired 3D model. Second, the user can slice layer of the remanufacturing model according to the remanufacturing stacking parameters. The zone that surrounded by the contour of each sliced layer is the robotic GMAW remanufacturing stack region. Third, the robotic GMAW remanufacturing path is planed within the region mentioned above and the executable program is generated to carry out the remanufacturing task layer by layer. Moreover, the worn coupler knuckle was repaired by adopting Robotic GMAW Process. The mechanical performances of component were tested, the results indicate that the remanufactured coupler knuckle satisfying the operating requirements.

Simulation Machining of Hardened Gear Shaping and Finite Element Analysis

Existing simulation processing methods are difficult to obtain the tooth surface that is close to the actual processing. This paper proposes a high-precision simulation processing method for hard tooth surface gearing. Through the establishment of a high-precision cutter and tooth blank geometric model, analysis of the kinematics principle and meshing relationship between the cutter and tooth blank, combined with the functions of rotation, translation and Boolean operation in the 3D software, the high-precision shaping simulation processing of hardened gears is realized. By measuring the normal distance between the standard involute and the gear tooth profile, the tooth surface error analysis is completed. The simulation model is reconstructed, and the models are analyzed by finite element method (FEM) respectively, and the effectiveness of the method in this paper is verified by comparing the analysis results.

An Antiquity to the contemporary of Secret Sharing Scheme

Secret Sharing (SS) scheme divides a secret image into shadow images (referred to as shares) in a way that requires the shadows in a certain privileged coalition for the secret reconstruction. However, the secret image cannot be revealed if they are not combined in a prescribed way. In this paper, the evolution of the traditional secret sharing scheme to the contemporary of secret sharing scheme has been presented based on its technology adoption. The basic comparison between the traditional secret sharing scheme and Visual cryptography is presented. The image-based share generation process has been explained in the context of pixel sharing patterns and its process. The reconstruction image is obtained by the XOR /OR Boolean operation. The threshold-based share generation schemes are explained mathematically and the comparative analysis of these schemes also presented.