Gradient Cleaning Method of Potato Based on Multi-Step Operation of Dry-Cleaning and Wet Cleaning

In view of the poor effectiveness of existing potato cleaning methods in China and reflecting the findings of a research analysis of basic sizes and types of impurities on potato tubers, a gradient cleaning method for potato based on a multi-step dry-cleaning and wet cleaning operation was proposed. The method mainly consists of dry-cleaning and wet cleaning. The dry-cleaning stage, which combines vibration and brushing, could effectively remove impurities such as residual rhizomes, peeled potato skin, and large pieces of soil and crushed stone from the surface of potato tubers. The wet cleaning stage adopts the gradient cleaning method of pre-cleaning, rough cleaning and fine cleaning, which could further remove soil and crushed stone attached to the surface and hidden in the sprout eyes of potato tubers. The optimal parameter combination for the gradient cleaning method was determined as follows. The potato feeding amount was 3 t/h, the speed of the rubber chain rod mechanism was 25 r/min, the speed of the first and third brush roller was 40 r/min, the speed of the second and fourth brush roller was 56 r/min, the moving speed of the immersion mechanism conveying net chain was 0.04 m/s, the speed of the brush roller in the high pressure spray and brush roller combination mechanism was 40 r/min, the ultrasonic power was 1200 W, the ultrasonic frequency was 33 kHz, the bubble intensity was 300 L/min, and the moving speed of the conveying net chain in the ultrasonic and bubble combination mechanism was 0.05 m/s. Taking the impurity removal rate and damage rate of potato tuber as the test indexes, a potato cleaning performance test was carried out under the optimal parameters combination. The results showed that the average impurity removal rate and damage rate of potato tubers were 99.05% and 2.48%, respectively. Additionally, the operational performance fully met the requirements for potato cleaning. This study provides a new method for potato cleaning in China and can also provide a reference for cleaning other root and tuber crops.

Carbon dioxide snow cleaning of paper

The cleaning of particles from smooth and rough paper surfaces using a high-speed CO2 snow jet was investigated. The measurements included characterization of the jet properties, determination of the cleaning efficiency, and evaluation of any possible adverse effects. The method was compared with nitrogen jet cleaning and dry cleaning by commercial materials. The results showed that the CO2 snow jet is able to effectively remove particles from the paper surface and did not cause any observable degradation. The CO2 snow jet cleaning compared with the mechanical dry cleaning showed similar effectiveness without any adverse effects on the paper surface. It was proved that the CO2 snow technique is a suitable method for cleaning common types of paper materials.

Study on the Dry-Cleaning Process of Mink Fur Based on Subcritical Solvent

It is significant to apply environmentally benign technology to fur processing. In this paper, subcritical extraction with n-pentane was used to dry clean mink fur and the effect on the quality of mink fur was studied. The dispersion degree of the leather fibers and the morphology of the wool fiber were characterized with SEM, the mechanical properties, shrinkage temperature and oil content left in fur were determined and analyzed. The results showed that the fibers of mink fur were well separated and no excess lipids in the fibers or on the surface of mink fur and the hair of the mink fur is not damaged. The tensile strength and elongation of mink fur show slight increase respectively, and the shrinkage temperature of mink fur that was treated by subcritical solvent was significantly increased compared with that of the mink fur treated with tetrachloroethylene by conventional dry cleaning method.

Literature Review: Biological Monitoring of Occupational Tetrachloroethylene Exposure in Workers

Introduction: One of the most common chlorinated solvents in the world is tetrachloroethylene (TCE) because it is widely used in various industries. Exposure to tetrachloroethylene can cause health problems so biological monitoring is necessary to do. The aim of this research is to assess which one is more feasible to use among the various types of biological monitoring for tetrachloroethylene exposure, based on the evidence-based literature. Methods: The literature searching was performed via electronic databases from PubMed, Scopus, and Proquest. The keywords used were “biological monitoring”, “biomonitoring”, “tetrachloroethylene”, “perchloroethylene”, “work” and “occupation”. The articles were chosen based on the given inclusion and exclusion criteria. Selected articles were then critically appraised. Results: Initially 29 papers were collected, but only6 cross-sectional articles were selected after the screening process and manual searching. Based on the selected evidence-based literatures, statistically meaningful associations were found between tetrachloroethylene exposure and tetrachloroethylene in blood in pre- and end-of-shift, in urine at end of shift, and in exhaled air at end-of-shift. Moreover, micronucleus frequency and DNA damages between dry cleaning workers and the controls differed significantly. Conclusion: The level of tetrachloroethylene in blood, urine, and exhaled air becomes an appropriate biological exposure index for assessing tetrachloroethylene exposure in dry-cleaning workers. In Indonesia, biomonitoring that is more feasible to be implemented is micronucleus frequency evaluation from buccal mucosal epithelial smears since it is a simpler, faster, and less expensive procedure.Keywords: biological monitoring, biomonitoring, occupational exposure, tetrachloroethylene

Process Steps for High Quality Si-Based Epitaxial Growth at Low Temperature via RPCVD

The key process steps for growing high-quality Si-based epitaxial films via reduced pressure chemical vapor deposition (RPCVD) are investigated herein. The quality of the epitaxial films is largely affected by the following steps in the epitaxy process: ex-situ cleaning, in-situ bake, and loading conditions such as the temperature and gaseous environment. With respect to ex-situ cleaning, dry cleaning is found to be more effective than wet cleaning in 1:200 dilute hydrofluoric acid (DHF), while wet cleaning in 1:30 DHF is the least effective. However, the best results of all are obtained via a combination of wet and dry cleaning. With respect to in-situ hydrogen bake in the presence of H2 gas, the level of impurities is gradually decreased as the temperature increases from 700 °C to a maximum of 850 °C, at which no peaks of O and F are observed. Further, the addition of a hydrogen chloride (HCl) bake step after the H2 bake results in effective in-situ bake even at temperatures as low as 700 °C. In addition, the effects of temperature and environment (vacuum or gas) at the time of loading the wafers into the process chamber are compared. Better quality epitaxial films are obtained when the samples are loaded into the process chamber at low temperature in a gaseous environment. These results indicate that the epitaxial conditions must be carefully tuned and controlled in order to achieve high-quality epitaxial growth.

Carbon Dioxide Snow Cleaning of Paper

Cleaning of particles from smooth and rough paper surfaces was investigated using a high-speed CO2 snow jet. The measurements included characterization of the jet properties, determination of the cleaning efficiency, and evaluation of the possible adverse effects. The method was compared with the nitrogen jet cleaning and the dry cleaning by commercial materials. The results showed that the CO2 snow jet is able to effectively remove particles from the paper surface and did not cause any observable degradation. The CO2 snow jet cleaning compared with the mechanical dry cleaning showed similar effectiveness without any adverse effects on the paper surface. It was proved that the CO2 snow technique is a suitable method for cleaning of common types of paper materials.

PENCARIAN DRIVER DRY CLEAN TERDEKAT DENGAN METODE HAVERSINE FORMULA

Sistem pemesanan dry cleaning konvensional tidak bisa menemukan driver terdekat dengan pemesan. Penelitian ini bertujuan untuk membangun sistem untuk membantu pencarian driver terdekat dengan pemesan agar cepat dalam mengambil pakaian kotor dan sebaliknya mencari driver terdekat dari dry cleaning jika pakaian sudah selesai. Penelitian ini menerapkan metode haversine formula untuk pencarian driver terdekat, Google Maps sebagai pembangun peta digital, dan dikembangkan berbasis mobile. Sistem perancangan pada penelitian ini menggunakan Unified Modeling Language (UML) yang terdiri dari Use Case Diagram, Activity Diagram, Class Diagram, Sequence Diagram, dan Deployment Diagram. Pengujian sistem dilakukan dengan menggunakan white box testing dan beta testing.