Research and development of a self-centering clamping device for deep-water multifunctional pipeline repair machinery

When multifunctional pipeline repair machinery (MPRM) is used in the deep sea area, it is difficult to grip the pipeline and ensure concentricity between the cutter heads and the pipeline during its operation. In view of this, a new system of two-arm holding self-centering pipeline clamping device was proposed. The system is composed of two groups of parallelogram double-rocker mechanism and cranking block mechanism which are symmetrically distributed on the frame. The geometric parameter solutions of the clamping device were analyzed with motion and transmission as the constraints. A mechanical model was established to associate the friction torque of clamping points with the driving force. Clamping device and machinery were designed and manufactured for the Ø304.8–457.2 mm pipelines used in this test. ADAMS simulation experiments were conducted underwater, and the cutting and beveling tests were carried out onshore. The following results are achieved. First, the smaller the pipe diameter, the smaller the transmission angle of the oscillating slider mechanism; the longer the hydraulic cylinder stroke, the greater the transmission angle of the double rocker mechanism. Second, the driving force of the clamping device increases with the increase of the pipe diameter. When the diameter reaches 457.2 mm, the hydraulic cylinder driving force of the clamping device should be greater than 10219 N. Third, the feed rate of the cutters increases suddenly due to the slight shaking of the machinery which occurs at the beginning of the pipe cutting, so it is necessary to adopt a small feed rate. And fourth, onshore experiment results agree well with the theoretical design and simulation results, proving the rationality of the system. The research results in this paper provide technical basis for the research and development of similar engineering prototypes

Environmentally-Friendly Extraction of Flavonoids from Cyclocarya paliurus (Batal.) Iljinskaja Leaves with Deep Eutectic Solvents and Evaluation of Their Antioxidant Activities

Deep eutectic solvents (DESs) are commonly employed as environmentally-friendly solvents in numerous chemical applications owing to their unique physicochemical properties. In this study, a novel and environmentally-friendly extraction method based on ultrasound assisted-deep eutectic solvent extraction (UAE-DES) was investigated for the extraction of flavonoids from Cyclocarya paliurus (Batal.) Iljinskaja (C. paliurus) leaves, and the antioxidant activities of these flavonoids were evaluated. Nine different DES systems based on either two or three components were tested, and the choline chloride/1,4–butanediol system (1:5 molar ratio) was selected as the optimal system for maximizing the flavonoid extraction yields. Other extraction conditions required to achieve the maximum flavonoid extraction yields from the leaves of C. paliurus were as follows: DES water content (v/v), 30%; extraction time, 30 min; temperature, 60 °C; and solid-liquid ratio, 20 mg/mL. Liquid chromatography-mass spectrometry allowed the detection of five flavonoids in the extract, namely kaempferol-7-O-α-l-rhamnoside, kaempferol, quercetin, quercetin-3-O-β-d-glucuronide, and kaempferol-3-O-β-d-glucuronide. In vitro antioxidant tests revealed that the flavonoid-containing extract exhibited strong DPPH and ABTS radical-scavenging abilities. Results indicate that UAE-DES is a suitable approach for the selective extraction of flavonoids from C. paliurus leaves, and DESs can be employed as sustainable extraction media for other bioactive compounds

Chemical Compositions, Extraction Optimizations, and In Vitro Bioactivities of Flavonoids from Perilla Leaves (<i>Perillae folium</i>) by Microwave-Assisted Natural Deep Eutectic Solvents

Natural deep eutectic solvents (NADESs) have been gradually applied to green extraction of active ingredients. In this study, microwave-assisted NADESs were applied to the extraction of flavonoid compounds from perilla leaves. Through comparative experiments, NADES-3 (choline chloride and malic acid at a molar ratio of 1:1) was found to have the highest extraction efficiency of total flavonoids, including apigenin 7-O-caffeoylglucoside, scutellarein 7-O-diglucuronide, luteolin 7-O-diglucuronide, and scutellarein 7-O-glucuronide by HPLC-MS. The following optimal extraction parameters were obtained based on response surface design: water content in NADES of 23%, extraction power of 410 W, extraction time of 31 min, and solid–liquid ratio of 75 mg/mL, leading to the extraction yield of total flavonoids of 72.54 mg/g. Additionally, the strong antimicrobial and antiallergic activity, inhibition of nitrosation, and antioxidant activity of total flavonoids by using NADESs were confirmed. This new extraction method provides a reference for the further exploration of NADES systems and may be widely used for the green extraction of natural active ingredients

Combined Use of Deep Eutectic Solvents, Macroporous Resins, and Preparative Liquid Chromatography for the Isolation and Purification of Flavonoids and 20-Hydroxyecdysone from Chenopodium quinoa Willd

Deep eutectic solvents (DESs) were used in combination with macroporous resins to isolate and purify flavonoids and 20-hydroxyecdysone from Chenopodium quinoa Willd by preparative high-performance liquid chromatography (HPLC). The extraction performances of six DESs and the adsorption/desorption performances of five resins (AB-8, D101, HPD 400, HPD 600, and NKA-9) were investigated using the total flavonoid and 20-hydroxyecdysone extraction yields as the evaluation criteria, and the best-performing DES (choline chloride/urea, DES-6) and macroporous resin (D101) were further employed for phytochemical extraction and DES removal, respectively. The purified extract was subjected to preparative HPLC, and the five collected fractions were purified in a successive round of preparative HPLC to isolate three flavonoids and 20-hydroxyecdysone, which were identified by spectroscopic techniques. The use of a DES in this study significantly facilitated the preparative-scale isolation and purification of polar phytochemicals from complex plant systems