Synchronized Injection Molding Machine with Servomotors

Injection Molding Machine (IMM) is one of the most important equipment in plastic industry. As a cyclic process, injection molding can be divided into three steps includes filling process, packing-holding process and cooling process, among which filling process and packing process are both most important phases for the quality of part, and the corresponding crucial process variables are injection velocity and packing pressure in filling and packing phases. Moreover the determining a suitable injection time, screw position and cavity pressure for transfer from injection velocity control to packing pressure control which is commonly called filling to packing switchover point is also critical for high quality part. This study is concerned with two research aspects: double servomotors synchronization control for injection unit, and filling to packing switchover methods. The simulation result of switching method based on injection time and ball screw position those are similar, and the result of switching method based on the cavity pressure that is better

Study on synthesis of some new derivatives of Malloapelta B isolated from Mallotus apelta

Six new benzopyran derivatives were synthesized by reduction reaction and Michael reaction from malloapelta B. Their structures were determined as 8-(1’-oxo-butyl)-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (2), 8-(1’-oxo-3’(R)-methyl-4’-acetyl-5’-oxo-hexyl)-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (3), 8-(1’-oxo-3’(R)-methyl-4’(S/R)-(methyl fomiate)-5’-oxo-hexyl)-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (4,4’), 8-(1’-oxo-3’(R)-methyl-4’(S/R)-(ethyl formiate)-5’-oxo-hexyl)-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (5,5’) by spectroscopic data, including two-dimensional NMR techniques and ESI spectrum.Keywords: Malloapelta B; Michael reaction; reduction reaction; 5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran

Structure elucidation off seven steroids from Sinularia conferta.

Seven steroids were isolated from the methanol extract of the soft corals Sinularia conferta. These steroids were elucidated as 7a-methoxyergosta-5,24(28)-diene-3b-ol (1), ergosta-5-ene-3β,7α-diol (2), 3β,7α-dihydroxyergosta-5,24(28)-diene (3), 3β-hydroxyergosta-5,24(28)-diene-7-one (4), ergosta-24(28)-ene-3β,5α,6β-triol-6-acetate (5), ergosta-24(28)-ene-3β,5α,6β-triol (6), and ergosta-3β,5α,6β-triol (7) by 1D and 2D-NMR experiments and comparison with reported data. Keywords. Sinularia conferta, Alcyoniidae, soft coral, steroid

STRUCTURE ELUCIDATION OF FOUR STEROIDS FROM THE SOFT CORAL SINULARIA NANOLOBATA

Four steroids namely 3β-hydroxyergosta-5,24(28)-diene-7-one (1), dissesterol (2), 16α-hydroxysarcosterol (3), and sarcophytosterol (4) were isolated form the soft coral Sinularia nanolobata using various chromatographic methods. Their structures were elucidated by detailed analysis of the 1D and 2D NMR data and comparison with the reported values

EFFECTS OF COD/TN RATIO AND LOADING RATES ON PERFORMANCE OF MODIFIED SBRs IN SIMULTANEOUS REMOVAL OF ORGANIC MATTER AND NITROGEN FROM RUBBER LATEX PROCESSING WASTEWATER

Two modified sequencing batch reactors (SBRs) specially configured to consist of both oxic and anoxic zones, and be operated with only a single simultaneous oxic/anoxic phase in each treatment batch were tested to evaluate their applicability in treatment of rubber latex processing (RLP) wastewater. The former, R1 was operated with constant aeration, whereas the latter, R2 was operated with air flow varied from lower rate in the early period of the reaction phase to higher rate in the later one. Effects of the chemical oxygen demand (COD) to total nitrogen (TN) ratio and their loading rates on performance of the modified SBRs in simultaneous removal of organic matter and nitrogen from RLP wastewater were investigated. It was observed that performance of the two reactors in removal of COD and ammonium nitrogen was similar, and did not remarkably change when varying COD/TN ratio, as well as COD and TN loading rates in the ranges of 3.4 – 6.0 gCOD/gN, 0.8 – 1.7 kgCOD×m-3×d-1 and 0.15 – 0.34 kgN×m-3×d-1, respectively. The average COD removal efficiencies were over 95%. Ammonium nitrogen was almost completely eliminated in both reactors with effluent concentrations lower than 1.0 mg/L. Nevertheless, TN removal efficiencies of both reactors were significantly increased with increasing the COD/TN ratio from 3.4 to 6.0, and slightly decreased when increasing the TN loading rate from 0.15 to 0.34 kgN×m-3×d-1. The most effective COD/TN ratios were in the range of 5 – 6, at which the maximal TN removal efficiencies of R1 and R2 were 92% and 97%, respectively

Research antioxidant activity of chitooligosacchride by UV-VIS absorption spectrocopy

Chitosan with 80% degree of deacetylation was hydrolyzed by cellulase of Trichoderma viride to prepare chitooligosaccharides (COSs) by the fractionation of the COSs with ultrafiltration membrane. The antioxidant activities of the COSs were clarified in this study by reducing power and free radical scavenging ability assay by UV-VIS absorption spectrum. The results show that the COS 1 (10,000-5,000 Da), COS 2 (5,000-3,000 Da), COS 3 (3,000-1,000 Da) and COS 4 (less than1,000 Da) segments have antioxidant properties.The antioxidant activitives of the COSs increased with the increment of concentration, and they also depended on molecular weight

Sterols isolated from the soft coral sinularia dissecta

Using various chromatographic methods, five sterols, gorgost-4-ene-3-one (1), ergost-4-ene-3-one (2), 24-methyleneergost-4-ene-3-one (3), ergost-4-ene-3,6-dione (4), and 24-methylenecholest-4-ene-3,6-dione (5), were isolated from the methanol extract of the soft coral Sinularia dissecta. Their structures were elucidated by 1D and 2D-NMR experiments and comparison of their NMR data with reported values. These compounds were isolated from S. dissecta for the first time

Saponins isolated from the Vietnamese sea cucumber Stichopus chloronotus.

Using various chromatographic methods, three triterpene saponins neothyonidioside (1), stichoposide D (2), and holothurin B (3), were isolated from the methanol extract of the sea cucumber Stichopus chloronotus. Their structures were elucidated by 1D and 2D-NMR experiments and comparison of their NMR data with reported values. Compound 1 was isolated from S. chloronotus for the first time

ANTIMICROBIAL COMPOUNDS FROM RHIZOPHORA STYLOSA

(6S,7E,9R)-6,9-dihydroxy-4,7-megastiymadien-3-one 9-O-[α-L-arabinopyranosyl-(l→6)-β-D-glucopyranoside] (1), blumenol A (2), and kaempferol 3-rutinoside (3) were isolated from the methanol extract of the leaves of mangrove plant Rhizophora stylosa Griff. Structural elucidation of the metabolites was carried out by analysis of their spectroscopic data and by comparison with those reported in the literature. All these compounds exhibited antimicrobial activity and were isolated from this genus for the first time

GLUCOSIDES AND UREA DERIVATIVES FROM THE SEEDS OF SCAPHIUM MACROPODUM (MIQ.) BEUMÉE

Five known compounds {carbonylbis[imino(6-methyl-3,1-phenylenel)]}bis[carbamic acid] dimethyl ester (1), (1'R,3'S,5'R,8'S,2E,4E-dihydrophaseic acid) 3'-O-beta-D-glucopyranoside (2), 3-methylbutan-1-ol beta-D-glucopyranoside (3), astragalin (4) and daucosterol (5) were isolated from the methanol extract of the seeds of Scaphium macropodum (Miq.) Beumée. The structures of the isolated compounds were elucidated by the spectroscopic methods including NMR and MS, and also by comparison with the literature data. Compounds 1-3 were isolated from this plant for the first time