Effects of a constricted nozzle on the arc phenomena in the TIG welding process

Effects of a constricted nozzle on the arc phenomena in the tungsten inert gas (TIG) welding process are investigated by numerical simulation. the obtained results show that the temperature and velocity of the arc plasma are increased by attaching an additional gas nozzle, which is called the "constricted nozzle". As a result, the iron vapour does not diffuse upward but is transported outward. In addition, the heat transfer to the base metal surface is enhanced.     

Characterization and gas‐permeation properties of crosslinked diacetylene‐containing polymer membranes from ferulic acid

Thermally and UV crosslinked poly[propargyl(3‐methoxy‐4‐propargyloxy) cinnamate] (PPOF) were investigated in terms of their physical, thermal, optical, and gas‐permeation properties. The crosslinked membranes had high gel contents because of the formation of a diacetylene network. The wide‐angle X‐ray diffraction patterns showed that all of the membranes were amorphous in structure, regardless of the type of crosslinking reaction. The membrane density increased after the crosslinking reaction; this suggested that the free volume of the crosslinked membrane was lower than that of the untreated membranes. Drastic color changes in the membranes were also observed because of the highly conjugated crosslinked network of diacetylene. In addition, the conjugation caused by diacetylene crosslinking led to visible absorption within the range 400–600 nm. The gas permeation of the crosslinked membrane was reduced compared with that of the untreated membranes. In particular, the gas permeability of the thermally crosslinked membrane was lower than that of UV‐irradiated membrane. On the basis of this result, the degree of crosslinking by thermal treatment was higher than that of UV irradiation. Hence, the crosslinked PPOF membranes showed improved gas‐barrier properties due to the high conjugation of the crosslinked diacetylene network induced by thermal treatment and UV irradiation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

EXTRACTION OF METAL IONS WITH DZEHPA FROM MIXED AQUEOUS-ORGANIC MEDIA

Extraction of metal ions from the aqueous-organic solution containing dimethyl formamide(DMF), dimethyl sulfoxide(DMSO) and acetonitrile(AN) was investigated by using di-2-ethylhexyl-phosphoric acid(D2EHPA) as an extractant. The organic phase was a binary solution of D2EHPA and n-hexane, or D2EHPA and toluene, while the polar phase was a three component solution of metal salt, non-aqueous solvent and water. The extracted metal ions were Cr(III), Fe(III), Al, Cu, Ni, Co(II), Mg and Ag.

The extraction behaviors may be explained by the solvation ability of non-aqueous solvents, the decrease in distribution of the extractant and extract into the organic phase, and the interaction between the extractant and non-aqueous solvents due to the dissolution of non-aqueous solvents in the organic phase.     

Effect of polycarbonate–poly(methyl methacrylate) graft copolymer as a modifier improving the surface hardness of polycarbonate

In this study, poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid) (PAMPS) was synthesized using potassium persulfate (K₂S₂O₈) as initiator. PAMPS (M _n = 36,000 g/mol) was partially converted to a lithium salt (PAMPS–Li), and particle size was determined to be 40 μm. Suspensions of PAMPS–Li at various concentrations were prepared in silicone oil, mineral oil, dioctylphthalate (DOP), and trioctyltrimellitate (TOTM) insulating oils. Colloidal stabilities of these suspensions were determined at 20 and 80°C. The PAMPS–Li suspensions were observed to provide an electrorheological (ER) response upon the application of an external dc electric field. ER properties of these suspensions were investigated at various shear rates (γ˙) and electric field strengths (E). Further, effects of polar promoters and high temperature on ER activity were determined, and excess shear stresses (Δτ) were calculated. A shear‐thinning non‐Newtonian viscoelastic behavior was observed for the PAMPS–Li suspensions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1106–1112, 2002     

Relationship between the composition of polycarbonate copolymers and the refractive index

With a polycarbonate (PC)–poly(methyl methacrylate) (PMMA) graft copolymer and a PC–poly(dimethyl siloxane) (PDMS) block copolymer, the relationship between the composition of PC copolymers and the refractive index (n_D) was investigated. According to the results, with a PMMA content of 38 wt %, the n_D value of the PC–PMMA graft copolymer was nearly the same as that of electrical (E) glass (n_D = 1.545), and with a PMMA content of 6 wt %, it was nearly the same as that of electrical corrosion resistance (ECR) glass (n_D = 1.579). However, with a PDMS content of 19 wt %, the n_D value of the PC–PDMS block copolymer was nearly the same as that of E glass, and with a PDMS content of 2 wt %, it was nearly the same as that of ECR glass. The combination of the PC–PDMS block copolymer and the glass fibers (GFs) of ECR glass led to haze values of 8 and 16% with GF contents of 10 and 20%, respectively. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 514–521, 2002; DOI 10.1002/app.2355     

Pd-SiO2复合膜的氢气选择渗透特性

Palladium membranes were prepared on an a-alumina support by metal-organic compound chemical vapor deposition (MOCVD) method from palladium(Ⅲ) acetate precursor. Permeation properties of hydrogen and helium gas were studied as a function of the number of times of deposition of palladium on the peeling off phenomenon of palladium, which is common in electroless plated membrane, was observed. Silica was introduced into the pores to prevent the palladium grain from peeling off. The palladium-silica conjugated membrane does not show the peeling off phenomenon and can withstand the high temperature up to 800℃ which is the upper limit of our apparatus.The separation factor for hydrogen gas over carbon dioxide gas was improved with the increase of number of times of silica coating by sacrificing the H2 permeation and finally increased to four times. The improvement on the separation of hydrogen gas over carbon dioxide for pulladium-silica conjugated membrane was evaluated and a model of permeation pattern (palladium and silica) was proposed. This model suggests that the separation factor for hydrogen over carbon dioxide could be improved by introducing silica layer because the silica layer fills the pores and reduces the gas permeation without sacrificing the hydrogen permeation through the palladium region. These results indicate that the introduction of silica into the palladium grain is a promising means to improve the hydrogen separation performance of palladium based composite membranes.     

Selective photo-oxidation of various hydrocarbons in the liquid phase over V2O5/Al2O3

More than 0.22 mmol of isolated VO₄ species of V₂O₅/Al₂O₃ exhibited the highest evolution of the partial oxidation products (alcohol and ketone) in the oxidation of cyclohexane and cyclopentane. The conversion of cyclohexane and the selectivity of the partial oxidation products were achieved to be 0.49% and 85% over 0.8 g of 3.5 wt.% V₂O₅/Al₂O₃, respectively, where the K/A ratio was 6.2. In addition, V₂O₅/Al₂O₃ can selectively oxidize various hydrocarbons in the liquid phase by the one-step oxygen atom insertion to CH bond. The order of priority was tertiary carbon > secondary carbon > primary carbon > benzene ring.     

Dietary Glucosylceramide Enhances Cornified Envelope Formation via Transglutaminase Expression and Involucrin Production

In this study, we investigated whether dietary glucosylceramide (GlcCer) and its metabolite sphingoid bases, sphingosine (SS), phytosphingosine (PS), sphingadienine (SD) and 4-hydroxysphingenine (4HS), influence cornified envelope (CE) formation. CE is formed during terminal differentiation of the epidermis through crosslinking of specific precursor proteins by transglutaminases (TGases), and is essential for the skin's barrier function. Oral administration of GlcCer (0.25 mg/day) for 14 consecutive days dramatically reduced transepidermal water loss, an indicator of the skin barrier condition, in hairless mice with barrier perturbation induced by single-dose ultraviolet B (UVB) irradiation. The GlcCer treatment also increased the level of TGase-1 mRNA in UVB-irradiated murine epidermis approximately 1.6-fold compared with the control. Further, all four sphingoid bases at 1 μM concentration enhanced CE formation of cultured normal human keratinocyte cells. Among them, SS, PS and SD, but not 4HS, stimulated production of involucrin, one of the CE major precursor proteins. SD increased the expression of TGase-1 mRNA, while SS increased the expression of TGase-3 mRNA. These results indicate that the skin barrier improvement induced by oral GlcCer treatment might be at least partly due to a reinforcement of CE formation in the epidermis mediated by sphingoid bases metabolically derived from GlcCer.     

Comparison of performance between benzoindoline and indoline dyes in zinc oxide dye-sensitized solar cell

The cell performance of novel benzoindoline dyes on zinc oxide prepared by template cathode electro-deposition method was compared with that of known indoline dyes. Among cyanoacrylic, single and double rhodanine acetic acid derivatives, the cyanoacrylic benzoindoline dye showed better performance than the indoline dye (D131) due to larger J_sc value which comes from its positive E_ox level and bathochromic UV-vis absorption band.