Effect of interpass temperature on microstructure,impact toughness and fatigue crack propagation in joints welded using the GTAW process on steel ASTM A743-CA6NM

Mainly due to their great toughness, martensitic stainless steels are used for manufacturing hydraulic turbines. However, these steels have some restrictions regarding regions recovered by welding, mainly due to the formation of non-quenched martensite, which causes a reduction in toughness. Considering repair of hydraulic turbines, there is a great interest in developing welding procedures that increase impact toughness and avoid post-welding heat treatment (TTPS). This study aims to analyse the influence of interpass temperature on microstructure, impact toughness and fatigue crack propagation in multipass welded joints on martensitic stainless steel CA6NM, using AWS410NiMo filler metal and the gas tungsten arc welding (GTAW) process. In the sample with interpass temperature of 80°C, influence of the interpass temperature on the formation of ferrite δ, with intragranular formation in the two-phase δ field, was observed, while in the sample welded at 150°C, the formation of ferrite δδ occurred mainly in the single-phase field. The change in the formation of ferrite δ, with the low interpass temperature, promoted an increase in impact toughness and a decrease in the fatigue crack propagation when compared with the sample welded with a higher interpass temperature. The results obtained indicate that the TIG process is an excellent alternative for the repair of CA6NM steel, with a significant influence from the interpass temperature.     

A short‐cut DNA extraction from cod caviar

Caviars represent the most consumed form of fish roe products. Due to high demand, ingredient roes of fish are often susceptible to illegal substitution with those of related fish. This study developed a simple and inexpensive protocol enabling the rapid extraction of DNA of acceptable quality and amount to PCR amplification from both cod caviars and their ingredient pollack roes. The protocol was based on extracting total genomic DNA from eggs using urea and a Chelex 100 chelating resin, and could be completed in less than 15 min. Approximately 8 µg of DNA were reproducibly obtained from single eggs of cod caviars and pollack roes in eight individual experiments, and the quality and amount of DNA were sufficient to serve as template for hundreds of PCR reactions of polymorphic DNA markers for phylogenetic analysis. Being applicable to various caviars, this protocol can be useful to detect illegal substitution among ingredient roes of related fishes in PCR‐based food inspection. Copyright © 2005 Society of Chemical Industry     

Jamming layered membrane gripper mechanism for grasping differently shaped-objects without excessive pushing force for search and rescue missions

A gripper comprising a jamming membrane was developed with the capability of grasping collapsible, soft, and fragile objects without applying heavy pressure. In disaster sites, it is necessary for robots to grab various types of objects, such as fragile objects. Deformable grippers that contain bags filled with powder cannot handle collapsible or soft objects without excessive pressure. Changing powder density relatively by changing inner volume is one approach to overcome this problem. By expanding the concept and simplifying the variable inner volume of the gripping mechanism, we developed a jamming membrane comprising the following three layers: outer layer and inner layer made of rubber and a powder layer in between the outer and inner rubber layer. This jamming membrane allows collapsible, soft, or fragile objects to be held securely without applying too much pressure. We designed and developed a prototype of the jamming membrane gripper. Our experiments confirmed the validity of the proposed jamming membrane mechanism.     

Medium-energy ion scattering spectroscopy with a position-sensitive and time-resolving detector

A Si (1 0 0) sample covered with a thin Ho layer was measured with a three-dimensional medium-energy ion scattering spectrometer. The spectrometer is an extended version of a time-of-flight spectrometer for medium-energy ion scattering, equipped with a large position-sensitive detector. The device is used for composition depth profiling and crystal structure determination. The intensity distribution of detected particles was visualized to present medium-energy scattering phenomena. Circular shapes were observed in images created with part of the data containing particles scattered from the surfaces of the sample layers. Images show leading edges of “clouds” of arriving scattered particles were detected using the flat surface of the detector, integrated over 2 ns intervals. The center positions of shapes produced by particles scattered on Ho and Si atoms are different. This is explained by the different kinematic-factor dependences on scattering angle of particles scattered on Si and Ho atoms. The depth resolution of the time-of-flight spectra acquired with the full solid acceptance angle of the detector is limited by the kinematic spread. Using position information of detected particles from the detector, corrections for the kinematic spread and variations of flight path lengths were applied to spectra, increasing the depth resolution.     

Vinyl polymerization by metal complexes. XVI. Photopolymerization of vinyl monomers by metal-amine systems

The photopolymerization of vinyl monomers was studied by the system of metal-amine complex and carbon tetrachloride. Addition of amines to the initiating system generally accelerates the polymerization. The acceleration by various sorts of amines in different solvents was examined. It was confirmed that the photopolymerization in question is of free radical character. The polymerization mechanism was discussed.     

Phase transfer agents. II. Stereospecific hydroxylation of oleyl and elaidyl alcohol and periodic acid cleavage of epoxides

Oleyl and elaidyl alcohol have been stereospecifically hydroxylated by cold, dilute alkaline potassium permanganate toerythro- andthreo-9,10-dihydroxyoctadecanol, respectively, in 40–80% yields in a water-methylene chloride heterogeneous system. Phase transfer agents (PTA) were used to transport permanganate ion from the aqueous to the organic phase. In the absence of PTA, hydroxylation did not take place. Periodic acid cleavage of epoxides in a water-methylene chloride system was studied in the absence and presence of PTA. At slow stirring rates PTA exert a rate accelerating effect in cleaving certain epoxides to aldehydes but with vigorous stirring use of PTA has only a marginal advantage.     

Phase transfer agents. I. Transfer of permanganate,periodate, and cyanate ions from aqueous to organic phases. Preparation of quaternary onium periodates

Several quaternary ammonium and phosphonium halides have been shown to be useful phase transfer agents (PTA) for the efficient transport of permanganate, periodate, and cyanate ions from aqueous to organic phases (benzene and/or methylene chloride). Chemical and spectral methods of analysis were used to measure ion transfer quantitatively and to assess the relative efficiency of PTA.     

Sinus node recovery time and abnormal postpacing phase in the aged patients with sick sinus syndrome

The sinus node function was evaluated by rapid atrial pacing in 35 aged patients (mean age 78.2 years) including 10 aged controls, 12 cases with various degrees of AV block, 6 with bradycardia-tachycardia syndrome (BTS), and 7 with sinus bradyarrhythmia (SB). AV block was further divided into A-H block (7 cases) and H-V block (5 cases) by His bundle electrogram which was simultaneously recorded with 3 leads of surface electrocardiogram. Sinus node recovery time (SRT) was measured and its maximum value (SRTmax) was selected from SRTs obtained after pacing with various rates and durations in each patient. SRTmax was also expressed as percentage of the control P-P interval (%SRTmax). For patients in whom the study was repeated 3 to 8 months later, %SRTmax was reproducible in 9 of 14 instances. Prolongation of SRT was not always observed as the rate and/or duration of pacing was increased. SRTmax and %SRTmax were 1,363 +/- 188 msec and 147 +/- 19% (mean +/- SD), respectively, for aged controls, 1,597 +/- 442 msec and 156 +/- 31% for patients with AV block, 2,087 +/- 1,315 msec and 203 +/- 132% for those with BTS, and 3,069 +/- 1,287 msec and 247 +/- 115% for those with SB. SRTmax exceeding the range for aged controls was noted in 4 of 7 cases (57%) with A-H block, 2 of 6 (33%) with BTS, and 5 of 7 (71%) with SB; normal SRT was not infrequently observed in patients with sick sinus syndrome, especially in those with BTS. Analysis of 10 consecutive atrial cycles following cessation of pacing revealed that in 8 cases the first P-P interval (SRT) was followed by longer ones in some occasions (secondary suppression). It was observed almost exclusively in patients with sick sinus syndrome. The possibility of this phenomenon to reflect another feature of sinus node abnormality was discussed.     

Molecular Identification of Commercial Spicy Pollack Roe Products by PCR-RFLP Analysis

ABSTRACT: Spicy pollack roe products are a popular seafood item made from fish eggs that should be made with salt-cured mature roes of walleye pollack Theragra chalcogramma . Because of high demand and poor catch of walleye pollack, however, spicy pollack roe products are often susceptible to substitution with roes of closely related codfish. In this study, a simple method identifying the ingredients of commercial spicy pollack roe products was developed to differentiate walleye pollack from codfish substitutes such as gray cod Gadus macrocephalus using PCR-RFLP (Restriction Fragment Length Polymorphism) analysis. PCR amplification of the mitochondrial cytochrome b gene yielded single fragments commonly from pollack and cod. Direct digestion of the PCR products with Mph 11031 restriction enzyme showed an unique restriction fingerprint only in pollack. This PCR-RFLP analysis enabled the reliable identification of commercial spicy pollack roe products made by only pollack roes from products padded with cod roes. It thus can be useful to expose substitution of pollack roes with lower valued codfish roes in commercial spicy pollack roe products.     

Rotating fullerene chains in carbon nanopeapods

The rotation of fullerene chains in SWNT peapods is studied using low-voltage high resolution transmission electron microscopy. Anisotropic fullerene chain structures (i.e., C300) are formed in situ in carbon nanopeapods via electron beam induced coalescence of individual fullerenes (i.e., C60). A low electron accelerating voltage of 80 kV is used to prevent damage to the SWNT. The large asymmetric C300 fullerene structure exhibits translational motion inside the SWNT and unique corkscrew like rotation motion. Another asymmetric fullerene chain containing mixed fullerene species is prepared by fusing smaller C60 fullerenes to a larger Sc@C82 fullerene, and this also exhibits corkscrew rotational motion. Chains of Sc3C2@C80 in SWNT peapods adopt a zigzag packing structure, and the entire zigzag chain rotates inside the SWNT to induce structural modifications to the SWNT diameter and cross-sectional shape of the SWNT. The expansion and contraction of the diameter of the SWNT is measured as 17%, demonstrating nanoactuation behavior in carbon nanopeapods.