X100试验管线钢管的规范和生产

介绍了位于英国诺林伯利亚,钢管直径1 219 mm(48 in),输气压力18 MPa(180 bar),由英国BP公司承建的X100试验管线的建设概况.根据X100试验管线的设计参数制定了相应的钢管规范,设计了X100管线钢管母材、焊缝金属和热影响区的合金成分.按设计的合金成分由住友金属鹿岛钢铁厂生产了钢材、钢板,并...     

Physical, Chemical and Sensory Changes in Irradiated Fresh Pork Packaged in Modified Atmosphere

The effects of irradiation dose (0, 0.5 and 1.0 kGy), headspace oxygen (0, 10 and 20% O₂, balance nitrogen) and storage temperature (5, 15 and 25°C) on the physical, chemical and sensory changes in fresh pork were studied using factorial design experiments. Irradiation in the absence of oxygen extended the sensory shelf life of pork from 9 to 26 days at 5°C and from & lt; 2 to 2 days at 25°C. Oxygen in the package headspace combined with irradiation adversely affected physical, chemical and sensory characteristics of the end product.     

Equilibrium Cation Distribution in NiAl2O4, CuAl2O4, and ZnAl2O4 Spinels

Stoichiometric NiAl₂O₄, CuAl₂O₄, and ZnAl₂O₄ spinels were prepared and equilibrated at temperatures from 600° to 1400°C. The parameters u and x , denoting the oxygen position and fraction of divalent cations on tetrahedral sites, respectively, were determined from a detailed X-ray diffraction analysis. In NiAl₂O₄, x increased from 0.07 at 595° to 0.26 at 1391°C; in CuAl₂O₄, x decreased from 0.68 at 613° to 0.64 at 1195°C; and in ZnAl₂O₄, x decreased from 0.96 at 905° to 0.94 at 1197°C. The form of the temperature dependence of x could not be described using theoretically based equations advanced in the literature. A more general equation which allows for a non-distributional contribution to the configurational entropy was derived and observed to properly describe the temperature dependence; the results indicate that short-range order is of definite significance in these intermediate aluminate spinels.     

Electronic Sensing of Aromatic Volatiles for Quality Sorting of Blueberries

An electronic sniffer using semi-conductor gas sensors that nondestructively measured aromatic volatile gas emissions from fruit was developed to assess blueberry quality. The sniffer detected soft and damaged fruit in packaged containers at a 5% level of damage and distinguished four of five fruit ripeness classes: (1) mature-green and green-pink; (2) blue-pink; (3) blue; and (4) ripe fruit. Sniffer response increased as fruit ripened, as did total concentration of aromatic volatiles. Sniffer response correlated with berry firmness, pH, titratable acidity, and color, and detected differences among 10 cultivars, as did impact response analysis. The electronic sniffer is rapid, nondestructive and may be used to sort and quality check for presence of unripe or damaged fruit in closed packs of fresh berries.     

SENSORY QUALITY AND NUTRIENT COMPOSITION OF THREE HAWAIIAN FRUITS TREATED BY X-IRRADIATION

Papayas, rambutans, and Kau oranges were irradiated at 0 (control) and 0.75 (irradiated) kGy and stored for 2 and 9 days to determine the effect of X‐irradiation on objective and sensory quality attributes. Irradiation at 0.25 kGy, as a minimum dose, has been approved as a quarantine treatment for the export of tropical fruits grown in Hawaii. The effects of irradiation and storage on specific sensory attributes were dependent on the specific fruit. Aroma and flavor tended to be more intense in the irradiated fruit. Firmness decreased as a result of irradiation and storage, though significant only in rambutans. The color of the rambutans and oranges were significantly affected by irradiation. Irradiation did not contribute to significant changes in the ascorbic acid and carotenoid contents, pH, titratable acidity, and total soluble solids. Adaptation of X‐ray irradiation as a quarantine treatment should enhance the marketability of tropical fruits.     

DETECTION OF THE VIABLE BUT NONCULTURABLE STATE IN ESCHERICHIA COLI O157:H7

Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is recognized as a frequent cause of gastroenteritis ranging from mild to severe bloody diarrhea. The Shiga-like toxin produced by EHEC can result in hemolytic uremic syndrome, now the major cause of acute kidney failure in children in the United States. Inadequately cooked beef is most commonly implicated in the transmission of EHEC, although only a small fraction of cattle appear to harbor the organism. In several studies EHEC positive herds were detected only in the summer months correlating with the occurrence of human infections. Numerous E. coli strains have been shown to enter a viable but nonculturable (VBNC) state as a result of environmental stresses, including low temperature. Using traditional plating methods and the BacLight Molecular Probe, we monitored EHEC strains incubated in river water (RW) and artificial sea water (ASW) at temperatures of 5C and 25C for their entry into the VBNC state. EHEC strains remained culturable for over 40 days in both ASW and RW incubated at 25C. In ASW, these levels were higher than a non-EHEC control. At 5C, the number of culturable EHEC cells dropped gradually in both RW and ASW. Using the BacLight Molecular Probe, we were able to demonstrate that these cells, though not culturable, were viable indicating entry into the VBNC state. Our study suggests that temperature and not salinity is the primary signal for entry into this state .     

Reversible Stress-Induced Martensitic Transformation in ZrO2

Optical observations and X-ray measurements were used to detect the martensitic transformation of tetragonal ZrO₂ to the monocline structure during room-temperature stressing of Mg-PSZ. The transformation occurs at stresses as low as ∼200 MPa and is reversible. Additional observations of transformation around Vickers indentations and cracks suggest that application of much higher stresses prevents the reverse transformation on unloading.     

CONTROL OF BACILLUS CEREUS IN HIGH-pH CRUMPETS

Studies were performed to determine the effects of sorbic hydroxamic acid (SHA) and mastic oil–ethanol (ME) or water‐ethanol (WE) emitters on the growth of Bacillus cereus in high‐moisture, high‐pH (～8.9) English‐style crumpets stored at ambient temperature (25C). While SHA (3000 p.p.m.), alone or in combination with ME emitters, was effective in inhibiting the growth of B. cereus for 14 days in high‐pH crumpets, only SHA formulated crumpets packaged in air had acceptable sensory scores at the end of storage. However, ME emitters alone were ineffective in controlling the growth of this pathogen. This lack of inhibition in crumpets was attributed to the poor absorption of mastic volatiles from the package headspace into the food matrix. Whatever the reason, these preliminary studies showed that SHA has the potential to control the growth of B. cereus in high‐moisture, high‐pH crumpets without compromising product quality.