Change in grain size and flow strength in P/M Rene 95 under isothermal forging conditions

The changes in microstructure induced by plastic deformation in hot isostatically pressed (HIPed) P/M Rene 95 under isothermal conditions are discussed. Results of the constant true strain rate compression tests are presented for initially fine (7 μm) and coarse (50 μm) grained compacts deformed at temperatures of 1050 °C, 1075 °C and 1100 °C and at strain rates in the range from 10⁻⁴ s⁻¹ to 1 s⁻¹. Under these test conditions, both the fine and coarse-grained compacts recrystallize and their grain size are refined during flow. This grain refinement gives rise to softening in both materials. Ultimately, their microstructures transform into the same equiaxed fine-grained microduplex structure at which point their flow strength becomes identical. Continued deformation at that point produces no further change in grain size or flow strength. Under this steady state regime of deformation, the microduplex grain size and flow strength are independent of the original microstructure but are conditioned by the strain rate at a given temperature. The steady state grain size increases whereas the steady flow strength decreases with a decrease in strain rate and/or an increase in temperature.     

Heavy metal levels in two fish species Leuciscus cephalus and Lepomis gibbosus

The concentrations of heavy metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were measured in muscle, gill and liver of two fish species (Leuciscus cephalus and Lepomis gibbosus) caught from Saricay, South-West Anatolia. Levels of metals varied depending on different tissues in species. The mean concentrations (μg g⁻¹ wet weight) of heavy metals in tissues of Leucis cephalus were as follows: Cd: 0.010–0.084, Co: nd–0.131, Cu: 0.193–2.611, Fe: 4.240–172.000, Mn: 0.112–24.230, Pb: 0.068–0.874, Zn: 6.350–28.550, and in tissues of Lepomis gibbosus were as follows; Cd: 0.008–0.082, Co: nd–0.233, Cu: 0.065–4.360, Fe: 11.200–125.000, Mn: nd–12.434, Pb: 0.070–0.920, Zn: 6.540–16.064. Ni was not determined in all organs studied.     

Ayka,a Novel Curtobacterium Bacteriophage,Provides Protection against Soybean Bacterial Wilt and Tan Spot

Diseases caused by the Gram-positive bacterium Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) inflict substantial economic losses in soybean cultivation. Use of specific bacterial viruses (bacteriophages) for treatment of seeds and plants to prevent the development of bacterial infections is a promising approach for bioprotection in agriculture. Phage control has been successfully tested for a number of staple crops. However, this approach has never been applied to treat bacterial diseases of legumes caused by Cff, and no specific bacteriophages have been known to date. This paper presents detailed characteristics of the first lytic bacteriophage infecting this pathogen. Phage Ayka, related to φ29-like (Salasmaviridae) viruses, but representing a new subfamily, was shown to control the development of bacterial wilt and tan spot in vitro and in greenhouse plants.     

Declarative paradigm of test coverage

Two facts about declarative programming prevent the application of conventional testing methods. First, the classical test coverage measures such as statement, branch or path coverage, cannot be used, since in declarative programs no control flow notion exists. Second, there is no widely accepted language available for formal specification, since predicate logic, which is the most common formalism for declarative programming, is already a very high-level abstract language. This paper presents a new approach exending previous work by the authors on test input generation for declarative programs. For this purpose, the existing program instrumentation notion is extended and a new logic coverage measure is introduced. The approach is mathematically formalized and the goal of achieving 100% program logic coverage controls the automatic test input generation. The method is depicted by means of logic programming; the results are, however, generally applicable. Finally, the concepts introduced have been used practically within a test environment. © 1998 John Wiley & Sons, Ltd.