The amylase-producing microflora of semi-preserved canned sausages

Summary Thirteen strains of amylase-producing bacteria were isolated from semi-preserved canned sausages and their ingredients. All belonged to the genusBacillus, and could be separated into 4 diffärent groups. Two groups were diffärent strain ofB. subtilis, one wasB. amyloliquefaciens and the last wasB. macerans. The identification of the different bacteria species was supported by disc gel electrophoresis of the supernatant culture fluid, after growth. The amylases were chracterizied with regard to temperature optimum, pH optimum and thermostability. Although some of the amylases appear to be quite thermostable, the only explanation for starch degradation in semi-preserved foods seems to be the amylase production from outgrowing spores which survived the heat treatment.

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Die amylaseproduzierenden Mikroben der Dosen-Würstchen als HalbkonservenIdentifizierung der Mikroben und Charakterisierung ihrer Amylasen

Zusammenfassung Dreizehn Stämme von Amylase produzierenden Bakterien wurden von halbkonservierten Dosenwürstchen und ihren Bestandteilen isoliert. Alle gehörten zum GenusBacillus und konnten in 4 verschiedenen Gruppen geteilt werden. Zwei der Gruppen waren verschiedene Stämme vonB. subtilis, eine warB. amyloliquefaciens und die letzte Gruppe warB. macerans. Die Identifizierung der verschiedenen Bakterienarten wurden nach Wachstum durch Diskgelelektrophorese der überstehenden Kulturflüssigkeit unterstützt. Die Amylasen wurden durch auf Temperatur-, pH-Optimum und Thermostabilität charakterisiert. Obwohl einige der Amylasen sehr thermostabil sind, scheint die einzige Erklärung des Stärkeabbaues in halbkonservierten Nahrungsmittel das Überleben der Sporen mit nachfolgender Auskeimung, Wachstum und Amylaseproduktion zu sein.

     

Nonuniform cooling in multifilament melt spinning of polypropylene fibers: Cooling air speed limits and fiber-to-fiber variations

The cooling of the spinning stage in a commercial compact-spinning line has been studied. A rectangular fiber bundle is extruded from the spinneret and cooled by air entering from one side. The speed of the cooling air is considerably reduced through the fiber bundle. There are practical lower and upper limits for the cooling air entrance speed, corresponding to filament breakage at the leeward and windward sides, respectively. These limits are functions of the material and processing parameters. Due to the nonuniform cooling, fibers sampled at the windward side generally have higher molecular orientation, lower amorphous fraction, higher density, and higher tensile modulus and strength. For most combinations of spinning and material parameters, the structure is either bimodally oriented α-crystalline or uniaxially oriented mesomorphic at all spinneret positions. Fibers with different structure types show opposite windward/leeward side trends with regard to local order and melting behavior. The structure may be mesomorphic at the leeward side and α-crystalline at the windward side, if the average spin-line stress is close to a critical value for orientation-induced crystallization, and the air speed difference across the spinneret is large. The cooling air speed affects the spin-line stress. Hence, the fiber-to-fiber variations due to nonuniform cooling are discussed in terms of the molecular orientation in the melt and the effective time available for arranging molecules into ordered structures. © 1995 John Wiley & Sons, Inc.     

Logic Synthesis with High Speed CMOS Circuit Techniques

Systems for automated logic synthesis with the True Single Phase Clocking circuit technique (TSPC) and a modified form of the Clock and Data Precharged Dynamic (CDPD) circuit technique, are presented. The CDPD system synthesizes high speed one clock cycle modules of unate Boolean functions in short design time. A novel true single phase clocking (TSPC) flip-flop suitable for CDPD synthesis simplifies interfacing with standard edge triggered clocking schemes. Also, a TSPC cell library for automatic logic synthesis with the TSPC circuit technique is presented. The library is targeted for high performance DSP applications. Fabricated test circuits synthesized by both the CDPD and TSPC synthesis systems in a 0.8m standard CMOS process are described and their performance is verified. Clock frequencies up to 700MHz were measured.     

Relationships between the properties of fibers and thermally bonded nonwoven fabrics made of polypropylene

Typical polypropylene fibers for use in light nonwoven fabrics were produced in a full scale compact-spinning line. Molecular weight distribution (MWD), extrusion temperature, draw-down ratio, and draw ratio were varied. The fibers were thermally bonded (welded) into nonwoven fabrics, at different bonding temperatures, using a pilot calender line. The tensile properties of the fabrics are influenced by the MWD and the processing conditions of the fibers, and the effects of these fiber parameters increase with increasing bonding temperature. The fabric strength increases with increasing M_w/M_n, decreasing draw ratio, and increasing extrusion temperature, while in all these cases the fiber strength generally follows the opposite trend. Furthermore, the fabric strength, as well as the fiber strength, have a maximum as a function of draw-down ratio. The tensile properties of the fabrics seem to be governed by the bonding properties of the constituent fibers, not the fiber strength per se. Bond characteristics are discussed in terms of skin-core structures. Some details of the macroscopic fracture mechanisms of fabrics were revealed by scanning electron microscopy and the shape of load-elongation curves. © 1995 John Wiley & Sons, Inc.     

In‐line versus off‐line rheological measurements on S‐PVC formulations releant for flow in extrusion dies

The supermolecular structures present in S‐PVC during processing are dependent on the thermomechanical history and affect the rheological behavior. Motivated by the need to have reliable rheological data relevant for numerical modeling of 3D flows in extrusion dies, we compared standard off‐line capillary measurements with‐inline measurements obtained from an instrumented die mounted on an extruder. Different PVC formulations showed different slip behavior in‐line, and also differences in comparison with the off‐line results. Cogswell analysis on entry pressure drops was used in order to obtain elongational information. For one formulation, with plug flow both in off‐line and in‐line measurements, an analysis based on the resistance to flow in contracting zones was the only way to get flow data that could be used in 3D profile simulations. The temperature sensitivity of measurements was used in order to discuss our results in terms of structural changes within the melt due to differences in thermomechanical history and formulation. Finally, an example of a 3D simulation of the flow of this formulation in an industrial extrusion die is given and compared with observations.     

Über den Weg zur neuen deutschen Erdbebennorm DIN 4149: 2005‐04

About the way to the new German Seismic Code DIN 4149: 2005‐04. Developments are presented, which have lead to the elaboration of the new German Seismic Code DIN 4149: 2005‐04 on the basis of Eurocode 8. So beside of a new version of the seismic zoning map a complete revision of the definition of the seismic action, of safety verifications and of detailing rules is performed. Finally some particularities of the new code, differing from Eurocode 8, are shown, the maintenance of which is recommended also in case of a later substitution of DIN 4149: 2005‐04 by EC 8.     

Guidance of Loop Ordering for Reduced Memory Usage in Signal Processing Applications

Data dominated signal processing applications are typically described using large and multi-dimensional arrays and loop nests. The order of production and consumption of array elements in these loop nests has huge impact on the amount of memory required during execution. This is essential since the size and complexity of the memory hierarchy is the dominating factor for power, performance and chip size in these applications. This paper presents a number of guiding principles for the ordering of the dimensions in the loop nests. They enable the designer, or design tools, to find the optimal ordering of loop nest dimensions for individual data dependencies in the code. We prove the validity of the guiding principles when no prior restrictions are given regarding fixation of dimensions. If some dimensions are already fixed at given nest levels, this is taken into account when fixing the remaining dimensions. In most cases an optimal ordering is found for this situation as well. The guiding principles can be used in the early design phases in order to enable minimization of the memory requirement through in-place mapping. We use real life examples to show how they can be applied to reach a cost optimized end product. The results show orders of magnitude improvement in memory requirement compared to using the declared array sizes, and similar penalties for choosing the suboptimal ordering of loops when in-place mapping is exploited.