Physicochemical differences between Croatian cheese matured in a lamb skin sack (Sir iz misine) and cheese matured in a rind throughout ripening

The aim of this study was to research differences in physicochemical parameters between Croatian cheese in a lamb skin sack (Sir iz misine) and cheese in a rind throughout ripening. Cheese in a sack had significantly (P < 0.05) lower content of total solids, fat, proteins and salt which showed the ‘protective’ effect of skin sack and higher permeability of natural rind. The water‐soluble nitrogen in the total nitrogen (%TN) and 12% trichloroacetic acid‐soluble nitrogen (%TN) at the end of ripening was significantly (P < 0.05) higher in cheese in a sack than in cheese in a rind which indicates intensive proteolysis in cheese in a sack.     

The production switching heuristic: A practical revision

Production Switching Heuristics (PSH) have been suggested as realistic, practical alternatives to more sophisticated aggregate planning and scheduling models. A modified, two-level heuristic is presented and its properties investigated by use of the classical paint factory data (Linear Decision Rule). Even under relatively extreme circumstances, its cost performance is promising when compared with the LDR, LP and the original PSH.     

Generalized approach for model algorithmic control

This paper considers the development of a general model algorithmic control (MAC). It is shown that the proposed structure contains all the features and principles of MAC. The scheme developed allows choices of prediction and reference trajectories. The regulation effect is studied and non-minimum phase systems are also exemplified. The tracking and regulation properties of the proposed MAC depend on the choice of regulator and controller parameters. Results of simulation studies indicate the effectiveness of the developed algorithmic control.     

Polymorphism and Hydration of Tricalcium Silicate Doped With ZnO

Up to 4.7% ZnO can be incorporated into the crystalline lattice of C₃S. Five allotropic forms (i.e. T_I, T_II, M_I, M_II, and R) can be stabilized at room temperature, depending on the amount of ZnO. When heated to high temperature, the C₃S-ZnO solid solution decomposes and ZnO escapes from the crystalline lattice. The hydration and strength development of C₃S are altered by ZnO doping.     

A PARALLEL IMPLEMENTATION OF A TWO-DIMENSIONAL HYDRODYNAMIC MODEL FOR MICROWAVE SEMICONDUCTOR DEVICE INCLUDING INERTIA EFFECTS IN MOMENTUM RELAXATION

A self-consistent numerical transport model based on the hydrodynamic equations obtained from Boltzmann's transport equation (BTE) is presented. The model includes both the temporal and spatial variation in electron velocity. A parallel implementation of the solution method, using FDTD techniques, is illustrated. Numerical results for a GaAs MESFET device are generated using this complete hydrodynamic model (CHM) and compared with results obtained from the more commonly used energy or simplified hydrodynamic model (SHM). The results indicate that for short gate-lengths (less than 0⋅5 μm) the two models lead to different DC steady-state results which in turn lead to different microwave small-signal models for the device. © 1997 by John Wiley & Sons, Ltd.     

Deposition and characterization of diamond-like nanocomposite coatings grown by plasma enhanced chemical vapour deposition over different substrate materials

Diamond-like nanocomposite (DLN) coatings have been deposited over different substrates used for biomedical applications by plasma-enhanced chemical vapour deposition (PECVD). DLN has an interconnecting network of amorphous hydrogenated carbon and quartz-like oxygenated silicon. Raman spectroscopy, Fourier transform–infra red (FT–IR) spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) have been used for structural characterization. Typical DLN growth rate is about 1  ${\upmu} $ m/h, measured by stylus profilometer. Due to the presence of quartz-like Si:O in the structure, it is found to have very good adhesive property with all the substrates. The adhesion strength found to be as high as 0·6 N on SS 316 L steel substrates by scratch testing method. The Young’s modulus and hardness have found to be 132 GPa and 14· 4 GPa, respectively. DLN coatings have wear factor in the order of 1 × 10^???7 mm ³ /N-m. This coating has found to be compatible with all important biomedical substrate materials and has successfully been deposited over Co–Cr alloy based knee implant of complex shape.     

A Static Variable-Frequency Three-Phase Source Using the Cycloconverter Principle for the Speed Control of an Induction Motor

This paper describes a variable-frequency source employing the cycloconverter principle. SCR's have been used as the principal switching and voltage-regulating devices. The logic of the firing circuit has been discussed. The factor affecting output frequency stability has also been presented. A three-phase variable low-frequency oscillator has been used as the reference to achieve the variation of frequency. Voltage variation has been affected by phase delaying of the firing pulses in a manner similar to that in a phase-controlled rectifier. Provision has been made for changing the phase sequence at the output in order to facilitate reversal of the direction of rotation of the motor. Experimental results include output waveforms of various frequencies (0-30 Hz), and speed variations of the experimental motor (1 hp, 100 V, 1700 r/min) in either direction of rotation thereby providing the practical feasibility of the SCR cycloconverter for speed control of induction motors.     

Hydration Reactions in the System CaO-SiO2-CaF2

The phases existing in the system CaO-SiO₂-CaF₂ were synthesized and their hydraulicity was determined. Out of these only the phase which corresponds to the formula Ca_6–0.5xSi₂O_10-xF_x exhibited distinct hydraulic properties. The hydration rate of tricalcium silicate doped with CaF₂ declined with increasing degree of doping, while its compressive strength—found at a given degree of hydration—increased. The stoichiometry and specific surface area of the formed hydrates were altered because of the presence of fluorine in the crystalline lattice.     

New model reduction scheme for bilinear systems

A new method for the approximation of bilinear systems is proposed. The reduction scheme applies to both stable and unstable bilinear systems. The technique uses generalized input normal representations to retain the dominant part of the original system. The algorithm is evaluated on a synchronous induction generator and is shown to lead to acceptable reduced approximations of the original system. A frequency weighting is also introduced in the reduction scheme to further improve the approximation.     

Remote,surface and laboratory detection of radioactive minerals of Rosetta black-sand beach deposits,Egypt

Abstract

Detailed aerial and ground radiometric surveys were conducted on the coastal plain of the Mediterranean Sea, on both sides of the estuary of the Rosetta branch of the River Nile. Auger samples representing the upper 1 m, were collected and analysed for the two principal radioactive minerals in the black sands, zircon and monazite.

The results obtained by the various methods, particularly aeroradiometry, revealed five main zones of heavy mineral concentration along the beach to the east and west of the Rosetta estuary. The present-day Rosetta branch is responsible for the formation of the first zone of mineral concentration. The second and fifth zones can be related to the ancient extinct estuaries of the Bolbitine and Sebennytic branches mentioned by Ball (1942) (after Herodotus, 450 B.C.). The third and fourth zones are believed to correspond to two ancient extinct estuaries of the River Nile, which were probably not in existence at the time of Herodotus and therefore were not reported by Ball (1942).

The study revealed that there is a general direct correlation between the aerial data and that from ground radiometry and zircon and monazite tenors as in the case of Damietta black-sand beach deposits (Meleik et al. 1978).

It was found that the mean background radioactivity either from the air or from the ground, as well as the correlation coefficients, are generally higher and stronger on the western side of the Rosetta estuary than on its eastern side. Moreover, the mean concentration of zircon on the western side (0·62 per cent) reaches approximately 1·5 times that on the eastern side (0·39 per cent), while that of monazite remains almost the same westwards (0·16 per cent) and eastwards (0·14 percent).