In this research, the heat transfer coefficient (HTC) and pressure drop of alternating cross-section flattened (ACF) tubes were investigated experimentally compared with same parameters a circular tube. Three different ACF fabricated from copper tubing an internal diameter 4.5 mm, thickness 1 length 400 mm. The twist angles 30, 45, 90°. experimental ranges covered mass flux 729–1,434 kg/m2s 12–...

arcinorna of the esophagus comprises 2 percent of all malignant tumors and 10 percent of all esophagogastrointestinal tumors. The national figures in Table 1' point out the magnitude of the problem. The treatment of this condition is palliative in some 75 percent of the cases, since at diagnosis 75 percent of the cases have regional or distant nodal metastases. In untreated patients, 75 percent...

The constrained Hamiltonian systems admitting no gauge conditions are considered. The methods to deal with such systems are discussed and developed. As a concrete application, the relationship between the Dirac and reduced phase space quantizations is investigated for spin models belonging to the class of systems under consideration. It is traced out that the two quantization methods may give s...

The optical destruction thresholds of conventionally etched and tube-etched near-field optical probes were measured. One of the main advantages of tube-etched tips is their smooth glass surface after taper formation. Presumably for this reason, a destruction limit of over 120 microJ was obtained, almost twice as large as that of the rougher, conventionally etched fibre probes. The use of additi...