SPIFI: a direct-detection imaging spectrometer for submillimeter wavelengths

The South Pole Imaging Fabry-Perot Interferometer (SPIFI) is the first instrument of its kind-a direct-detection imaging spectrometer for astronomy in the submillimeter band. SPIFI's focal plane is a square array of 25 silicon bolometers cooled to 60 mK; the spectrometer consists of two cryogenic scanning Fabry-Perot interferometers in series with a 60-mK bandpass filter. The instrument operates in the short submillimeter windows (350 and 450 microm) available from the ground, with spectral resolving power selectable between 500 and 10,000. At present, SPIFI's sensitivity is within a factor of 1.5-3 of the photon background limit, comparable with the best heterodyne spectrometers. The instrument's large bandwidth and mapping capability provide substantial advantages for specific astrophysical projects, including deep extragalactic observations. We present the motivation for and design of SPIFI and its operational characteristics on the telescope.     

Medical image enhancement algorithm based on NSCT and the improved fuzzy contrast

In order to solve the problem of noise amplification, low contrast and image distortion in the process of medical image enhancement, a new algorithm is proposed which combines NSCT (nonsubsampled contourlet transform) and improved fuzzy contrast. The image is decomposed by NSCT. Firstly, linear enhancement method is used in low frequency coefficients; secondly the improved adaptive threshold function is used to deal with the high frequency coefficients. Finally, the improved fuzzy contrast is used to enhance the global contrast and the Laplace operator is used to enhance the details of the medical images. Experimental results show that the proposed algorithm can improve the image visual effects, remove the noise and enhance the details of medical images. © 2015 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 25, 7–14, 2015     

Electric field–temperature phase diagram of sodium bismuth titanate-based relaxor ferroelectrics

The electric field–temperature phase diagrams of three bismuth sodium titanate-based relaxor ferroelectrics are reported, namely 0.94(Na_1/2Bi_1/2TiO₃)–0.06(BaTiO₃), 0.80(Na_1/2Bi_1/2TiO₃)–0.20(K_1/2Bi_1/2TiO₃) and 0.75(Na_1/2Bi_1/2TiO₃)–0.25(SrTiO₃). Relaxor behavior is demonstrated by temperature-dependent dielectric permittivity measurements in the unpoled and poled states, as well as by the field-induced phase transition into a ferroelectric phase from the relaxor phase. From temperature-dependent thermometry measurements, we identified the threshold electric field to induce the ferroelectric phase and obtained the released latent heat of the phase transition. We determined the nonergodic and ergodic relaxor phase temperature range based on the absence or presence of reversibility of the relaxor to ferroelectric transition. For all three compositions, the electric field–temperature phase diagram was constructed and a critical point was identified. The constructed electric field–temperature phase diagrams are useful to find optimum operational ranges of ferroelectrics and relaxors for electromechanical and electrocaloric applications.     

Formulation of consistent restoring stiffness in ship hydroelastic analysis

In this article, the role of the restoring stiffness, as one of the basic parameters in ship hydroelastic analysis, is brought out. It is formulated using the variational principle and the method of virtual displacements. It is shown that asymmetry of the restoring stiffness is a physical reality. Moreover, it is confirmed that modal variation, still disputed in the relevant literature, has to be taken into account to satisfy the ship’s stability. Consistent stiffness is formulated here by regarding stiffness definition as relation between forces and displacements. Hybrid stiffness known from the literature is wrong since some terms are specified as relation between forces and displacement gradient. Influence of the consistent and symmetrized stiffness matrix, and the hybrid one, on dynamic response is illustrated for a prismatic pontoon and a large container ship. It is found that the latter two matrices do not assure convergence of transfer functions of sectional forces to zero value as the wave frequency approaches zero. The rigid body and elastic responses are compared, and pertinent conclusions are drawn. It is also shown that it is not necessary to use the unified geometric and restoring stiffness for ordinary hydroelastic analysis of ship structures. The consistent formulation of the restoring stiffness matrix will be useful for extending linear potential theory hydrodynamic codes for rigid body analysis to deformable bodies.     

Solving partner selection problem in cyber-physical production networks using the HUMANT algorithm

The idea of non-hierarchical production networks consisting of autonomous enterprises has been present in scientific community for more than 20 years. Although some global corporations are using their own production networks across continents, they are not similar to the original idea of non-hierarchical production networks in many aspects. It seems that this idea waited for production systems to acquire proper information and communications technology (ICT) or new industrial platforms, like Industry 4.0. The result is a new type of production network called Cyber-Physical Production Network (CPPN). The CPPN is, from ICT point of view, ready to act as non-hierarchical production networks consisting of autonomous production systems with many automated processes. One of the most important processes of the CPPN is a selection of optimal partners (enterprises) to be part of a new virtual enterprise, created inside production network. An optimisation problem emerges in this process, and it is called Partner Selection Problem (PSP). It is non-polynomial-hard combinatorial problem. Since metaheuristic algorithms are well-proven in solving that kind of problem, a specially designed metaheuristic algorithm derived from ant colony optimisation and named the HUMANT (HUManoid ANT) algorithm is used in this paper. It is multi-objective optimisation algorithm that successfully solves different instances of PSP with two, three, four or more objectives.     

Fractal substructure of a nanopowder generated by repeated fragmentation and sedimentation: the rôle of the dust

Packings of cohesive nanoparticles, that is nanopowders, may be obtained as the result of repeated fragmentation–reagglomeration cycles (Schwager et al. in Phys Rev Lett 100:218002, 2008) such that the resulting sediment reveals a fractal structure. The size distribution of the fragments after a fragmentation step is a superposition of a narrow distribution of large particles (chunks) whose size is determined by the cutting length and a power-law distribution for small particles, representing scale invariant dust. It was shown that the exponent of the power-law, \(\tau \), is in non-trivial relation to the fractal dimension, \(d_f\), via \(d_f(2-\tau )=1\). This poses the question for the structure of the sediment created by repeated fragmentation–reagglomeration cycles when the dust particles are excluded from the reagglomeration step. We found that even in this case, repeated fragmentation–reagglomeration cycles yield a sediment of fractal structure with slightly reduced fractal dimension while the dust exponent, \(\tau \), remains unchanged.     

Grid deformation strategies for CFD analysis of screw compressors

Customized grid generation of twin screw machines for CFD analysis is widely used by the refrigeration and air-conditioning industry today, but is currently not suitable for topologies such as those of single screw, variable pitch or tri screw rotors. This paper investigates a technique called key-frame re-meshing that supplies pre-generated unstructured grids to the CFD solver at different time steps. To evaluate its accuracy, the results of an isentropic compression-expansion process in a reciprocating piston cylinder arrangement have been compared. Three strategies of grid deformation; diffusion equation mesh smoothing, user defined nodal displacement and key-frame remeshing have been assessed. There are many limitations to key-frame re-meshing. It requires time consuming pre-processing, has limited applicability to complex meshes and leads to inaccuracies in conservation of calculated variables. It was concluded that customized tools for generation of CFD grids are required for complex screw machines.     

Adrenocortical and adrenomedullary homologs in eight species of adult and developing teleosts: morphology, histology, and immunohistochemistry

Morphology, histology, and immunohistochemistry of the adrenocortical and adrenomedullary homologs (adrenal glands) of the following developing and adult teleosts were examined: Salmoniformes-Oncorhynchus mykiss (rainbow trout), Salmo trutta fario (brown trout), Coregonus lavaretus (white fish); Cyprinodontiformes-Gambusia affinis (mosquito fish). Perciformes-Dicentrarchus labrax (sea bass), Sparus aurata (sea bream), Diplodus sargus (white bream), Oblada melanura (saddled bream). The anatomical relationships of the gland with the renal system and venous vessels were also noted. In adults of all species steroidogenic and catecholaminergic chromaffin cells were found in the head kidney, which is pronephric in origin and subsequently transformed into a hematopoietic lymphatic organ. In Perciformes, chromaffin cells are distributed around the anterior and posterior cardinal veins and ducts of Cuvier; in Salmoniformes, around the posterior cardinal veins and in the hematopoietic tissue; and in G. affinis, around the ducts of Cuvier and posterior cardinal veins, while a few are visible also around the sinus venosus. In Perciformes and Salmoniformes, numerous chromaffin cells are also present in the posterior kidney, derived from the opisthonephros, in contact with the caudal vein. Steroidogenic cells are always confined to the head kidney. During development chromaffin and steroidogenic cells appear early after hatching in the pronephric kidney, at the level of the ducts of Cuvier and of the cephalic part of the posterior cardinal veins. Later, chromaffin cells in Perciformes reach the anterior cardinal veins, and subsequently, in both Perciformes and Salmoniformes, they reach the developing posterior kidney. Their localization along the posterior kidney is still in progress about 4 months after hatching and is completed about a year after hatching. These findings support the concept that the structure of the adrenal gland in teleosts is intermediate between that of the other actinopterygians and that of tetrapods. The development differs from that of tetrapods in that it occurs mainly in the pronephros and only later do chromaffin cells reach the opisthonephric kidney.     

Identification and changes in the higher fatty acids of dried red pepper and red pepper powder

Summary The higher fatty acids of dried red pepper of the variety of Gorogled were identified by gas chromatography with using help of authentic compounds. Their amounts were determined using on absolute calibration method.The following acids were established: lauric, myrastic, palmitic, palmitoleic, stearic, oleic, linoleic, linolenic,arachidic and behenic acids. The results obtained from the quantitative measurements showed that linoleic, linolenic and palmitic acids amounted to 80% of the total acids.The quantitative changes of identified acids in red pepper, of dried at 60°, 70°, 80° and 90 °C red pepper and stored as dried red pepper and red pepper powder over a 6-months period investigated.The results show that under the drying temperatures applied the amount of all fatty acids decreased with an increase in the temperature. During a storage a period of 3 months the amount of the respective acids decreased while the process was the most expressed in red pepper dried at a temperature of t = 70 °C.After a 6-months storage period under the drying condition applied the dried red pepper contained a greater amount of fatty acids compared with stored for 3 months.

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Identifikation und Veränderungen der höheren Fettsäuren von gemahlenem Paprika und von getrockneten ungemahlenen Paprikaschoten

Zusammenfassung Es wurden gaschromatographisch mit Hilfe von Vergleichsubstanzen die höheren Fettsäuren, die im gemahlenen Paprika (Sorte Gorogled) enthalten sind, identifiziert. Die Mengen wurden nach der Methode der absoluten Kalibrierung bestimmt. Es wurden folgende Säuren festgestellt: Laurinsäure, Myristin-, Palmitin-, Palmitoolein-, Stearin-, Olein-, Linol-, Linolen-, Arachin- und Behensäure. Die quantitativen Ergebnisse zeigen, daß die Menge der Linolen-, Linol- und Palmitinsäure 80% der Gesamtsäurenmenge darstellt. Es wurden die quantitativen Veränderungen der Fettsäuren von Paprika (Sorte Gorogled) bei Temperaturen von 60 °, 70 °, 80 ° und 90 °C, getrocknet und als getrockneter ungemahlener bzw.gemahlener Paprika, gelagert und innerhalb von 6 Monaten in Abständen von 3 Monaten verfolgt. Bei den angewendeten Trocknungstemperaturen nimmt die Menge der einzelnen Fettsäuren in dem getrockneten ungemahlenen Paprika mit Erhöhung der Trocknungstemperatur ab. Die Lagerung des getrockneten ungemahlenen Paprikas innerhalb von 3 Monaten führt zur Abnahme der einzelnen Fettsäuren, wobei dieser Prozeß am stärksten bei einer Trocknungstemperatur von 70 °C verläuft. Nach einer 6monatigen Lagerung des getrockneten und ungemahlenen Paprikas, nach Trocknung und bei den o. g. vier Temperaturen, ist die Menge der Fettsäuren höher im Vergleich zu jener der Fettsäuren in getrocknetem ungemahlenem Paprika nach 3 Monaten. Nach 3 Monaten enthält der gemahlene Paprika weniger Fettsäuren als der getrocknete und ungemahlene Paprika.