Type Of Ducts Research Articles

Thermoeconomic analysis of duct works for air-conditioned building in Thailand

Energy savings in air-conditioning systems are important for achieving energy efficient buildings. A central air-conditioning system in the large building is installed with air ductwork. Alternative materials are replacing conventional (Galvanized Iron Steel) air ducts for supplying air to the air-conditioned area. This research studies the objective function relationship between exergy and economic variables in the alternative air ductwork compared with conventional air ductwork. The optimization method to identify the optimal type and thickness of air ducts in Thailand's buildings. The result shows that the alternative ductwork has achieved maximum worthiness with more useful exergy than conventional air ductwork. The Pre-insulated duct (PID) with 30.00 mm wall thickness is 82.14 %. It is the maximum of all exergies generated by the Air Handling Unit.

A new species of Pseudopoda (Araneae, Sparassidae) from China, with the description of different and distinctive internal ducts of the female vulva.

One new species of the genus Pseudopoda Jäger, 2000, Pseudopodadeformis Gong & Zhong, sp. nov. (♂, ♀), is described and documented with digital images from Shennongjia Forestry District, Hubei Province, China, based on morphology and DNA barcodes. This new species is separated from other Pseudopoda species by the unique type of internal ducts of the female vulva that are curved longitudinally, forming a narrow triangle or trapezoidal shape. In addition, DNA barcodes for this species are provided.

Numerical assessment of the effect of length, angle of attack, and type of ducts on hydrodynamic parameters of a linear-jet propulsion system

Achieving noble and more practical propulsion systems is still a major concern for engineers and researchers. Accordingly, many researchers have strived to opt for better and suitable system for the targeted vessels. One of the marine propulsion systems is linear-jet propulsion which includes rotor and stator. In this paper, the effects of geometrical shape of the duct in the form of different length and angle of attack for two types of the accelerating and decelerating ducts are comprehensively explored. Furthermore, section of rotor from Kaplan series are selected and the geometrical shape effects of the rotor on hydrodynamic performance of linear-jet propulsion system are also investigated. Therefore, to obtain the effects of the expressed parameters on the hydrodynamic characteristics of this propulsion system, Ansys-CFX software has been used. The governing equations of the studied problem are RANS equations and SST k-omega turbulent model is utilized. The obtained results are presented in the form of dimensionless coefficients of the forces applied on the propulsion system. The existing data for a ducted propeller are used to validate the numerical solution. Based on the results of the numerical solution, it is concluded that use of a decelerating duct increases the efficiency of the linear-jet system. On the other hand, the use of accelerating ducts reduces the hydrodynamic efficiency of the linear jet, so the performance is not desirable at high advance ratio. Therefore, the use of decelerating ducts in the linear-jet system is found to be the appropriate choice. Results further illustrate that, if the duct length increases, the generated thrust by the rotor increases. It is also concluded that, by increasing the angle of attack of the decelerating duct, the overall efficiency of the linear-jet propulsion system decreases.

UN PROCESO ROBUSTO PARA EL ACABADO EN PRECISIÓN DE PIEZAS FABRICADAS POR IMPRESIÓN METÁLICA

The additive manufacturing industry has developed significantly, which includes metal printing techniques; with a wide range of applications, great projections and future expectations. Technologies such as SLM or LMD have gone from being considered as a rapid prototyping process to consolidating in a primary manufacturing process Despite the great advances made in metal printing, there are still aspects of quality, dimensional and finish that require the need for subsequent actions to metallic printing (thermal treatments, subtractive manufacturing) for the scope of structural integrity and dimensions definitive This paper presents a methodology based on the robust design approach, which allows to integrate the main hybrid process with 4 support processes for the control of performance metrics and the mitigation of the effects of noise factors through the strategic use of the controllable factors under a predictive, preventive and technical approach. A case study is presented where the phase of the vibration control applied to a type of elbowed ducts is analyzed, which allows to obtain an adequate tendency of the type and location of fixation system that leads to improve the quality of the finishing. Keywords: SLM, machining, geometric distortion, dimensional control, heat treatment, robust design

Histologic Features Associated With Columnar-lined Esophagus in Distal Esophageal and Gastroesophageal Junction (GEJ) Biopsies From GERD Patients: A Community-based Population Study.

There are inherent problems with the endoscopic and pathologic criteria for columnar-lined esophagus (CLE). Furthermore, the clinical and biological significance of an irregular squamocolumnar junction (SCJ) is unclear. The aim of this study was to evaluate the association between histologic features in SCJ biopsies and CLE and to gain insight into the significance of an irregular SCJ. The study was a cross-sectional analysis of 2176 mucosal biopsies of the SCJ from 544 patients in a large prospective community clinic-based study of gastroesophageal reflux disease in Washington State. Biopsy samples were evaluated blindly for a wide variety of histologic features, such as the presence and type of mucosal glands, submucosal glands and ducts, goblet cells, multilayered epithelium (ME), inflammation, and buried columnar epithelium. Histologic findings were correlated with the endoscopic findings (normal Z-line, irregular Z-line, or CLE) and evaluated by logistic regression and receiver operating characteristic analysis.Five histologic features were associated with CLE: pure mucous glands, ME, presence of goblet cells, ≥50% of crypts with goblet cells, and buried columnar epithelium. Pure oxyntic glands were inversely associated with CLE. The features most strongly related to CLE included biopsies with ≥50% of crypts with goblet cells, ME, and mucosal gland type (area under the curve=0.71; 95% confidence interval=0.66-0.76). Patients with an irregular Z-line were histologically similar to those with CLE. Certain histologic features in biopsies of the SCJ are associated with the presence of CLE. Irregularity of the Z-line is probably indicative of ultrashort segment CLE, instead of being a potential variation of normal.

Observations Concerning the Structure of the Major Salivary Glands in Chinchilla (Chinchilla lanigera)

The structure of the salivary glands is different depending on the species and diet. The glandular secretion can be serous, mucous or mixed. Within the same order, for instance in rodents, there are dissimilarities between the major salivary glands, even if the diet is similar. In this study, we used three chinchillas, slaughtered for their fur. We harvested the major salivary glands which were histologicaly processed. The parotid gland in chinchilla is highly similar to the one in other mammal species, regarding its general microscopic aspect. It contains only one type of acini (serous) and numerous secretory ducts. On the other hand, the submaxillary gland has a particular type of acini, with a narrow lumen and cells with a round nucleus. They resemble the serous ones, but the glanular aspect of the cytoplasm suggests that the secretion of this gland is different in comparison to the one in the parotid gland. The structure of the sublingual gland in chinchilla is similar to the one in most of the mammals, containing typical mucous acini, with a foamy cytoplasm. The major salivary glands in chinchilla, highly resemble those in most of the mammal species. The parotid gland presents serous acini and the sublingual one, typical mixed acini. Instead, the submaxillary gland has a particular aspect: its acini do not present the serous demilune, they resemble the typical serous acini (contain round nuclei), but they are larger.

Numerical study on the impacts of the bogus data assimilation and sea spray parameterization on typhoon ducts

The Weather Research and Forecasting model version 3.2 (WRF v3.2) was used with the bogus data assimilation (BDA) scheme and sea spray parameterization (SSP), and experiments were conducted to assess the impacts of the BDA and SSP on prediction of the typhoon ducting process induced by Typhoon Mindule (2004). The global positioning system (GPS) dropsonde observations were used for comparison. The results show that typhoon ducts are likely to form in every direction around the typhoon center, with the main type of ducts being elevated duct. With the BDA scheme included in the model initialization, the model has a better performance in predicting the existence, distribution, and strength of typhoon ducts. This improvement is attributed to the positive effect of the BDA scheme on the typhoon’s ambient boundary layer structure. Sea spray affects typhoon ducts mainly by changing the latent heat (LH) flux at the air-sea interface beyond 270 km from the typhoon center. The strength of the typhoon duct is enhanced when the boundary layer under this duct is cooled and moistened by the sea spray; otherwise, the typhoon duct is weakened. The sea spray induced changes in the air-sea sensible heat (SH) flux and LH flux are concentrated in the maximum wind speed area near the typhoon center, and the changes are significantly weakened with the increase of the radial range.

Observational Occurrence of Tropical Cyclone Ducts from GPS Dropsonde Data

AbstractOn the basis of global positioning system dropsonde data, Japan Meteorology Agency Regional Spectral Model analysis data, National Centers for Environmental Prediction reanalysis data, satellite products from the Naval Research Laboratory, and best-track tropical-cyclone (TC) datasets from the Shanghai Typhoon Institute, the statistical characteristics of the ducts induced by TCs (TC ducts) over the western North Pacific Ocean were analyzed for the period from September 2003 to September 2006, and two typical strong-duct cases with remarkable differences in formation cause were analyzed and compared. Of the total of 357 dropsondes, there are 212 cases that show ducting conditions, with an occurrence percentage of ~59%. Of the 212 TC-duct events, profiles with multiple ducting layers make up nearly one-half, with the main type of ducts being elevated ducts; in contrast, weak ducts make up over one-half, resulting in a weak median duct strength and thickness. Ducts formed in the transition zone, especially on the left side of TC tracks, tend to be much stronger and thicker than those formed inside TCs. The former are induced by the interaction between TCs and their surrounding systems, such as the inrush of dry and cold air from the north on the left side of TC tracks. The latter are associated with successive subsidence in the gaps between spiral cloud bands. With increasing TC intensities, the associated ducts inside TCs tend to be much stronger and thicker and to appear at higher altitudes.

Aberrant Confluence of Intrahepatic Biliary Ducts - A Case Report

Aim: Besides the most frequent-modal type of confluent patterns intrahepatic biliary ducts, there are cases with aberrant type of confluence. The aim of this report is to present a case with aberrant confluence of intrahepatic biliary ducts. Material and Methods: Injection-corrosive method was used to obtain acrylic cast from biliary and portal systems of one human liver. Biliary ducts were followed parallel to the adjoint portal ramification from the initial part of segmental ductules. Results: Nine portal segments of the liver were established. Segmental biliary ducts and their confluence subsequently from IV to I order, were also seen. The right hepatic duct was absent. The posterior and anterior right sectorial ducts joined consecutively the opposite left hepatic duct in front of the portal bifurcation. As to the segmental ducts 2 nd segment duct inflow the left hepatic duct, then 3 rd segment duct had merging pattern of double medial sector duct as well as three segmental ducts 5 th , 6 th and 7 th had inflow pattern in posterior sector duct. This specimen with aberrant confluence of intrahepatic ducts has been selected to point out the “close” relationship of found aberrant bile ducts in the liver region. Conclusion: The knowledge of the aberrant anatomy of biliary ducts emphasizes the importance in clinical practice of basic information for portobiliary topography.

Laminar fully developed flow through square and equilateral triangular ducts with rounded corners subjected to H1 and H2 boundary conditions

The present paper deals with the evaluation of pressure drop and heat transfer characteristics of laminar fully-developed flow through ducts of square and equilateral triangular cross sections with rounded corners, for both H1 and H2 boundary conditions. The dimensionless radius of curvature ( R c ) of both type of ducts is varied from zero to the maximum possible value (1 for square duct and 1 / 3 for triangular duct). The solutions for velocity and temperature are considered in the form of a harmonic series. The constants of the series are evaluated by ‘least square technique’. From the velocity and temperature solutions, fRe and Nu are calculated. The results show that for square duct, at lower values of R c , both fRe and Nu increase rapidly with R c and for higher values of R c , both fRe and Nu asymptotically assume their values corresponding to that for the circular duct. For triangular ducts, Nu shows a similar behaviour. fRe, on the other hand, shows a similar behaviour only for lower values of R c . At moderate R c , fRe attains its maximum value around R c ≈ 0.35 and with further increase in R c , fRe drops slightly and finally tends to its value corresponding that of a circular ducts in an asymptotic manner. For both type of ducts, Nu for H1 boundary condition is always higher than that for H2 boundary condition. It is also observed that the straight portion of the duct is always more effective than the circular duct, where as, the effectiveness of the rounded portion, which is always less than the circular duct, increases with the increase in R c . Correlations, in two different forms, are obtained for all the cases and they show excellent agreement with the computed data.

Viscous Standing Asymptotic States of Isentropic Compressible Flows Through a Nozzle

In this work we consider a viscous regularization of a well-known one-dimensional model for isentropic viscous compressible flows through a nozzle. For the existence and multiplicity of standing asymptotic states for a certain type of ducts, a complete analysis in a framework of dynamical systems is provided. As an application of the geometric singular perturbation theory, we show that all standing asymptotic states admit viscous profiles.

Morphology of Deep Gland of the Third Eyelid in Pig Foetuses

The morphological and histological examinations of the deep gland of the third eyelid were carried out on pig foetuses coming from the 35th, 50th, 63rd, 94th and 112th day of gestation. The morphological examinations were conducted using the method of macroscopic preparation with a forehead magnifying glass and binocular (magnification 1.5-5.0x). In order to make anatomical elements more visible, 60-80% absolute alcohol and 0.5-4% acetic acid solution were used for the examinations. For the histological examinations, the whole eyeball with developing accessory organs was collected from the pig foetuses on the 35th day of gestation. On the 50th, 63rd, 94th and 112th day of gestation only the deep gland of the third eyelid was collected. Staining with haematoxylin-eosin and Azan method was performed. It was found during the examinations that the process of the formation of the deep gland of the third eyelid starts on the 35th day of gestation. On the 50th day of gestation, the gland cells are evenly distributed in the connective tissue stroma. On the 63rd day of gestation, the connective tissue divides the gland parenchyma into indistinct lobes composed of 6-15 lobules. On the 94th day of gestation, the gland lobes become visible; the efferent ducts are situated in the central part of the lobe. On the 112th day of gestation, the lobes are composed of a high number of lobules composed of two kinds of excretory ducts. The first type of the excretory ducts is lined with the simple cuboid epithelium whose nuclei are situated at the base of the cell. The other type of the excretory ducts is lined with the simple cuboid epithelium whose nuclei are round and arranged less or more peripherally.

MHD-turbulence generation by cylinders in insulated ducts with different cross sections

Mercury experiments were performed to investigate the magnetohydrodynamic- (MHD)-turbulence generation by cylinders in ducts having two different cross sections: (i) a rectangular duct with two walls parallel to the orientation of the magnetic field B (side walls) and two sides perpendicular to B (Hartmann walls), and (ii) a trapezoid duct with one inclined Hartmann wall. The experiments covered the following ranges: the Reynolds number ( Re)=2×10 3–10 4, the Hartmann number ( Ha)=230–890, and the interaction parameter ( N)=4–200. Distributions of the mean velocity and turbulence level downstream the cylinders were determined with two arrays of 20 electrodes. It is demonstrated that the turbulence is not damped in the rectangular duct compared with that in the trapezoid duct. In the latter one the damping is stronger in general in that part with the shorter side wall except for small distances. This might indicate that for small distances between turbulence promoters a heat transfer improvement might be also reached in this type of ducts.

True hermaphroditism: Geographical distribution, clinical findings, chromosomes and gonadal histology

We reviewed 283 cases of human true hermaphroditism published from 1980 to 1992. Of the 96 cases described in Africa 96.9% showed a 46,XX karyotype. In Europe 40.5% of 74 cases and 21.0% of the patients in North America had chromosomal mosaicism. The 46,XY karyotype is extremely rare (7%) and equally distributed through Asia, Europe and North America. Of 283 cases 87 were of black or black mixed origin with a 46,XX chromosomal constellation. The most common gonad in patients with true hermaphroditism, an ovotestis, was found in 44.4% of 568 gonads. Gonads with testicular tissue were more frequent on the right side of the body, while pure ovarian tissue was more common on the left. Histologically the testicular tissue was described to be immature and only twice was spermatogenesis reported while the ovarian portion often appeared normal. This coincides with 21 pregnancies reported in ten true hermaphrodites while only one true hermaphrodite apparently has fathered a child. Of the patients 4.6% were reported to have gonadal tumours. Position and type of the genital ducts, frequency of clinical findings such as genital abnormalities and gynaecomastia, correlations between assigned sex and karyotype as well as the age at diagnosis are reported.

CLINICAL STUDY ON ABERRANT BILE DUCT

Clinical cases of aberrant bile duct experienced at the department for the past 9 years and 4 months were analyzed to elucidate the surgical problems in prevention of intraoperative injury of aberrant bile ducts. The frequency of the diseases was 8 per 976 cases (0.82%) undergoing cholecystectomy. Number of cases and frequency in each type by modified Hisatsugu's classification was as follows; type I:3 cases (38%), III:2 (25%), N:1(13%), and V:2 (25%). There was no relationship between type or diameter of aberrant bile ducts and intraoperative injury. A result that the preoperative diagnostic methods in two injured cases were both DIC suggests the importance of comprehension of forms of the bile ducts with direct cholangiography at preoperation. There was no relationship between the degree of inflammation at Calot's triangle and intraoperative injury, but the operative methods in two injured cases were both mixed cholecystectomy in which normograde cholecystectomy was performed after temporary ligation of the cystic duct. These results suggest that normograde cholecystectomy, including mixed cholecystectomy, is not always a safety method and careful attention at operation is most important to prevent injury of the aberrant bile duct regardless of operative method.

Gross dissection and immunohistochemical studies on branch fusion type of ventral and dorsal pancreatic ducts: A case report

A case of fusion via two inferior branches between the ventral and dorsal pancreatic ducts was studied both macroscopically and immunohistochemically, based on the organogenesis of the pancreas. Radiologically, the branch fusion seemed to be composed of an inferior branch of the ventral pancreatic duct and an inferior branch of the dorsal pancreatic duct. By mapping pancreatic polypeptide cells in the material obtained by pancreatoduodenectomy, however, the branch was identified as a branch of the dorsal pancreatic duct. Thus, fusion between two inferior branches was not established, but was found to consist of an inferior branch of the dorsal pancreatic duct connected with the ventral pancreatic duct. We therefore challenge the concept of the ansa pancreatica.

Relationships between congenital biliary dilatation and ventral pancreatic duct in patient with branch fusion type of ventral and dorsal pancreatic ducts

Relationships between congenital biliary dilatation and ventral pancreatic duct in patient with branch fusion type of ventral and dorsal pancreatic ducts

Treatment of biliary atresia: A study of our operative results

The operative results in 87 biliary atresia cases were investigated from the aspect of the histologic findings in the liver and the remnant of the extrahepatic bile ducts, and the details of the operative procedures. The degree of liver fibrosis, the liver cell changes, and the type of extrahepatic bile ducts are closely related to our operative results. Our operative results have been improving since 1977 due to the advancement of microsurgical techniques and a new type of operative procedure for prevention of ascending cholangitis. Twenty-five of 29 cases (86.2%) surgically corrected are alive, showing bile excretion, and are in a satisfactory general condition.

Histopathological studies on intrahepatic bile ducts in the vicinity of porta hepatis in biliary atresia.

Intrahepatic bile ducts in the vicinity of the porta hepatis were histologically investigated in 9 cases of biliary atresia and the pattern of bile duct was divided into two groups. In the first group, there were a few large bile ducts which had continuity to the extrahepatic bile duct. In the second group, many small bile ducts were histologically observed, but there was no large bile duct at the porta hepatis. This type of abnormal bile ducts was seen in the cases of obliteration of bile ducts at porta hepatis.

Morphology of Ceroplastes pseudoceriferus GREEN with Special Refernce to the Wax Secretion

Morphological observations on Ceroplastes pseudoceriferus GREEN, one of the common scale insects in Japan, were carried out throughout the postembryonic development with a special interest on the relations of the dermal gland pores and ducts to the wax secretion. The progress of morphological changes during the development from the first instar larva to the adult was described in detail, with reference to the external appearance of the waxy coverins of each instar. The dermal gland pores and ducts could be classified into six types : Simple pore, cuciform pore, quinquelocular disc pore, multiocular disc pore, tubular duct and filamentous duct. On the basis of the distribution and the time of apperance on the body surface it is inferred that the simple pore is responsible for the secretion of wet wax which is produced after the third instar, the quinquelocular disc pore for powdery was in the stigmatic furrows, and the multilocular disc pore for powdery wax around the vulva. By the method used, no type of pores or ducts which are responsible for the secretion of dry wax in the first and second instars, was found.