Pneumatic Duct Research Articles

High -temperature duct thermal insulation debonding analysis for civil aircraft

The paper focuses on the problem of the composite thermal insulation of High-temperature Pneumatic ducts for civil aircraft debonding phenomenon. The performance of thermal insulation material is tested to explain the reason why debonding. A model based on the test and thermal kinetic analysis is proposed to quantify the life of the insulation. Based on the model, a certain duration of thermal insulation is calculated. This methodology can predict the life of thermal insulation.

Single-cell analysis of shared signatures and transcriptional diversity during zebrafish development

During development, animals generate distinct cell populations with specific identities, functions, and morphologies. We mapped transcriptionally distinct populations across 489,686 cells from 62 stages during wild-type zebrafish embryogenesis and early larval development (3-120h post-fertilization). Using these data, we identified the limited catalog of gene expression programs reused across multiple tissues and their cell-type-specific adaptations. We also determined the duration each transcriptional state is present during development and identify unexpected long-term cycling populations. Focused clustering and transcriptional trajectory analyses of non-skeletal muscle and endoderm identified transcriptional profiles and candidate transcriptional regulators of understudied cell types and subpopulations, including the pneumatic duct, individual intestinal smooth muscle layers, spatially distinct pericyte subpopulations, and recently discovered best4+ cells. To enable additional discoveries, we make this comprehensive transcriptional atlas of early zebrafish development available through our website, Daniocell.

Swim bladder inflation failure and associated spinal deformities in giant grouper Epinephelus lanceolatus

Giant grouper (Epinephelus lanceolatus, GG) is a valuable aquaculture species in Southeast Asia. Its farming is challenging, and the occurrence of spinal deformities is one of the bottlenecks found in aquaculture production. This study investigated the development of the swim bladder (SB) in GG and a possible causative relationship between failing to inflate the SB and spinal deviations in juvenile fish. The study of the ontogeny of the SB in GG revealed that the organ is connected through the pneumatic duct to the digestive tube from day 4 to day 7 post hatching (DPH). Repeated observations of larvae over this period showed that GG SB inflation period commences on day 5 DPH and lasts until the end of day 7 DPH. However, a proportion of day 7 DPH larvae failed to inflate their SB showing unorganised acidophilic tissue in the lumen of the organ. Assessment of skeletal anomalies in post metamorphic fish (42 DPH) revealed a relationship between the lack of an inflated SB and anomalies in the caudal region; more specifically, the urostyle (p < 0.05). Morphological assessment of juvenile fish showed a direct relationship between the lack of an inflated SB and lordotic/kyphotic anomalies. This was confirmed by X-ray of fish with and without an inflated SB following separation by hypersaline flotation. These findings show that SB inflation failure is the major contributing factor to spinal anomalies in GG. Also, this study described the timing of the SB inflation period in GG and its development.

MORPHO-FUNCTIONAL AND DEVELOPMENTAL STUDY OF SWIM BLADDER IN PRE TO POST FLEXION STAGES LARVAE OF HIMALAYAN SNOW TROUT SCHIZOTHORAX PLAGIOSTOMUS (HECKEL) REARED IN ARTIFICIAL AND NATURAL CONDITIONS

Present study deals with histology, gross morphology of the larvae and its behavioural aspects to describe the progression of the development of swim bladder in pre to post flexion stages larvae of the Himalayan Snow Trout Schizothorax plagiostomus (Heckel) reared in laboratory as well as in natural site. It reveals a very significant information in respect to derivation, tissue differentiation, initial inflation as well as factors responsible for noninflation of swim bladder especially among laboratory reared larvae. At hatching (108-110 and 124-130 hours after fertilization in laboratory and natural site respectively), larvae measured 9.00 mm and 10.5 mm in laboratory and natural site respectively, and their body cavity was mostly occupied with a huge amount of yolk. The mouth, pharynx and esophagus were impervious till 3rd day post hatching (dph). Primordial swim bladder appeared on 3rd.dph as a cluster of mesenchymal cells evaginating from the posterior dorsal surface of the differentiating esophagus. Later on it grows toward the caudal direction below the differentiating vertebral column and kidney. Initial swim bladder inflation occurred by 6-dph when larvae attained 12.50–13.50 mm length, with the onset of first exogenous feeding. During this phase a mucous like substance was also observed in the pneumatic duct as well as lumen of swim bladder of some laboratory reared larvae and later on they got mortality. By 8-dph well differentiated and inflated swim bladder becomes externally visible and pneumatic duct extended to join the dorsal wall of esophagus. A number of biotic and abiotic factors were found associated with preventing swim bladder inflation during Pre flexion to Post flexion stages.

Swim Bladder Disorders in Koi Carp (Cyprinus carpio).

Simple SummaryPhysostomous fish like cyprinids possess a swim bladder with a pneumatic duct in connection with the foregut, permitting the gas to enter into or be released through the alimentary canal. Due to this peculiar anatomic structure, bacteria and mycetes can potentially ascend the duct and colonize the swim-bladder. Besides inflammatory reactions, other swim bladder disorders include fluid accumulation, collapse, overinflation, and herniation. These swim bladder disorders and consequent buoyancy problems can be encountered in ornamental fish. Nonetheless, details about comprehensive disease management are poorly represented in the koi carp (Cyprinus carpio) literature. A clinical–pathological and microbiological investigation was performed in nine koi carp presenting abdominal swelling and abnormal swimming behavior. Swim bladder deformation, accumulation of clear fluid within the swim bladder, chronic aerocystitis, and bacteria identified as Aeromonas hydrophila/caviae group and Shewanella xiamenensis were the main findings. A wide range of sensitivity was shown to antimicrobials for isolated S. xiamemensis strains. Accordingly, antibiotic treatment succeeded in the full recovery of three cases in which S. xiamemensis infection was detected. Along with these results, the contribution of this study to the scientific field is to document a multidisciplinary clinical–pathological and microbiological investigation of these animals, which are rightly considered pets and should be similarly approached.Swim bladder disorders and consequent buoyancy problems are encountered in ornamental fish, including koi carp. Nevertheless, beyond clinical and pharmacological management, they are largely underdiagnosed. In this study, nine koi carp showing abdominal swelling and abnormal swimming behavior were investigated. Clinical approach, varying from case to case, included ultrasonographic and X-ray investigations, bacteriological analysis of the collected fluid, antimicrobial susceptibility pattern, and possibly histological analysis. Diagnostic imaging, corroborating gross examination, documented swim bladder deformation/dislocation and serous fluid within the swim bladder chambers of most animals. Bacteria belonging to the Aeromonas hydrophila/caviae group and Shewanella xiamenensis were identified. S. xiamenensis strains showed a sensibility to all tested molecules except for one strain, which was resistant to tetracycline and cyprofloxacin. Antibiotic treatment succeeded in the full recovery of three cases in which S. xiamemensis infection was detected. Chronic aerocystitis was histologically documented where tissue was available. The swim bladder histopathological findings highlighted a chronic process that had compromised the quality of life of the animals. A multidisciplinary clinical–pathological and microbiological approach is highly suggested to recognize swim bladder conditions as early as possible, aiming to drive medical intervention and raising the chances of fish survival.

The gas bladder of Pantodon buchholzi: Structure and relationships with the vertebrae.

We report here on the histological and structural characteristics of the gas bladder, the vertebral morphology, and the bladder-vertebra relationships of the butterfly fish, Pantodon buchholzi. The bladder opens at the boundary between the pharynx and the esophagus by a middle slit. A pneumatic duct is absent. The bladder shows a dorsolateral wall that adapts to the anfractuosities of the coelomic cavity and a ventral wall in contact with the abdominal organs. The vertebral bodies are formed by an hourglass shaped autocentrum, and by an arcocentrum reduced to several longitudinal ridges. The transverse processes adopt the structure of a cage whose walls are formed by bone trabeculae of variable size and distribution pattern. The dorsolateral wall of the bladder is a membrane that covers the kidney, adapts to the irregular shape of the vertebrae, and invades the transverse processes at several points before extending laterally. However, invasion of the vertebral bodies, the presence of a labyrinth, or the formation of respiratory parenchyma were not observed. The luminal surface of this wall is a thin respiratory barrier containing a single epithelial cell type. In addition, the wall contains numerous eosinophils that may be implicated in immune defense. The bladder ventral wall is a membrane rich in collagen, vessels, smooth muscle, and nerves that lacks a respiratory barrier. Its luminal surface contains ciliated and nonciliated cells. The two cell types appear implicated in surfactant production.

Impact of the precleaner pneumatic duct on the grain dresser performance

There is a wide variety of seed cleaners capable of functioning in seed treatment mode as part of the grain dresser. The most promising is the modernization of existing seed cleaning units, since it is possible to use their construction part, which will significantly reduce the cost of upgrading the production line for obtaining the seed material in the post-harvest processing. The goal during the equipping is to create an optimal set of grain dressers that allow getting seed material in one pass through the unit, minimizing micro and macro damage, which in turn affect future productivity. The goal of the research was to assess the impact of the precleaner pneumatic duct on the operation of the entire cleaning department.

In-depth analysis of swim bladder-associated microbiota in rainbow trout (Oncorhynchus mykiss)

Our knowledge regarding microbiota associated with the swim bladder of physostomous, fish with the swim bladder connected to the esophagus via the pneumatic duct, remains largely unknown. The goal of this study was to conduct the first in-depth characterization of the swim bladder-associated microbiota using high-throughput sequencing of the V4 region of the 16 S rRNA gene in rainbow trout (Oncorhynchus mykiss). We observed major differences in bacterial communities composition between swim bladder-associated microbiota and distal intestine digesta microbiota in fish. Whilst bacteria genera, such as Cohnella, Lactococcus and Mycoplasma were more abundant in swim bladder-associated microbiota, Citrobacter, Rhodobacter and Clavibacter were more abundant in distal intestine digesta microbiota. The presumptive metabolic function analysis (PICRUSt) revealed several metabolic pathways to be more abundant in the swim bladder-associated microbiota, including metabolism of carbohydrates, nucleotides and lipoic acid as well as oxidative phosphorylation, cell growth, translation, replication and repair. Distal intestine digesta microbiota showed greater abundance of nitrogen metabolism, amino acid metabolism, biosynthesis of unsaturated fatty acids and bacterial secretion system. We demonstrated swim bladder harbors a unique microbiota, which composition and metabolic function differ from microbiota associated with the gut in fish.

Morphological features of an endangered Japanese strain of Cyprinus carpio: reconstruction based on seven SNP markers.

Morphological analyses of 183 specimens of Japanese common carp Cyprinus carpio (171 from Lake Biwa and 12 from nursery ponds) using genetic hybrid indices demonstrated that the typical native Japanese strain of C. carpio has a more elongate body, more branched dorsal-fin rays, fewer and shorter gill rakers, more developed pneumatic bulb, more coiled pneumatic duct, longer posterior swimbladder and shorter intestine than the typical introduced C. carpio. These results provide a basis for a better understanding of the ecological characteristics and taxonomic status of the endangered Japanese strain of C. carpio.

Manipulating the air-filled zebrafish swim bladder as a neutrophilic inflammation model for acute lung injury.

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS), are life-threatening diseases that are associated with high mortality rates due to treatment limitations. Neutrophils play key roles in the pathogenesis of ALI/ARDS by promoting the inflammation and injury of the alveolar microenvironment. To date, in vivo functional approaches have been limited by the inaccessibility to the alveolar sacs, which are located at the anatomical terminal of the respiratory duct in mammals. We are the first to characterize the swim bladder of the zebrafish larva, which is similar to the mammalian lung, as a real-time in vivo model for examining pulmonary neutrophil infiltration during ALI. We observed that the delivery of exogenous materials, including lipopolysaccharide (LPS), Poly IC and silica nanoparticles, by microinjection triggered significant time- and dose-dependent neutrophil recruitment into the swim bladder. Neutrophils infiltrated the LPS-injected swim bladder through the blood capillaries around the pneumatic duct or a site near the pronephric duct. An increase in the post-LPS inflammatory cytokine mRNA levels coincided with the in vivo neutrophil aggregation in the swim bladder. Microscopic examinations of the LPS-injected swim bladders further revealed in situ injuries, including epithelial distortion, endoplasmic reticulum swelling and mitochondrial injuries. Inhibitor screening assays with this model showed a reduction in neutrophil migration into the LPS-injected swim bladder in response to Shp2 inhibition. Moreover, the pharmacological suppression and targeted disruption of Shp2 in myeloid cells alleviated pulmonary inflammation in the LPS-induced ALI mouse model. Additionally, we used this model to assess pneumonia-induced neutrophil recruitment by microinjecting bronchoalveolar lavage fluid from patients into swim bladders; this injection enhanced neutrophil aggregation relative to the control. In conclusion, our findings highlight the swim bladder as a promising and powerful model for mechanistic and drug screening studies of alveolar injuries.

Modeling of milled straw heap separation in air-flow classificator with three pneumatic ducts

The research subject is a multivariate analysis of the air-flow classification process of the straw heap with a predetermined fractional composition supplied to the cleaning after the drum destroyer. The work objective is to identify patterns of the air separation using three pneumatic ducts with a linkage parameter variation. The investigative technique is an analytical modeling. The effect of probabilistic characteristics of the heterogenic thrashed heap supply, airflow velocity distribution by the separator width, and density function of heap components terminal velocity on the separation is evaluated. The air-flow classification process on each section of the pneumatic duct is considered. To this end, the mathematical expressions averaging the air classification indicators of the consistently functioning three pneumatic ducts and a stochastic quasistatic mathematical model of the separator operation with three pneumatic ducts in series are used. The results of the separator parametric synthesis and its technological parameters are presented. The fractional constituents of the heap components and their percent-sizes in each air-classified fraction are shown. The possibility of the air-flow classification of the crushed straw heap in the predetermined factions at the preset productivity of 0.6-0.7 kg/m∙s is revealed. It is found that under the rational functioning of the air separator, the straw content in the service faction is 97.03%. In this case, the minimum grain content is 0.03%, and mineral impurities are 0%. It is revealed that the air separator with three pneumatic ducts in series is sufficient for separating the crushed straw heap with the predetermined agro-technical requirements.

Influence of Diversion Tunnels on Insulation Design of the High Temperature Pneumatic Duct

Based on the research of air-duct system in ARJ21-700, insulation design is studied in this paper. Considering its specific characteristics, CFD method based on FLUENT is taken to its thermodynamic calculation. The result shows that diversion tunnels along the pipeline have remarkable effects on the skin temperature distribution of the heat-insulating layer, while differ with diversion tunnels’ amounts. These effects should be adopted into the engineering algorithm and these works would be helpful to the design and optimization of the air-duct system.

Improvement Design of the Insulation Structure of High Temperature Pneumatic Duct System of the Aircraft

Based on the study of the duct leak detection system of commercial aircraft in existence, the insulation structure of high temperature pneumatic duct system of the aircraft is improved with multilayer insulation method and its engineering calculation method is derived. Also, the insulation experiment platform of the high temperature pneumatic duct system is built to verify the applicability and feasibility of the engineering calculation method. The research result shows that the results from the engineering calculation method is not fit the experimental data perfectly, the margin of error is 17 percentage. The main reason is that the diversion tunnels has a little effect on the temperature distribution and in these cases parameter modification method should be adopted in the engineering calculation method. These works would be helpful for the design and optimization of the high temperature pneumatic duct system.

Моделирование процесса сепарации измельчённого соломистого вороха в пневмосепараторе с двумя пневмоканалами

The functional diagram of a grain-cleaner with two ducts and certain air speed characteristics is described. Each pneumatic duct is segmented into blocks with various probabilistic characteristics of the airflow velocity distribution, various density composition and terminal velocities of each component. The mathematical expressions averaging the air separation indices full-width of two sequentially operating pneumatic ducts are defined. A stochastic quasi-static mathematical model of the operation process of a grain-cleaner with two pneumatic ducts is developed. The air-separation process at the specified manufacturing characteristics of the heap components, their fractional value in the heap, and of the structure of the airflow entering the pneumatic ducts, is simulated. The results of the parametric air-flow classification synthesis, the technological characteristics of its operation are described; the heap fractional makeup and measurable characteristics in each separated fraction are given; the possibility of the air-flow classification of the crushed haulm heap on the controlled factions with the output of 0,689 kg/(m∙s) is defined.

Anatomical and Histological Comparative Study of the Esophagus and Stomach in Rainbow Trout, from Different Growth Systems

Due to modernization of growth technologies and the increasing of growth trout densities, were highlighted differences in terms of the final products obtained quality. Therefore, we aimed to identify the possible morphological and histologica l changes of the digestive system of rainbow trout, by adequate investigation on some specimens from two different farming systems, one classical and the oth er superintensive-recirculating. Respecting the workin g protocols, were slaughtered trout from each syste m, being prelevated samples and segments of the esophagus and stomach. The results did not reveal morphological and histological differences, except for some lipids deposits. Introduction: One of the most intensively exploited fish species, both nationally and throughout the world, is rainbow trout ( Oncorhynchus mykiss ). Even if they have done anatomical and histological studies of the digestiv e tract (Geyiko glu et al ., 2004; Khojasteh, 2012), we believe they are insufficient, this being the reason we want to bring our contribution at the completion of the literature. Aims and Objectives. From the perspective of diversification of rearing technologies and replacing animal protein ingredien ts with plant constituents in the forage structures (economical reason), we intend to invest igate the changes that occur in the digestive tract, both anatomically and histological ly. Materials and Methods. Experiments were conducted in 2012, being slaughtered 10 rainbow trout from each group. The origin of the bi ological material was common, from the same population (Fiad trout nursery, Bistri Ńa-Nasaud County). The collected samples were fixed in 10% formalin and then, were included in paraffin , passing then through all stages of hydration, re-hydration and the microtome sectionin g. Coloration protocols were hematoxylin- eosin and goldners'trichrome. Anatomical observations were made macroscopically. Results and Discussions. At the esophageal mucosa level, respectively esoph ageal lumen, are present parallel longitudinal folds. In terms of coloring, they have a pale tinge in the first third (in close proximity to pharyngo-eso phageal junction), gradually becoming pale pink in the middle third, and later, the hue of pin k to become more evident in the last third, sometimes with reddish tints. The role of these pro minences is to enable esophagus to dilate, when the catch is large prey. On the back part of t he first third of the esophagus, are present the pneumatic duct that connects the esophagus and air bladder. Precisely for this reason, rainbow trout is fall within pfizostoumos fish cate gory, less evolved. Highly evolved fish (as fish belonging to the Cyprinidae family), no have this duct. Boundary demarcation be tween the esophagus and stomach is evident, and is resemb les at the eso-gastric junction with a pseudo-sphincter.

Developmental Expression of the Nfe2-Related Factor (Nrf) Transcription Factor Family in the Zebrafish, Danio rerio

Transcription factors in the CNC-bZIP family (NFE2, NRF1, NRF2 and NRF3) regulate genes with a wide range of functions in response to both physiological and exogenous signals, including those indicating changes in cellular redox status. Given their role in helping to maintain cellular homeostasis, it is imperative to understand the expression, regulation, and function of CNC-bZIP genes during embryonic development. We explored the expression and function of six nrf genes (nfe2, nrf1a, nrf1b, nrf2a, nrf2b, and nrf3) using zebrafish embryos as a model system. Analysis by microarray and quantitative RT-PCR showed that genes in the nrf family were expressed throughout development from oocytes to larvae. The spatial expression of nrf3 suggested a role in regulating the development of the brain, brachia and pectoral fins. Knock-down by morpholino anti-sense oligonucleotides suggested that none of the genes were necessary for embryonic viability, but nfe2 was required for proper cellular organization in the pneumatic duct and subsequent swim bladder function, as well as for proper formation of the otic vesicles. nrf genes were induced by the oxidant tert-butylhydroperoxide, and some of this response was regulated through family members Nrf2a and Nrf2b. Our results provide a foundation for understanding the role of nrf genes in normal development and in regulating the response to oxidative stress in vertebrate embryos.

Modal Analysis of the High Temperature and Pneumatic Duct System of the Aircraft

Based on the analysis of the loads, constraints and its mechanisms applying to the duct system, a finite element model of the anti-ice system is developed and the Lanczos algorithm is used for modal analysis. Then, the first eight natural frequencies and vibration modes are obtained. The thermodynamic parameters of the gas and the kinetic parameters of the ball joint which have influence on the modal analysis are considered. The results show that the first eight order natural frequencies of the anti-ice Part1 are low and concentrated, and decrease with temperature of the gas while increase with pressure of the gas. Meanwhile, the natural frequencies increase with the stiffness and starting torque of the ball joint. This work could be helpful for reliability design of civil-aircraft ducting system.

Ontogeny of body density and the swimbladder in yellowtail kingfish Seriola lalandi larvae

The ontogeny of larval body density and the morphological and histological events during swimbladder development were investigated in two cohorts of yellowtail kingfish Seriola lalandi larvae to understand the relationship between larval morphology and body density. Larvae <3 days post hatch (dph) were positively buoyant with a mean ± s.d. body density of 1.023 ± 0.001 g cm(-3). Histological evidence demonstrated that S. lalandi larvae are initially transient physostomes with the primordial swimbladder derived from the evagination of the gut ventral to the notochord and seen at 2 dph. A pneumatic duct connected the swimbladder to the oesophagus, but degenerated after 5 dph. Initial swimbladder (SB) inflation occurred on 3 dph, and the inflation window was 3-5 dph when the pneumatic duct was still connected to the gut. The swimbladder volume increased with larval age and the epithelial lining on the swimbladder became flattened squamous cells after initial inflation. Seriola lalandi developed into a physoclist with the formation of the rete mirabile and the gas-secreting gland comprised low-columnar epithelial cells. Larvae with successfully inflated swimbladders remained positively buoyant, whereas larvae without SB inflation became negatively buoyant and their body density gradually reached 1.030 ± 0.001 g cm(-3) by 10 dph. Diel density changes were observed after 5 dph, owing to day time deflation and night-time inflation of the swimbladder. These results show that SB inflation has a direct effect on body density in larval S. lalandi and environmental factors should be further investigated to enhance the rate of SB inflation to prevent the sinking death syndrome in the early life stage of the fish larvae.

Numerical Simulation and Improvement of Diesel Pneumatic Motor Inlet Duct

Because traditional method combined experiential design with steady flow and experiment, couldn’t get the ideal results. It was very necessary to adopt intelligent analytic methods studying three-dimension inlet duct characteristics of diesel pneumatic motor. This paper established the inlet duct model with Gambit and conducted numerical simulation with Fluent. The results explained that chamfer and linear was related with inlet duct efficiency. Results show that, larger inner, outer chamfer and good streamline can well enhance the efficiency of diesel pneumatic motor inlet duct, which provide important guidelines to inlet duct's optimal design and improvement.

Forensic Reconstruction of the Explosion that Occurred at the Cordero Flour Mill, Cuneo, Italy

This paper contains the forensic reconstruction of a powerful explosion that occurred in a flour mill in Italy in 2007. The mill produced wheat flour and was organised over 4 floors inside a very old building. The explosion occurred just after a tanker had been loaded with flour which was to be delivered to customers. Since the truck was loaded with a slight excess of flour, a small amount was sent back to one of the silos, via pneumatic transport, through a rubber hose connected to a steel pipe. The explosion destroyed the building and killed 5 workers. Through an analysis of the collected evidence, the testimony of the witnesses and an examination of the debris, the causes and dynamics of the explosion are here described. It was recognised that the explosion was ignited because of an electrostatic arc that occurred in the pneumatic transport duct. Signs of the explosion in the duct were evident because of the deformation that was provoked by internal overpressure. The triggering discharge occurred at the joint between the hose and the pipe. The pipe deformations were coherent with calculations of an internal pressure increase according to EN 14491. The explosion propagated to a flour silo and then to the whole building through the elevator case, and resulted in many secondary explosions. The explosion dynamics are here described and the lesson that have been learned are also proposed. 1. Plant description The Cordero Mill, in which the accident occurred in 2007, was a flour mill with a production of more than 0.2 t per day. It was located in a rectangular masonry building in the town of Fossano. The building consisted of a central four storey plus a basement; the products warehouse and the offices were located in a more recent three-storey construction. The main building, in which the production area was located, was organized in four main sections, separated by brick thick walls. Access to the area was through a hoist and an internal staircase. The production area which was located in the “B” rooms, while the “A” rooms were used as floor storage areas and for the preparation of the wheat for milling operations can be seen in Figures 1 and 2, which represent the ground and the top floor of the main building.