Air Inside Research Articles

Czech primary radon measurement equipment

The Authorized Metrological Centre (AMS) working by SUJCHBO (National Institute for Nuclear, Chemical and Biological Protection) ensures for the Czech Republic the metrological traceability for devices that measure the radon concentration and the energy equivalent radon concentration connected with the radon decay products (RnDP). The evaluation and the calibration of measuring devices for radon and RnDP require the stable conditions (first of all radon and the RnDP concentrations). The new AMS radon-aerosol chamber in Kamenná consists of the walk-in testing chamber with a volume of 10 m(3) and of the handling box with a volume of 0.3 m(3). The design of the chamber allows measurement and a control of environmental parameters such as the temperature, the pressure of air inside and outside of the chamber, the relative humidity of air, the concentration and the size distribution of aerosol particles and the air velocity.

Development of Exchangeable Fins for Heat Transfer Enhancement in Existing Shell and Tube Heat Exchangers

To conventionally extend heat transfer area in shell-and-tube heat exchangers, a method is proposed where sheet materials with high thermal conductivities are stretched among tubes. The numerical simulations are carried out to predict the performance of heat exchanger with or without the sheets. As a result, it is found that thermal contact resistances between the sheet and tubes rather than thickness and thermal conductivity of the sheet influence overall heat transfer coefficient. In the experiments, the carbon fibers clothes (27 W m-1 K-1) are pass zigzag though the tubes whose pitch is 20 mm. The heat transfer rate between hot water flowing in the tube side and air in the shell side are measured. No substantial improvement of heat transfer is unfortunately observed experimentally due to contact thermal resistance. The method proposed in this study conclusively has a potential that the heat transfer rate improves no less than a few ten percents.

Behavior of sandwich structures and spaced plates subjected to high‐velocity impacts

AbstractThis work evaluates the behavior of sandwich and spaced plates subjected to high‐velocity impacts. The sandwich structures were made of glass/polyester face‐sheet and a PVC foam core. The spaced plates were made of two plates of the same material of the sandwich face‐sheet at a distance equal to the core thickness. The residual velocity, the ballistic limit, and the damage area were selected to compare the response of both structures. The residual velocity and ballistic limit was very similar in both cases. Nevertheless, the damage area of sandwich structures and spaced plates differed due to the dissimilar properties between the sandwich core and the air inside of the spaced plates. An analytical model, based on energy criteria, was applied to estimate the residual velocity of the projectile, the absorbed energy by each face‐sheet, and the ballistic limit in the spaced plates. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers

Screw-Driven Multi-Channel Peristaltic Pump for Pneumatic Micro Actuator System

The authors have developed a miniaturized peristaltic pump which is characterized by multi-channel, low pulsation, high pressure resistance and portability. The pump mainly consists of a disposable pumping channel unit and reusable actuating parts. The pumping channel unit, made of silicone elastomers, has eight pumping channels. The operation principle is based on the peristaltic motion of pumping channels that are occluded by the screw shaft. The shaft rotating inside the pumping channel unit has a spirally arranged projection which deforms and closes down the channels. While the shaft rotates, the pinched locations in the channels move either way according to direction of rotation, squeezing out the air inside. The maximum discharge pressure generated was about 160 kPa at rotating speeds of 30 ~ 180 rpm. A micro pneumatic actuator was fabricated to demonstrate the performance of the pump. The validity of the pump for pneumatic actuation was reported.

Heat transfer and hydrodynamics analysis of a novel dimpled tube

In the present investigation, heat transfer and hydrodynamics analysis of a new enhanced heat transfer tube with ellipsoidal dimples was carried out. The dimples are disposed to form a certain specified angle between the major axis of the ellipsoid and flow direction, and the direction of the major axis of each adjacent ellipsoidal dimple in the same cross-section is alternated. Experimental tests were carried out with heating water on the shell side with a constant flow rate, and cold air in the tube side with flow rates range from 1 to 55 m 3/h. The temperatures and pressures for the inlet and outlet of both sides were measured. The heat transfer and pressure drop of the new dimpled tube were investigated and compared with the results of a dimpled tube with spherical dimples and a conventional smooth tube. The computed results indicated that the Nusselt number for ellipsoidal dimpled tube and spherical dimpled tube are 38.6–175.1% and 34.1–158% higher than that for the smooth tube respectively. The friction factors of dimpled tube increase by 26.9–75% and 32.9–92% for ellipsoidal and spherical dimples compared with the smooth tube respectively. It was perceived that ellipsoidal dimple roughness accelerates transition to critical Reynolds numbers down to less than 1000. By integrated performance evaluation of ( Nu a/ Nu s)/( f a/ f s), a maximum of about 87% heat transfer enhancement with the same friction penalty could be achieved by optimize the dimpled tube design.

Experimental testing and modelling of an industrial insulated pipeline for deep sea application

Ultra-deep water (up to 3000 m) is one of the next frontiers for oil offshore exploitation. It requires the use of conduits having to resist in the long run (durability about 25 years) the mechanical and environmental requests. One of the key points is the thermal insulation of the structure to avoid the formation of hydrates and paraffin plugs inside of the steel pipe. Over the past 10 years, many studies were performed to better understand the behaviour of the syntactic foams used as thermal insulation of pipes for deepwater production, but few tests were run on industrial prototypes to reach the actual thermal properties of the systems. This paper presents the numerical and experimental characterizations of an industrial multilayered insulated pipeline tested in service conditions. Two thermomechanical finite element modellings of the coated pipeline have been developed to predict its behaviour during service condition tests. The first model considers pure conduction through the inner air inside of the structure and the second model considers convection phenomenon between the inner air and the metallic surfaces inside of the structure. In parallel, industrial pipe tests on an immersed instrumented pipeline, internally heated to temperatures up to 95 °C and subjected externally to hydrostatic pressure up to 300 bar are presented. Experimental data obtained during industrial pipe tests and related model predictions are compared and discussed. Thermal properties of the syntactic foam are determined with steady and transient states analysis. In complement, a study of the model results sensitivity to the input Poisson coefficient is presented.

2A1-E11 吸盤振動型ポンプレス壁面移動ロボット

This paper proposes a new technique that can keep a vacuum sucker to the wall without any pump, even on a slightly leaky wall condition. By pushing and pulling cyclically, an elastic sucker can be kept attached to the wall. When the sucker is pushed, air inside is exhausted, and in every time of pulling phase, the sucker keeps its vacuum in a short time. The important character is that the impulse (product of force and time) of pulling phase can be larger than that of pushing. This means multi sucker alternate push-pull system can be realized for wall climbing. This paper also demonstrate it can make a locomotion driven by adjacent wheels with keeping suckers attached to the wall.

Developing research on a fully passive solar lumber drying apparatus – Creation of a new concept and establishment of a soft technology

Looking through the past research works again, a new effect created in combination of a few old techniques was noticed. One main technology; a transparent hot house for passive solar radiation collection, and two elementary techniques; a carbon fiber sheet (CF-sheet) of excellent absorber for solar radiation incidence and an insulated cylinder for passive exhaustion of moist air inside of the house were unified altogether, and so a fully passive solar lumber drying apparatus could be established practically as a soft technology of lumber drying.

Systemic Air Embolization Originating from a Pleural Air Leak via a Left Ventricular Assist Device Cannula Anastomosis Site

A patient presented with cardiogenic shock, and a left ventricular assist device (LVAD) was inserted. Transthoracic echocardiography demonstrated air in the left side of the heart whenever the patient coughed. A chest x-ray and computed tomography of the chest did not reveal a pneumothorax. Air appeared to enter the left atrium (LA) around the LA cannula. The working diagnosis was a right pleural tear with intermittent passage of air from the pleural space (supra-atmospheric during coughing) into the LA (around the cannula), which contained a large-bore LVAD cannula on -40 mm Hg suction. This was confirmed by inserting a right-sided chest drain, and no air appeared during coughing. This case demonstrates an unusual complication of LVAD use (systemic air embolization) and highlights the point of variable physiology during dynamic versus static imaging procedures.

Mechanically Ventilated Broiler Sheds: a Possible Source of AerosolizedSalmonella,Campylobacter, andEscherichia coli

This study assessed the levels of two key pathogens, Salmonella and Campylobacter, along with the indicator organism Escherichia coli in aerosols within and outside poultry sheds. The study ranged over a 3-year period on four poultry farms and consisted of six trials across the boiler production cycle of around 55 days. Weekly testing of litter and aerosols was carried out through the cycle. A key point that emerged is that the levels of airborne bacteria are linked to the levels of these bacteria in litter. This hypothesis was demonstrated by E. coli. The typical levels of E. coli in litter were approximately 10(8) CFU g(-1) and, as a consequence, were in the range of 10(2) to 10(4) CFU m(-3) in aerosols, both inside and outside the shed. The external levels were always lower than the internal levels. Salmonella was only present intermittently in litter and at lower levels (10(3) to 10(5) most probable number [MPN] g(-1)) and consequently present only intermittently and at low levels in air inside (range of 0.65 to 4.4 MPN m(-3)) and once outside (2.3 MPN m(-3)). The Salmonella serovars isolated in litter were generally also isolated from aerosols and dust, with the Salmonella serovars Chester and Sofia being the dominant serovars across these interfaces. Campylobacter was detected late in the production cycle, in litter at levels of around 10(7) MPN g(-1). Campylobacter was detected only once inside the shed and then at low levels of 2.2 MPN m(-3). Thus, the public health risk from these organisms in poultry environments via the aerosol pathway is minimal.

Hydrogen production by partial oxidation of methane: Modeling and simulation

Abstract A one-dimensional non-isothermal model for oxygen permeable membrane reactor has been developed to simulate the partial oxidation of methane to produce hydrogen. The performance of two fixed bed reactors (FBRs) viz. one with pure O2 in feed (FBR1), other with air in feed (FBR2), and a membrane reactor (MR) having air in non-reaction side have been studied at various feed conditions and inlet temperatures in order to investigate the effect of these parameters on conversion of methane and yield of hydrogen. The fixed bed reactor with pure O2 in feed has been found to provide better performance as compared to fixed bed reactor with air and membrane reactor.

ASSESSMENT OF AIRBORNE MICROFLORA IN SHELTERS FOR DAIRY COWS

The aim of this work was the assessment of the microbiological quality of the air inside of the dairy cow’s shelters. The study was ruled in three dairy farms with tied raising syistem, in Alba county. The research was made in Ianuary 2008. There were determinated the total number of germs and the groups with hygienical signification: Staphylococcus spp., Gram negatives and fungus, using the method of sedimantation. The obtained results shows that the air is unproper in microbiological point of view in all of the three investigated shelters

Crossflow fan에 의한 컴퓨터 케이스 내부의 유동특성에 관한 연구

The purpose of this study is to find out a flow characteristics when a crossflow-fan is installed inside the computer case and to provide information about the preliminary data of cooling efficiency of CPU and a flow inside and outside of a computer case. Under the condition of operating the fan inside the experimental duct we changed the position of a installation of the slot, and the experiment measured with PIV and the results are as follows. Under the influence of the crossflow-fan installed to the air discharging side, mean velocity between 35 to 45 on the point 80 of the Slot 0.2.3 of the case increased and it influences discharging the air inside of the computer case. On the left-upper end. which isn`t directly influenced by the suction-discharging fan installed inside the PC, a flow occurs caused by vortex due to the Sirocco-Fan and Slot installed on the center of the right side. We can see that a flow distribution increases when the Sirocco-Fan operates and a whirl appears stronger between the slot and the suction fan. It is thought that this phenomenon is influenced by a flow while it is on the way of entering from the suction-fan and going out to the discharging-fan.

Porous polymer fibers for low-loss Terahertz guiding

We propose two designs of effectively single mode porous polymer fibers for low-loss guiding of terahertz radiation. First, we present a fiber of several wavelengths in diameter containing an array of sub-wavelength holes separated by sub-wavelength material veins. Second, we detail a large diameter hollow core photonic bandgap Bragg fiber made of solid film layers suspended in air by a network of circular bridges. Numerical simulations of radiation, absorption and bending losses are presented; strategies for the experimental realization of both fibers are suggested. Emphasis is put on the optimization of the fiber geometries to increase the fraction of power guided in the air inside of the fiber, thereby alleviating the effects of material absorption and interaction with the environment. Total fiber loss of less than 10 dB/m, bending radii as tight as 3 cm, and fiber bandwidth of approximately 1 THz is predicted for the porous fibers with sub-wavelength holes. Performance of this fiber type is also compared to that of the equivalent sub-wavelength rod-in-the-air fiber with a conclusion that suggested porous fibers outperform considerably the rod-in-the-air fiber designs. For the porous Bragg fibers total loss of less than 5 dB/m, bending radii as tight as 12 cm, and fiber bandwidth of approximately 0.1 THz are predicted. oupling to the surface states of a multilayer reflector facilitated by the material bridges is determined as primary mechanism responsible for the reduction of the bandwidth of a porous Bragg fiber. In all the simulations, polymer fiber material is assumed to be Teflon with bulk absorption loss of 130 dB/m.

Beauty Looks Down on Me

Beauty Looks Down on Me Eun Hee Kyung (bio) Translated by Sora Kim-Russell (bio) Spring Snow I cannot forget the day I first saw Botticelli's The Birth of Venus. A late spring snow was fluttering down. As I followed my father into the carpeted Italian restaurant, I realized it was a world apart from any place I had ever known. Small flower vases and candlesticks were set on the tables, and the air in the room was quietly stirred by the subdued conversations of affluent, refined looking people skilfully handling Western-style silverware. Father and I were shown to a reserved table beside a window. A waiter took my father's elegant overcoat and my old, clumpy parka and hung them on a coat stand. From the moment I sat facing him, I directed my gaze at a large painting dimly lit by a spotlight on the wall behind him. I couldn't look him in the face. The air inside was warm and sweat soon began to ooze along the folds on my neck. Now that you're a middle school student, you must do more for your mother. I nodded almost imperceptibly in response to Father's words. And you can call me whenever you want. That sounded a bit like a lie. As soon as the food arrived, I lowered my eyes and pretended to be absorbed in eating. Transferring a shrimp to my plate after dipping it in sauce, Father spoke again. You have a healthy appetite. Don't worry. When [End Page 201] you grow up, the fat will melt off on its own. Why, when I was your age, my nickname was Pork Bun. I thought that sounded like a lie too. Once all the food was eaten and the plates cleared away, I had nowhere to focus my eyes, so I looked up at the painting again. Following my gaze, Father turned to see where I was looking. A superior smile rose to his lips. That's Venus. The scene where she's born out of the sea foam. Why did I feel so sad the moment I heard those words? Was it because of the smooth, beautiful face like that of a porcelain doll, milky-hued with a touch of green? Or the long, blond hair wrapped around her slender, naked body and fluttering in the breeze, or the defenseless-looking, bare, white feet poised on a great gaping shell? Or was it because of the mysterious sorrow deep in her eyes that were gazing up into the empty air? I'm sorry, Father said mournfully, sighing deeply, when he saw that my eyes were brimming with tears. Looking back, as I followed my father around that day, I was constantly tormented by the question of why I was born. Every time my footsteps lagged behind, he would stop and stand waiting for me, probably thinking, just as other people did, that it was on account of my size. I was already used to that kind of misunderstanding. Having been a fat kid, I always looked crabby or unhappy, when in fact I was merely shy. On the days I met Father, I always went home feeling sad because I was convinced I could never please him. He seemed especially displeased with the fact that I was fat. Had he been with a bright, innocent child, he could have been the tragic hero, but a fat kid who looks stupid or crabby could never amount to any more than someone who reminded him of his own mistake, his one moment of folly. Venus Once I was old enough to be able to buy things I liked with my own money, I hung a picture of Botticelli's Venus on the wall of my room. Since it had a naked woman in it, my friends thought it was [End Page 202] a different style of pornographic poster. B said that fat people are obsessed with the classics as a form of psychological compensation to try to prove how refined and sensitive they are. But neither the sensuous Venus welcoming her lover Mars into her bed, nor the pure, innocent Venus standing...

Measurement of the flow and its vibration in Japanese traditional bamboo flute using the dynamic PIV

All wind instruments produce sound due to the vibration of air inside of the instrument. In the case of a trumpet or a clarinet, the mouth or a reed helps to generate variable tones. In the case of a flute, there is no mechanical vibration. Additional detail about the flow and the sound vibration inside and outside of the flute are investigated in order to understand the mechanism of the wind instrument and to aid in the manufacture of quality instruments. In this report, a traditional Japanese bamboo flute was investigated experimentally. The dynamic PIV technique was applied to measure the vibration. Two kinds of experiments were performed. Argon-gas flow containing an oil mist as tracer particles both inside and outside the bamboo flute was measured using a high frequency pulse laser. The periodical flow near a hole of the bamboo flute was successfully measured. The flow was found to go into and out from the flute and the balance of a mass flow rate and the averaged velocity were almost zero at the hole. Then, the flow in the bamboo flute was visualized when a human played the instrument, using a CW-laser and water-mist as the tracer. It was discovered that the two instructors had unique methods for playing the flue instrument.

Method for evaluation of radiative properties of glass samples

The paper presents a simple calculation method which serves for an evaluation of radiative properties of window glasses. The method is based on a computer simulation model of the energy balance of a thermally insulated box with selected glass samples. A temperature profile of the air inside of the box with a glass sample exposed to affecting radiation was determined for defined boundary conditions. The spectral range of the radiation was considered in the interval between 280 and 2500 nm. This interval is adequate to the spectral range of solar radiation affecting windows in building facades. The air temperature rise within the box was determined in a response to the affecting radiation in the time between the beginning of the radiation exposition and the time of steady-state thermal conditions. The steady state temperature inside of the insulated box serves for the evaluation of the box energy balance and determination of the glass sample radiative properties. These properties are represented by glass characteristics as mean values of transmittance, reflectance and absorptance calculated for a defined spectral range. The data of the computer simulations were compared to experimental measurements on a real model of the insulated box. Results of both the calculations and measurements are in a good compliance. The method is recommended for preliminary evaluation of window glass radiative properties which serve as data for energy evaluation of buildings.

Potential of solid phase microextraction and gas chromatography for quarantine‐required detection of wood packaging in shipping containers

Solid phase microextraction (SPME) coupled with gas chromatography (GC) was used to detect terpene hydrocarbons inside shipping containers entering New Zealand. The utility of this system for the rapid detection of undeclared wood packaging for quarantine purposes was demonstrated. A portable dynamic air-sampling device was built to house a SPME fibre and allow the air from shipping containers to be sampled. The effects of sample flow rate and sampling time were investigated and sampling conditions of 100 mL/min for 30 s were chosen to keep sampling within the linear range. A CV of less than 15% (n = 12) was obtained for all the compounds analysed under these conditions. To obtain an estimate for the limit of detection (LOD) for the terpene hydrocarbons of interest, small quantities of lime oil were placed in an empty shipping container and the air inside was analysed. LOD (S/N = 3) was estimated to be in the order of 50-100 ng/L of air using GC with flame ionisation detection (GC-FID). Finally, the device was tested in fully laden containers and was shown to be effective for trapping terpene hydrocarbons indicative of wood packaging.

Effects of Elliptical Nature of Rotating Electric Field on Partial Discharge Pattern in a Three-phase Construction

Discharge characteristics in single-phase equipment are a well-known and well-established art, however, those in three-phase equipment are far less understood. Because the electric field in the insulating material of three-phase equipment is not linear, but rotates with power frequency, it can be expected that the discharge characteristics in three-phase equipment will be different from those in single-phase equipment. In this paper, the effects of rotating electric field on partial discharge pattern in a three-phase construction are reported. The simplified model of a three-phase GIS with air inside is used. The electric field in the construction was analyzed, and the discharge characteristics were observed. The electric field vector locus in a three-phase construction is elliptical, although the shape differs locally. The elliptical nature of rotating electric field is expressed as an electric field ratio. The experimental results showed that the phase widths where partial discharge current pulses appeared were different depending on the electric field ratio even for the same applied voltage. The phase width where partial discharge current pulses appeared was also influenced by the applied electric field. These results are analysed from the relationship between the value and the locus of the applied electric field and the critical electric field of air.

Making silicon hydrophobic: wettability control by two-lengthscale simultaneous patterningwith femtosecond laser irradiation

We report on the wettability properties of silicon surfaces, simultaneously structured on themicrometre-scale and the nanometre-scale by femtosecond (fs) laser irradiation to rendersilicon hydrophobic. By varying the laser fluence, it was possible to control the wettingproperties of a silicon surface through a systematic and reproducible variation of thesurface roughness. In particular, the silicon–water contact angle could be increased from66° to morethan 130°. Such behaviour is described by incomplete liquid penetration within the silicon features,still leaving partially trapped air inside. We also show how controllable design andtailoring of the surface microstructures by wettability gradients can drive themotion of the drop’s centre of mass towards a desired direction (even upwards).