Big Chamber Research Articles

Vacuum system of the Space Plasma Environment Research Facility

The Space Plasma Environment Research Facility (SPERF) being built in Harbin provides a laboratory platform for research on space plasma. The vacuum system, as an essential subsystem, is designed to set up an experimental vacuum environment for plasma experiments. However, the SPERF with a large volume of 2.315×105 l contains a lot of outgassing loads and hundreds of interfaces, which poses a big challenge for high vacuum acquisition. In addition, the plasma experiments on the SPERF require a pure background vacuum environment. In this study, the vacuum system is designed to meet the experimental requirements for the vacuum environment, with emphasis on the pumping system configuration and the vacuum acquisition process. Benefiting from the great construction techniques and advanced configuration of the pumping system, the target ultimate pressure of 1.0×10−4 Pa in the chamber can be obtained within 24 h and the leakage rate of the vacuum chamber is 30% smaller than the target value. It is significant that the high vacuum environment is efficiently achieved in such a big chamber, and the design may throw some new light on constructing other similar large-scale vacuum systems.

Accretion Processes of Oceanic Crust in Slow‐spreading Ridges: Plagiogranite Perspective of the Xigaze Ophiolite, South Tibet

AbstractStructural and petrological data suggest that the Xigaze ophiolite from the Yarlung Zangbo Suture Zone (YZSZ) in south Tibet was a typical slow‐spreading ridge. A new field, geochemical, mineral, and U‐Pb zircon dataset of plagiogranite intrusions were used to constrain the dynamic processes of oceanic accretion in this slow‐spreading ridge. Plagiogranites mainly occur as dykes or intrusions intruded into the whole sequence of the ophiolite and have a similar orientation to the dolerite dykes developed in the late stage of detachment faulting. U‐Pb zircon ages of 122–123 Ma were obtained for two types of plagiogranites and associated dolerite dykes. Detailed geochemical and mineralogical examinations suggest that the plagiogranites are the product of low‐pressure (2–3 kbar) fractional crystallization of mid‐ocean ridge basalt‐like magma and unlikely to have been derived from the partial melting of hydrous gabbroic rocks. The complex cross‐cut relationship between the plagiogranites and ophiolite sequence reflects that they are controlled by small discontinued melt lenses rather than a big magma chamber under the ridge axis and reveals multiple injections during the oceanic crust accretion. The formation of plagiogranites possibly reflects the complex characteristic of oceanic accretion at slow‐spreading ridges, time‐dependent on structural (external) and magmatic (internal) processes.

Are Wild Blueberries a Crop with Low Photosynthetic Capacity? Chamber-Size Effects in Measuring Photosynthesis

Wild lowbush blueberries, an important fruit crop native to North America, contribute significantly to the economy of Maine, USA, Atlantic Canada, and Quebec. However, its photosynthetic capacity has not been well-quantified, with only a few studies showing its low photosynthetic rates. Its small leaves make accurate leaf-level photosynthetic measurements difficult and introduce potential uncertainties in using large leaf chambers. Here, we determined the photosynthetic rate for five different wild blueberry genotypes using a big leaf chamber enclosing multiple leaves and a small leaf chamber with a single leaf to test whether using big leaf chambers (branch-level measurements) underestimates the photosynthetic capacity. Photosynthetic rates of wild blueberries were significantly (35–47%) lower when using the big leaf chamber, and they are not a crop with low photosynthetic capacity, which can be as high as 16 μmol m−2 s−1. Additionally, wild blueberry leaves enclosed in the big chamber at different positions of a branch did not differ in chlorophyll content and photosynthetic rate, suggesting that the difference was not caused by variation among leaves but probably due to leaf orientations and self-shading in the big chamber. A significant linear relationship between the photosynthetic rate measured by the small and big leaf chambers suggests that the underestimation in leaf photosynthetic capacity could be corrected. Therefore, chamber-size effects need to be considered in quantifying photosynthetic capacity for small-leaf crops, and our study provided important guidelines for future photosynthesis research. We also established the relationship between the Electron Transport Rate (ETR) and photosynthetic CO2 assimilation for wild blueberries. ETR provides an alternative to quantify photosynthesis, but the correlation coefficient of the relationship (R2 = 0.65) suggests that caution is needed in this case.

Surface Acoustic Wave Humidity Sensors Based on ZnO/ZnO/Quartz Structures

Surface acoustic wave (SAW) devices integrated with a sensing layer of homo-buffer sputtering zinc oxide (ZnO) nanostructured film were fabricated and their adsorption mechanism and sensing performance for water molecules were focused. In the nanostructured film, ZnO homo buffer layer helps to form a uniform nanoparticles film structure while ZnO nanoparticles provide hydrophilic sites for adsorption of water molecules. Through the comparative studies, SAW device based ZnO top layer of 0.5 Pa presents a larger frequency shift to moisture at flow rate range of 0.04–0.3 l min−1 than its counterparts. In addition, the ZnO-SAW device in a big chamber was found to be more sensitive to different relative humidity than in a small chamber. The maximum sensitivities of the ZnO-SAW devices in large and small chambers are 333.3 Hz/%RH and 106.6 Hz/%RH, respectively. The experiment conclusions are qualitatively in accordance with the theoretical calculations.

Characterization of Lipid Metabolism and Atherosclerotic Phenotypes in Novel Humanized ApoE Knockin Rats

Apolipoprotein E (ApoE) is one of the essential plasma apolipoproteins involved majorly in lipids’ metabolism. Human ApoE has three isoforms (E2, E3, and E4) differing by one or two amino acids. E3 is the most common one with a population allelic frequency of 78% and considered normal. E2 (7%) is associated with genetic disorder type III hyperlipoproteinemia. E4 (15%) is the major susceptibility gene related to the onset of Alzheimer's disease (AD) and cardiovascular diseases (CVDs). Gene modified mice carrying a mutant ApoE gene or different ApoE isoforms, such as ApoE knockout (ApoE KO) mouse and humanized ApoE knockin (hApoE KI) mice, provide a series of beneficial mouse models in the studies of atherosclerosis, hyperlipidemia, and AD. However, alternative animal models are necessary to investigate the roles and underlying mechanisms of ApoE in human diseases. Recently, the novel hApoE KI rat models created by Envigo RMS, Saint Louis, MO (preciously named Horizon Discovery and SAGE Labs respectively) by replacing endogenous rat ApoE with human ApoE2, E3, or E4 allele are available. Hypothesis The hApoE KI rats could recapitulate the diversities of metabolic phenotypes in human carrying polymorphic ApoE proteins, and will be ideal animal models to study the roles of ApoE proteins. Methods We examed the body weight, serum lipid levels, the mass of fat tissue, and vascular atherosclerotic lesions of these hApoE rat models in comparison to wide-type Sprague Dawley (WT) and ApoE KO rats, as well as the metabolic changes, death rate, and development of vascular atherosclerosis of these rats with 4-months atherogenic Paigen diet (PD) (40 kcal% Fat, 1.25% Cholesterol, 0.5% Cholic Acid). Results We investigate the body weight starting from week seven till month six, and found that all the hApoE KI and ApoE KO rats had a lower body weight than WT at the corresponding age. The hApoE2 KI rats showed lowest body weight. At six months (P6m), all hApoE KI and KO rats had lower anti-atherogenic lipoprotein HDL. The total cholesterol (TC), total triacylglycerol (TG), and LDL/VLDL of hApoE2 KI rats were higher than those of WT, hApoE3 KI and hApoE4 KI rats. ApoE KO rats also exhibited elevated total cholesterol and LDL/VLDL, but not total triacylglycerol. Surprisingly, the mass of white fat was less in hApoE2 KI rats. No obvious aortic plaques were identified in the en face aortas stained by Oil Red O of all normal diet-fed hApoE KI and ApoE KO rats at P6m. A mild atherosclerotic lesion was detected in frozen section of hApoE2 KI and ApoE KO aortic roots. After challenged with the PD, hApoE2 KI and ApoE KO rats died within two and half weeks. Causes of death were different: hApoE2 KI rats might be due to fat embolism in big vessels and heart chambers; ApoE KO rats might be caused by massive pulmonary alveolar hydrops (accompanying considerable lipid-laden macrophages accumulated in the lung). Thicker walls of small vessels in lung and heart, as well as necrosis of cardiomyocytes, were demonstrated in hApoE4 KI rats after four months PD. Conclusion hApoE2 rats develop hyperlipoproteinemia but are not a suitable animal model for the study of atherosclerosis. With the assistance of a PD challenge, hApoE4 KI rats could be a good model for the analysis of CVDs.

Synthesis of anisotropic colloids with concave and convex structures.

Anisotropic colloidal particles with concave and convex structures are useful in both theoretical studies and applications. In this work, we mass-produced polystyrene (PS) colloidal particles with multiple concavities through dispersion polymerization techniques. By increasing the delayed feeding time td of the cross-linker divinylbenzene (DVB), the morphological evolution of particles can be classified into two stages, during which the formation of different concavities is consistent with either the buckling mechanism or phase separation mechanism. By varying the DVB dosage, we found that the size of the big chamber formed on the particle surfaces decreases as the DVB dosage increases. Then, using these concave particles as seeds, 2-5 μm anisotropic colloids with various shapes, including spherical, ellipsoidal, snowman and multi-protrusion, were synthesized by seeded emulsion polymerization. Moreover, our results show that both the chambers and long narrow ditches on the surface of seeds can be the active sites for monomers to gather and polymerize, but monomers in the big chamber have a priority to polymerize first when big and small concavities both exist on seeds. The results of this study could mean great potential in synthesizing a variety of anisotropic particles with well-controlled concave morphologies.

Complex geometry automotive muffler sound transmission loss measurement by experimental method and 1D simulation correlation

A muffler is a device to attenuate noise from the exhaust. The muffler performance determined by the acoustic performance is called sound transmission loss (STL). This paper aims to measure the STL experimentally and correlated with the 1D simulation result. STL was measured using the impedance tube. Four-pole method (microphone) and two-load method were applied to measure the STL. The STL was also determined through the 1D simulation tools software. Three types of mufflers STL were measured; small expansion chamber, big expansion chamber and complex muffler. The respective error between simulation and experiment were 0.17%, 7.89%, and 11.40%. Hence, the STL experiment result was well correlated with the 1D simulation model.

Macro- and Microscopic Analyses of Anatomical Structures of Chinese Gallnuts and Their Functional Adaptation

The galls induced by Schlechtendaia chinensis, Schlechtendaia peitan and Nurudea shiraii on Rhus chinensis and gall induced by Kaburagia rhusicola rhusicola on Rhus potaninii Maxim. are the largest plant galls and have great economic and medical values. We examined the structures of galls and their functional adaptation using various macro- and microscopic techniques. The highly adapted structures include a stalk at the base that is specialized for mechanical support and transport of nutrients for aphids, and a network of vascular bundles which accompanying schizogenous ducts arranged in a way to best support aphid feeding and population growth. There are many circular and semicircular xylems traces in an ensiform gall in cross sectional views, which would provide more nutrition and occupy less space. We infer the evolution trail was flower-like gall, horned gall, circular gall and ensiform gall. And the possible evolutionary trend of the gall was bigger chamber, more stable mechanical supporting, easier for exchanging substance and transporting nutrients.

Numerical simulation of mono-disperse droplet spray dryer: Coupling distinctively different sized chambers

The discrete phase model (DPM) has been widely used in CFD simulations to track discrete particles or droplets in a continuum fluid filed. This powerful technique, however, may face tremendous difficulty in tracking droplets flying through chambers with significantly different sizes. In such cases, it becomes very challenging to develop effective mesh for the big and small chambers together with the transition zone that can ensure solution convergence within reasonable computational time. In this work, a systematic method is introduced to tackle this problem. This method allows simulation of different sized chambers separately to avoid the meshing difficulty. A unique coupling approach offers smooth transition of droplets from one chamber to the other with rigorous conservation of their mass, energy and momentum. The effectiveness of the method is demonstrated through the simulation of skim milk droplet drying in a mono-disperse droplet spray dryer (MDSD), where droplets must pass through a small dispersion chamber before entering the main big drying chamber. For the first time, droplet drying process from exiting nozzle to the arrival at the dryer outlet can be simulated. The new model can be used in the future to optimize the spray drying process.

Experimental Quantification of Air Permeability of Building Envelope with Installed Controlled Ventilation System - Case Study

To meet the increasingly stringent requirements of standard energy consumption and thus reducing operating costs of buildings, it is necessary to use energy-saving elements of technical equipment and eliminate heat loss through the building envelope. The biggest losses are caused by heat transmission and ventilation in the form of uncontrolled air infiltration through the building envelope. Their elimination can be achieved by improving the thermal technical quantification of building envelope and increase its airtightness. Determination of air permeability as a measure of quality building envelope is possible using the method of measuring devices Blower-Door test. Any defects can be detected by detection tools, then propose a suitable method for their removal and thus prevent unwanted unregulated air infiltration into the interior. On the other hand, are opposed to the health requirements required air exchange in the room, which is a significant reason for the transformation of this mode of ventilation by uncontrolled air infiltration to a controllable ventilation system. The subject of the paper is in-situ measurement of air permeability of specific apartment envelope by Blower-Door test method and comparison the efficacy of the installed controlled ventilation system and hygiene requirements of the ventilation intensity for residential buildings. Laboratory verification of façade ventilation unit parameters in big pressure chamber - measurement of inlet ventilation flap airflows at variable pressure differences. Methodology for the measurement by Blower-Door test method to determine the air permeability of building envelope structures and functionality of controlled ventilation system was based on a series of 10 measurements in 5 regimes. The overall air permeability of the building envelope or its integrated part may be verified using the total air exchange rate n50at 50 Pa pressure difference, determined experimentally according to STN EN 13829. Comparison of measured values with standard values recommended by some European countries with a similar climate with sealed and with unsealed ventilation flaps, which can determine the impact on the overall airtightness of the building envelope. Calculation of total hygiene required air exchange rate of the apartment and its comparison with actual measured values by Blower-Door test method.

Опыт использования аналитического стенда для проведения аэрозольных испытаний в контролируемых условиях

Air quality monitoring is essential when it comes to protecting the urban population, especially that of big metropolises, from biohazards including biopathogens (BPs). This process is aided by different samplers and analyzers of aerosol pollutants, filters and disinfection systems. Their performance is tested using experimental aerosol formulations with a predetermined composition. Unfortunately, the majority of such systems available in Russia are only able to process a few hundred liters of air per time unit, which is too little. Big aerosol chambers (10 to 20 m3) are very expensive and may not fit into a lab, necessitating an extensive overhaul. In this work we present a workstation for the detection of BP markers under controlled conditions based on the microbiological safety box MSB-III-Laminar-C-1.5 (380.150.01) that was originally designed to test the performance of samplers and analyzers of experimental aerosol formulations. Our workstation can handle the majority of BSL-1-2 BPs and, given the chamber volume that satisfies the requirements of aerosol experiments (> 4 m3), can be installed in a lab with an area of >10 m2.

Microwave attenuation in kraft recovery boiler

The authors' research group is developing a mobile sensor for operation inside combustion chambers of big industrial power plants. The aim of developing the ball-formed sensor is to measure process information inside big combustion chambers (heat power over 100 MW), hopefully mainly from places which cannot be reached by ordinary measurement equipment outside the chamber. The sensor ball needs means for communication during operation. In order to provide a reliable communication link through the extreme harsh conditions, one must clarify the basic phenomena inside combustors, especially electromagnetic noise and attenuation. According to measurements, attenuation at frequency band 2–18 GHz is ∼10 dB/m.

Thermal warpage measurement system for environmental test of automotive devices

As automotive semiconductor market has expanded, the importance of measurement of temperature-dependent warpage (thermal warpage) has been increasing. For automobiles, high reliability is necessarily demanded because their failures are directly linked to people's life. Therefore automotive industry had established AEC qualification standards for automotive devices. The standard demands environmental tests that include not only high temperature test but also negative temperature test reaching -55 ℃. In view of this situation, we have developed a thermal warpage measurement system that has the ability to change sample temperature from -60 to 260 ℃ which can meet the demands of the standard. The following are some features of the system. <(1)Warpage measurement ability>Measurement is performed by confocal method which is well known as accurate optical metrology. Generally speaking, confocal method is time consuming method for measurement. But our technique we call non-scanning confocal method overcomes such a drawback maintaining advantages of confocal method and the non-scanning confocal method has already been used widely for in-line coplanarity inspection of flip-chip bumps. Conventional warpage measurement technique like Moire method needs sample preparation like de-ball and painting. But the non-scanning confocal method doesn”™t need any sample preparation. The method can measure not only substrate warpage accurately without de-ball but even ball height/coplanarity. Moreover the system can deal with even several tens of micron diameter bumps, because it has 8.0um pixel resolution regardless of sample size. Unlike conventional warpage measurement system, the field of view (FOV) size of 13x13mm is constant and bigger samples than the FOV can be measured by stitching FOVs using a XY translation stage up to 136x323mm (JEDEC tray size).<(2)Heating and cooling ability>The system has a big size chamber for heating and cooling so that a whole JEDEC tray can be measured. In order to heat all samples in the big chamber uniformly, convection heating is used as heating method. Convection heating has many advantages compared to radiation heating that is normally used by conventional systems. The advantages are as follows.

The important points for determining the requirements of EMC chambers

The establishment of complex EMC test facility requires very big budget, area, and special featured building. Due to these reasons, determining the requirements of EMC Chambers is very important. The purpose of this article is providing general overview of the chamber requirements content and briefly addressing a few aspects of some specification elements. This article especially evaluates the chambers, compatible for different applications such as military equipment, commercial equipment, and military vehicle. Big chambers can be used for vehicle tests and as 10 m semianechoic chamber provided that the requirements are met. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:367–372, 2016.

Condensation of Water Vapour in the Functional Gap of Window - Experimental Measurement of Exfiltration at 15 Pa

The article is focused on the experimental analysis of water vapour in functional gap of wooden window. The experimental measurements were held in a laboratory of heat engineering of the Slovak university of Technology in Bratislava – in a big climatic chamber for synergic phenomena of heat transfer, water vapour diffusion and air filtration.

Some new and interesting caverns in tunnels and along stretches of the Croatian Highways (Dinaric Karst, Croatia)

During the construction of almost all the tunnels in the Croatian Dinaric Karst in the last 50 years thousands of caves have been encountered that represented the major problems during the construction works. Geological features (fissures, folding, faults, etc.) are described in this contribution, together with the hydrogeological conditions (rapid changes in groundwater levels). Special engineering geological exploration and survey of each cave, together with the stabilization of the tunnel ceiling, and groundwater protection actions according to basic engineering geological parameters are also presented. In karst tunneling in Croatia over 150 caves longer than 500 m have been investigated. Several caves are over 300 m deep, and 10 are longer than 1000 m. Different solutions were chosen to cross the caves depending on the size and purpose of the tunnels (road, rail, pedestrian tunnel, or hydrotechnical tunnels). This paper presents interesting examples of stabilization of ceilings in big cave chambers, construction of bridges inside tunnels, deviations of tunnels, filling caves, grouting, etc. A complex type of karstification has been found in the cavern at the contact between the Palaeozoic clastic impervious formations and the Mesozoic complex of dolomitic limestones in the Vrata Tunnel and at the contact with flysch in the Ucka Tunnel. However, karstification advancing in all directions at a similar rate is quite rare. The need to have the roadway and/or tunnel above water from a spring is the biggest possible engineering-geological, hydrogeological and civil engineering challenge. Significant examples are those above the Jadro spring (Mravinci tunnel) in flysch materials or above the Zvir spring in Rijeka (Katarina tunnel), and in fractured Mesozoic carbonates.

Measurement of Ultra-low Ion-Beam Energy

Measurement of ion-beam energy is important for assuring equipment operation. When an ion beam is decelerated, its energy becomes very low; the measurement of such low energy is investigated here. Low ion-beam energy has been measured using a retarding field and detector. This research, however, used a deflecting electrostatic field, a simpler and more accurate method. The basic principle of the electrostatic-field application for measuring ion-beam energy is that when an ion beam passes through parallel plates of the electrical field, the beam will be bent from its axial trajectory as a function of the applied field. The bending distance of the ion beam can be used to determine the ion-beam energy. Results of measuring ion-beam energy in this study were compared with theory and simulation results. The SIMION program version 8.0 was used to perform the simulation. A system to measure the ion-beam energy was designed, constructed and installed. The system consisted of a pair of parallel electrode plates, a copper rod measurement piece, a vernier caliper, a stepping motor and a webcam-camera. The entire system was installed under an ion-beam deceleration lens inside the big chamber of the 30-kV bioengineering vertical ion-beam line (CMU3) at Chiang Mai University. The copper rod was moved by the stepping motor to measure the ion-beam current profile, which depended on the beam spot position. The beam profiles were compared between the plates, with and without the electrostatic field, for extracting the ion-beam bending distance and then the ion-beam energy. The ion-beam current, which was on order of 10 nA, was measured by a digital nano-ammeter. Argon ion beams at various energies, ranging from 10 to 20 keV, passed through the deceleration lens resulting in ion energy lower than 1 keV. The measurement results were in good agreement with theoretical and simulated results, demonstrating that the method worked well.

An Automatic Critical Care Urine Meter

Nowadays patients admitted to critical care units have most of their physiological parameters measured automatically by sophisticated commercial monitoring devices. More often than not, these devices supervise whether the values of the parameters they measure lie within a pre-established range, and issue warning of deviations from this range by triggering alarms. The automation of measuring and supervising tasks not only discharges the healthcare staff of a considerable workload but also avoids human errors in these repetitive and monotonous tasks. Arguably, the most relevant physiological parameter that is still measured and supervised manually by critical care unit staff is urine output (UO). In this paper we present a patent-pending device that provides continuous and accurate measurements of patient's UO. The device uses capacitive sensors to take continuous measurements of the height of the column of liquid accumulated in two chambers that make up a plastic container. The first chamber, where the urine inputs, has a small volume. Once it has been filled it overflows into a second bigger chamber. The first chamber provides accurate UO measures of patients whose UO has to be closely supervised, while the second one avoids the need for frequent interventions by the nursing staff to empty the container.

Numerical simulation of flow fields induced by a supersonic projectile moving in tubes

Numerical study of the shocked flows generated by a supersonic projectile released from a launch tube into a big chamber has been performed in this paper. Based on fixed Cartesian grids, the two-dimensional axisymmetric Euler equations are solved by the fifth-order WENO scheme implemented with moving boundary conditions. Both the level set technique and ghost fluid method are used for capturing the moving interface of the projectile implicitly. The numerical results show that complex shock phenomena exist in the transient shock flow, resulting from shock-wave reflection, shock-wave focusing, shock-wave/projectile interaction and shock-wave/contact surface interactions. The relationships between the acceleration of the projectile and the transient shock flow are also discussed in detail.

Influence of heat and particle fluxes nonlocality on spatial distribution of plasma density in two-chamber inductively coupled plasma sources

This study presents 2D simulations of the two-chamber inductively coupled plasma source where power is supplied in the small discharge chamber and extends by electron thermal conductivity mechanism to the big diffusion chamber. Depending on pressure, two main scenarios of plasma density and its spatial distribution behavior were identified. One case is characterized by the localization of plasma in the small driver chamber where power is deposed. Another case describes when the diffusion chamber becomes the main source of plasma with maximum of the electron density. The differences in spatial distribution are caused by local or non-local behavior of electron energy transport in the discharge volume due to different characteristic scale of heat transfer with electronic conductivity.