Control Chamber Research Articles

Phase Behavior of Charged Vesicles Under Symmetric and Asymmetric Solution Conditions Monitored with Fluorescence Microscopy

Phase-separated giant unilamellar vesicles (GUVs) exhibiting coexisting liquid-ordered and liquid-disordered domains are a common biophysical tool to investigate the lipid raft hypothesis. Numerous studies, however, neglect the impact of physiological solution conditions. On that account, the current work presents the effect of high-salinity buffer and trans-membrane solution asymmetry on liquid-liquid phase separation in charged GUVs grown from dioleylphosphatidylglycerol, egg sphingomyelin, and cholesterol. The effects were studied under isothermal and varying temperature conditions. We describe equipment and experimental strategies applicable for monitoring the stability of coexisting liquid domains in charged vesicles under symmetric and asymmetric high-salinity solution conditions. This includes an approach to prepare charged multicomponent GUVs in high-salinity buffer at high temperatures. The protocol entails the option to perform a partial exchange of the external solution by a simple dilution step while minimizing the vesicle dilution. An alternative approach is presented utilizing a microfluidic device that allows for a complete external solution exchange. The solution effects on phase separation were also studied under varying temperatures. To this end, we present the basic design and utility of an in-house built temperature control chamber. Furthermore, we reflect on the assessment of the GUV phase state, pitfalls associated with it and how to circumvent them.

Effect of chitosan coatings on the quality of persimmon under commercial storage conditions.

The chitosan coating effectiveness for enhancing the shelf life and retaining the carotenoids content of persimmons under commercial storage was investigated. Persimmons ( Diospyros kaki L.) var. “Kyoto” were disinfected, immersed, drained, dried at room temperature, packaged and stored in a controlled temperature chamber. Physical and chemical properties were measured. The coating application reduced significantly the hue angle values compared with the control which suggests a slight ripening by the coating effect. Finally, the analysis of the carotenoid concentration for the five specific carotenoids determined that the β-cryptoxanthin was the most abundant pigment and it was not significantly differences during the storage and coating application. The storage time did not influence the carotenoid content for uncoated samples excluding the α-carotene analysis. The chitosan coating influenced on the lutein and zeaxanthin concentration during the last storage and on the α-carotene and β-carotene concentration for some cases.

Efektywność kontroli NIK na tle wybranych funkcji kontroli państwowej

Artykuł dotyczy zagadnienia efektowności kontroli państwowej. W myśl art. 202 ust. 1 Konstytucji Rzeczypospolitej Polskiej, naczelnym organem kontroli państwowej jest Najwyższa Izba Kontroli, a zatem to przez pryzmat jej działań można wskazać na sposób wypełniania wyodrębnionych w literaturze funkcji. Dokonanie analizy podejmowanychprzez nią czynności wykaże jak wypełnia ona przypisane kontroli państwowej funkcje. Niniejszy artykuł koncentruje się na tym zagadnieniu w odniesieniu do wybranych funkcji kontroli państwowej. Pozwoli to w pewnym stopniu na przeprowadzenie oceny oddziaływania NIK na inne organy i podmioty, a w konsekwencji, efektywności kontrolipaństwowej.

Thoracic and respirable aerosol fractions of spray products containing non-volatile compounds

ABSTRACTA versatile and simple mass balance method for the measurement of the release fraction of thoracic and respirable particles of non-volatile compounds of spray products is presented. The release fractions are defined as the ratio between the mass of suspended non-volatile particulate matter in the thoracic and respirable particle size range and the total mass of non-volatile material released with the spray action. For its determination, a spray bolus of short duration and of defined mass is sprayed into a well stirred control chamber. The respirable and thoracic aerosol mass associated with the spray bolus is determined by measuring the time averaged mass concentration inside the control volume and the half time of the exponential concentration decrease to be expected in well stirred systems to correct for mass losses during sampling. The method is used for a wide range of spray products and technologies for which the release fractions vary by orders of magnitude. A set of data is presented elucidating the relationship between spray technology and fine particle release. Furthermore, a simple rule of thumb was derived from the data that allows for estimation of the release fractions based on a characteristic diameter of the spray droplets. The usefulness of the mass balance method for substance classification as well as for generating input data for exposure assessment and indoor air quality modeling is discussed.

A zero-power warming chamber for investigating plant responses to rising temperature

Abstract. Advances in understanding and model representation of plant and ecosystem responses to rising temperature have typically required temperature manipulation of research plots, particularly when considering warming scenarios that exceed current climate envelopes. In remote or logistically challenging locations, passive warming using solar radiation is often the only viable approach for temperature manipulation. However, current passive warming approaches are only able to elevate the mean daily air temperature by ∼ 1.5 °C. Motivated by our need to understand temperature acclimation in the Arctic, where warming has been markedly greater than the global average and where future warming is projected to be ∼ 2–3 °C by the middle of the century; we have developed an alternative approach to passive warming. Our zero-power warming (ZPW) chamber requires no electrical power for fully autonomous operation. It uses a novel system of internal and external heat exchangers that allow differential actuation of pistons in coupled cylinders to control chamber venting. This enables the ZPW chamber venting to respond to the difference between the external and internal air temperatures, thereby increasing the potential for warming and eliminating the risk of overheating. During the thaw season on the coastal tundra of northern Alaska our ZPW chamber was able to elevate the mean daily air temperature 2.6 °C above ambient, double the warming achieved by an adjacent passively warmed control chamber that lacked our hydraulic system. We describe the construction, evaluation and performance of our ZPW chamber and discuss the impact of potential artefacts associated with the design and its operation on the Arctic tundra. The approach we describe is highly flexible and tunable, enabling customization for use in many different environments where significantly greater temperature manipulation than that possible with existing passive warming approaches is desired.

Development of a tool to aid the radiologic technologist using augmented reality and computer vision.

This technical innovation describes the development of a novel device to aid technologists in reducing exposure variation and repeat imaging in computed and digital radiography. The device consists of a color video and depth camera in combination with proprietary software and user interface. A monitor in the x-ray control room displays the position of the patient in real time with respect to automatic exposure control chambers and image receptor area. The thickness of the body part of interest is automatically displayed along with a motion indicator for the examined body part. The aim is to provide an automatic measurement of patient thickness to set the x-ray technique and to assist the technologist in detecting errors in positioning and motion before the patient is exposed. The device has the potential to reduce the incidence of repeat imaging by addressing problems technologists encounter daily during the acquisition of radiographs.

Temperature effects on the shear capacity of external bonded fiber reinforced polymer on concrete

The use of Fibre Reinforced Polymer (FRP) for the strengthening of concrete structures involves their exposure to temperature variations. This paper investigates the combined effect of the temperature and mechanical loads on FRP-concrete bonds. The investigation refers to a double lap shear test conducted in a controlled temperature chamber with temperature ranging from −40°C to 120°C. Both experimental and theoretical analyses are performed. The experimental results demonstrate (i) a decrease of the failure loads for temperatures higher than the Tg (40°C) of the adhesive matrix, (ii) an increase of the failure loads for temperatures lower than Tg which, however, decreases for very low temperatures (lower than −20°C), and (iii) the cohesive failure modes for temperatures ranging from −40°C to 40°C to de-cohesive failure modes for temperatures above 40°C. Analytical and finite element analysis helps to illuminate the experimental results and indicates that the difference in the coefficient of thermal expansions, as well as the mechanical loads, have an impact on the stress/strain distribution. Finally, the finite element model was used to analyse the typical solar radiation effects (during summer and winter days) on the reinforced systems. The cyclic variations of stress due to the sun thermal effects highlight the need of using an adhesive matrix with a high fatigue limit for FRP reinforcement.

Material handling and registration for an additive manufacturing-based hybrid system

The final functionality of parts produced by Additive Manufacturing (AM) can, in part, be improved by the inclusion of multi-material capabilities. The Multi3D Manufacturing System uses material extrusion printing (fused deposition modeling technology from Stratasys), solid conductor wire embedding, direct-write, component placement, and micromachining to enable the fabrication of multi-functional products. The material handling methodology, implemented by the Multi3D System, transports a workpiece between manufacturing stations via a six-axis robot, portable build platform, and a controlled temperature environment or chamber that travels to each manufacturing station. Also discussed in this work, is the investigation and improvement of registration parameters between the two material extrusion printers within this system. The registration was ultimately quantified to have minimal errors: 69μm along the x-axis, 183μm along the y-axis, and 215μm along the z-axis. The fabrication of a multi-colored part demonstrated the automated transfer of the workpiece, which offers early promise for an automated solution for multi-material fabrication using commercially-available fused deposition modeling machines.

Stabilization of pilot valve system using linear flow resistance

In a pilot valve system, the pressure in the control chamber of the main valve is straightforwardly affected by pressure oscillation in the downstream pipeline or the pilot tube. To solve this problem, an orifice is generally installed in the pilot tube to restrain the oscillation. However, the orifice is a nonlinear flow resistance; the amplitude of the oscillation alters the gain curve of the control pressure response. In this study, a linear flow resistance such as a porous material is employed to stabilize the pilot valve system. A test pilot valve was manufactured, and a pilot valve system was developed in the laboratory of the authors of this article. A mathematical model of the pilot valve system using linear and nonlinear flow resistances was simulated in MATLAB. The linearity of the P–Q characteristics of the linear flow resistance was confirmed, and a series of frequency response experiments were performed to examine the dynamic characteristics of the pilot valve system with various flow resistances. The experimental results were in accord with the simulation results. This implied that when porous materials were used in the pilot valve system, the gain of the pressure response did not vary regardless of the varying pressure vibration amplitude. Therefore, porous materials are suitable to be used in the pilot valve system instead of an orifice to enhance its stability.

Study on control performance of pilot high-speed switching valve

High-speed switching valves have been widely studied as pilot valves because of their advantages on easy digital control, low power loss, and non-sensitive to oil pollution. However, there are still lots of difficulties and problems between discrete flow and response time. In this article, two high-speed switching valves are used to pilot a three-way main stage valve. By adjusting the duty ratio of pulse width modulation control signals, the main stage can output continuous flow and pressure. The control performances of two pilot stage methods, which are high-speed switching valve and proportional valve, are compared through the theoretical analysis and the dynamic simulation. It is found that three factors directly affect the response time of the main stage, which are the control signal, the operating frequency of high-speed switching valve, and the pressure of the control chamber. The main valve can achieve better performance if optimized parameters are applied.

Drivers of Plot-Scale Variability of CH4 Consumption in a Well-Aerated Pine Forest Soil

While differences in greenhouse gas (GHG) fluxes between ecosystems can be explained to a certain degree, variability of the same at the plot scale is still challenging. We investigated the spatial variability in soil-atmosphere fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to find out what drives spatial variability on the plot scale. Measurements were carried out in a Scots pine (Pinus sylvestris L.) forest in a former floodplain on a 250 m2 plot, divided in homogenous strata of vegetation and soil texture. Soil gas fluxes were measured consecutively at 60 points along transects to cover the spatial variability. One permanent chamber was measured repeatedly to monitor temporal changes to soil gas fluxes. The observed patterns at this control chamber were used to standardize the gas fluxes to disentangle temporal variability from the spatial variability of measured GHG fluxes. Concurrent measurements of soil gas diffusivity allowed deriving in situ methanotrophic activity from the CH4 flux measurements. The soil emitted CO2 and consumed CH4 and N2O. Significantly different fluxes of CH4 and CO2 were found for the different soil-vegetation strata, but not for N2O. Soil CH4 consumption increased with soil gas diffusivity within similar strata supporting the hypothesis that CH4 consumption by soils is limited by the supply with atmospheric CH4. Methane consumption in the vegetation strata with dominant silty texture was higher at a given soil gas diffusivity than in the strata with sandy texture. The same pattern was observed for methanotrophic activity, indicating better habitats for methantrophs in silt. Methane consumption increased with soil respiration in all strata. Similarly, methanotrophic activity increased with soil respiration when the individual measurement locations were categorized into silt and sand based on the dominant soil texture, irrespective of the vegetation stratum. Thus, we suggest the rhizosphere and decomposing organic litter might represent or facilitate a preferred habitat for methanotrophic microbes, since rhizosphere and decomposing organic are the source of most of the soil respiration.

Influence of environmental temperature during grain filling period on granule size distribution of rice starch and its relation to gelatinization properties

High temperature (HT) is the major environmental factor affecting grain starch properties of cooking rice cultivars. However, little information has been available on the effect of environmental temperature on the starch granule size distribution of rice grains. In this paper, five indica rice genotypes, including the wild type (9311) and its four mutants differing in amylose content (AC), were used to investigate the effect of environmental temperature on the starch granule size distribution, as well as its relation to AC and gelatinization properties of rice starch. Two temperature treatments (HT and NT) at filling stage were imposed to rice plants under the controlled temperature chambers. The result showed that HT increased the average diameter of starch granules and enhanced the proportion of large starch granules (LSG, D > 2.6 μm) by number, volume and surface area, respectively. However, influence of HT on GT and starch granule size distribution was relatively independent of their alteration in AC level for different rice genotypes. Therefore, HT-induced increase in the average diameter of starch granules and LSG percentage was strongly responsible for the higher starch gelatinization temperature and inferior cooked palatability of HT-ripening rice grains, which be not inherently associated with their varying AC level.

Assessment of Climate Change Impact on Rice Using Controlled Environment Chamber in Tamil Nadu, India

Impacts of elevated temperature and carbon dioxide (CO 2 ) enrichment on rice were assessed by carrying out an experiment with four dates of planting (1 June and 15 June, 1 and 15 July) during 2014 under two different environmental conditions, viz. ambient and modified (climate control chamber) with +4°C compared to the ambient temperature and CO 2 enrichment of 650 ppm. Crops grown under modified environment recorded reduced growth characters (leaf area index, dry matter production, number of tillers m -2 ), lesser dry matter partitioning towards grain, yield attributes (number of productive tillers m -2 , number of filled grains panicle -1 ) and lower grain yields compared to those grown under ambient condition. Crops subjected to elevated temperature and enriched CO 2 attained panicle initiation, flowering and maturity earlier than those under open ambient condition.

Contemporary multi-use concert hall design: Experience and analysis

The acoustic design practice at Arup in New York has designed multiple performing arts spaces with a wide range of acoustic characteristics and functions, several of which have opened within the past few years. Many of these spaces make use of adjustable acoustics to accommodate a wide range of program within a single space, including acoustics control chambers, adjustable-height canopies, adjustable sound absorbing curtains and banners, and flexible configurations of various stage elements. Traditional objective parameters have been examined for both audience and stage acoustics, and additional spatial analysis is explored through visualization of 3D impulse responses. The relationships between these parameters and each venue’s program goals will be addressed. Our experiences and findings obtained through the process of design, construction, and post-opening will be shared.

Effect of hydrocarbon molecular decomposition on palladium-assisted laser-induced plasma ablation.

The Q-switched Nd:YAG laser is focused on a palladium target in the control chamber filled with various hydrocarbon atmospheres (C1-C4) to investigate their effect on the palladium ablated mass, gas reaction products, and corresponding plasma parameters (such as electron density Ne and plasma temperature Te) during molecular decomposition. The plasma parameters arise mainly from the Pd nanocatalytic activity during the laser-induced plasma process. We compare synthetic air atmosphere to hydrocarbon media to understand how the latter generates excess heat via oxygen-free exothermic (recombination) reactions. Subsequently, this gives rise to more energetic plasma and higher temperature, regarding the large amount of nanoparticles released into the plasma. The dynamics of the decomposition/recombination events accompany the nanocatalyst activity, leading to soot deposition all over the chamber.

Emission factors for PM2.5, CO, CO2, NOx, SO2 and particle size distributions from the combustion of wood species using a new controlled combustion chamber 3CE.

The objective of this research was to determine emission factors (EF) for particulate matter (PM2.5), combustion gases and particle size distribution generated by the combustion of Eucalyptus globulus (EG), Nothofagus obliqua (NO), both hardwoods, and Pinus radiata (PR), softwood, using a controlled combustion chamber (3CE). Additionally, the contribution of the different emissions stages associated with the combustion of these wood samples was also determined. Combustion experiments were performed using shaving size dried wood (0% humidity). The emission samples were collected with a tedlar bag and sampling cartridges containing quartz fiber filters. High reproducibility was achieved between experiment repetitions (CV<10%, n=3). The EF for PM2.5 was 1.06gkg-1 for EG, 1.33gkg-1 for NO, and 0.84gkg-1 for PR. Using a laser aerosol spectrometer (0.25-34μm), the contribution of particle emissions (PM2.5) in each stage of emission process (SEP) was sampled in real time. Particle size of 0.265μm were predominant during all stages, and the percentages emitted were PR (33%), EG (29%), and NO (21%). The distributions of EF for PM2.5 in pre-ignition, flame and smoldering stage varied from predominance of the flame stage for PR (77%) to predominance of the smoldering stage for NO (60%). These results prove that flame phase is not the only stage contributing to emissions and on the contrary, pre-ignition and in especial post-combustion smoldering have also very significant contributions. This demonstrates that particle concentrations measured only in stationary state during flame stage may cause underestimation of emissions.

Effect of mud drying temperature on surface characteristics of a polycarbonate PV protective cover

Chemo-mechanical characteristics of mud formed on polycarbonate PV cover are studied in relation to solar photovoltaic applications. Mud is formed from environmental dust and water condensate mimicking humid air conditions. Effect of mud drying temperature on chemo-mechanical and optical characteristics of mud-polycarbonate interface is investigated. Mud drying temperatures are set in the control chamber according to daily temperature distribution in Dammam area. Dry mud is later removed from surfaces, by pressurized distilled water, and mud residues left over on polycarbonate surface are examined. Analytical tools including scanning electron and atomic force microscopes, energy dispersive spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and inductively coupled plasma mass spectrometry are incorporated for the characterization of mud solution, dry mud, and polycarbonate surface after dry mud removal. Adhesion work required to remove dry mud from polycarbonate surface is also determined from scratch tests data. It is found that alkaline (Na, K) and alkaline earth metals (Ca) compounds in dust particles dissolve in condensed water while forming chemically active mud solution, which settles at the interface between mud and polycarbonate surface under the gravity. This has a detrimental effect on cleaning of dusted polycarbonate surface because of mud solution, upon drying, increases adhesion between dry mud and surface as well as modifies microhardness and surface texture of polycarbonate surface. Mud residues left over on surfaces alters the friction coefficient of polycarbonate surface, which is more pronounced for the case in which drying temperature is high.

Propane decomposition and conversion into other hydrocarbons using metal target assisted laser induced plasma

It is shown that the propane molecules are strongly decomposed in the metal assisted laser induced plasma based on the nano-catalytic adsorption. A Q-Switched Nd:YAG laser is employed to irradiate the propane gas filled in the control chamber in the presence of the reactive metals such as Ni, Fe, Pd, and Cu in order to study the effect of catalysts during the decomposition. The catalytic targets simultaneously facilitate the plasma formation and the decomposition events leading to generate a wide distribution of the light and heavy hydrocarbon molecules, mainly due to the recombination processes. Fourier transform infrared spectroscopy and gas chromatography instruments support the findings by detecting the synthetic components. Furthermore, the optical emission spectroscopy of the laser induced plasma emissions realizes the real time monitoring of the reactions taking place during each laser shot. The subsequent recombination events give rise to the generation of a variety of the hydrocarbon molecules. The dissociation rate, conversion ratio, selectivity, and yield as well as the performance factor arise mainly from the catalytic effects of the metal species. Moreover, the ablation rate of the targets of interest is taken into account as a measure of the catalytic reactivity due to the abundance of the metal species ablated from the target. This leads to assess the better performance factor for Pd among four metal catalysts of interest during propane decomposition. Finally, the molecules such as ethane and ethylene are identified as the stable abundant species created during the successive molecular recombination processes.

On the Seebeck Coefficient and Its Temperature Dependence for Standard CMOS Materials

This paper presents an extensive experimental study of the Seebeck coefficients in several conductive materials offered by standard CMOS technology when subject to a high temperature gradient. The measurements have been carried out on specific devices designed and fabricated in high-temperature SOI technology, comprising: one heating element, several thermopiles with different combinations of materials, and two highly sensitive, low leakage SOI diodes used to calibrate the absolute temperature in different points of the structure. To increase the accuracy, the chip characterization is performed in a controlled temperature chamber, with different values of the environmental temperature in the range 20 °C to 40 °C. This analysis leads to the extraction of the relative Seebeck coefficients for all thermocouples made with specific CMOS materials and, from that, the absolute values for the various materials at high temperature.

Response of photosynthetic characteristics and accumulation and distribution of assimilation products in tobacco to different light environments

In order to reveal the photosynthetic characteristics and the mechanism about accumulation and distribution of photosynthetic assimilation products under different light environments, potted tobacco was cultivated in a climate control chamber, there were three light intensity treatments (shading: (400±15)-(500±15) μmol·m-2·s-1; natural light: (800±15)-(1000±15) μmol·m-2·s-1; high light: (1500±15)-(1800±15) μmol·m-2·s-1). The results showed that with the decrease of light intensity, the biomass and root allocation, the net photosynthetic rate (Pn), stomata conductance (gs) and transpiration rate (Tr) were decreased, but the intercellular CO2 concentration (Ci) increased. The maximum net photosynthetic rate (Amax), light saturation point (LSP), light saturation point (LCP) and dark respiration rate (Rd) reached the maximum level under high light condition while the apparent quantum efficiency was higher in low light environment. The effects of light intensity on the absorption, accumulation and distribution of 13C in tobacco were significant, with a reduced proportion of enriched 13C distributed to the root under shading. The changes in the external light environment not only significantly affected the photosynthetic cha-racteristics and biomass accumulation of tobacco leaves, but also the distribution pattern of photosynthetic carbon in tobacco plant-soil system.