Flexible Enclosure Research Articles

Corrigendum to “Transient conjugate free convection within flexible enclosure having discrete heat source”

Corrigendum to “Transient conjugate free convection within flexible enclosure having discrete heat source”

Transient conjugate free convection within flexible enclosure having discrete heat source

Transient conjugate free convection in flexible enclosure is examined numerically. Isoflux heat sources are mounted in a left wall of finite thermal conductivity while a right wall is assumed to be hyper-flexible. The finite element method (FEM) is adopted to solve the governing partial differential equations, an arbitrary Lagrangian–Eulerian (ALE) approach inherent in the unstructured mesh. The governing parameters under consideration are: the number of the heat source, [Formula: see text], the thickness of the heat source, [Formula: see text], and the Rayleigh number, [Formula: see text]. It is determined that the development of conjugate convection heat transfer experiences through an initial phase, a transition phase, and a steady state phase. Each phase interval is shifted by adjusting the thickness of the heat source. Higher number and thicker of heat source cases had an ignorant effect on the shape of the flexible wall, but they tend to suppress the heat transfer rate. Increasing the block amplitude by 25% for [Formula: see text] results in reductions of the values of [Formula: see text] to 24%, 20%, and 28% respectively.

Monitoring of Cortisol Levels in Hog Deer with Varying Environment Exposure

Hog deer (Axis porcinus) is one of the least studied animal species in Pakistan. It belongs to Order Artiodactyla and the family Cervidae. IUCN classified Axis porcinus as an endangered species in 2008. The present study was conducted to investigate the effects of varying environmental exposure, genders, and seasonal changes on captive hog deer (A. porcinus) at Lahore Zoo, Safari Zoo, and Jallo Park in Lahore, Pakistan. Non-invasive techniques were used to monitor stress levels in hog deer. For sample collection, four definite months belonging to two seasons’ winter and summer were considered. A total of 48 urine and faecal samples were collected from both male and female hog deer. Seasonal fluctuations have been found to have a significant impact on faecal and urinary cortisol levels. Higher cortisol levels were found in both male and female hog deer in the summer season at all three visited sites. Fluctuations in environmental exposure at three research sites had a significant impact on faecal and urinary cortisol levels. Higher levels of cortisol were found in both male and female hog deer at Jallo park and Lahore Zoo, as compared to Safari Zoo. It was concluded that lower cortisol levels at Safari Zoo might be due to better environmental conditions and more flexible enclosure size and interaction of various species of deer. Temperature affected hog deer cortisol levels in summer, as higher levels were measured in summer compared to winter. In addition, sex did not predict any stress levels in hog deer. It has been suggested that a large enclosure size can control levels of cortisol in hog deer.

Optimization research based on local exhaust of oil mist particles in cutting machine tool

Oil particles generated from metalworking fluids(MWFs) in machining process can lead serious health problem to operator. Local exhaust hood is an effective engineering method to capture oil particles and other contamination which is wildly used in manufacture workshop. In this paper, exhaust hood capture efficiency with various height, air volume and particle size was gotten by Computational Fluid Dynamic(CFD) technology. Though further analysis of the CFD result, feature air velocity was introduced. Then an equation of feature velocity and capture efficiency was established by multi regression method. According to this equation one improvement solution was studied: Set to flexible enclosure for up exhaust hood. The solution raised particle capture efficiency on each size significant, the result is equivalent to low down up exhaust hood for 60cm.

Microstructure of cement paste subject to ambient pressure carbonation curing

This study investigated the microstructure of ordinary Portland cement paste subject to early age ambient pressure carbonation curing in a flexible enclosure. The high-pressure carbonation at 5 bar and the normal hydration were used as references. Both ambient-pressure and high-pressure carbonation was carried out with pure gas (99.9% CO2) for 12 h. It was found that ambient pressure carbonation could achieve comparable carbon uptake and strength gain as high pressure at both early and late age. Nevertheless, ambient carbonation was more economic and practical for precast products of different sizes and shapes. In order to examine this mechanism, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), 29Si nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and nitrogen adsorption/desorption (NAD) were adopted to characterize the microstructural development after early carbonation curing under both ambient pressure and high pressure. Ambient pressure carbonation reaction took place more on the surface than in the core due to the limited CO2 diffusion so that the surface layer was more densified. The NAD results showed that ambient pressure performed better than high pressure in terms of reducing the cumulative pore volume and refining the capillary pore size. Ambient pressure could produce well crystalline carbonates as high pressure as deduced by XRD, TGA, FTIR and SEM images. The generation of calcium carbonate and its intermingling effect with hydration products were the main reasons for the strength gain and microstructural development of paste after early carbonation. Besides, SEM images showed that ambient pressure tended to produce calcium carbonates along the surface of C-S-H filling pore structure. As subsequent hydration proceeded, the increase of well crystalline carbonates was seen more in ambient pressure carbonation than high pressure based on TGA. NMR revealed that ambient pressure could enhance the polymerization of silicon in C-S-H promoting the early strength gain and maintain high Ca/Si ratio.

Carbonation Curing of Concretes in a Flexible Enclosure under Ambient Pressure

Early-age carbonation curing of concrete is considered an alternative curing method that efficiently utilizes carbon dioxide to improve the performance of concrete and reduce carbon emission. Carbonation curing is commonly implemented in a pressure chamber at high pressure. The application is therefore limited only to special products such as concrete masonry units. To promote wider applications of the technology for general precast concrete with any shapes and sizes, an ambient pressure carbonation system in a flexible enclosure is needed. This paper presents a study on developing a new carbonation curing system at a curing pressure of 1.4 kPa (0.014 bar), which is considered as ambient pressure. The system includes a flexible enclosure made from a plastic sheet with a pressure-resistant zipper that can accommodate any shape and size of precast concrete products and can be made either in a factory or on a job site. Compared to the traditional high-pressure carbonation at 0.5 MPa (5 bars), which generates 12% CO2 uptake, carbonation in the ambient-pressure system at 1.4 kPa (0.014 bar), can achieve a carbon dioxide uptake of 11% with a comparable strength at both the early and late ages. Besides, the ambient pressure carbonation has shown less pH reduction and smaller carbonation depth than high pressure, which would have the advantage of protecting the reinforcing steel in concrete from carbonation-induced corrosion. Furthermore, ambient pressure carbonation-cured concretes were found to have higher compressive strength, higher surface electrical resistivity, lower porosity, and faster ultrasonic pulse velocity than normal hydration concretes at both the early and late hydration stage. Microstructure analysis indicated that carbonates were intermingled with C─ S─ H, contributing to the strength gain and performance improvement of concretes subject to ambient pressure carbonation curing.

A Flexible Enclosure to Protect Respiratory Therapists During Aerosol-Generating Procedures.

Exposure of respiratory therapists (RTs) during aerosol-generating procedures such as endotracheal intubation is an occupational hazard. Depending on the hospital, RTs may serve as laryngoscopist or in a role providing ventilation support and initiating mechanical ventilation. This study aimed to evaluate the potential exposure of RTs serving in either of these roles. We set up a simulated patient with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in an ICU setting requiring endotracheal intubation involving a laryngoscopist, a nurse, and an RT supporting the laryngoscopist. All participants wore appropriate personal protective equipment (PPE). A fluorescent marker was sprayed by an atomizer during the procedure using 3 different methods for endotracheal intubation. The 3 techniques included PPE alone, a polycarbonate intubating box, or a coronavirus flexible enclosure, which consisted of a Mayo stand with plastic covering. The laryngoscopist and the supporting RT were assessed with a black light for contamination with the fluorescent marker. All simulations were recorded. When using only PPE, both the laryngoscopist and the RT were grossly contaminated. When using the intubating box, the laryngoscopist's contamination was detectable only on the gloves: the gown and face shield remained uncontaminated; the RT was still grossly contaminated on the gloves, gown, neck, and face shield. When using the coronavirus flexible enclosure system, both the laryngoscopist and the RT were better protected, with contamination detected only on the gloves of the laryngoscopist and the RT. Of the 3 techniques, the coronavirus flexible enclosure contained the fluorescent marker more effectively during endotracheal intubation than PPE alone or the intubating box based on exposure of the laryngoscopist and supporting RT. Optimizing containment during aerosol-generating procedures like endotracheal intubation is a critical component of minimizing occupational and nosocomial spread of SARS-CoV-2 to RTs who may serve as either the laryngoscopist or a support role.

Divide and Conquer treemaps: Visualizing large trees with various shapes

Most existing treemaps achieve the space utilization of a single geometrical area, mostly rectangle. Limiting visualization to rectangles could block the human capability on graph recognition, including orientation, shape and differentiation etc. To relax rectangular constraint, we propose a flexible enclosure approach with three algorithms. It partitions large hierarchical structures within a confined display area with different shapes for real-time applications. Our approach is based on the combination of Divide-and-Conquer method and the treemap paradigm. The partitioning algorithms generate three types of layouts with polygonal, angular and rectangular titling, which are flexible to be used separately or combined. We present technical details including the visualization results in the experiments and in the cases studies with real data sets. We evaluated the visualization based on graph drawing aesthetics and optimization criteria. Our usability study shows that (1) treemaps with layout variability support utilization of human capability in graph perception and (2) treemaps adopted in different shaped containers could have a positive impact on user satisfaction and awareness during visual data exploration.

Relationship between Phytoplankton and Nutrient Dynamics in the Enclosed Waterbody, Dianchi Lake

An analysis of 170 simples acquired monthly from August 2011 to December 2012 in the closed waterbody suggests that the concentration of algae bloom (Cyanophyta) is dependent on the nutrient dynamics. Without the overlying of nitrate concentrations carried by the external algae bloom, the enclosed waterbody isolated by the flexible enclosure maintains a lower nitrate level. Algae bloom tends to dominate (TN: TP < 12) and to rare (TN: TP>12). Cyanophyta is dominant for the whole year.

Active Vibration Control of Acoustically Loaded Flexible Plate Enclosure Using Multi-Channel Control Algorithm

This paper presents the multi-channel active vibration control of a flexible plate of the acoustically loaded enclosure. The flexible plate was excited acoustically with sinusoidal and white noise input. The control was performed by two piezo ceramic actuators and two accelerometers. The experimental results were compared with the single channel control results. In the case of white noise input, 20 dB of vibration reduction was achieved below 300Hz frequency range. The experimental results demonstrate that multi-channel filtered-x LMS algorithm is effective than single-channel filtered-x LMS algorithm in active vibration control of plate.

Audio transducer with flexible foam enclosure

An audio transducer includes a rigid base plate and a flexible foam element attached to the plate. The foam element has a "B" shaped cross section, with a plastic film diaphragm conformally attached to the dual semi-cylindrical front surface of the foam element. The foam element defines a large circular bore for receiving a magnet assembly attached to the plate, with a electrical coil attached to the diaphragm and received within a gap defined within the magnet assembly. The plate and diaphragm are sealed to the foam element to provide an environmentally sealed chamber within the bore.

Automated architectural acoustical modeling with the SeDReS system.

A computer‐controlled architectural modeling system was developed to allow the enclosure and materials of a room to be rapidly and precisely varied for acoustical testing using ultrasonic sparks and miniature microphones at various scales (depending upon the size of the model room to be tested). A system of stepper motors moves segmented wall, ceiling, and floor panels of a large, flexible enclosure. The walls, ceiling, and floor can be moved to configure a wide variety of rooms from a small lecture room to a large arena. The locations and angles of the enclosing surfaces of the room for multiple design motifs can be stored in the memory of the computer. One can then push several keystrokes to reconfigure the room and proceed with acoustical testing and simulation using the acoustical research instrumentation for architectural spaces (ARIAS) system. Impulse responses, acoustical measurements, and aural simulations from alternative designs can be compared at the earliest stages of the design process when one is considering basic choices of finish materials, room shape, and wall angles. [Work supported by NSF.]

Wearable audio reception device

A wearable audio reception device includes an elongated flexible enclosure removably attachable to an article of clothing and the radio in turn being removably attachable to the flexible enclosure.

In-situ estimation of an acoustic source in an enclosure and prediction of interior noise by using the principle of vibroacoustic reciprocity

The volume velocity of an acoustic source can be widely used in determining the vibroacoustic transfer functions, in measuring the acoustic transfer impedances, and in finding the generated power of an acoustic source. Several techniques utilizing special experimental devices have been proposed for this purpose, including the laser velocimetry, the internal pressure measurement, and the face-to-face electroacoustic measurement. However, for a source in an enclosure with flexible walls, the vibroacoustic coupling should be considered, especially in the case of a loudspeaker source that has low internal mechanical impedance. The present method, which uses the principle of vibroacoustic reciprocity, can give a reasonable estimation of the transfer functions and can be used in determining the volume velocity of a source in situ. Because the present method does not require a special facility or the information on the source surface vibration, the method can be applied to any irregularly shaped source in a flexible enclosure. With the obtained vibroacoustic transfer functions, the interior noise field in an enclosure can be predicted by vectorial summation when the boundary points are excited by uncorrelated dynamic forces. The predicted internal pressure in an enclosure is in good agreement with the measured internal pressure even in the presence of sound absorbers inside the enclosure.

Gauge for nondestructive measurement of the internal pressure in powder-filled evacuated panel superinsulation

A gauge that measures the internal pressure (P) in powder-filled evacuated panels (PEPs) is described. PEPs are superinsulators consisting of high thermal resistivity powders encapsulated in hermetically sealed flexible barriers enclosing a vacuum. To measure P, the gauge supplies a vacuum to the outer surface of the barrier. When the P in the PEP exceeds that supplied by the gauge, the barrier deflects. This deflection is sensed by a bifurcated-fiber-optic light system that converts the motion of the barrier into a voltage proportional to the displacement of the barrier. A pressure transducer mounted in the gauge provides a dc voltage proportional to P at the interface of the barrier and PEP. An X-Y recorder displays the relationship between these two signals. Experiments show that the gauge yields P measurements with uncertainties of +0.27 kPa and reproducibilities of ±0.16 kPa for PEPs with 0.13-mm-thick flexible polymer barriers. To achieve more accurate measurements, the gauge should first be calibrated on a PEP of known internal P then used to measure P on similar PEPs with unknown P’s. Besides PEPs, experiments suggest that the gauge can nondestructively and rapidly measure the pressure in a hermetically sealed container having a flexible enclosure, such as vacuum-packaged food. Patent applications for this gauge are on file with the United States Patent Office.

Loudspeaker enclosure arrangement for voice communication terminals

The invention provides an enclosure arrangement for a loudspeaker (10) adapted to be mounted in a voice communication terminal. The invention provides primary and secondary enclosures for the loudspeaker. The primary enclosure comprises a piece of resilient open cell foam material (15) having one face provided with a concavity suitable for receiving the spider (12) and the voice coil structure (11) of the loudspeaker (10). The peripheral edge of the one face of the foam material (15) is secured to the peripheral edge (14) of the spider (12) and the outer surface of the foam material has a flexible layer (16) of substantially air-impermeable material, whereby the loudspeaker is provided with an attached flexible enclosure (33). The secondary enclosure comprises the housing (30) in which the loudspeaker is mounted. The flexibility of the primary enclosure allows energy to be coupled between itself and the secondary enclosure.

Bubble silencer for an underwater voice communicator

A bubble silencer for use with scuba equipment is comprised of a flat flexible enclosure attached to a scuba regulator valve. Exhaust bubbles issuing from the regulator into the enclosure coalesce into large air parcels to be expelled at low velocity through a rearward exit port. The large size and low velocity of the exhaust bubbles leaving the enclosure are much quieter than the small high velocity bubbles issuing from the regulator itself.

STERILE OPERATING-THEATRE SYSTEM

Assuming that normal sterile procedures are adopted and that the air-supply to the operating-theatre is filtered, the only other sources of infection are the surgical team and the patient. It is proposed that the surgical team should be totally enclosed in suits of impermeable material and should carry individual air-conditioning units. It is further proposed that the patient should be introduced into an open-ended enclosure of flexible material which projects into the theatre through a hole in the wall of the theatre and which is sealed to the wall opening. After application of a double-sided adhesive strip to the operation site, the flexible enclosure is locally sealed to the strip and the incision is made through both the enclosure and the strip.