Ambient Parameters Research Articles

Implementation of Darcy–Forchheimer effect on magnetohydrodynamic Carreau–Yasuda nanofluid flow: Application of Von Kármán

Transient MHD flow in Carreau–Yasuda nanofluid produced by impulsively started rotating disk is examined in the occurrence of Darcy–Forchheimer and chemical reactive species considering conventional Fourier’s and Fick’s laws. Appropriate transformations are used to transform the constitutive equations into nonlinear ordinary differential equations and then solve by using improved form of RK-4 Fehlberg scheme (Cash and Karp). The deviation in flow field due to velocity, friction factor, temperature, heat diffusion rate, nanoparticle concentration, and mass transfer rate is analyzed subsequent to various ambient parameters appearing in the problem. The results of the study reveal that Weissenberg number appearing in the equations leads to deceleration of the radial and tangential velocities while the power law index tends to accelerate the radial and tangential velocities.

Using a high-performance bioreactor system to cultivate peanut kernels for the induction of stilbenoids

ABSTRACTResveratrol and its bioactive component, trans-arachidin-1, which is extracted from Arachis hypogaea, can be taken as dietary supplements to promote health and potentially to extend lifespan. In this study, a high-performance bioreactor was developed. The rotation of the chamber, temperature, humidity, and CO2 concentration were 76–89 rpm, 26–35°C, 75%, and 850 ppm, respectively. During incubation, sets of peanut slices were sampled at intervals and analyzed with high-performance liquid chromatography (HPLC). The stilbenoid profiles varied quantitatively and qualitatively with the time of incubation. After 24 h of incubation, the slices were dried, ground, and defatted with n-hexane. The slices were then extracted and subjected to HPLC analysis. The trans-resveratrol, trans-arachidin-1, trans-arachidin-3, and trans-isopentadienyl resveratrol levels were 0.374, 1.507, 8.558, and 5.246 mg/g defatted powder, respectively. We demonstrated that the designed device (equipped with a human–machine interface and a programmable logic controller) can perform real-time monitoring of the ambient parameters.

Relationships between perceived health status and ambient air quality parameters in healthy Japanese: a panel study

BackgroundThere has been growing global concern about air pollution due to its great risk to public health. In Japan, although industrial- and traffic-related air pollution has been decreasing, concerns about particulate matter air pollution has been growing in recent years. In this study, we examined the effects of air pollution on symptoms and the health status of healthy subjects in Japan.MethodsParticipants (n = 2887) who visited healthcare centers in Kumamoto or Niigata prefectures in February from 2010 to 2015 were asked to fill out a questionnaire, which was a self-completed booklet containing questions on the characteristics of participants, their respiratory symptoms, and questionnaires on their health status in February, May, and July. Generalized estimating equation analyses were performed to predict the factors associated with the symptoms and health status using two-week averages of air quality parameters obtained from 49 monitoring stations as independent variables.ResultsOnly allergy was associated with air quality in both areas. Prevalence of the other respiratory symptoms were correlated with air quality only in Kumamoto. The health statuses including the ‘physical fitness’, ‘daily activities’, and ‘social activities’ domains were related only to time spent outdoors. The ‘overall health’ was associated with time spent outdoors and concentrations of nitrogen dioxide and suspended particulate matters (SPM) in Kumamoto, and with temperatures and SPM in Niigata. The ‘pain’ score was correlated with temperature and carbon monoxide concentration only in Kumamoto. In Kumamoto, the ‘quality of life (QoL)’ was worse in those who spent shorter hours outdoors, were exposed to lower humidity, higher concentrations of oxidants, SPM, and PM2.5, and who experienced more Asian sand dust (ASD) events. In Niigata, a worsened ‘QoL’ was associated with time spent outdoors, temperature, and SPM.ConclusionsThe associations between air quality and the health status was found mainly in the comprehensive domain of the health status such as ‘overall health’ and ‘QoL’. The effect of short-term exposure to larger particles, such as SPM, on health status was observed when compared to smaller particles such as PM2.5 and gaseous pollutants.

Sources of solar energetic particles.

Solar energetic particles are an integral part of the physical processes related with space weather. We present a review for the acceleration mechanisms related to the explosive phenomena (flares and/or coronal mass ejections, CMEs) inside the solar corona. For more than 40 years, the main two-dimensional cartoon representing our understanding of the explosive phenomena inside the solar corona remained almost unchanged. The acceleration mechanisms related to solar flares and CMEs also remained unchanged and were part of the same cartoon. In this review, we revise the standard cartoon and present evidence from recent global magnetohydrodynamic simulations that support the argument that explosive phenomena will lead to the spontaneous formation of current sheets in different parts of the erupting magnetic structure. The evolution of the large-scale current sheets and their fragmentation will lead to strong turbulence and turbulent reconnection during solar flares and turbulent shocks. In other words, the acceleration mechanism in flares and CME-driven shocks may be the same, and their difference will be the overall magnetic topology, the ambient plasma parameters, and the duration of the unstable driver. This article is part of the theme issue 'Solar eruptions and their space weather impact'.

CFD simulations to study the effect of ventilation rate on 220Rn concentration distribution in a test house

Measurement and interpretation of the distribution patterns of indoor 220Rn concentration is important for inhalation dosimetry in occupational and residential areas. The shorter half-life of radioactive 220Rn gas greatly affects its patterns resulting in non-homogeneity in the spatial concentration profile. In addition, the distribution profile also changes with variations in the ambient atmospheric parameters (ventilation rate, humidity etc.). The Computational fluid dynamics (CFD) technique has gained a lot of attention in recent times for the prediction and visualization of the distribution pattern of indoor 222Rn/220Rn concentration. This study aims to apply the CFD technique for studying the effect of variations in the ventilation rate on the distribution pattern of the 220Rn concentration in a thoron test house. Experimentally measured 220Rn flux from the surfaces of the experimental test house is used as input for the CFD simulations. Ventilation rate is varied from 0.1 h−1 to 9.0 h−1 and the simulated results of velocity and 220Rn concentration profile for the entire test domain are interpreted. It is observed that the increase of ventilation rate leads to the flow induced turbulence enhancing the mixing of 220Rn in indoor air. Results of this study demonstrate the inter-play of radionuclide half-life and turbulent mixing induced transportation. Inferences are discussed in order to improve the dosimetric deductions for indoor conditions.

PRODUCTION OF DAIRY COWS AT DIFFERENT ENVIRONMENTAL CLIMATIC PARAMETERS

Cattle have a constant body temperature, which held up to a certain limit. Due to changing ambient climatic parameters (temperature, humidity, THI index), can lead to certain consequences which have a deleterious effect on the health of the animals, and even can cause death of the animal. The assumption of this research was that the environmental climatic parameters have an impact on cows in milk production.The study involved 50 Holstein cows, which were divided in the same building and in the two groups: the first (n = 25) = 30 kg milk and 2 (n = 25) = 30 and more kg of milk. The results showed that the surface temperature of the body was measured on the left side of the body cows (area rumen) increased no matter what was the level of milk production. However, the surface temperature of the udder measured from the back of the cows showed a different trend. The temperature of the udder of the cow in the first (with a milk production of less than 30 kg) was constant (average of 34.95 ° C), in contrast to the other groups of cows (with a milk production of 30 kg or more), where the surface temperature is increased as the udder increased and THI index in the barn.The increase in metabolic activity in animals (such as dairy cows) and leads to an increase in surface heat in certain parts of the body, and what is even more pronounced when the animals are in inadequate surroundings or barn that is not adapted to cows with high milk production.

The Benefits of Using a Network of Superconducting Gravimeters to Monitor and Study Active Volcanoes

AbstractWe present results from a mini‐array of three iGrav superconducting gravimeters (SGs) at Mount Etna. This is the first network of SGs ever installed on an active volcano. Continuous gravity measurements at active volcanoes are mostly accomplished with spring gravimeters that can be operated even under harsh field conditions. Nevertheless, these instruments do not provide reliable continuous measurements over periods longer than a few days due to the instrumental drift and artifacts driven by ambient parameters. SGs are free from these instrumental effects and thus allow to track even small gravity changes (1–2 μGal) over a wide range of time scales (minutes to months). However, SGs need host facilities with main electricity and a large installation surface, implying that they cannot be deployed in close proximity to the active structures of tall volcanoes. At Mount Etna the three iGrav SGs were installed at distances from the summit active craters ranging between 3.5 and 15 km. Despite the relatively unfavorable position of the installation sites, we show that these instruments can detect meaningful (i.e., volcano‐related) changes that would otherwise remain hidden, like, for example, the weak gravity signature (within a few μGal) of gas buildup at intermediate depth in the plumbing system of Etna, during noneruptive intervals. Our results prove that iGrav SGs are powerful tools to monitor and study active volcanoes and can provide unique information on the bulk processes driving volcanic activity.

Cache Bypassing and Checkpointing to Circumvent Data Security Attacks on STTRAM

Spin-Transfer Torque RAM (STTRAM) is promising for cache applications. However, it brings new data security issues that were absent in volatile memory counterparts such as Static RAM (SRAM). This is primarily due to the fundamental dependency of this memory technology on ambient parameters such as magnetic field and temperature that can be exploited to tamper with the stored data. The magnetic attack could be gradually ramping and/or sudden in nature. In this paper, we propose three techniques to avoid errors in presence of magnetic attack, (a) stalling where the system is halted during attack; (b) cache bypass during gradually ramping attack where the last level cache (LLC) is bypassed and the upper level caches interact directly with the main memory; and, (c) checkpointing along with bypass during sudden attack where the processor states are saved periodically and the LLC is written back at regular intervals. During attack, the system goes back to the last checkpoint and the computation continues with bypassed cache. We performed simulation for different duration and frequency of attack on SPLASH and PARSEC benchmark suites. The results show an average of 13 percent IPC degradation and 6.5 percent energy overhead for a one-time attack lasting for 100 percent of the execution time for cache bypass. For checkpointing to mitigate sudden attack, results show 10 percent IPC degradation and 4.5 percent energy overhead for attack lasting for 50 percent of the execution time.

Tunable hybridization induced transparency for efficient terahertz sensing.

Hybridization induced transparency (HIT) resulting from the coupling between the material absorption resonance and the artificial structure (metamaterial) resonance provides an effective means of enhancing the sensitivity in the terahertz spectroscopic technique-based sensing applications. However, the application of this method is limited by the versatility to the samples with different volumes, because the samples usually have a refractive index larger than unity and their presence with different thicknesses will lead to a shift of the structure resonance, mismatching the material absorption. In this work, we demonstrate that by using InSb coupled rod structures, whose electromagnetic response in the terahertz band can be easily controlled by using ambient parameters like the temperature or magnetic field, the HIT effect can be easily tuned so that without the needs to change the rod geometry, one can realize efficient terahertz sensing with different sample thickness.

Experimental analysis of the thermohygrometric effects on the dynamic behavior of adobe systems

Abstract Through long-term monitoring, modal parameters identified in-situ can provide important information about the safety state of civil buildings and infrastructures. Unfortunately, structures are subjected to changing environmental conditions that can mask variations in the dynamic properties caused by damage and, therefore, lead to an incorrect condition assessment. The quantification of the influence of environmental conditions on modal parameters is a crucial step to eliminate their interference in a safety evaluation. Under current state-of-the-art considerations, this step is still an open challenge because environmental variables are time-dependent non-uniform quantities that have different influences on structural systems depending on the predominant material. In this paper, the effects of ambient temperature and humidity on the dynamic properties of earthen constructions are investigated using laboratory tests. A dynamic monitoring system was successfully implemented on adobe walls of different thicknesses to examine the influence of seasonal and daily variations of temperature and humidity. Three 1:1 scale adobe masonry walls were built and exposed to ambient conditions for 240 days. Temperature and humidity variations on the exterior, as well as in the inner walls, were continuously recorded together with the dynamic behavior using ambient vibration. The results provide useful insights on the influence of thermohygrometric parameters on the dynamic properties of adobe systems. The seasonal results indicate unclear correlations of ambient parameters and environmental variables. On the other hand, at a daily scale, the results indicate the existence of a clear relationship between inner measurements and dynamic properties. Moreover, the results indicate the existence of a delayed effect of external ambient parameters in the dynamic behavior of earthen systems.

Allium cepa Bio Assay to Assess the Water and Sediment Cytogenotoxicity in a Tropical Stream Subjected to Multiple Point and Nonpoint Source Pollutants.

The present study was conducted to assess the cytotoxicity of water and sediments of an industrial effluent receiving water body in the western province of Sri Lanka using Allium cepa bioassay. Six sampling sites (Site A: Urban; B: Industrial; C: Water intake for public water supply; D: Industrial; E: Agricultural; F: Reference) were selected from the study area. Ten replicate water and sediment samples were collected from each site, and physical and chemical parameters were measured using standard analytical methods. Cytotoxicity of water and sediment elutriates were measured using Allium cepa bioassay. Despite the significant spatial variations, the overall water and sediment quality parameters of the study sites were in accordance with the standard ambient environment parameters to sustain a healthy aquatic life. In the A. cepa bulbs exposed to water samples, significant root growth variations were not observed within 48 hours of exposure. However, significant root length variations were observed in A. cepa bulbs exposed to sediment elutriates within the 48-hour exposure and the percentage root growth inhibition increased with increase of exposure time. Similar trend was observed in mitotic activity indicating significantly lower mitotic indices (compared to that of the reference site) in A. cepa root tip cells exposed to sediment elutriates than those exposed to water samples. Further, the highest number of nuclear abnormalities was recorded from root tip cells of A. cepa exposed to water and sediment samples from sites B, C, and D. Therefore, it is of extreme importance to identify the composition and speciation of these cytogenotoxic compounds in the tropical climatic conditions and to propose possible clean-up or treatment solutions to overcome this environmental and public health risk associated problem.

Dust charge distribution in the interstellar medium

We investigate the equilibrium charge distribution of dust grains in the interstellar medium (ISM). Our treatment accounts for collisional charging by electrons and ions, photoelectric charging due to a background interstellar radiation field, the collection of suprathermal cosmic ray electrons and photoelectric emission due to a cosmic ray induced ultraviolet radiation field within dense molecular clouds. We find that the charge equilibrium assumption is valid throughout the multi-phase ISM conditions investigated here, and should remain valid for simulations with resolutions down to AU scales. The charge distribution of dust grains is size, composition, and ISM environment dependent: local radiation field strength, $G$, temperature, $T$, and electron number density, $n_{\mathrm{e}}$. The charge distribution is tightly correlated with the `charging parameter', $G\sqrt{T}/n_{\mathrm{e}}$. In the molecular medium, both carbonaceous and silicate grains have predominantly negative or neutral charges with narrow distributions. In the cold neutral medium, carbonaceous and silicate grains vary from negative and narrow distributions, to predominantly positive and wide distributions depending on the magnitude of the charging parameter. In the warm neutral medium, grains of all sizes are positively charged with wide distributions. We derive revised parametric expressions that can be used to recover the charge distribution function of carbonaceous and silicate grains from 3.5 {\AA} to 0.25 $\mu$m as a function of the size, composition and ambient ISM parameters. Finally, we find that the parametric equations can be used in environments other than Solar neighborhood conditions, recovering the charge distribution function of dust grains in photon dominated regions.

Experimental investigation on operation parameters of 3Å molecular sieve desiccant coated total energy recovery wheel for maximum effectiveness

The object of this research study was to investigate the maximum effectiveness values of the energy wheel by experimental tests conducted under extreme difference ambient air conditions parameters, different air volume flow rates, and energy wheel rotation speeds. Air temperature and humidity experimental tests were performed using a test facility that was developed and installed into the Indoor Air Quality and Thermal Comfort Laboratory of Budapest University of Technology and Economics. Our objective was to get the effectiveness values of sorption coated air-to-air energy recovery wheel for steady-state conditions under different ambient air (as supply air inlet) conditions. It was found that the sensible effectiveness increases by decreasing the volumetric flow rate through the wheel, and the optimum values of the effectiveness were given at the maximum wheel rotation speed based on the tests. As for the latent and total effectivenesses, their characteristics show an increasing trend by decreasing the air volume flow rate, ambient air temperature and relative humidity and increasing the wheel rotation speed.

Exergy analysis of the thermal behavior of battery cooling processes for HEV and BEV applications

This paper presents the results of a holistic exergy analysis of the cooling circuits for HEV and BEV battery cooling systems. The aim of the performed analysis is to give a proposal for the best possible thermohydraulic solution of the cooling system for battery units. The exergy analysis helps to detect possibilities to improve thermal processes and systems. Exergy is defined as the maximum useful work possible during a reversible process that brings the system into equilibrium with the local ambient parameters. The exergy analysis can help to establish a quality rating of counter-clockwise cyclic processes (e.g. air conditioning, heat pump) with a COP value smaller or even greater than 1. Using evaluation coefficients for the hierarchic exergetic analysis (efficiency, loss coefficient, significance factor and loss component), it is possible to identify the maximum potential of each individual component and also of the total cooling system itself. New optimized concepts for the cooling and heating of battery units are proposed by a numerical analysis of the current cooling circuit for selected operation points. The final effect of the proposed solution is an increase of the vehicle cruising range, an increase of the overall vehicle efficiency and finally—a reduction of the lifecycle costs.

Pervasive and Personalized Ambient Parameters Monitoring: A Wearable, Modular, and Configurable Watch

An innovative, small, compact, light-weighted, configurable, and low power consumption wrist-worn prototype in the area of ambient parameters monitoring, in five physical layers, is introduced. The prototype is based on the multi-layer multi-sensor approach and is capable of measuring a wide range of toxic/hazardous gases, physical ambient parameters, and motion tracking. The proposed device operates in the stand-alone (BLE disconnected) and configurable (BLE connected) modes. The stand-alone mode supports real-time data monitoring on the display and data storage in an integrated external memory. The logged data are retrieved once BLE is resumed based on the user decision. In the configuration mode, sensors are activated and configured by the user via sending a command from the smartphone. The chemical parameters monitoring includes three hazardous gases (SO 2 , NO 2 , and CO one at each time). The toxic gas sensor along with the gas sensor driver forms the gas sensor node which is located at the top of the proposed device. Hardware flex interface is utilized as the second layer to facilitate the display and sound module connected to the host platform. The main platform that is expandable from both the sides in z -axis hosts the integrated sensors, microcontroller, and the chip antenna. Notification driver for the early user warning of abnormal status and battery holder is placed at the bottom of the device in two separate layers. Furthermore, the adjustable sensor sampling rate according to the battery level is applied in order to manage power consumption. Device configuration, prototype validation, data storage, power dissipation, and experimental results are discussed in detail at the end of this paper.

Monitoring the Effective Ambient and Sky Temperature Based on Infrared Sensor for Advanced Thermal Calculations

Building performance simulations and advanced thermal analysis are becoming the basis for a well-established practice of a building sector. This approach requires many input data which are typically not available on site. Apart from already well-practiced climate variable quantities, such as ambient temperature, solar radiation and parameters of wind, more complex data are needed for advanced building thermal analysis. One of those is based on longwave radiation level. A pyrgeometer is a device that measures longwave radiation part of whole thermal radiation phenomena. This can be determined based on sky or effective ambient temperature monitoring. Secondly, both variables might be approximated by infrared sensors as an applicable option in the calculation of longwave radiation heat exchange between the external surface and the ambient building environment. The paper presents data obtained both by pyrgeometer and infrared sensor corresponding to their mutual comparison to demonstrate its application when longwave radiation exchange needs to be calculated or analyzed in advanced. Integrating of the infrared sensor with aim to monitor the effective ambient and/or sky temperature enables its applicability as an alternative, integrated and less cost consuming method towards the monitoring by commercial pyrgeometer.

Online Monitoring of Flexural Damage Index of a Cable‐Stayed Bridge

This work introduces a recent application of the online nondestructive damage assessment system into a cable‐stayed bridge. A set of ambient modal parameters are automatically extracted every 20 minutes using real‐time signal data collected from a total of 26 accelerometers attached on the deck plate of the bridge. Then, a set of modal flexibilities are reconstructed by the combination of the extracted modal parameters with the approximated modal mass of the girder. Next, the curvature of the modal flexibility is approximated by a central difference formula. Finally, the set of flexural damage index equations is constructed by comparing the modal curvature of the damaged state to that of the undamaged state. Solving the overdetermined flexural damage index equations, the desired damage index is finally quantified. The resulting index clearly indicates the location and severity of the potential structural damage on the girder. Based on the overall performance of the implemented health monitoring system, the bridge operator’s damage index control criteria are set to ±20% of the undamaged state.

MODELING WAVE ATTENUATION DUE TO SALTMARSH VEGETATION USING A MODIFIED SWAN MODEL

Vegetated shorelines have been increasingly recognized for their contribution to natural coastal protection due to their ability to dissipate wave energy. Within the UK, salt marshes are beginning to be included in flood defence schemes. Predicting wave dissipation over vegetation requires accurate representation of salt marsh canopies and the feedback relationship between vegetation and wave conditions. We present a modification to the SWAN vegetation model, which includes a variable drag coefficient and a spatially varying vegetation height. Its application is demonstrated by modelling wave propagation over UK salt marshes. The third generation wave model, SWAN includes a vegetation module for calculation of wave attenuation over vegetation. Wave dissipation is determined based on the vegetation properties and a drag coefficient. This drag coefficient, C_D, is used to calibrate the model, and a fixed value is used per model run. Empirically the drag coefficient has been found to vary with ambient wave conditions. Typically the drag coefficients are defined empirically as a function of either the stem Reynolds number, Rev, or the Keulegan-Carpenter number, KC. The parameter values have been shown to vary with vegetation type. In this paper, we modify the SWAN vegetation module to include a temporally varying CD. This allows the drag coefficient to vary with ambient wave parameters, which gives an improved prediction under time varying wave conditions (e.g. passage of a storm) and includes the change in wave conditions as they travel through the vegetation. We also incorporate spatially varying vegetation height into the model to further improve the representation of the complexity of vegetated shorelines. Using the new formulation we find improved prediction of wave dissipation over both idealized laboratory and field salt marsh vegetation.

The account of water activity in the calculation of the rate of food product shrinkage

Refrigiration treatment and storing of the food product involves its mass loss due to its drying. The loss of mass and quality of food products is determined by ambient temperature and moisture parameters and water activity of the product itself. The use of existing formulas for calculating heat and mass exchange processes of refrigeration treatment and storage of food product is limited, because they don’t lake into account water activity and its temperature dependence on this parameter. A formula has been obtained for calculating the rate of food product shrinkage, considering the hygrothermal and thermophysical properties of the product and the environment, as well as the conditions for heat and mass transfer. The technological parameter of "water activity", with the increase of which the rate of evaporation of moisture from the product surface increases linearly, has been account in this formula. For determining dependence of food product water activity on temperature range within negative meaning it is suggested to use an analogue of tissue moisture possessing properties of diluted molecular solution. A criterion adequacy behavior of tissue moisture of food product and its analogue may be the share of frozen water. As analogue of tissue juice of food products the water solution of ethyl alcohol with mass concentration of 0.025 and temperature of freezing beginning 1(C is taken. Satisfactory results of comparing calculated and experimental data for temperature range of (1…34)(C have been obtained, which corresponds to industrial modes of buck food products refrigeration processes. Within this temperature range the water activity of water solution of ethyl alcohol drops with the temperature lowering from 0.990 to 0.748, in average amounts to water activity decrease of 0.007 to each degree of temperature drop.

Multi-spectral Magnetic Particle Spectroscopy for the investigation of particle mixtures

Magnetic Particle Spectroscopy (MPS) records the non-linear response of magnetic nanoparticles (MNP) to large ac magnetic fields. It captures a harmonic spectrum for the characterization of MNP samples, especially in the context of Magnetic Particle Imaging (MPI). MPS is sensitive to minute variations in magnetization response, thus different particle types or batches are easily distinguished. Also, since the dynamic magnetization of the particles is driven by both the Néel and the Brownian relaxation mechanisms, the harmonic spectra in MPS scale with ambient parameters, such as temperature, viscosity or binding state of the particles. Previous studies mostly observed low-frequency harmonic ratios (e.g. 5f0/3f0) to distinguish particles or to obtain ambient parameters. Here, we propose a multi-spectral analysis technique, using the full available spectrum, to decompose the collective response of different particles from an integral measurement on an MNP sample. This work focuses on the description of the multi-spectral method and its application to quantify binary and ternary mixtures of different particles.