scholarly journals Atomization Control to Improve Soft Actuation Through Vaporization

2021 ◽  
Vol 8 ◽  
Author(s):  
Han-Joo Lee ◽  
Esteban Guerra-Bravo ◽  
Arturo Baltazar ◽  
Kenneth J. Loh
Keyword(s):  
Droplet Evaporation ◽  
Bulk Liquid ◽  
Droplet Growth ◽  
Vibration Modes ◽  
Heater Surface ◽  
Small Temperature ◽  
Atomization Process ◽  
Temperature Changes ◽  
Vaporization Process ◽  
Insight Into

Soft actuation through droplet evaporation has significantly improved the actuation speed of methods that utilize liquid vaporization. Instead of boiling bulk liquid, this method implements atomization to disperse small droplets into a heater. Due to the large surface area of the droplets, the liquid evaporates much faster even at small temperature changes. However, further analysis is required to maximize the performance of this complex multi-physics method. This study was conducted to provide further insight into the atomizer and how it affects actuation. Numerical simulations were used to inspect the vibration modes and determine how frequency and voltage affect the atomization process. These results were used to experimentally control the atomizer, and the droplet growth on the heater surface was analyzed to study the evaporation process. A cuboid structure was inflated with the actuator to demonstrate its performance. The results show that simply maximizing the atomization rate creates large droplets on the surface of the heater, which slows down the vaporization process. Thus, an optimal atomization rate should be determined for ideal performance.

scholarly journals ANALYSIS OF ANNUAL VARIATIONS IN GROUND TEMPERATURE AT AN OTTAWA SITE

1964 ◽  
Vol 1 (2) ◽  
pp. 146-157 ◽  
Author(s):  
L. W. Gold
Keyword(s):  
Gradual Increase ◽  
Ground Temperature ◽  
Small Temperature ◽  
Temperature Changes ◽  
Annual Variations ◽  
Periodic Fluctuations ◽  
A Site

Observations over a 5-year period at a site at Ottawa showed that the ground temperature had significant Fourier components with period [Formula: see text]and 2 years. The average annual ground temperature and amplitudes of the Fourier components of period 1 year and [Formula: see text] year underwent non-periodic fluctuations of almost 1 C degree at a depth of 10 cm. The amplitude of this fluctuation decreased with depth, and its maximum occurred later in time. There was evidence of a gradual increase in average annual ground temperature amounting to about 0.2 C degree over the 5-year period at the 610-cm depth. The significance of such small temperature changes in areas where the ground temperature is close to 0 °C is pointed out.

FaceBit

2021 ◽  
Vol 5 (4) ◽  
pp. 1-44
Author(s):  
Alexander Curtiss ◽  
Blaine Rothrock ◽  
Abu Bakar ◽  
Nivedita Arora ◽  
Jason Huang ◽  
...  
Keyword(s):  
Health Management ◽  
Face Mask ◽  
Temperature Changes ◽  
Battery Lifetime ◽  
Frontline Workers ◽  
Breathing Motion ◽  
Skin Contact ◽  
Passive Devices ◽  
Research Platform ◽  
Insight Into

The COVID-19 pandemic has dramatically increased the use of face masks across the world. Aside from physical distancing, they are among the most effective protection for healthcare workers and the general population. Face masks are passive devices, however, and cannot alert the user in case of improper fit or mask degradation. Additionally, face masks are optimally positioned to give unique insight into some personal health metrics. Recognizing this limitation and opportunity, we present FaceBit: an open-source research platform for smart face mask applications. FaceBit's design was informed by needfinding studies with a cohort of health professionals. Small and easily secured into any face mask, FaceBit is accompanied by a mobile application that provides a user interface and facilitates research. It monitors heart rate without skin contact via ballistocardiography, respiration rate via temperature changes, and mask-fit and wear time from pressure signals, all on-device with an energy-efficient runtime system. FaceBit can harvest energy from breathing, motion, or sunlight to supplement its tiny primary cell battery that alone delivers a battery lifetime of 11 days or more. FaceBit empowers the mobile computing community to jumpstart research in smart face mask sensing and inference, and provides a sustainable, convenient form factor for health management, applicable to COVID-19 frontline workers and beyond.

Small temperature changes matter

2018 ◽  
Vol 1 (4) ◽  
pp. 235-235
Author(s):  
Jan-Stefan Völler
Keyword(s):  
Small Temperature ◽  
Temperature Changes

Modal Analysis of a Utility Bicycle From the Perspective of Riding Comfort

2019 ◽  
Author(s):  
Alberto Doria ◽  
Edoardo Marconi ◽  
Pierluca Cialoni
Keyword(s):  
Modal Testing ◽  
Vibration Modes ◽  
Response Functions ◽  
The Road ◽  
Power Spectral ◽  
Vehicle Structure ◽  
Power Spectral Densities ◽  
On The Road ◽  
The Relationship ◽  
Insight Into

Abstract The correlation between the modal properties and the comfort characteristics of a utility, step-through frame bicycle are investigated. In-plane modal testing of the vehicle is carried out both without and with the rider, and the major differences between the results obtained with the two conditions are highlighted. In order to have an insight into the contribution of the various bicycle components to the transmission of vibrations, the frequency response functions (FRFs) between the main interface points in the vehicle structure are measured and studied. Finally, the modal characteristics are compared with road tests data, emphasizing the relationship between the in-plane vibration modes and the main peaks in the acceleration power spectral densities (PSDs) measured on the road.

Low-Velocity Subcooled Nucleate Flow Boiling at Various Orientations

1995 ◽  
Vol 117 (2) ◽  
pp. 380-386 ◽  
Author(s):  
K. M. Kirk ◽  
H. Merte ◽  
R. Keller
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Liquid Velocity ◽  
Flow Boiling ◽  
Copper Substrate ◽  
Nucleate Boiling ◽  
Bulk Liquid ◽  
Heater Surface ◽  
Low Velocity ◽  
Buoyant Force

Subcooled forced convection nucleate boiling experiments with R-113 were conducted at low velocities using both thin film semitransparent gold-on-quartz and gold-coated copper substrate flat heaters at various orientations. The experiments demonstrate that if buoyancy is significant relative to bulk liquid momentum, then a decrease in the buoyant force normal to and away from the heater surface enhances the heat transfer, with the effect being greatest at low values of heat flux. Furthermore, the effect of the bulk liquid velocity is shown to be dependent on the surface orientation.

scholarly journals Active Coacervate Droplets Are Protocells That Grow and Resist Ostwald Ripening

2021 ◽  
Author(s):  
Karina K. Nakashima ◽  
Merlijn H. I. van Haren ◽  
Alain A. M. André ◽  
Irina Robu ◽  
Evan Spruijt
Keyword(s):  
Electrostatic Interactions ◽  
Protein Concentration ◽  
Ostwald Ripening ◽  
Population Level ◽  
Cellular Growth ◽  
Droplet Growth ◽  
Experimental Conditions ◽  
Active Processes ◽  
Cellular Behaviour ◽  
Insight Into

Active coacervate droplets are liquid condensates coupled to a chemical reaction that turns over their components, keeping the droplets out of equilibrium. This turnover can be used to drive active processes such as growth, and provide an insight into the chemical requirements underlying (proto)cellular behaviour. Moreover, controlled growth is a key requirement to achieve population fitness and survival. Here we present a minimal, nucleotide-based coacervate model for active droplets, and report three key findings that make these droplets into evolvable protocells. First, we show that coacervate droplets form and grow by the fuel-driven synthesis of new coacervate material. Second, we find that these droplets do not undergo Ostwald ripening, which we attribute to the attractive electrostatic interactions within complex coacervates, active or passive. Finally, we show that the droplet growth rate reflects experimental conditions such as substrate, enzyme and protein concentration, and that a different droplet composition (addition of RNA) leads to altered growth rates and droplet fitness. These findings together make active coacervate droplets a powerful platform to mimic cellular growth at a single-droplet level, and to study fitness at a population level.<br>

Modification des pressions intracristallines et intergranulaires des roches soumises aux variations de temperature

1961 ◽  
Vol S7-III (4) ◽  
pp. 338-344 ◽  
Author(s):  
Georges Deicha
Keyword(s):  
Small Temperature ◽  
Temperature Changes ◽  
History Of ◽  
Proper Perspective ◽  
Proper Interpretation ◽  
Tectonic Movements ◽  
Natural Means

Abstract Effects of variations of temperature on intracrystalline and intergranular pressures in rocks are reviewed, with particular stress on the importance of maintaining the several factors involved in proper perspective, in order that sequence of changes in a rock during its history may not be misconstrued and that undue importance is not assigned to a given factor merely because it has been investigated in detail while others have been investigated inadequately. Distinguishing between liquid and gaseous inclusions of mineralogic versus metallogenic periods is especially difficult. Proper interpretation of inclusions ruptured by natural means must be supplemented by painstaking care to recognize the ruptures resulting from artificial means such as those produced in preparation of petrographic specimens, blows of the geologic hammer , and during transportation of samples. Liquid CO&lt;2) and other inclusions have been known to rupture from small temperature changes. Water in inclusions in mineral grains can influence the geochemical constitution of water imprisoned in the sediments at time of deposition. Tectonic movements may rupture inclusions, and thereby influence the geophysical history of rocks.

On the Vibration of a Nearly Cyclic System

1996 ◽  
Vol 210 (3) ◽  
pp. 267-275
Author(s):  
G F Wu ◽  
X J Liu
Keyword(s):  
Weak Coupling ◽  
Solution Method ◽  
Structural Model ◽  
Normal Modes ◽  
Vibration Modes ◽  
Effective Solution ◽  
Physical Insight ◽  
New Perspective ◽  
Component Assembly ◽  
Insight Into

In this paper, the vibration modes of the structural model of a nearly cyclic multiply mono-coupled multi-degree-of-freedom (multi-DOF) component assembly are examined. The attention is focused on the mode similarity phenomenon among the vibration deformation shapes of all the components for the disordered assemblies with relatively weak coupling. By means of this particular characteristic of the normal modes of such a system, an effective solution method based on the analysis of a single component system is developed, which can be used to find any specified structural frequency within any given frequency band and its corresponding mode of the system directly. This solution scheme, in a new perspective, provides a direct physical insight into the relation between the imperfection effects and the various structural and imperfection parameters. Numerical examples are given at the end.

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