A Novel Design of Water-Activated Variable Stiffness Endoscopic Manipulator with Safe Thermal Insulation

In natural orifice transluminal endoscopic surgery (NOTES), an ideal endoscope platform should be flexible and dexterous enough to go through the natural orifices to access the lesion site inside the human body, and meanwhile provide sufficient rigidity to serve as a base for the end-effectors to operate during the surgical tasks. However, the conventional endoscope has limited ability for maintaining high rigidity over the length of the body. This paper presents a novel design of a variable stiffness endoscopic manipulator. By using a new bioplastic named FORMcard, whose stiffness can be thermally adjusted, water at different temperatures is employed to switch the manipulator between rigid mode and flexible mode. A biocompatible microencapsulated phase change material (MEPCM) with latent heat storage properties is adopted as the thermal insulation for better safety. Experiments are conducted to test the concept design, and the validated advantages of our proposed variable stiffness endoscopic manipulator include: shorter mode activation time (25 s), significantly improved stiffness in rigid mode (547.9–926.3 N·cm2) and larger stiffness-adjusting ratio (23.9–25.1 times).

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Latent heat storage for hot beverages

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.13.3.2019.27.0453 ◽

2019 ◽

Vol 13 (3) ◽

pp. 5653-5664

Author(s):

M. S. M. Al-Jethelah ◽

H. S. Dheyab ◽

S. Khudhayer ◽

T. K. Ibrahim ◽

A. T. Al-Sammarraie

Keyword(s):

Latent Heat ◽

Food Industry ◽

Heat Storage ◽

Food Storage ◽

Thermal Engineering ◽

Engineering Applications ◽

Latent Heat Storage ◽

The Impact ◽

Encapsulated Phase Change Material ◽

Change Material

Latent heat storage has shown a great potential in many engineering applications. The utilization of latent heat storage has been extended from small scales to large scales of thermal engineering applications. In food industry, latent heat has been applied in food storage. Another potential application of latent heat storage is to maintain hot beverages at a reasonable drinking temperature for longer periods. In the present work, a numerical calculation was performed to investigate the impact of utilizing encapsulated phase change material PCM on the temperature of hot beverage. The PCM was encapsulated in rings inside the cup. The results showed that the encapsulated PCM reduced the coffee temperature to an acceptable temperature in shorter time. In addition, the PCM maintained the hot beverage temperature at an acceptable drinking temperature for rational time.

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Experimental Study on Thermal Characteristics of Finned Coil LHSU Using Paraffin as Phase Change Material

Journal of Heat Transfer ◽

10.1115/1.4035321 ◽

2017 ◽

Vol 139 (4) ◽

Cited By ~ 1

Author(s):

Guansheng Chen ◽

Nanshuo Li ◽

Huanhuan Xiang ◽

Fan Li

Keyword(s):

Heat Transfer ◽

Experimental Study ◽

Phase Change ◽

Phase Change Material ◽

Water Flow ◽

Water Flow Rate ◽

Thermal Characteristics ◽

Heat Transfer Fluid ◽

Latent Heat Storage ◽

Change Material

It is well known that attaching fins on the tubes surfaces can enhance the heat transfer into and out from the phase change materials (PCMs). This paper presents the results of an experimental study on the thermal characteristics of finned coil latent heat storage unit (LHSU) using paraffin as the phase change material (PCM). The paraffin LHSU is a rectangular cube consists of continuous horizontal multibended tubes attached vertical fins at the pitches of 2.5, 5.0, and 7.5 mm that creates the heat transfer surface. The shell side along with the space around the tubes and fins is filled with the material RT54 allocated to store energy of water, which flows inside the tubes as heat transfer fluid (HTF). The measurement is carried out under four different water flow rates: 1.01, 1.30, 1.50, and 1.70 L/min in the charging and discharging process, respectively. The temperature of paraffin and water, charging and discharging wattage, and heat transfer coefficient are plotted in relation to the working time and water flow rate.

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The Respiration of some Planktonic copepods II. The Effect Of Temperature

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400011607 ◽

1953 ◽

Vol 31 (3) ◽

pp. 447-460 ◽

Cited By ~ 28

Author(s):

D. T. Gauld ◽

J. E. G. Raymont

Keyword(s):

Respiratory Rate ◽

The Body ◽

The Other ◽

Effect Of Temperature ◽

Acartia Clausi ◽

Temora Longicornis ◽

Different Temperatures ◽

Planktonic Copepods ◽

The Difference ◽

The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

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Experimental Characterization of Phase Change Materials for Refrigeration Processes

Energies ◽

10.3390/en14113033 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3033

Author(s):

Anastasia Stamatiou ◽

Lukas Müller ◽

Roger Zimmermann ◽

Jamie Hillis ◽

David Oliver ◽

...

Keyword(s):

Energy Density ◽

Phase Change ◽

Thermophysical Properties ◽

Phase Change Materials ◽

Cost Effective ◽

Latent Heat Storage ◽

Lower Energy Density ◽

Change Material ◽

Storage Units

Latent heat storage units for refrigeration processes are promising as alternatives to water/glycol-based storage due to their significantly higher energy densities, which would lead to more compact and potentially more cost-effective storages. In this study, important thermophysical properties of five phase change material (PCM) candidates are determined in the temperature range between −22 and −35 °C and their compatibility with relevant metals and polymers is investigated. The goal is to complement existing scattered information in literature and to apply a consistent testing methodology to all PCMs, to enable a more reliable comparison between them. More specifically, the enthalpy of fusion, melting point, density, compatibility with aluminum, copper, polyethylene (PE), polypropylene (PP), neoprene and butyl rubber, are experimentally determined for 1-heptanol, n-decane, propionic acid, NaCl/water mixtures, and Al(NO3)3/water mixtures. The results of the investigations reveal individual strengths and weaknesses of the five candidates. Further, 23.3 wt.% NaCl in water stands out for its very high volumetric energy density and n-decane follows with a lower energy density but better compatibility with surrounding materials and supercooling performance. The importance of using consistent methodologies to determine thermophysical properties when the goal is to compare PCM performance is highlighted.

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ON THE SURVIVAL AND METABOLISM OF NORMAL AND HYPOTHERMIC PRE-VIABLE HUMAN FOETUSES

Journal of Endocrinology ◽

10.1677/joe.0.0230069 ◽

1961 ◽

Vol 23 (1) ◽

pp. 69-77 ◽

Cited By ~ 2

Author(s):

S. KULLANDER ◽

B. SUNDÉN

Keyword(s):

Body Temperature ◽

Survival Time ◽

Glycogen Content ◽

Adrenal Glands ◽

Early Stage ◽

The Body ◽

Protein Nitrogen ◽

Different Temperatures ◽

Human Foetuses ◽

General Reduction

SUMMARY A total of twenty-three human pre-viable foetuses (7–400 g.) were removed by abdominal hysterotomy (legal abortions) and studied during survival in an anoxic state at different temperatures. The duration of survival, as judged by ECG waves, at 37° c was about 3 hr.; it was longer for female foetuses than for males, and longer for large foetuses than for small ones. General reduction of the body-temperature to 4° c during periods varying between 30 min. and 6 hr. with subsequent rewarming to and maintenance at 37° c increased the survival time by a further 1–2 hr. The blood sugar did not decrease either during the period of survival or during hypothermia, but the non-protein nitrogen increased, while acidosis and hyperkalaemia developed. The glycogen content of the liver decreased during the anoxic period of survival and diminished further during hypothermia. The adrenal glands produced adrenaline in addition to noradrenaline during the anoxic phase, and this may occur in a very early stage of intrauterine life.

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