scholarly journals Natural Materials for Thermal Insulation: Mulch and Lava-Rock Characterizations

2014 ◽  
Vol 705 ◽  
pp. 8-13
Author(s):  
Aurélien P. Jean ◽  
Craig Adams ◽  
Mario A. Medina ◽  
Frédéric Miranville
Keyword(s):  
Thermal Conductivity ◽  
Statistical Data ◽  
Thermal Characterization ◽  
Temperature Sensors ◽  
The Other ◽  
Natural Materials ◽  
Data Manipulation ◽  
Heating Source ◽  
Building Insulation ◽  
Wall System

This paper reports on the thermal characterization, via the thermal conductivity, of natural materials, such as mulch and lava rock and their usefulness as building insulation. Experiments were carried out using a scale one monitored wall (i.e. heat flux and temperature sensors) exposed to a heating source on one side and to an air conditioned space on the other. The wall system was composed of an 8.85 cm thick cavity, where the mulch and lava rock were placed. The cavity was enclosed between two layers of pine wood (40 mm thick each). After the experiments and statistical data manipulation, the estimated thermal conductivity of the materials were 0.48 ± 0.001 W.m-1.K-1 and 0.129 ± 0.003 W.m-1.K-1 for mulch and lava-rock, respectively. That is, mulch has a thermal conductivity comparable to that of bulk hemp while lava rock has a thermal conductivity comparable to that of hemp brick. These values indicate the usefulness of mulch, compared to the impracticality of using lava-rocks materials for building insulation.

Methods of Increasing Thermal Conductivity of Plasma Sprayed Tungsten-Based Coatings

2008 ◽  
Vol 59 ◽  
pp. 82-86 ◽  
Author(s):  
Jiří Matějíček ◽  
Karol Iždinský ◽  
Petr Vondrouš
Keyword(s):  
Thermal Conductivity ◽  
Thermal Characterization ◽  
High Heat ◽  
Molten Copper ◽  
Point Of View ◽  
The Other ◽  
High Heat Flux ◽  
Plasma Facing Components ◽  
Graded Layers ◽  
Plasma Sprayed

Tungsten is the main candidate material for the armor of plasma facing components for ITER and future fusion devices [1]. Plasma spraying is an alternative method for manufacturing tungsten-based coatings, including composites and graded layers, having a number of advantageous features [2]. On the other hand, the main limitation to application of these coatings on high heat flux components, is their low thermal conductivity, originating in the layered structure [3]. This paper is focused on four methods of improving the coatings’ thermal conductivity. First method consists in modification of the basic spraying parameters, which have a direct influence on the coating structure and therefore properties. The other three methods involve post-processing of the coatings: molten copper infiltration, laser remelting and densification by HIPping. The latter encompasses also tungsten-copper composites of various compositions. Experimental results, including structural and thermal characterization, are presented for each method. Finally, the applicability of these methods, from the point of view of manufacturing the plasma facing components, is discussed.

Maximizing Heat Transfer Through Joint Fin Systems

2005 ◽  
Vol 128 (2) ◽  
pp. 203-206 ◽  
Author(s):  
A.-R. A. Khaled
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Performance ◽  
Critical Length ◽  
The Other ◽  
Rigid Fixation ◽  
Convection Coefficient ◽  
Heat Transfer Characteristics ◽  
Cold Side ◽  
Transfer Characteristics

Heat transfer through joint fins is modeled and analyzed analytically in this work. The terminology “joint fin systems” is used to refer to extending surfaces that are exposed to two different convective media from its both ends. It is found that heat transfer through joint fins is maximized at certain critical lengths of each portion (the receiver fin portion which faces the hot side and the sender fin portion that faces the cold side of the convective media). The critical length of each portion of joint fins is increased as the convection coefficient of the other fin portion increases. At a certain value of the thermal conductivity of the sender fin portion, the critical length for the receiver fin portion may be reduced while heat transfer is maximized. This value depends on the convection coefficient for both fin portions. Thermal performance of joint fins is increased as both thermal conductivity of the sender fin portion or its convection coefficient increases. This work shows that the design of machine components such as bolts, screws, and others can be improved to achieve favorable heat transfer characteristics in addition to its main functions such as rigid fixation properties.

scholarly journals Apparatus for routine measurements of the thermal conductivity of ice cores

1999 ◽  
Vol 29 ◽  
pp. 151-154 ◽  
Author(s):  
Crescenzo Festa ◽  
Aristide Rossi
Keyword(s):  
Thermal Conductivity ◽  
Ice Cores ◽  
Maximum Temperature ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Standard Samples ◽  
Experimental Conditions ◽  
Heating Source ◽  
Central Segment ◽  
Wire Method

AbstractAn apparatus is described for measuring the thermal conductivity of ice by the transient hot-wire method. Thermal conductivity A, is determined by tracking the thermal pulse induced in the sample by a heating source consisting of a platinum resistor. A central segment of the same platinum heating resistor acts also as a thermal sensor. A heat pulse transferred to the ice for a period of 40s gives a maximum temperature increment of about 7-14°C. In good experimental conditions, the expected reproducibility of the measurements is within ±3%. The accuracy of the method depends on whether the instrument has been calibrated by reliable standard samples, certified by absolute methods.

scholarly journals Thermal Characterization of Recycled Materials for Building Insulation

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3564
Author(s):  
Arnas Majumder ◽  
Laura Canale ◽  
Costantino Carlo Mastino ◽  
Antonio Pacitto ◽  
Andrea Frattolillo ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Environmental Sustainability ◽  
Building Materials ◽  
Raw Materials ◽  
Natural Fibers ◽  
Thermal Characterization ◽  
Recycled Materials ◽  
Building Insulation ◽  
Operational Phase

The building sector is known to have a significant environmental impact, considering that it is the largest contributor to global greenhouse gas emissions of around 36% and is also responsible for about 40% of global energy consumption. Of this, about 50% takes place during the building operational phase, while around 10–20% is consumed in materials manufacturing, transport and building construction, maintenance, and demolition. Increasing the necessity of reducing the environmental impact of buildings has led to enhancing not only the thermal performances of building materials, but also the environmental sustainability of their production chains and waste prevention. As a consequence, novel thermo-insulating building materials or products have been developed by using both locally produced natural and waste/recycled materials that are able to provide good thermal performances while also having a lower environmental impact. In this context, the aim of this work is to provide a detailed analysis for the thermal characterization of recycled materials for building insulation. To this end, the thermal behavior of different materials representing industrial residual or wastes collected or recycled using Sardinian zero-km locally available raw materials was investigated, namely: (1) plasters with recycled materials; (2) plasters with natural fibers; and (3) building insulation materials with natural fibers. Results indicate that the investigated materials were able to improve not only the energy performances but also the environmental comfort in both new and in existing buildings. In particular, plasters and mortars with recycled materials and with natural fibers showed, respectively, values of thermal conductivity (at 20 °C) lower than 0.475 and 0.272 W/(m⋅K), while that of building materials with natural fibers was always lower than 0.162 W/(m⋅K) with lower values for compounds with recycled materials (0.107 W/(m⋅K)). Further developments are underway to analyze the mechanical properties of these materials.

Evaluation of Thermal Characterization Techniques and Tools for Thermal Conductivity Measurement of Sub 100 Angstrom Thick Silicon Layers

2007 ◽  
Author(s):  
Keivan Etessam-Yazdani ◽  
Mehdi Asheghi
Keyword(s):  
Thermal Conductivity ◽  
Conductivity Measurement ◽  
Thermal Characterization ◽  
Phonon Transport ◽  
Thermal Conductivity Measurement ◽  
Great Success ◽  
Silicon Structures ◽  
Thin Silicon ◽  
20 Nm

Experimental measurement of thermal conductivity is considered the most reliable tool for the study of phonon transport in ultra-thin silicon structures. While there has been a great success in thermal conductivity measurement of ultra-thin silicon layers down to 20 nm over the past decade, it is not clear if the existing techniques and tools can be extended to the measurements of sun 100 Angstrom layers. In this paper, an analytical study of the feasibility of electrical Joule heating and thermometry in patterned metal bridges is presented. It is concluded that thermal conductivity of silicon layers as thin as 5 nm can be obtained (uncertainty 20%) by performing steady-state measurements using an on-substrate nanoheater structure. The thermal characterization of silicon layers as thin as 1 nm may be possible using frequency domain measurements.

scholarly journals Sędziowski wymiar kary za przestępstwa zagrożone identycznymi sankcjami w świetle danych statystycznych

2019 ◽  
Vol 28 (4) ◽  
pp. 101
Author(s):  
Aneta Michalska-Warias
Keyword(s):  
Detailed Analysis ◽  
Statistical Data ◽  
Criminal Code ◽  
The Other ◽  
Sexual Freedom ◽  
Group Iii ◽  
Group I ◽  
Initial Hypothesis ◽  
Group Ii

<p>The article is devoted to the analysis of court punishment practice in the case of offences which have the same statutory punishment. Three groups of such offences are selected: offences punished with imprisonment from 2 to 12 years (group I), offences punished with imprisonment from 3 months to 5 years (group II) and offences punished with imprisonment from 1 month to 3 years (group III). Most of the analysed offences belonged to the group of offences against freedom (including sexual freedom) and the other chosen offences were against other socially cherished values were those quite popular in practice (therefore, the statistical data in their cases are quite representative). The analysed year was 2016. The starting hypothesis was that offences which have identical punishments in the Criminal Code (which means that the lawmaker perceives them as socially harmful in a similar way) will not be treated in such a similar way in practice and in all groups there would be offences which would be punished with visibly more severe and lighter punishments. Detailed analysis of statistical data referring to punishments imposed for the discussed offences confirmed the initial hypothesis, showing also the already known fact that courts tend to impose punishments which are closer to the minimum than to the maximum provided by the lawmaker.</p>

scholarly journals Extraction of Key Motifs as a Preview from 2017 Nobel Prize Winning Novel, ‘Never Let Me Go’

2021 ◽  
Vol 7 (2) ◽  
pp. 83-98
Author(s):  
Zafar Ullah ◽  
Muhammad Uzair ◽  
Arshad Mehmood
Keyword(s):  
Knowledge Discovery ◽  
Mixed Method ◽  
Statistical Data ◽  
The Other ◽  
Human Cognition ◽  
The Novel ◽  
Learning Tools ◽  
Indelible Mark ◽  
Word Cloud ◽  
Word Clouds

Word clouds manifest interactive visuals along with their statistical data. Thus knowledge discovery and aesthetic data visualization interlink to produce interactive word cloud which is an interesting, textual, statistical and visual data. This study aims to generate interactive word cloud—Cirrus—on the basis of statistical data to preview text of the novel for readers. So cirrus tool is selected from Voyant open access tools to produce interactive statistical word cloud. Then the generated word cloud and statistical data are analyzed with mixed method and its analysis draws insight from Rakesh Aggrawal’s Knowledge Discovery Theory which seeks innovative and interesting knowledge patterns. This thematic word cloud verifies already known themes and discovers innovative interesting themes. Current study reveals that all mentioned key themes can be easily extracted from a voluminous novel with the help of Cirrus tool. Key motifs have been presented in the word cloud for the readers. On the other hand, unwritten themes can’t be extracted through machine learning tools, rather it is the task of human cognition. Primarily, this novel based study reveals names of chief characters, for instance “Tommy (496),” “Ruth (455)” and “I (Kathy) (355).” Furthermore, motifs of nostalgic memories with word “remember (143),” “thought (126)” about “Hailsham (203),” “carer (74),” “sex (80),” sex “lectures (8)” have been discovered as a preview. Previewing technique prepares reader’s mind and gives an epigrammatic digital view of the text. The visual themes as knowledgeable word cloud leave an indelible mark on the slate of memory.

Ultrastructural features of the sensori-motor cortex of the primate

1979 ◽  
Vol 285 (1006) ◽  
pp. 123-139 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Motor Cortex ◽  
Thin Layer ◽  
Liquid Helium ◽  
Thermal Insulation ◽  
Solid Surfaces ◽  
The Other ◽  
Experimental Chamber ◽  
Short Discussion ◽  
Inside Wall

cooled to 2°K or lower. Rollin (1936) found that the thermal insulation of vessels containing liquid helium was much worse below than above the A point. He explained his observation by assuming the existence of a thin layer of liquid helium on the inside wall of the connecting tube, and thought it probable that the change in thermal conductivity of this film at the A point gave rise to the anomalous effects observed. As the result of more recent (unpublished) experiments Rollin and Simon* have put forward the other explanation that the film creeps up the tube and evaporates eventually. It is obvious that all these phenomena may have a common explanation and it was the object of the experiments described in this paper and the following paper to investigate the behaviour of He 11 in contact with solid surfaces systematically. The phenomena had to be investigated from various aspects and this made experiments necessary which varied in purpose and character to some extent. For simplicity’s sake we will therefore give, together with the description of each experiment, a short discussion and summarize at the end of the second paper all results in a general discussion on the whole phenomenon. All experiments were carried out in the same cryostat; and for different experiments only the experimental chamber and the experimental arrangement in it were altered.

De rol van de burgemeester

Res Publica ◽  
1997 ◽  
Vol 39 (1) ◽  
pp. 27-44
Author(s):  
Johan Ackaert
Keyword(s):  
Role Models ◽  
Statistical Data ◽  
The Other ◽  
Community Life ◽  
Other Hand ◽  
Educational Degree ◽  
The One ◽  
Individual Service

This article confronts several theoretical role-models about mayor's behaviour with their own perception. For this purpose, the statistical data is drawn from a survey among Flemish mayors. Mayors perceive the ''father of the community" role as the most prevailing one. This perception is reflected in their timespending. More than 1/4 of their time is dedicated towards activities such as participation in the community life, individual service rendering to citizens and having individual contacts with them.The father of the community' role lives strongly among mayors with a lower educational degree and less among the higher educated ones. It is also more perceived among mayors being recent office-bolders, while the more experienced ones seem more to maintain a certain distance from this role. Moreover, mayors with a lower educational degree are recordholders in having individual contacts with citizens. Finally, no relation has been found between roleperception and timespending on the one hand and party background on the other hand.

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