scholarly journals Effect of wall orientation of the sand concrete lightened by wood shavings on the time lag and the decrement factor

2020 ◽  
Vol 330 ◽  
pp. 01013
Author(s):  
Belkacem Belhadj ◽  
Adeline Goullieux ◽  
Madani Bederina ◽  
Michèle Quéneudec
Keyword(s):  
Thermal Properties ◽  
Thermophysical Properties ◽  
Lightweight Concrete ◽  
Time Lag ◽  
Arid Environment ◽  
Orientation Effect ◽  
Optimal Composition ◽  
The North ◽  
Wood Shavings ◽  
Local Materials

The development of new lightweight concrete based on the valorization of local materials and waste in construction is an environmental and sustainable approach. In this context, the studied composite is a sand concrete (dune and alluvial) lightened by wood shavings to improve its thermophysical properties. The objective is to investigate the orientation effect of an outside wall made with this material in an arid environment on the thermophysical properties of the wall, namely the time lag (Φ) and the decrement factor (f). The experimental study has been dedicated, first of all, to determine the optimal composition of sand concrete lightened by wood shavings, which the content is 60 kg/m3. This composition is a compromise between studied compactness and workability. Then, to study the thermal properties of the sand concrete without wood shavings (SC-W-WS) and sand concrete lightened by wood shavings (SC-WS). Finally, a numerical simulation using the EnergyPlus software was made to study the wall orientation effect designed in the Laghouat city (south of Algeria). The results obtained show that the substitution of sand by wood shavings has improved thermal properties of the wood sand concrete namely: the thermal conductivity, the specific heat and the thermal diffusivity. The simulation results are very interesting, because all orientations are right for the sand concrete lightened by wood shavings (SC-WS). Nevertheless, the north and the west orientations are wrong in the case of the sand concrete (SC-W-WS). However, the east orientation has the longest time lag, which is consistent with the literature. The advantage of these results is in favour of concrete having improved thermophysical properties.

scholarly journals Thermal Performance of Structural Lightweight Concrete Composites for Potential Energy Saving

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 461
Author(s):  
Yeong Huei Lee ◽  
Nicholas Chua ◽  
Mugahed Amran ◽  
Yee Yong Lee ◽  
Ahmad Beng Hong Kueh ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Thermal Properties ◽  
Thermal Performance ◽  
Energy Analysis ◽  
Lightweight Concrete ◽  
Time Lag ◽  
Building Envelope ◽  
Industrial Wastes ◽  
Conventional Concrete ◽  
Human Comfort

Residential consumption dominates the energy expenditure of heating and cooling systems, especially in tropical climates where building envelopes play an important role in energy efficiency. The thermal properties of concrete that are commonly employed as the building envelope material affect directly human comfort in a building. In addressing both the concrete thermal performance and industrial waste issues, this paper experimentally studies the concrete compressive strength and thermal properties used later for comparative energy analysis for human comfort. Four design mixes and a conventional concrete as control specimen are considered utilizing industrial wastes; palm oil fly ash (POFA), lightweight expanded clay aggregate (LECA), oil palm shell (OPS), and quarry dust, as constituents. These mixes are cast for cube compressive strength (to ensure the achievement of structural concrete requirement) and small-scaled wall tests. The measurement of surface temperatures of scaled wall tests is conducted in a polystyrene box to determine the concrete time lag and decrement factor. It is found that the density of concrete governs the compressive strength and that air pockets in the concrete matrix play an essential role as far as the thermal properties are concerned. From the energy analysis, structural lightweight concrete may save approximately 50% of the residential energy consumption.

Pemilihan Tipe Bangunan Pelindung Pantai di Desa Sikeli Berbasis Bahan Lokal

2020 ◽  
Vol 24 (1) ◽  
pp. 100-105
Author(s):  
Herawati Herawati ◽  
Muhammad Arsyad Thaha ◽  
Chairul Paotonan
Keyword(s):  
Analytical Hierarchy Process ◽  
Movement Pattern ◽  
Terrestrial Ecosystems ◽  
Coastal Protection ◽  
The North ◽  
Sea Wall ◽  
Hierarchy Process ◽  
Local Materials ◽  
Current Movement ◽  
Process Method

Abstrak Wilayah pesisir merupakan pertemuan antara wilayah laut dan wilayah darat, dimana daerah ini merupakan daerah interaksi antara ekosistem darat dan ekosistem laut yang sangat dinamis dan saling mempengaruhi. Tujuan penelitian ini adalah untuk menentukan material lokal yang potensial dapat digunakan sebagai bahan bangunan pelindung pantai dan memilih tipe bangunan pelindung pantai yang sesuai kondisi hidro-oseanografi di lokasi studi dengan metode Analythic Hierarchy Process. Lokasi penelitian berada di Provinsi Sulawesi Tenggara, tepatnya di Pulau Kabaena, Kecamatan Kabaena Barat Desa Sikeli kabupaten Bombana. Pulau Kabaena memiliki luas 873 km2. Secara geografis terletak antara 4°22’ 59,4” - 5°28’ 26,7” Lintang Selatan serta antara 121°27’46,7”-122°09’,4” Bujur Timur. Hasil penelitian menunjukkan perairan disepanjang tanjung perak sangat mempengaruhi hidro-oseonografi disekitar pantai desa Sikeli. Kondisi ini berpengaruh terhadap pola pergerakan arus dan tinggi gelombang datang disekitar pantai desa Sikeli. Tinggi gelombang rata-rata yang paling besar merambat dari arah barat sebesar 0.49 m dengan presentase kajadian sebesar 32.42 %, disusul arah barat laut sebesar 0.39 m (20.56 %), arah tenggara sebesar 0.31 m (8.72 %) arah barat daya sebesar 0.31 m (7.99 %), arah utara sebesar 0.20 m (6.94 %), arah timur sebesar 0.15 m (11.81 %), arah selatan sebesar 0.12 m (3.42 %), dan arah timur laut sebesar 0.11 m (8.15 %). Pengambilan keputusan untuk memilih tipe bangunan pelindung pantai dengan metode AHP (Analytical Hierarchy Process) untuk penanganan abrasi pesisir pantai desa Sikeli berbasis bahan lokal diperoleh bahwa alternatif bangunan dengan nilai keterpilihan yang tertinggi adalah detached breakwater (0,4432) disusul groin (0,2479), sea-wall (0,1700) dan revetment (0.1389). Detached breakwater berfungsi untuk menahan laju sedimen kearah laut, mengurangi ketinggian dan meredam energi gelombang dan tidak dibangun sepanjang garis pantai yang akan dilindungi sehingga kapal nelayan dapat ditambat dipesisir pantai dengan aman. Abstract The Selection Type of Coastal Protection Structures in Sikeli Village Based on Local Materials. The coastal area is a meeting point between the sea and land areas, where this area is an area of interaction between terrestrial ecosystems and marine ecosystems which are very dynamic and influence each other. The purpose of this research is to determine local materials that can be used as coastal protection materials and to select the type of coastal protection that is suitable for the hydro-oceanographic conditions in the study location using the Analythic Hierarchy Process method. The research location is in Southeast Sulawesi Province, precisely on Kabaena Island, Kabaena Barat District, Sikeli Village, Bombana Regency. Kabaena Island has an area of 873 km2. Geographically it is located between 4° 22' 59.4"- 5° 28' 26.7" South Latitude and between 121° 27' 46.7 "-122° 09' 4" Longitude East. The results showed that the waters along Tanjung Perak greatly affect the hydro-oseonography around the coast of Sikeli village. This condition affects the current movement pattern and the height of the incoming waves around the coast of Sikeli village. The largest average wave height propagating from the west is 0.49 m with a kajadian percentage of 32.42%, followed by the northwest direction of 0.39 m (20.56%), southeast direction of 0.31 m (8.72%) to the southwest of 0.31 m (7.99%), to the north of 0.20 m (6.94%), to the east of 0.15 m (11.81%), to the south of 0.12 m (3.42%), and to the northeast of 0.11 m (8.15%). The decision to choose the type of coastal protection using the AHP (Analytical Hierarchy Process) method for the coastal abrasion management model in Sikeli village based on local materials was obtained that the alternative building with the highest electability value was the detached breakwater (0.4432) followed by groins (0.2479), sea-wall (0.1700) and revetment (0.1389). The detached breakwater model which functions to restrain the sediment rate towards the sea, reduce the height and reduce wave energy and is not built along the coastline which will be protected so that fishing boats can be moored to the coast safely.

scholarly journals Climatic Zone and Soil Properties Determine the Biodiversity of the Soil Bacterial Communities Associated to Native Plants from Desert Areas of North-Central Algeria

2021 ◽  
Vol 9 (7) ◽  
pp. 1359
Author(s):  
Elisa Bona ◽  
Nadia Massa ◽  
Omrane Toumatia ◽  
Giorgia Novello ◽  
Patrizia Cesaro ◽  
...  
Keyword(s):  
Soil Properties ◽  
Bacterial Communities ◽  
Arid Environment ◽  
Climatic Zone ◽  
Indigenous Plants ◽  
North Central ◽  
The North ◽  
Desert Areas ◽  
Plant Microbiota ◽  
Semi Arid

Algeria is the largest country in Africa characterized by semi-arid and arid sites, located in the North, and hypersaline zones in the center and South of the country. Several autochthonous plants are well known as medicinal plants, having in common tolerance to aridity, drought and salinity. In their natural environment, they live with a great amount of microbial species that altogether are indicated as plant microbiota, while the plants are now viewed as a “holobiont”. In this work, the microbiota of the soil associated to the roots of fourteen economically relevant autochthonous plants from Algeria have been characterized by an innovative metagenomic approach with a dual purpose: (i) to deepen the knowledge of the arid and semi-arid environment and (ii) to characterize the composition of bacterial communities associated with indigenous plants with a strong economic/commercial interest, in order to make possible the improvement of their cultivation. The results presented in this work highlighted specific signatures which are mainly determined by climatic zone and soil properties more than by the plant species.

scholarly journals Influence of Lightweight Aggregate Concrete Materials on Building Energy Performance

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 94
Author(s):  
Tara L. Cavalline ◽  
Jorge Gallegos ◽  
Reid W. Castrodale ◽  
Charles Freeman ◽  
Jerry Liner ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Building Materials ◽  
Energy Savings ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Building Energy ◽  
Energy Performance ◽  
Energy Simulation ◽  
Building Energy Simulation ◽  
Building Energy Performance

Due to their porous nature, lightweight aggregates have been shown to exhibit thermal properties that are advantageous when used in building materials such as lightweight concrete, grout, mortar, and concrete masonry units. Limited data exist on the thermal properties of materials that incorporate lightweight aggregate where the pore system has not been altered, and very few studies have been performed to quantify the building energy performance of structures constructed using lightweight building materials in commonly utilized structural and building envelope components. In this study, several lightweight concrete and masonry building materials were tested to determine the thermal properties of the bulk materials, providing more accurate inputs to building energy simulation than have previously been used. These properties were used in EnergyPlus building energy simulation models for several types of commercial structures for which materials containing lightweight aggregates are an alternative commonly considered for economic and aesthetic reasons. In a simple model, use of sand lightweight concrete resulted in prediction of 15–17% heating energy savings and 10% cooling energy savings, while use of all lightweight concrete resulted in prediction of approximately 35–40% heating energy savings and 30% cooling energy savings. In more complex EnergyPlus reference models, results indicated superior thermal performance of lightweight aggregate building materials in 48 of 50 building energy simulations. Predicted energy savings for the five models ranged from 0.2% to 6.4%.

scholarly journals Carbon-14 in the Southern Indian Ocean

Radiocarbon ◽  
1980 ◽  
Vol 22 (3) ◽  
pp. 684-692 ◽  
Author(s):  
Georgette Delibrias
Keyword(s):  
Surface Water ◽  
Indian Ocean ◽  
Water Samples ◽  
Sea Water ◽  
Time Lag ◽  
Vertical Profiles ◽  
Carbon 14 ◽  
Middle Latitudes ◽  
The North ◽  
The Indian Ocean

14C measurements were carried out on sea water samples collected in 1973, in the Indian ocean. The results obtained for 9 vertical profiles between 27° S and 48°S are presented. In surface water, the bomb 14C content is maximum at middle latitudes. A time lag relative to the north hemisphere bomb 14C delivery is apparent. In the more southern latitudes, 14C content remains very low.

Thermal Properties Evaluation of Thin Films, Wafers And Substrates

1990 ◽  
Vol 203 ◽  
Author(s):  
R.P. Tye ◽  
A. Maesono
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Steady State ◽  
Thermal Performance ◽  
Thermophysical Properties ◽  
Emerging Technologies ◽  
Layered Structures ◽  
Current Transient ◽  
Performance Characteristics ◽  
Transient And Steady State

ABSTRACTMaterials in use or under consideration for many applications in new and emerging technologies are often available only in small quantities and many times in the form of thin films, wafers and sheets. Such size and form limitations present a number of challenges to those wishing to evaluate thermal performance characteristics. This has resulted in a need to develop totally new transient or modify current transient and steady state techniques significantly. Various new or modified techniques to measure thermophysical properties are described. Illustrations of, applications to and results on semiconductors, superconductors, diamonds, polymers, composites and layered structures will be discussed.

scholarly journals The Analysis of Properties of Thermal Sensitive Elements in Measuring Devices for Thermal Properties of Materials

2021 ◽  
Vol 27 (3) ◽  
pp. 461-467
Author(s):  
A. D. Loskutova ◽  
A. P. Korolev
Keyword(s):  
Thermal Properties ◽  
Thermophysical Properties ◽  
Infrared Radiation ◽  
Measuring Devices ◽  
Thermal Properties Of Materials ◽  
Properties Of Materials ◽  
Output Characteristics

The analysis of properties of thermosensitive elements used in devices for monitoring the temperature and thermophysical properties of the medium and materials is carried out. Thermal converters made of various materials are considered: metals, semiconductors, oxides. The sensitivity to infrared radiation of the considered elements is analyzed. The range of measured temperatures and the linearity of the output characteristics of the converters are investigated. A conclusion is made about the purposefulness of using one or another type of thermosensitive elements.

scholarly journals TRADITIONAL DWELLING OF M`ZAB VALLEY IN ALHERIA: THE POINT OF ADAPTATION TO THE ENVIREMENT

2021 ◽  
pp. 159-169
Author(s):  
Nourel Houda Rezig
Keyword(s):  
Renewable Resources ◽  
Social Values ◽  
Arid Environment ◽  
Arid Climate ◽  
Simple Design ◽  
Unesco World Heritage ◽  
Sustainability Strategies ◽  
Local Materials ◽  
Different Levels ◽  
Passive Techniques

The article deals with the traditional dwellings in the UNESCO World Heritage ancient settlements (ksour) of M’zab Valley in Algerian desert. The Mozabite habitats are reflection of cultural and social values embodied in the architecture, with simple design in their forms deep in their indications, they are organized with a set of principles and rules known as customs that were inspired by religion and adapted to the environment. This latter helped to preserve Mozabite dwellings for more than a millennium. In this article the attention has been drawn to the dwelling’s design and distribution of its spaces according the activities and lifestyle of Mozabite community considering the arid environment needs. Sustainability strategies have significant presence in different levels of the dwelling appearing from the usage of passive techniques which depend on the principles of conservation energy and water, exploiting renewable resources and usage of local materials. These techniques are what make dwellings integrate completely within arid climate.

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