Evaluation of a permissible roadbed thawing depth in permafrost

2021 ◽  
Vol 5 ◽  
pp. 18-22
Author(s):  
Alexandr Galkin
Keyword(s):  
Thermal Resistance ◽  
Biot Number ◽  
Seasonal Changes ◽  
Construction Materials ◽  
Thermal Conditions ◽  
Road Base ◽  
Thawing Depth ◽  
Roadway Construction ◽  
Selection Of ◽  
Purpose Of Evaluation

Roadbed thermal conditions in permafrost are subject to seasonal changes affecting roadway resilience. A roadbed thawing depth is important for road base processing, especially in permafrost. This research had the purpose of evaluation of a permissible roadbed thawing depth based on the Biot number reflecting general thermal resistance of roadbed layers. These results will contribute to understanding road bed thermal resistance and selection of roadway construction materials.

scholarly journals Fire Resistance Behaviour of Geopolymer Concrete:An Overview

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 82
Author(s):  
Salmabanu Luhar ◽  
Demetris Nicolaides ◽  
Ismail Luhar
Keyword(s):  
Compressive Strength ◽  
Thermal Resistance ◽  
Building Materials ◽  
Elevated Temperatures ◽  
Construction Materials ◽  
Flexural Behavior ◽  
Thermal Shrinkage ◽  
Physico Chemical ◽  
The Impact ◽  
Loss Of Strength

Even though, an innovative inorganic family of geopolymer concretes are eye-catching potential building materials, it is quite essential to comprehend the fire and thermal resistance of these structural materials at a very high temperature and also when experiencing fire with a view to make certain not only the safety and security of lives and properties but also to establish them as more sustainable edifice materials for future. The experimental and field observations of degree of cracking, spalling and loss of strength within the geopolymer concretes subsequent to exposure at elevated temperature and incidences of occurrences of disastrous fires extend an indication of their resistance against such severely catastrophic conditions. The impact of heat and fire on mechanical attributes viz., mechanical-compressive strength, flexural behavior, elastic modulus; durability—thermal shrinkage; chemical stability; the impact of thermal creep on compressive strength; and microstructure properties—XRD, FTIR, NMR, SEM as well as physico-chemical modifications of geopolymer composites subsequent to their exposures at elevated temperatures is reviewed in depth. The present scientific state-of-the-art review manuscript aimed to assess the fire and thermal resistance of geopolymer concrete along with its thermo-chemistry at a towering temperature in order to introduce this novel, most modern, user and eco-benign construction materials as potentially promising, sustainable, durable, thermal and fire-resistant building materials promoting their optimal and apposite applications for construction and infrastructure industries.

scholarly journals SELECTION OF WIRELESS TECHNOLOGY FOR TRACKING CONSTRUCTION MATERIALS USING A FUZZY DECISION MODEL / BELAIDŽIO RYŠIO TECHNOLOGIJŲ ATRANKA STATYBINĖMS MEDŽIAGOMS STEBĖTI, TAIKANT NEAPIBRĖŽTŲJŲ AIBIŲ SPRENDIMO MODELĮ

2012 ◽  
Vol 18 (1) ◽  
pp. 43-59 ◽  
Author(s):  
Shaohua Jiang ◽  
Won-Suk Jang ◽  
Mirosław J. Skibniewski
Keyword(s):  
Decision Making ◽  
Construction Projects ◽  
Large Scale ◽  
Construction Materials ◽  
Point Of View ◽  
Wireless Technologies ◽  
Scope Of Application ◽  
Fuzzy Decision Model ◽  
Specific Technology ◽  
Selection Of

As the size and scale of construction projects increase, inefficiencies related to the manual operations about field data in current tracking systems are becoming an important issue. While emerging wireless technologies are providing a feasible vision of ubiquitous computing and sensor networks applicable to the large-scale construction industry, it has become even harder to select a suitable technology for tracking construction materials because of the differing functionalities, capabilities, and scope of application of the specific technology. This research proposes a multi-criteria decision-making model that leverages the decision process in choosing various wireless technologies available on the market. To justify the selection of a specific technology, a fuzzy method was adopted to provide an appropriate way to decide among five alternatives (e.g., RFID, GPS, Wi-Fi, Zigbee, and UWB). Fuzzy ranking was obtained from the aggregated fuzzy appropriate index (FAI) based on a person's point of view (optimist, pessimist, or neutral). The results showed that Wi-Fi might be a suitable solution for optimists and neutral persons, but UWB might be the better alternative for pessimists. The results of this research may assist construction engineers in applying reasonable decision-making procedures in a fuzzy environment such as construction sites, and rank the relative importance of the various criteria and alternatives specified in this research. Santrauka Augant statybos projektų mastui, rankinis dabartinių stebejimo sistemų duomenų apdorojimo neefektyvumas tampa svarbia problema. Nors naujos belaidžio ryšio technologijos gali sudaryti galimybę įvesti visur prieinamus kompiuterinius ir jutiklių tinklus, naudojamus plataus masto statybos pramonėje, tampa vis sudėtingiau pasirinkti tinkamas technologijas statybinėms medžiagoms stebėti, nes kiekviena technologija atlieka skirtingas funkcijas, skiriasi jų galimybės ir taikymo apimtis. Šiame tyrime siūlomas daugiakriterinis sprendimų priėmimo modelis, kuris, sprendimų priėmimo procesą pasirenkant rinkoje, siūlomas belaidžio ryšio technologijas išskaido į atskirus lygius. Siekiant pagrįsti tam tikros technologijos pasirinkimą, buvo pritaikytas neapibrežtųjų aibių metodas, pasirenkant geriausią technologiją iš penkių alternatyvų (t. y. RFID, GPS, Wi-Fi, Zigbee ir UWB technologijų). Neapibrežtumo rangas buvo gautas taikant agreguotą neapibrežtumo tinkamumo indeksą (FAI), atsižvelgiant į asmens požiūrį (optimistinis, pesimistinis ar neutralus). Gauti rezultatai parodė, kad Wi-Fi technologija yra tinkama optimistams ir neutraliems asmenims, o UWB technologija būtų geresnė alternatyva pesimistams. Šio tyrimo rezultatai gali padėti statybos inžinieriams priimti pagrįstus sprendimus neapibrėžtoje aplinkoje, tokioje kaip statybos aikštelės, ir suranguoti pagal svarbą įvairius kriterijus bei aptartas šiame tyrime alternatyvas.

The Optimum Energy Saving Measures for Retrofitting Residential Buildings

2016 ◽  
Vol 41 (1) ◽  
pp. 88-92
Author(s):  
Rong-Yue Zheng ◽  
Jian Yao
Keyword(s):  
Energy Saving ◽  
Energy Savings ◽  
Residential Buildings ◽  
Thermal Conditions ◽  
High Energy ◽  
Cold Winter ◽  
Efficiency Measures ◽  
Optimum Energy ◽  
Potential Energy Saving ◽  
Selection Of

A large number of residential buildings in hot summer and cold winter zone of China are non-energy efficient with poor indoor thermal conditions. Retrofitting residential buildings with energy efficiency measures is thus important for residents. However, this work progressed slowly because practically applicable measures that not only have high energy savings but also improve indoor thermal performance have not been studied. Thus, this paper carried out a simulation study on the selection of suitable energy saving measures for residential buildings in hot summer and cold winter zone of China. Five potential energy saving options are considered and the energy, indoor thermal comfort and economic performance are compared. The results show that adding movable solar shades is the optimum option with all performance indices ranking first. Meanwhile, this measure is also the only acceptable energy saving solution for residents since its payback period is less than the lifespan of a building. As a conclusion, it is recommended to use movable solar shades as a first priority when retrofitting residential buildings.

A Simulation and Monitoring Based Case Study Regarding the Dynamic Thermal Conditions in Non-Used Attic Space

2019 ◽  
Vol 887 ◽  
pp. 467-474
Author(s):  
Radoslav Ponechal ◽  
Renáta Korenková ◽  
Daniela Štaffenová
Keyword(s):  
Thermal Resistance ◽  
Air Temperature ◽  
Thermal Conditions ◽  
Adjustment Factor ◽  
Solar Absorption ◽  
Roofing Material ◽  
Dark Color ◽  
The Mean ◽  
The Difference

This study solves a problem of the dynamic thermal performance of the residential attic space in moderate climatic zone. Heat loss into the attic space is difficult to be accurately determined by the quasi-stationary method. It depends on the thermal resistance of the ceiling, thermal resistance of the roof, ventilation characteristics and other details, such as the solar absorption of the roofing material or roof orientation. The paper presents results of some parametric simulative calculations, which were calibrated with measurements of air temperature in the attic space during the summer, winter and transitional season. It compares the mean air temperature in the ventilated and non-ventilated attics. The difference between the use of bright and dark color of the roof cover is also compared. An alternative with half thickness of thermal insulation was also simulated. Based on measurements and then the simulation the adjustment factor adjustment factor for heat transfer coefficient was quantified..

scholarly journals Experimental Strength of Earth-Based Construction Materials in Different Regions of China

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Kun Zhang ◽  
Bairu Lu ◽  
Yihong Wang ◽  
Zhijun Lei ◽  
Zhanshen Yang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Construction Materials ◽  
Earth Construction ◽  
Strength Tests ◽  
The World ◽  
Red Earth ◽  
Material Load ◽  
Earthen Buildings ◽  
Selection Of

According to the latest UN statistics, more than 2 billion people in the world still live in various forms of earthen buildings, including some in China. The variety of earth-based constructional materials is significant among different regions, with each region influencing the selection of local earth construction materials. In this study, earth materials from four regions of China were collected and sorted, with 10 samples from each source, and cube compressive strength tests were performed to analyze the composition and mechanical properties of the four materials, including northeast black earth, southeast red earth, northwest loess, and Xinjiang yellow sand earth. The results showed that significant differences existed in the composition of earth-based constructional materials from different regions, which have influence on the materials’ compressive strength. The order from large to small of compressive strengths was loess, black earth, yellow sandy earth, and red earth. Material load-displacement curves were influenced significantly by the plasticity index, but the overall failure processes of the various samples were basically the same.

scholarly journals Sustainable Illumination for Baroque Paintings with Historical Context Considerations

2020 ◽  
Vol 12 (20) ◽  
pp. 8705
Author(s):  
Pedro Luengo
Keyword(s):  
Eighteenth Century ◽  
Seasonal Changes ◽  
Light Exposure ◽  
Historical Context ◽  
Zero Energy ◽  
Museum Displays ◽  
Zero Energy Building ◽  
Sustainable Conservation ◽  
Scholarly Attention ◽  
Selection Of

The topic of museum illumination and conservation has been richly developed in recent years to take steps toward a zero-energy building concept. Most artworks preserved in museums’ expositions were designed for specifically defined light contexts, wherein daylight and seasonal changes were part of the artistic effect, an issue which has received little scholarly attention. From this premise, this paper aims to prove that defining the original illuminative context of artworks is required for a sustainable conservation, perception, and ultimate interpretation. To do this, a selection of seventeenth and eighteenth century churches and palaces from Europe, the Americas, and Asia will be presented using modern conservation frameworks for artworks. The results demonstrate that both aspects, chosen materials and light exposure, were connected, allowing the spaces to be effective without consuming too much electric lighting. This leads to a discussion about if museum displays should incorporate this context, if it is a more sustainable solution, and if it presents the artworks more accurately to visitors, even as other problems may arise.

Seasonal changes in diet and diet selection of great bustards (Otis t. tarda) in north-west Spain

1999 ◽  
Vol 247 (2) ◽  
pp. 201-214 ◽  
Author(s):  
S. J. Lane ◽  
J. C. Alonso ◽  
J. A. Alonso ◽  
M. A. Naveso
Keyword(s):  
Seasonal Changes ◽  
Diet Selection ◽  
North West ◽  
Selection Of
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