EXPERIMENTAL INVESTIGATIONS OF THE INFLUENCE OF HUMIDITY OF WALL CONSTRUCTION MATERIALS ON THE PERFORMANCE OF RADIO WAVES OF A RANDOM LINE

2018 ◽  
pp. 252-263 ◽  
Author(s):  
Anatoliy Satukov ◽  
◽  
Anatoliy Prystupa ◽  
Vladimir Zhurko ◽  
Mstislav Bivalkevich ◽  
...  
Keyword(s):  
Construction Materials ◽  
Experimental Investigations ◽  
Radio Waves ◽  
Random Line ◽  
Wall Construction

scholarly journals House improvements and community participation in the control of Triatoma dimidiata re-infestation in Jutiapa, Guatemala

2009 ◽  
Vol 25 (suppl 1) ◽  
pp. S168-S178 ◽  
Author(s):  
Carlota Monroy ◽  
Dulce Maria Bustamante ◽  
Sandy Pineda ◽  
Antonieta Rodas ◽  
Xochitl Castro ◽  
...  
Keyword(s):  
Construction Materials ◽  
Interdisciplinary Team ◽  
Ecosystem Approach ◽  
Laboratory Studies ◽  
Control Approach ◽  
Cultural Aspects ◽  
Wall Construction ◽  
Local Materials ◽  
Hygienic Conditions

The deterioration or absence of plaster walls in houses and poor hygienic conditions are the most important risk factors for indoor Triatoma dimidiata infestation in Guatemala. A cross-disciplinary study was conducted addressing T. dimidiata infestation, household hygiene, and housing construction. The study focused on local materials and cultural aspects (including gender roles) that could lead to long-term improvements in wall construction. A new plaster mix for walls was developed on the basis of laboratory studies on construction materials recommended by local villagers. Four villages with persistent (post-spraying) T. dimidiata infestation were studied. In two villages, an ecosystem approach was implemented, and the homeowners conducted wall improvements and household sanitation with the support of the interdisciplinary team (the ecosystem intervention). In the other two villages, a vector control approach based on insecticide spraying was adopted (traditional intervention). Both interventions were associated with a reduction in T. dimidiata infestation, but only the ecosystem approach produced important housing improvements (sanitation and wall construction) capable of preventing T. dimidiata re-infestation in the long term.

scholarly journals Absorption of 1-MCP by Nontarget Materials during Storage

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1131D-1131
Author(s):  
Fernando Vallejo ◽  
Randolph Beaudry
Keyword(s):  
Polyurethane Foam ◽  
External Surface ◽  
Construction Materials ◽  
Fire Retardant ◽  
External Surface Area ◽  
Sorptive Capacity ◽  
Holding Period ◽  
Storage Atmosphere ◽  
Wall Construction ◽  
The Impact

We tested the sorptive capacity of a number of nontarget materials found in apple storage rooms on their capacity to remove 1-MCP from the storage atmosphere and thereby compete with the fruit for the active compound. Furthermore, we evaluated the impact of temperature and moisture. Nontarget materials included bin construction materials [high density polyethylene (HDPE), polypropylene (PP), weathered oak, nonweathered oak, plywood, and cardboard] and wall construction materials (polyurethane foam and cellulose-based fire retardant). Each piece had an external surface area of 76.9 cm2. We placed our “nontarget” materials in 1-L mason jars and added 1-MCP gas to the headspace at an initial concentration of ≈30 μL·L-1. Gas concentrations were measured after 2, 4, 6, 8, 10, and 24 hours. The concentration of 1-MCP in empty jars was stable for the 24-hour holding period. Little to no sorption was detected in jars containing dry samples of HDPE, PP, cardboard, polyurethane foam, or fire retardant. Inclusion of plywood, nonweathered oak, and weathered oak lead to a loss of 10%, 55%, and 75% of the 1-MCP after 24 hours, respectively. Using dampened materials, no sorption resulted from the inclusion of HDPE, PP, polyurethane foam, or the fire retardant. However, the rate of sorption of 1-MCP by dampened cardboard, plywood, weathered oak, and nonweathered oak increased markedly, resulting in a depletion of ≈98%, 70%, 98%, and 98%, respectively. The data suggest that there are situations where 1-MCP levels can be compromised by wooden and cardboard bin and bin liner materials, but not by plastic bin materials or typical wall construction materials.

scholarly journals Full-scale experimental testing of dump-point safety berms in surface mining

2015 ◽  
Vol 52 (11) ◽  
pp. 1791-1810 ◽  
Author(s):  
Anna Giacomini ◽  
Klaus Thoeni
Keyword(s):  
Current Knowledge ◽  
Experimental Testing ◽  
Construction Materials ◽  
Surface Mining ◽  
Full Scale ◽  
Waste Rock ◽  
Experimental Investigations ◽  
Rules Of Thumb ◽  
Australian Coal ◽  
Experimental Findings

Waste rock (muck) piles are used as energy absorption barriers in many surface mining applications, such as berms at dumping points and at the crest of slopes, and in windrows as traffic separators or edge barriers on haul roads. The height of safety berms and windrows is currently designed using rules of thumb, such as height equal to half the maximum wheel diameter. However, over the last few decades, the dimensions of haul trucks have increased, and it is unclear if such rules of thumb are still applicable. This study, funded by the Australian Coal Association Research Program (ACARP), was carried out with the objective of improving the current knowledge on design and construction of dump-point safety berms in mining environments. Through full-scale experimental investigations on the dynamic impact of haul trucks on dump-point safety berms, significant data on berm design, construction materials, as well as principal berm characteristics were collected for the first time. The experimental findings suggested that the current rule of thumb might only be suitable for dump points where trucks travel at velocities lower than 10 km/h. The studies also showed that safety berms should be built using fresh, blocky, nonslaking waste rock materials and well maintained over their lifespan.

scholarly journals Influence of surface roughness on fatigue life of machine elements – the development in experimental investigations and simulations

Mechanik ◽  
2019 ◽  
Vol 92 (5-6) ◽  
pp. 307-313 ◽  
Author(s):  
Wit Grzesik
Keyword(s):  
Surface Roughness ◽  
Fatigue Life ◽  
Construction Materials ◽  
Fatigue Tests ◽  
Experimental Investigations ◽  
Fundamental Information ◽  
Aerospace Alloys ◽  
Machine Elements ◽  
Effect Of Surface

In this paper fundamental information on the influence of surface roughness on fatigue life/limit stresses of machine elements made of different construction materials using different machining/manufacturing processes are presented. The rules for the assessment of surface finish influence represented by the set of microscopic notches on the real machined surfaces, which allow the determination of the stress concentration factor and the correction of a fatigue life limit, are provided. The results of fatigue tests are compared with computed data and predictions using FEM based simulations. The effect of surface discontinues resulting from surface roughness are related to machine elements made of steels, aluminium alloys, aerospace alloys – titanium and nickel based superalloys and composite reinforced by graphite fibres.

scholarly journals Experimental Investigations and Microstructural Characterization of Construction Materials of Historic Multi-Leaf Stone-Masonry Walls

Heritage ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 2390-2415
Author(s):  
Osama Amer ◽  
Danila Aita ◽  
Ezzeldin K. Mohamed ◽  
Akram Torky ◽  
Ashraf Shawky
Keyword(s):  
Building Materials ◽  
Inner Core ◽  
Construction Materials ◽  
Core Layer ◽  
Mineralogical Composition ◽  
Stone Masonry ◽  
Thermal Resistivity ◽  
Experimental Investigations ◽  
Masonry Walls

In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the appropriate interventions for its conservation and preservation, comprehensive studies on its building materials should be carried out since the overall behaviour of masonry structures is highly dependent on the characterization of its construction materials. Consequently, an interdisciplinary procedure for construction material characterization used in multiple-leaf stone-masonry walls in Egypt has been implemented to enrich documentation, conservation and restoration issues of this type of wall. The research methodology integrates experimental data obtained through on-site sampling, conducted tests and analyses, historical information, and field survey observations. The fundamental physical and mechanical properties of the masonry elements were examined by incorporating stone blocks, mortars and core-infill materials. The mineralogical composition and interlocking textures of the collected samples were investigated utilizing a large range of complementary investigation and analysis techniques, including polarizing microscopy, X-ray diffraction (XRD), thermal analysis (TG/DTA), and environmental scanning electron microscope (ESEM) attached to an EDX unit. Through the results thus obtained, a complete characterization of the mineralogical composition; physical–mechanical, chemical, and thermal properties; and the interlocking textures of the construction materials of both the outer and inner-core layers was performed. The outer leaves of the majority of the multiple-leaf stone-masonry walls in medieval architectural heritage were mainly built of well-dressed limestone blocks with nearly uniform dimensions, while the inner-core layer was usually built of stone-rubble infill with bending lime-based mortar. The uniaxial compressive strengths of core infill (corresponding to the inner core layer) and lime-based mortar of the embedded joints are shown to be 85 and 92.5% lower than the limestone units of the outer layer, respectively. Moreover, experimental observations indicate that the inner core layer exhibits the highest porosity values; consequently, deteriorated, loose and cohesionless core infill could greatly affect the durability and thermal resistivity of this kind of wall. The results provide scientific support for investigating the overall structural behaviour of this type of walls and for decision-making in future conservation and restoration strategies.

An eco-friendly epoxy polymer binder for the treatment of Tunisian harbor sediments: Laboratory investigations for beneficial reuse

2020 ◽  
Vol 38 (8) ◽  
pp. 876-885 ◽  
Author(s):  
Afef Zouch ◽  
Yannick Mamindy-Pajany ◽  
Ilyas Ennahal ◽  
Nor-Edine Abriak ◽  
Mohamed Ksibi
Keyword(s):  
Construction Materials ◽  
Environmental Parameters ◽  
Dry Mass ◽  
Polymer Binder ◽  
Point Of View ◽  
Experimental Investigations ◽  
Geochemical Properties ◽  
Beneficial Reuse ◽  
Sediment Fraction

The management of dredged sediments poses serious environmental and economic problems because of their geochemical properties and in particular their pollutant content. In this research, marine sediments from Tunisian harbors were collected to study their beneficial reuse as construction materials using an eco-friendly polymer binder. Experimental investigations include the determination of physicochemical, mineralogical, and environmental parameters of sediments from the Sidi Mansour and Sidi Youssef areas in Tunisia. Prismatic mortar samples (4 × 4 × 16 cm) were prepared at laboratory scale using normalized sand and epoxy resin. Then their composition was modified by including a sediment fraction in the substitution of sand at rates ranging from 10 to 50% in dry mass. After a 7-day curing period, mortar samples were submitted to mechanical, physicochemical, and environmental analyses. Mortar samples including sediment fractions displayed lower strength than sand mortar used as control. This result is explained by the increase of porosity values in the mortar samples when sediment samples were incorporated. A positive relationship between porosity and compressive strength values was evidenced, suggesting that the compactness of granular skeleton could play an important role in the preparation of materials. From an environmental point of view, the mortar samples containing sediment fractions showed relatively low leaching levels, which confirms their suitability for the manufacturing of construction materials.

Experimental investigations of a rolling-based seismic isolation system

2016 ◽  
Vol 24 (2) ◽  
pp. 323-342 ◽  
Author(s):  
Mohammed Ismail ◽  
Jośe Rodellar
Keyword(s):  
Seismic Isolation ◽  
Construction Materials ◽  
Shear Stiffness ◽  
Experimental Tests ◽  
Horizontal Displacement ◽  
Shear Loading ◽  
Experimental Investigations ◽  
Loading Frequency ◽  
Isolation System ◽  
Test Parameters

This paper presents the results of an extensive series of experimental tests to identify the mechanical characteristics of a recently-proposed seismic isolation device known as the Roll- In-Cage (RNC) isolator. Several 1/10 reduced-scale experimental prototypes are examined considering different configurations, characteristics and construction materials. Cyclic horizontal displacement tests, varying the test parameters of shear displacement amplitude, axial load, and loading frequency are performed. The RNC isolator’s force-displacement relationship, shear stiffness and damping properties are investigated in terms of different test parameters. In addition, vertical cyclic displacement is applied to examine the RNC isolator’s capability to withstand vertical axial tension. Furthermore, tests at the ultimate-level consisting of an increasing monotonic shear loading beyond the bearing’s design displacement are also carried out to investigate its behavior after activating its self-stopping or buffer mechanism. Some experimentally obtained results are verified using numerical simulation models. A comparative analysis of the results is then performed to allow for highlighting the main features of the RNC isolator.

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