scholarly journals Traditional and Modern Plasters for Built Heritage: Suitability and Contribution for Passive Relative Humidity Regulation

Heritage ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 2337-2355
Author(s):  
Alessandra Ranesi ◽  
Paulina Faria ◽  
Maria do Rosário Veiga
Keyword(s):  
Relative Humidity ◽  
Indoor Air ◽  
Vapour Permeability ◽  
Sorption Behaviour ◽  
Hydraulic Lime ◽  
Built Heritage ◽  
Surface Areas ◽  
Natural Hydraulic Lime ◽  
Energy Demands ◽  
Different Types

Plasters have covered wide surface areas of buildings since antiquity, with a main purpose of indoor protection of the substrate on which they are applied. When no longer functional, they might require substitution with solutions that can combine compatibility with the substrate with the current need to mitigate building emissions. Indeed, plasters can contribute to lowering buildings’ energy demands while improving indoor air quality and the comfort of buildings’ users, as plasters can be used as passive regulators of relative humidity (RH). Hence, this study presents the relative-humidity-dependent properties of different plastering mortars based on clay, air lime, and natural hydraulic lime, and plastering finishing pastes based on gypsum and gypsum–air lime, in all cases tested using small size specimens. A cement-based plaster is also analysed for comparison. The clay-based plaster was the most promising material for RH passive regulation, and could be applied to repair and replace plasters in different types of buildings. Pastes based on air lime–gypsum could be applied as finishing layers, specifically on traditional porous walls. The sorption behaviour of cement plaster appeared interesting; however, its water vapour permeability was as expected, found to be the lowest, discouraging its application on historic walls.

LIGHTWEIGHT COATING MORTARS FOR BUILDINGS RESTORATION

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Jaroslav Pokorný ◽  
Lucie Zemanová ◽  
Milena Pavlíková ◽  
Zbyšek Pavlík
Keyword(s):  
Thermal Properties ◽  
Relative Humidity ◽  
Silica Sand ◽  
Hydraulic Lime ◽  
Natural Hydraulic Lime ◽  
Technical Requirements ◽  
Hygric Properties ◽  
Water Saturated ◽  
Thermo Physical Properties ◽  
Lightweight Mortar

In this paper, crushed lava-based aggregate was used in mortar mix composition as a full silica sand substitution to improve thermal properties of mortar fulfilling also other physical, mechanical and technical requirements. As a binder, natural hydraulic lime was used. Workability of fresh mortar mixes was characterized by spread diameter. The casted samples were matured for 28 days in a high relative humidity to avoid cracking. For the hardened samples, structural, mechanical, and hygric properties were tested. Thermo-physical properties of the developed mortars were measured as function of moisture content, from the dry to fully water saturated state. The application of lava-based aggregate led to the mortar’s increased porosity, improved mechanical strength, lower water absorption, and significantly better thermal performance compared to the control materials with silica aggregate. The newly developed lightweight mortar met the technical, compatibility and functional criteria on rendering mortar and was found well usable for conservation and restoration of historical and heritage masonry and buildings.

A Review on Various Methodologies for AC Duct Cleaning

2020 ◽  
Vol 07 (3&4) ◽  
pp. 1-5
Author(s):  
Soyab A Jamadar ◽  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Health Issues ◽  
Conventional System ◽  
Rectangular Shape ◽  
Inspection Robot ◽  
Different Types ◽  
Robot Systems ◽  
Articulated Robot

Cleaning of the AC ducts is the need because it creates problems such as the bad indoor air quality which results in health issues and it also causes the large maintenance of the system. The uncleaned air ducts become home for fungi, dust and harmful microbial. The causes and effects of this thing are mentioned following. The AC ducts can be cleaned through various methodologies i.e. conventional and by using robots. In the conventional system, there is manual cleaning by using some equipment. Cleaning the ducts by using robots would be a good solution for this. Different types of robot systems i.e. crawling robot, articulated robot and inspection robot are deployed for the application. There are different types of robots and their equipment according to size and type of duct. The cleaning of rectangular shape ducts is quite difficult than others. Finally, it results that cleaning ducts is the most important thing and using robots is the best methodology for it.

scholarly journals Bond Properties of NHL-Based Mortars with Viscosity-Modifying Water-Retentive Admixtures

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 685
Author(s):  
Tomáš Žižlavský ◽  
Patrik Bayer ◽  
Martin Vyšvařil
Keyword(s):  
Water Content ◽  
Adhesive Strength ◽  
Water Retention ◽  
Minor Role ◽  
Clay Brick ◽  
Hydraulic Lime ◽  
Natural Hydraulic Lime ◽  
Binder Ratio ◽  
Paste Viscosity ◽  
A Minor

This article studies the influence of biopolymeric viscosity-modifying admixtures with water-retentive function on the physico-mechanical properties of natural hydraulic lime-based mortars and their adherence to the traditional fired-clay brick substrate. The use of admixtures increases the water/binder ratio, which in turn leads to a decrease in the strength of the mortars. The viscosity-modifying function improves the adhesive strength between mortar and pre-wetter brick by increasing the binder paste viscosity, while the water-retentive function along with increased water content may lead to a decrease in adhesive strength. On the contrary, water retention and increased water content are beneficial on a dry surface, while paste viscosity plays only a minor role. When subjected to temperature-varying cycles, the mortars are more prone to in-mortar failure during the pull-off test. The air-entraining function of some admixtures improves the frost resistance of the mortars; however, it would negatively affect the adhesive strength by incorporating pores into the contact zone between the mortar and brick substrate. This study showed that the use of some of the studied admixtures may improve the adhesion of mortar to the brick substrate.

scholarly journals Indoor Air Quality (IAQ): Accuracy of Natural Ventilation for Temperature, Air Flow Rate and Relative Humidity (RH) in School Building Classrooms

2018 ◽  
Vol 7 (3.9) ◽  
pp. 42
Author(s):  
Norsafiah Norazman ◽  
Adi Irfan Che Ani ◽  
Nor Haslina Ja’afar ◽  
Muhamad Azry Khoiry
Keyword(s):  
Air Quality ◽  
Relative Humidity ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Air Flow ◽  
Weather Conditions ◽  
Potential Health ◽  
The Hours ◽  
Hot Weather

Indoor Air Quality (IAQ) is an essential matter in achieving students’ satisfaction for the learning process. Building’s orientation is a factor that may encourage sufficient natural ventilation for the classroom occupants. Inadequate ventilation is an issue for most existing classrooms. The purpose of this paper is to analyze the accuracy of natural ventilation in classrooms. Therefore, experimental on 20 classrooms has been conducted by using Multipurpose Meter at secondary school buildings in Malaysia. The findings indicated that the accuracy of natural ventilation testing was below the permissible limits throughout the hours monitored, thus this may cause potential health hazards to the students. Temperature and air flow rates were lower than 23 °C and 0.15 m/s respectively, it fulfilled the basic requirements as a standard learning environment. However, measurements taken showed the overall relative humidity (RH) in the classrooms can be categorized as acceptable with 40% to 70% range. On the basis of these findings, it is evident that naturally ventilated classrooms are important especially due to energy efficiency, whereas mechanical ventilation should only be installed as an alternative under extremely hot weather conditions.   

Influence of Sample Thickness and Capping on Characterization of Bedding Mortars from Historic Masonries by Double Punch Test (DPT)

2014 ◽  
Vol 624 ◽  
pp. 322-329 ◽  
Author(s):  
Enrico Sassoni ◽  
Elisa Franzoni ◽  
Claudio Mazzotti
Keyword(s):  
Compressive Strength ◽  
Poor Quality ◽  
Sample Thickness ◽  
Mortar Sample ◽  
Hydraulic Lime ◽  
Punch Test ◽  
Natural Hydraulic Lime ◽  
Wide Range ◽  
Surface Capping

For determination of compressive strength of bedding mortar used in historic masonries, a promising moderately-destructive technique is double punch test (DPT). DPT consists of loading prismatic samples of mortar (about 4×4×1 cm3) by means of two circular steel platens (typically 2 cm diameter) and then calculating mortar compressive strength as the ratio of the failure load to the cross section of the circular platens. In this study, the influence of mortar sample thickness and mortar sample capping on the reliability of results obtained by DPT was systematically investigated. The influence of sample thickness was assessed by comparing DPT results obtained for samples with 5, 10, 15 and 20 mm thickness with compressive strength determined by testing reference 4 cm-side cubes. Different mortars were considered (cement, lime-cement, natural hydraulic lime), in order to investigate a wide range of mortar mechanical characteristics. The influence of surface capping was evaluated on a lime-cement mortar by comparing compressive strength determined on reference cubes with strength obtained by DPT on proper samples, without capping and after capping with rubber, gypsum and cement. The results of the study indicate that sample thickness substantially influences mortar compressive strength determined by DPT, which may vary by up to three times depending on sample thickness. A good estimation of the actual mortar compressive strength was obtained when samples with thickness similar to the loading platens diameter were tested, which suggests that choosing the size of the loading platens for DPT based on the thickness of mortar joints under investigation may be an effective way for obtaining reliable estimations. As for the influence of surface capping, in those cases where no mortar sample regularization is possible, because of the poor quality of the mortar, the results of the study indicate that sample capping actually seems necessary in order to avoid significant underestimations of mortar compressive strength. Considering the higher practicality offered by gypsum with respect to rapid-setting cement for surface capping, the use of gypsum seems preferable.

scholarly journals Indoor Particulate Matter (PM2.5) and Comfort Parameters in a University Building

2020 ◽  
Vol 8 (2) ◽  
pp. 61-67
Author(s):  
Nurul Bahiyah Abd Wahid ◽  
Intan Idura Mohamad Isa ◽  
Ahmad Khairuddin Hassan ◽  
Muhammad Izzat Iman Razali ◽  
Ahmad Haziq Hasrizal ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Relative Humidity ◽  
Indoor Air ◽  
National Policy ◽  
Lecture Hall ◽  
Airborne Microorganisms ◽  
Code Of Practice ◽  
The Mean ◽  
Indoor Particulate Matter ◽  
Comfort Parameters

This study aims to determine the particulate matter (PM2.5) mass concentrations and the comfort parameters (total bacterial counts (TBC), total fungal counts (TFC), relative humidity and temperature) in a university building. The samplings were carried out in three different indoor areas, including lecture hall, laboratory and lecturer office. PM2.5 samples were collected over a period of 8 h sampling using a low volume sampler (LVS). The anemometer Model Kestrel 0855YEL was used to measure relative humidity and temperature parameters. The sampling of airborne microorganisms was conducted by using microbial sampler at 350 L air sampled volume. The results showed that the highest average of PM2.5 was at lecture hall (88.54 ± 26.21 µgm-3) followed by lecturer office (69.79 ± 19.06 µgm-3) and laboratory (47.92 ± 24.88 µgm-3). The mean of TBC and TFC readings recorded as follow; 32.71 ± 5.91 cfu m-3 and 76.71 ± 21.5 cfu m-3 for laboratory, 112.1 ± 29.06 cfu m-3 and 124.67 ± 23.35 cfu m-3 for lecturer office, 121.74 ± 19.33 cfu m-3 and 115.33 ± 8.08 cfu m-3 for lecture hall. The average of all comfort parameter was within the prescribed standard by Industry Code of Practice on Indoor Air Quality 2010 for all sampling sites. Therefore, all occupants of the building can work in a conducive and comfortable environment. This study is in line with the objectives of National Policy on the Environment (DASN), which focusing on achieving a clean, safe, healthy and productive environment for present and future generations.

scholarly journals PROGNOSTIC FACTORS IN SEVERE HEAD INJURY "A CLINICO RADIOLOGICAL STUDY"

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Dr. I. D. Chaurasia ◽  
Dr. Avais Ahmed Khan ◽  
Dr. Neeraj Mane ◽  
Dr. Prateek Malpani ◽  
Dr. M. C. Songara
Keyword(s):  
Heart Rate ◽  
Stress Responses ◽  
Severe Head Injury ◽  
Physiological Responses ◽  
Vital Signs ◽  
Behavioral Responses ◽  
Auditory Stimulation ◽  
Energy Demands ◽  
Significant Difference ◽  
Different Types

Overview:  Infants experience stressors. Stress responses in infants include physiological responses (HR and oxygen saturation) and behavioral responses (behavioral state, motor activity, and signs of behavioral distress). Modulation of the stress response in infants may reduce energy demands and enhance recovery. The characteristics of auditory stimulation provided by music differ from those of other types of auditory stimulation. The infants respond differently to music than to other random noises. This study was carried out to examine the effects of different types of music on vital signs of infants. Methodology: Thirty infants were included in the study. They were divided into two groups. Low and High pitched music was used with for two individual groups. The immediate effect was assessed through pre and post recordings for Heart rate, Reapiratory rate and O2 saturation level. Results: There was statistically significant change in Heart Rate, Respiratory Rate and O2 saturation individually. While comparing post data, except Heart Rate there was no significant difference found with both types of music. Conclusion: Low pitched music has better immediate effect than high pitched music Key words: High pitched music, Low pitched music, Infants

Sign in / Sign up

Export Citation Format

Share Document