Impact of Relative Humidity on Modified Alkoxysilane Gels

2016 ◽  
Vol 714 ◽  
pp. 95-99
Author(s):  
Barbora Benetková ◽  
Adéla Peterová ◽  
Monika Slavíková ◽  
Petr Kotlík
Keyword(s):  
Relative Humidity ◽  
Silicic Acid ◽  
Building Materials ◽  
Objective Evaluation ◽  
Partial Solution ◽  
Huge Impact ◽  
To Come ◽  
Stone Consolidants ◽  
Different Levels ◽  
Acid Esters

Silicic acid esters have been used as stone consolidants for 50 years now. During this time they became the most popular consolidants for building materials, mainly thanks to their good properties during application. Despise all these positives, the use of alkoxysilanes brings also some drawbacks. The gel of the silicic acid esters, which is responsible for the consolidation, cracks and decays during several years after the treatment so that the consolidation has to be repeated. To suppress the cracking, the alkoxysilanes are often modified. In recent studies, we focused on modification of silicic acid ester gels by SiO2 and Al2O3 nanoparticles. Some of the prepared mixtures cracked less than the unmodified mixture under ambient condition. This work builds on these experiments and works with the selected modified mixtures. As the consolidants are widely used outdoors, it was necessary to compare the degree of cracking of modified gels under various conditions. In this experiment we focused on their cracking under different levels of relative humidity. As the objective evaluation of cracking was needed, we believe to come up with partial solution to this problem – to assort the extent of cracking to some defined category. The categories were defined according to our former experiences with observation of cracking states of the gels. We found out, that the change of relative humidity has huge impact on the way and extent to which the gels cracked. Knowing this information we may be able to prepare the modified consolidant, that better withstands outdoor conditions and thus to preserve our cultural heritage for longer time.

scholarly journals Circular economy in the construction sector: advancing environmental performance through systemic and holistic thinking

2021 ◽  
Author(s):  
Magnus Sparrevik ◽  
Luitzen de Boer ◽  
Ottar Michelsen ◽  
Christofer Skaar ◽  
Haley Knudson ◽  
...  
Keyword(s):  
Life Cycle ◽  
Circular Economy ◽  
Building Materials ◽  
Construction Sector ◽  
Recursive Structure ◽  
Effective Implementation ◽  
Environmental Effectiveness ◽  
Standards And Regulations ◽  
Management Schemes ◽  
Different Levels

AbstractThe construction sector is progressively becoming more circular by reducing waste, re-using building materials and adopting regenerative solutions for energy production and biodiversity protection. The implications of circularity on construction activities are complex and require the careful evaluation of impacts to select the appropriate path forward. Evaluations of circular solutions and their environmental effectiveness are often performed based on various types of life cycle-based impact assessments. This paper uses systemic thinking to map and evaluate different impact assessment methodologies and their implications for a shift to more circular solutions. The following systemic levels are used to group the methodologies: product (material life cycle declarations and building assessments), organisation (certification and management schemes) and system (policies, standards and regulations). The results confirm that circular economy is integrated at all levels. However, development and structure are not coordinated or governed unidirectionally, but rather occur simultaneously at different levels. This recursive structure is positive if the methods are applied in the correct context, thus providing both autonomy and cohesion in decision making. Methods at lower systemic levels may then improve production processes and stimulate the market to create circular and innovative building solutions, whereas methods at higher systemic levels can be used, for example, by real estate builders, trade organisations and governments to create incentives for circular development and innovation in a broader perspective. Use of the performance methods correctly within an actor network is therefore crucial for successful and effective implementation of circular economy in the construction sector.

Removing NOx Pollution by Photocatalytic Building Materials in Real-Life: Evaluation of Existing Field Studies

2021 ◽  
Vol 02 ◽  
Author(s):  
Pernille D. Pedersen ◽  
Nina Lock ◽  
Henrik Jensen
Keyword(s):  
Air Pollutants ◽  
Building Materials ◽  
Evaluation Criteria ◽  
Real Life ◽  
Ambient Air ◽  
Well Being ◽  
Good Health ◽  
Objective Evaluation ◽  
Field Studies ◽  
Hazardous Air Pollutants

: The NOx gasses (NO and NO2) are among the most important air pollutants, due to the toxicity of NO2, as well as the role of NOx in the tropospheric oxidation of Volatile Organic Carbons (VOCs), contributing to the formation of other hazardous air pollutants. Air pollution is one of the biggest health threats world-wide, hence reducing NOx levels is an important objective of the UN sustainable development goals, e.g. #3, “Good health and well-being” and #11 “Sustainable cities and communities”. Photocatalysis using TiO2 and light is a promising technique for removing NOx along with other pollutants, as demonstrated on laboratory scale. Furthermore, a long range of real-life test studies of varying scales have been conducted during the past two decades. The results of these studies have been conflicting, with some studies reporting no effect on the ambient air quality and others reporting significant reductions of NOx level. However, the studies are very difficult to compare and assess due to the very different approaches used, which consequently vary in quality. In this review, we aim to develop a set of objective evaluation criteria to assess the quality of the individual studies in order to simplify the interpretation and comparison of the existing studies. Moreover, we propose some guidelines for future test-studies. Furthermore, the approaches and main conclusions from 23 studies are independently assessed and discussed herein.

The effect of post-harvest storage on the weight of Golden Delicious apples

2021 ◽  
Vol 13 (2) ◽  
pp. 7-11
Author(s):  
Salma Kassebi ◽  
Péter Korzenszky
Keyword(s):  
Relative Humidity ◽  
Storage Temperature ◽  
Extended Period ◽  
Food Products ◽  
Significant Loss ◽  
Loss Of Weight ◽  
Ambient Storage ◽  
Golden Delicious ◽  
Different Levels ◽  
Careful Management

Apples, like other fruits, are exposed to stress during their growth and development in the field, also during harvest and the postharvest environment (processing, storage, and transportation). The refrigeration system allows for bulk handling of food products from harvest to market, ensuring that food products are maintained in their freshness and integrity for an extended period through careful management of storage temperature and humidity. This study investigated the effects of storage on the weight loss of apples (Golden Delicious fruits harvested at maturity), under refrigerated conditions at a temperature of 5±0.5°C and relative humidity of 82% and under ambient storage at a temperature of 25 ±0.5 °C and relative humidity of 60 %, over 3 months. The findings revealed that the two groups of apples experienced weight reduction at different levels. Apples placed at cold storage presented a loss of weight between 3.31g and 4.49g; however, apples stored at ambient temperature showed a significant loss of weight between 21.9g and 31.76g.

scholarly journals Investigation of monthly variations in the efficiencies of photovoltaics due to sunrise and sunset times

2020 ◽  
Vol 18 (1) ◽  
pp. 310
Author(s):  
Armstrong O. Njok ◽  
Julie C. Ogbulezie ◽  
Manoj Kumar Panjwani ◽  
Raja Masood Larik
Keyword(s):  
Relative Humidity ◽  
Solar Energy ◽  
Electrical Energy ◽  
Time Of Day ◽  
Peak Efficiency ◽  
Pv Module ◽  
Average Relative Humidity ◽  
The Difference ◽  
Monthly Variations ◽  
Different Levels

<p>The effect of time of day and month on the efficient conversion of solar energy to electrical energy using a polycrystalline (PV) module in calabar was studied. A KT-908 precision digital hygrometer and thermometer, and a M890C+ digital multimeter were used in the process. Results obtained shows that photovoltaic produce different levels of peak efficiencies at different times of the day for different months due to the difference in sunrise and sunset times for the months. The results also indicated that photovoltaics will be more efficient in months with low average relative humidity couple with low panel temperature. A peak efficiency of 77% at 12:30 in the month of April was observed before dropping to 73% at 12:00 in the month of May, indicating that there might be further drop in efficiency as we proceed further into the year. Results also show that photovoltaics are more efficient before noon in the month of May than in April while the reverse will be observed in the afternoon. </p>

scholarly journals Implementation of Spatial-Scale Domain Based De-Noising Techniques using Different Thresholding

2020 ◽  
Vol 9 (3) ◽  
pp. 3594-3603
Keyword(s):  
Wavelet Transform ◽  
Root Mean Square Error ◽  
Signal To Noise Ratio ◽  
Objective Evaluation ◽  
Contourlet Transform ◽  
Discrete Wavelet ◽  
Mean Square ◽  
Stationary Wavelet Transform ◽  
Signal To Noise ◽  
Different Levels

This paper aims in presenting a thorough comparison of performance and usefulness of multi-resolution based de-noising technique. Multi-resolution based image denoising techniques overcome the limitation of Fourier, spatial, as well as, purely frequency based techniques, as it provides the information of 2-Dimensional (2-D) signal at different levels and scales, which is desirable for image de-noising. The multiresolution based de-noising techniques, namely, Contourlet Transform (CT), Non Sub-sampled Contourlet Transform (NSCT), Stationary Wavelet Transform (SWT) and Discrete Wavelet Transform (DWT), have been selected for the de-noising of camera images. Further, the performance of different denosing techniques have been compared in terms of different noise variances, thresholding techniques and by using well defined metrics, such as Peak Signal-to-Noise Ratio (PSNR) and Root Mean Square Error (RMSE). Analysis of result shows that shift-invariant NSCT technique outperforms the CT, SWT and DWT based de-noising techniques in terms of qualititaive and quantitative objective evaluation

scholarly journals Formal analysis of design process dynamics

2010 ◽  
Vol 24 (3) ◽  
pp. 397-423 ◽  
Author(s):  
Tibor Bosse ◽  
Catholijn M. Jonker ◽  
Jan Treur
Keyword(s):  
Design Process ◽  
Formal Analysis ◽  
Formal Theory ◽  
Generic Properties ◽  
Design Processes ◽  
Process Dynamics ◽  
To Come ◽  
Automated Support ◽  
Trace Language ◽  
Different Levels

AbstractThis paper presents a formal analysis of design process dynamics. Such a formal analysis is a prerequisite to come to a formal theory of design and for the development of automated support for the dynamics of design processes. The analysis was geared toward the identification of dynamic design properties at different levels of aggregation. This approach is specifically suitable for component-based design processes. A complicating factor for supporting the design process is that not only the generic properties of design must be specified, but also the language chosen should be rich enough to allow specification of complex properties of the system under design. This requires a language rich enough to operate at these different levels. The Temporal Trace Language used in this paper is suitable for that. The paper shows that the analysis at the level of a design process as a whole and at subprocesses thereof is precise enough to allow for automatic simulation. Simulation allows the modeler to manipulate the specifications of the system under design to better understand the interlevel relationships in his design. The approach is illustrated by an example.

Dry Mixes for Self-Leveling Floors Based on Composite Binder

2019 ◽  
Vol 802 ◽  
pp. 101-112
Author(s):  
Ruslan Aharonovich Abramov ◽  
Maksim Sergeevich Sokolov ◽  
Meir Nisonovich Surilov ◽  
Svetlana Vyacheslavovna Derevianko
Keyword(s):  
Building Materials ◽  
World Market ◽  
Domestic Market ◽  
Composite Binder ◽  
Russian Market ◽  
Consumption Structure ◽  
Low Level ◽  
The World ◽  
First Time ◽  
Different Levels

Currently, dry mixes (CDM) play an important role in the development of the world market of building materials. The industry of construction and finishing materials in Russia is quite young: the first time the dry building mixes appeared on the Russian market in the late 1980s, the consumption structure of CDM in the domestic market the main share (70%) are in the adhesive and plasters. The use of other compositions, in particular mixtures for self – leveling floors, does not have significant volumes and often the reason for this is the lack of design solutions and the low level of qualification of specialists at different levels from workers to designers who do not own CDM technologies.

scholarly journals Screening Methods and Further Sources of Resistance to Peanut Rust1

1980 ◽  
Vol 7 (1) ◽  
pp. 10-12 ◽  
Author(s):  
P. Subrahmanyam ◽  
R. W. Gibbons ◽  
S. N. Nigam ◽  
V. R. Rao
Keyword(s):  
Relative Humidity ◽  
Irrigation System ◽  
Germplasm Collection ◽  
Sprinkler Irrigation ◽  
Test Material ◽  
Screening Methods ◽  
Point Scale ◽  
Sources Of Resistance ◽  
Moderately Resistant ◽  
Different Levels

Abstract A germplasm collection of 6000 peanut entries was screened for resistance to rust at ICRISAT, India. Preliminary field screening was done during the 1977 rainy season when a natural epidemic of rust was in progress. The cultivars or lines which were rated between 2 and 5 on a 9-point scale during this screening were further tested during the 1977/78 dry season employing an infector row system of susceptible cultivars and spreader plants systematically interplanted with the test material. High relative humidity was maintained in the field by operating an overhead sprinkler irrigation system. Percentage leaf area damaged on the test material was estimated at 10 day intervals from approximately 90 days after their emergence until harvest. Each entry was also assessed on a scale proposed by Mazzani and Hinojosa. Two land races, NC.Ac. 17090 and EC. 76446 (292) were more resistant than either PI. 259747 or PI. 298115 which were reported resistant by other workers. In addition, NCAc. 17030, NCAc. 17132, NC.Ac. 17129, NC. Ac. 17135 and NC.Ac. 17124 were moderately resistant. Four cultivars or lines with different levels of resistance in the field were tested in the greenhouse at three different stages in development. The results indicated that resistance increased as the plants aged.

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