scholarly journals Eco-Friendly Fired Brick Produced from Industrial Ash and Natural Clay: A Study of Waste Reuse

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 877 ◽  
Author(s):  
Neslihan Doğan-Sağlamtimur ◽  
Ahmet Bilgil ◽  
Magdalena Szechyńska-Hebda ◽  
Sławomir Parzych ◽  
Marek Hebda
Keyword(s):  
Compressive Strength ◽  
Bottom Ash ◽  
Unit Weight ◽  
Waste Reuse ◽  
Industrial Solid Waste ◽  
Second Stage ◽  
Before And After ◽  
Fired Bricks ◽  
Two Stages ◽  
And Storage

Bottom ash (BA) is an industrial solid waste formed by the burning of coal. The environmental problems and storage costs caused by this waste increase with every passing day. In this study, the use of BA as an additive (clay substitute) in fired brick production was investigated. The study consisted of two stages. In the first stage, cylinder blocks were produced from clay used in brick production. The second stage was the examination of the experimental substitution of clay with 10, 20, 30 and 40% BA. Samples were fired at 900, 1000, 1100 and 1150 °C to produce fired brick samples. The unit weight, compressive strength (before and after freeze–thawing) and water absorption were analyzed for the samples. The unit weight values decreased in the samples containing BA. The mechanical properties met the conditions prescribed in the relevant standards; i.e., all of the samples fired at 1100 and 1150 °C had a sufficient compressive strength over 20 MPa. The high potential of fired bricks for the construction industry was proved. BA can be used as a clay substitute, while the developed protocol can be used to effectively produce fired bricks.

scholarly journals Awareness of COVID-19 Before and After Quarantine Based on Crowdsourced Data From Rabigh City, Saudi Arabia: A Cross-Sectional and Comparative Study

2021 ◽  
Vol 9 ◽  
Author(s):  
Mai Aldhahri ◽  
Rana Alghamdi
Keyword(s):  
Saudi Arabia ◽  
Online Survey ◽  
Control Measures ◽  
Infection Prevention And Control ◽  
Cross Sectional ◽  
Second Stage ◽  
Before And After ◽  
Prevention And Control Measures ◽  
Two Stages ◽  
And Control

Background: Infection prevention and control measures are critical for the prevention of the spread of COVID-19.Aim: In this study, we aimed to measure and evaluate the level of awareness and knowledge of the prevention, symptoms, and transmission control of COVID-19 before and after quarantine among the residents of Rabigh city and adjacent villages in Saudi Arabia.Methods: A cross-sectional online survey was conducted in two stages: the first stage took place before quarantine and the second stage took place after quarantine. The survey was filled out electronically.Results: A total of 448 participants responded and filled out the questionnaires. Females (73.70%) formed the largest number of participants for both stages. The majority of the participants were <30 years old (50.90%) and had a high education level in various sectors and levels (97.1%). It was noticeable that during the first stage, the participants' awareness of COVID-19 symptoms was not very high: 13.62% did not know about the symptoms. However, by the second stage, awareness about symptoms had increased (9.6%).Conclusion: The residents of Rabigh city and the surrounding villages had good levels of knowledge about COVID-19.

Rubberised fabric for fuel soft storage tanks*

2018 ◽  
Vol 45 (7) ◽  
pp. 322-324
Author(s):  
Yu.N. Rybakov ◽  
A.V. Dedov ◽  
D.S. Plokhoi ◽  
D.V. Kolotilin
Keyword(s):  
Diffusion Processes ◽  
Motor Fuel ◽  
Residual Monomer ◽  
Experimental Conditions ◽  
Second Stage ◽  
Before And After ◽  
Nitrile Rubbers ◽  
Two Stages ◽  
Kinetics Of

The kinetics of extraction of dibutyl sebacinate by different grades of motor fuel from rubberised fabric based on a blend of nitrile rubbers SKN-26M and SKN-40M was investigated. The kinetics was determined according to the GOST 9.030-74 standard from the change in weight of the specimen after holding in fuel at 50°C and drying. The change in quality of the fuel after contact with the fabric was recorded from the change in the content of existent gum in fuel according to GOST 1567-97 (ISO 6246-95) and its acidity according to GOST 5985-79 before and after contact with the rubberised fabric. It was shown that the process of extraction proceeds in two stages, the time of the first of which under experimental conditions is not dependent on the type of fuel. The rate of the first stage is much higher than the rate of the second stage. The relation of rates and proportion of extracted fuel at the first and second stages depends on the type of fuel. It can be asserted that the surplus amount of extracted substances is made up of impurities, which include residual monomer or its derivatives and substances used in the synthesis of the rubber. The mechanism of extraction with extractant counterflow into the vulcanisate and its dependence on the grade of petrol is proposed, based on allowance for the diffusion processes in the system.

scholarly journals Bentonite-based composites with ceramic and metallic powders additions for use as filters

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110118
Author(s):  
Simona Matei ◽  
Maria Stoicanescu ◽  
Varga Bela ◽  
Elena Tiron ◽  
Aurel Crisan
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Compressive Strength ◽  
Pore Size ◽  
Ceramic Powders ◽  
Metallic Particles ◽  
Metallic Powders ◽  
Second Stage ◽  
Two Stages ◽  
Cylindrical Samples

This paper represents the study of bentonite matrix composite reinforced with ceramic (Al2O3 and SiC) and metallic (Al and Fe) particles for the production of filters. Ceramic powders were used to generate pores and metallic particles to control the pore size (to finish them). These materials were added to composites in two stages. In the first stage, the ceramic particles (Al2O3 and SiC) were added to the bentonite matrix, thus obtaining two types of composites. In the second stage, for each type of composite, metallic powders of Al and Fe were added. The composites was prepared by mixing the components, cold pressing for compaction in cylindrical samples and, at the end, sintering at 1250°C. The samples thus produced underwent studies by optical and electron microscopy, diffractometry, dilatometry and thermal analysis and tests to determine the compressive strength and the porosity. Thus, there was obtained useful information regarding the behaviour and impact of the reinforcing materials in the process of producing the composites, and on their impact on the final properties of the composites produced.

scholarly journals Two phase leaching for metal recovery from waste printed circuit boards: Statistical optimization

2021 ◽  
pp. 22-22
Author(s):  
Manikkampatty Murugesan ◽  
Kannan Kandasamy ◽  
Venkata Myneni
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Circuit Boards ◽  
Two Phase ◽  
Aqua Regia ◽  
Printed Circuit ◽  
Second Stage ◽  
Waste Printed Circuit Boards ◽  
Before And After ◽  
Two Stages

The rapid growth of technology plays an inevitable role in humankind?s life and has a significant stint in the generation of e-waste. The electronic waste possess tremendous environmental and health effects and one such major contributor to it is printed circuit boards (PCBs). The present work deals with the recovery of heavy metals from PCBs by using aqua regia as leaching reagent by two stages (first stage HCl and HNO3 and second stage HCl and H2SO4). The studies carried by Response surface methodology (RSM) to determine the optimal conditions of recovery for the heavy metal ions showed that time 5 hrs, pulp density 25 gm L-1, and temperature 90.10C with desirability 0.761. These optimized values provide maximum recovery rate of Cu (97.06%), Sn (94.66%), Zn (96.64%) and Pb (96.89%) respectively. EDXs is used to analyze the metal concentrations of the sample before and after treatment.

Variations in the Short- and Long-Term Characteristics of Bridge Concrete Due to Transportation Techniques

2000 ◽  
Vol 1698 (1) ◽  
pp. 36-44
Author(s):  
Nur Yazdani ◽  
Michael Bergin ◽  
Ghulam Mujtaba
Keyword(s):  
Compressive Strength ◽  
Chloride Ion ◽  
Unit Weight ◽  
Concrete Durability ◽  
Long Term Effects ◽  
Chloride Permeability ◽  
Highway Projects ◽  
Air Content ◽  
Before And After

The short-term effects of pumping on concrete are well documented, although the long-term effects on concrete durability are not known. Pumping of concrete is widely used in large highway projects because of its convenience and economy of placement. Both types of effects were studied through collection and testing of 73 concrete samples from the Florida Department of Transportation (FDOT) bridge construction sites before and after pumping. The tests performed were air content, slump, unit weight, compressive strength, rapid chloride permeability, and water permeability. The air content and the slump of concrete decreased by about 1 percent and 13 mm (0.5 in.) on average, respectively, due to pumping. The unit weight and compressive strength of concrete increased by about 24 kg/m3 (1.5 pcf) and 1.83 MPa (266 psi), respectively, due to pumping. Pumping decreased the water and chloride ion permeabilities in the majority of tested samples. Results show that pumping does not have detrimental effects on concrete properties; in fact, in many cases, it results in stronger, denser, and more durable concrete. Results indicate that pumping can be continued with confidence as a means of concrete placement in FDOT projects.

scholarly journals Ukrainian banking system efficiency after double reducing of the number of bank institutions

2018 ◽  
Vol 13 (4) ◽  
pp. 51-60 ◽  
Author(s):  
Olena Prymostka ◽  
Liudmyla Prymostka
Keyword(s):  
Banking System ◽  
Financial Indicators ◽  
System Efficiency ◽  
Second Stage ◽  
Effective Period ◽  
Banking Activity ◽  
Before And After ◽  
System Functioning ◽  
And Performance ◽  
Two Stages

The article intends to evaluate the efficiency and performance of Ukrainian banking system based on two stages. The first stage, when the number of banks was on average the same during that period, and the second stage, that began in 2015 and when the number of banks began to fall quickly up to 82 institutions in 2018. The study is based on the model of dynamics norm of the banking system efficiency for two periods.The concept of efficiency was used based on the methods of non-parametric statistic to obtain performance estimates. The implementation of a dynamic model, based on the peculiarities of the banking system functioning, allows to obtain a generalized assessment of the economic efficiency of banking activity before and after critical change in the number of bank institutions. The correlation matrix between financial indicators of the banking system activity was created and the dynamic norm for the two periods was calculated. Given the analytical comparison of indicators, more effective period was identified. The general results of the study indicate that the overall efficiency of the banking system started to grow up since 2015.

scholarly journals Edukasi Etika Bisnis dan Investasi Syariah Bagi Pengelola dan Anak Asuh Yayasan Islamadina

2018 ◽  
Vol 2 (1) ◽  
pp. 124-135
Author(s):  
Tony Seno Aji ◽  
Yuyun Isbanah ◽  
Anang Kistyanto ◽  
Andre Dwijanto Witjaksono ◽  
Budiono Budiono
Keyword(s):  
Business Ethics ◽  
Wilcoxon Test ◽  
Test Results ◽  
Ethical Business ◽  
Second Stage ◽  
Simulation Techniques ◽  
Level Of Satisfaction ◽  
Before And After ◽  
Two Stages ◽  
Selection Of

       The orphanage's foundation has largely begun to grow the business. This is a form of development of financial independence. Orphanages no longer fully expect to fund from donors. In line with the above, the ability to manage ethical business and selection of sharia investment alternatives need to be understood by foundation managers and residents of orphanages. Training implementation methods using lecture, discussion, test, and simulation techniques. Training is carried out in two stages. The first stage of learning business ethics and sharia investment. The second stage is the simulation of investment instrument transactions. The target to be achieved is the acquisition of knowledge of managers/administrators and residents of orphanages related to business ethics and sharia investment instruments. Education of Business Ethics and Sharia Investment for the Managers and residents of Yayasan Islamadina was held on October 15, 2017. The activity was attended by 41 people. The results of the evaluation show that the level of satisfaction of the training and the ability of the resource persons are included in the high category. The results of the activities increased participants' understanding of business ethics and sharia investment instruments between before and after the training. This is demonstrated by the Wilcoxon Test results which show there are differences in pretest value with the posttest value, the conclusion there is increasing participants' understanding of the business ethics and sharia investment instruments between before training with after training.

scholarly journals Investigation on Recycled Sawdust in Controlling Sulphate Attack in Cemented Clay

2020 ◽  
Vol 10 (4) ◽  
pp. 1441 ◽  
Author(s):  
Amin Chegenizadeh ◽  
Mahdi Keramatikerman ◽  
Stefano Miceli ◽  
Hamid Nikraz ◽  
Ayad Salih Sabbar
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Dry Density ◽  
Main Body ◽  
Sulphate Attack ◽  
Maximum Dry Density ◽  
Second Stage ◽  
Third Stage ◽  
Before And After ◽  
Micro Analysis

Application of sawdust in civil engineering projects, specifically those with geotechnical applications, has been the interest of many studies. This study focuses on exposure of soil samples treated with sawdust to MgSO4. This study was conducted in three stages. The first stage was compaction. In this stage, the compaction characteristics of each mixture were derived. The second stage was to run unconfined compressive strength (UCS) testing and report the UCS peaks relevant to each mixture. The third stage was microstructural examination (i.e., SEM) conducted on the chosen samples before and after sulphate exposure to highlight the reactions during exposure. The results of first stage (i.e., compaction tests) suggested that increasing sawdust content, the OMC (Optimum moisture content) decreased and MDD (Maximum dry density) decreased. In the second stage, the UCS (Unconfined compressive strength) testing was conducted on 640 samples [including reliability tests] and the outcome suggested that sawdust increased the resistance of samples against sulphate attack. In stage three, the micro analysis backed the main body results, suggesting that sawdust had a positive effect on helping to form a better connection between the particles and therefore more resistance noted.

Behavior of Cement Pastes and Mortar Containing Phosphogypsum

2015 ◽  
Vol 668 ◽  
pp. 181-188 ◽  
Author(s):  
Hanan El Nouhy ◽  
Enas Khattab ◽  
Sayieda Zeedan
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Blended Cement ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
Initial Setting Time ◽  
Second Stage ◽  
Setting Times ◽  
Initial Setting ◽  
Two Stages

The aim of this study is to investigate the effects of phosphogypsum on the properties of both cement pastes and mortars. Normal Portland cement CEM Ι 32,5N, Limestone Blended cement CEM ΙΙ B-L32,5N, and Slag cement CEM ΙΙ A-S32,5N were used. These cements were partially substituted by 0,2,4,6,8,10,and 15% of phosphogypsum. The test program was divided to two stages. In the first stage, tests were conducted according to BSEN 196, namely setting times (initial and final), soundness, and compressive strength (at ages 7 and 28 days). In the second stage, X-ray diffraction (XRD), and scanning electron microscope (SEM) were conducted on selected mixes from first stage. The results show that the three types of cements with the various replacement percentages of phosphogypsum met the limit of initial setting time, as well as, provided soundness of 2 mm. Also, in terms of compressive strength, it was proven, that it is possible to partially replace the three tested types of cements by phosphogypsum by up to 8%and 15% with regard to cement/sand ratio of (1:3) and (1:2) respectively.

Properties of Cement-Based Materials Containing Melting Incinerator Bottom Ash

2011 ◽  
Vol 250-253 ◽  
pp. 834-838 ◽  
Author(s):  
An Cheng ◽  
Hui Mi Hsu ◽  
Sao Jeng Chao ◽  
Wei Ting Lin ◽  
Hao Hsien Chen ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Particle Size ◽  
Compressive Strength ◽  
Portland Cement ◽  
Bottom Ash ◽  
Pozzolanic Activity ◽  
Unit Weight ◽  
Maximum Particle Size ◽  
Cement Based Materials ◽  
Maximum Particle

This paper presents an experimental investigation on the effect of incinerator bottom ash (IBA) fineness and the cooled process of molten IBA on fresh mortar properties and compressive strength of hardened mortars. IBA with two finenesses, an original IBA, and a pulverizing incinerator bottom ash (PIBA) powder, with maximum particle size of 4.75 and 0.074 mm respectively were used to partially replace sand and Portland cement at 0%, 10%, 20%, 30%, and 40% by weight. The pozzolanic activity characteristics of powder were obtained from melting the above PIBA in an electric-furnace at 1450 °C for 1 h. and chilled by quenching in water (WIBA) and air (AIBA). Results indicate that incinerator bottom ash caused a reduction in compressive strength, unit weight, and flowability values when used as a replacement for sand and cement. However, IBA can be processed by melting to regain reactive pozzolanic activity, which may be used to partially replace cement.

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