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Full-Text Articles in Engineering

Behavior Of Concrete Mixes Using Recycled Aggregate Confined With Steel Sections, Latifa Sobhi Kassem, Adnan El-Masri, Nour Webhi Dec 2023

Behavior Of Concrete Mixes Using Recycled Aggregate Confined With Steel Sections, Latifa Sobhi Kassem, Adnan El-Masri, Nour Webhi

BAU Journal - Science and Technology

Recycled Concrete Aggregate (RAC) is a form of recycled concrete that has been studied for green building for the past 50 years. It can be used to create strong structures, such as seismic retrofitting of earthquake-prone structures. Studies have attempted to experimentally study the effect of using recycled aggregate in concrete, but the literature lacks the use of recycled concrete aggregate rapped with steel rings. This study examines the behavior of circular concrete columns with different percentages of recycled aggregate. It examines the behavior of a column with different percentages of recycled aggregate, one without jacketing, one with partial jacketing, …


Isolation And Characterization Of Caffeine-Degrading Bacteria From Coffee Plantation Areas In Malaysia, Elvina Clarie Dullah, Mohd Fazli Farida Asras Dec 2023

Isolation And Characterization Of Caffeine-Degrading Bacteria From Coffee Plantation Areas In Malaysia, Elvina Clarie Dullah, Mohd Fazli Farida Asras

Makara Journal of Technology

Decaffeination by microbial degradation is currently the most optimal and low-cost approach, involving only microbial cells and/or their enzymes. The bacterium was characterized using a series of biochemical tests. Positive results were obtained from carbohydrate fermentation, citrate utilization, and catalase tests, while negative results were obtained from Voges-Proskauer (VP) and indole tests. Three different caffeine concentrations of 0.25%, 0.4%, and 2% were tested and measured through Gas Chromatography-Mass Spectrophotometry (GC-MS) analysis. The highest caffeine reduction (89.25%) was found when 0.25% caffeine was used in the media. Only a small amount of caffeine was reduced to 0.4% and 2%, with 34.78% …


Optimization Of The Building Envelope And Roof Shading To Reduce The Energy Consumption Of College Low-Rise Buildings In Indonesia, Nasruddin Nasruddin, Azimil Gani Alam, Mohammad Imroz Sohel Dec 2023

Optimization Of The Building Envelope And Roof Shading To Reduce The Energy Consumption Of College Low-Rise Buildings In Indonesia, Nasruddin Nasruddin, Azimil Gani Alam, Mohammad Imroz Sohel

Makara Journal of Technology

Energy consumption in buildings is a crucial concern globally, prompting researchers to explore innovative solutions to mitigate its impact. This study investigates the optimization of building envelopes and roof shading systems of existing buildings in Indonesia to realize notable energy savings. Multiple scenarios were explored, with modifications to building envelopes and roof shading, highlighting the overall thermal transfer value as a key parameter. Using EnergyPlus simulations, the efficacy of natural ventilation in corridors and roof shading modifications was assessed in reducing energy consumption. The findings revealed that renovating existing buildings by optimization of the building envelope and roof shading by …


Effect Of Lime Content, Curing Temperature, And Aging Condition On Low-Alkaline Concrete, Mahdi Parsa Pour, Reza Shaban Sharghi, Faezeh Nejati, Elmira Khaksar Najafi Dec 2023

Effect Of Lime Content, Curing Temperature, And Aging Condition On Low-Alkaline Concrete, Mahdi Parsa Pour, Reza Shaban Sharghi, Faezeh Nejati, Elmira Khaksar Najafi

Makara Journal of Technology

This study determines how curing temperatures, aging condition, and hydrated lime contents affect the unconfined compressive strength (UCS), modulus of elasticity, and workability of low-alkaline concrete. Samples were prepared in two different groups to determine the optimum hydrated lime content and aging conditions to assess the mutual effect of NaOH molarity and curing temperature, that is, 70 °C for 48 h or room temperature, on samples with and without lime. The results showed that the increase in hydrated lime content affected alkali concentration. The samples with lime exhibited a clear peak in UCS (6 M NaOH) compared with the continuous …


Challenges In Optimization For The Performance On Sustainability Dimensions In Reverse Logistics Social Responsibility, Sumarsono Sudarto, Katsuhiko Takahashi, Mochammad Dewo Aug 2023

Challenges In Optimization For The Performance On Sustainability Dimensions In Reverse Logistics Social Responsibility, Sumarsono Sudarto, Katsuhiko Takahashi, Mochammad Dewo

Makara Journal of Technology

Reverse logistics social responsibility is preferred as the most acceptable solution for addressing the challenges in stakeholders’ debate regarding social responsibility in supply chains because it involves as many actors as possible in the supply chain to perform social responsibility to achieve sustainability. This paper explores the challenges in achieving optimal policies in sustainability dimensions for collection and recycling facilities in reverse logistics. Sustainability dimensions include economic, environmental, and social aspects. The reverse logistics is modeled on System Dynamics, and a simplified statistical analysis using a contour chart is employed in numerical experiments. Results show a narrow area of optimal …


Investigating The Resistance Properties Of Concrete Containing Waste Carpet Fibers, Faezeh Nejati, Ali Mahboobi Aug 2023

Investigating The Resistance Properties Of Concrete Containing Waste Carpet Fibers, Faezeh Nejati, Ali Mahboobi

Makara Journal of Technology

This research was conducted with the aim of investigating the use of waste carpet fiber (WCF) and assessing the resistance properties of concrete. The main goal of this study was to investigate the effect of the internal processing of concrete containing WCF on increasing its resistance properties. At the same time, the secondary goals pursued in the research included determining the optimal percentages of carpet fibers in improving compressive strength, tensile strength, and bending strength. The materials used included cement, aggregates, water, WCF, and super lubricant. This research applied seven mixing designs: A, B1, B2, C1, C2, D1, and D2. …


Improving Square Skirted Foundations Behavior On Sand, Tamer Al-Shyoukhi, Ayman Altahrany, Mahmoud Elmeligy Aug 2023

Improving Square Skirted Foundations Behavior On Sand, Tamer Al-Shyoukhi, Ayman Altahrany, Mahmoud Elmeligy

Mansoura Engineering Journal

Shallow foundations' behavior is enhanced by using skirts to confine the soil beneath the foundation. The bearing capacity and settlement of skirted foundations resting on the sand are influenced by the size of the skirt cell and shear strength of sand. Experimental modelling was carried out on an axially square-skirted footing resting on sand in this study. Plaxis-3D software was used for numerical analysis to support the experimental results. The numerical analysis results validated the experimental results. The outcomes of the study demonstrated that skirts wider than the footing size increased the bearing capacity of skirted foundations. In the case …


Recent Developments In Timber Design & Its Impact On Carbon Emissions, Raquel Jackson Jun 2023

Recent Developments In Timber Design & Its Impact On Carbon Emissions, Raquel Jackson

Spectra Undergraduate Research Journal

This paper explores recent developments in timber building designs and its potential towards reducing carbon emissions. Carbon dioxide emissions are a growing issue worldwide as urbanization and industrialization continues to increase. The rising concentration of carbon dioxide emissions pose significant concerns towards public welfare and environmental health. Despite current methods to reduce greenhouse gasses, carbon emissions remain difficult to reduce from steel and concrete industries. Increasing timber use in building design is a possible solution. Increasing more timber in building design can help reduce carbon emissions due to the carbon-absorbing properties of the construction material. Timber as a construction material …


Gömböc The Great, Indigo M. Strickert, Lori E. Bradford Feb 2023

Gömböc The Great, Indigo M. Strickert, Lori E. Bradford

The STEAM Journal

A sonnet written about the mathematics behind the self-righting shape of some tortoise shells.


Comparison Between Different Codes In Design Cold-Formed Steel Lipped Channel Section Subjected To Axial Load Or Bending Moment, Samar El-Sayed Ibrahim Atya, Ahmed Hussain Ali Abdelrahman, Fikry Abdo Salem, Nabil Sayed Mahmoud, Mohamed Ghannam Jan 2023

Comparison Between Different Codes In Design Cold-Formed Steel Lipped Channel Section Subjected To Axial Load Or Bending Moment, Samar El-Sayed Ibrahim Atya, Ahmed Hussain Ali Abdelrahman, Fikry Abdo Salem, Nabil Sayed Mahmoud, Mohamed Ghannam

Mansoura Engineering Journal

This paper presents a comparative analysis between Eurocode3 (EC3), the North American Specification (AISI), and the Egyptian Code of Practice (ECP-205) to design Cold-Formed Steel (CFS) compression and flexural members with channel profiles. The research recognizes similarities and variations in strength measures to facilitate the learning process in the design codes, as well as the expressions and limits provided in the ECP, EC3, and AISI design codes. A computer program was designed to improve the speed of the calculation process. The software was created utilizing the C+ programming language and was programmed to calculate the axial load and bending moment …