Effect of Zeolite on the Compressive Strength of Concrete with Different Types of Cement

Concrete is a material component in coastal area construction. With the increasing demand for concrete for construction purposes, there have been various innovations in concrete mixtures to improve the quality of the concrete, including the compressive strength value of concrete. In the concrete mixture, the researchers also add additive to the concrete mixture, one alternative is natural zeolite which is widely found in the earth. Research by testing concrete samples with variations of the zeolite mixture 0%, 15%, and 25% uses cement type V. The test results are then compared with the results of other studies using different types of cement. Comparative studies of zeolite concrete test with different types of cement show that the optimum proportion of zeolite is around 10% to 20% of the weight of cement to get the best compressive strength value.

Polyethylene Terephthalate Waste Utilisation for Production of Low Thermal Conductivity Cement Sand Bricks

There is a tremendous increase in plastic waste that negatively impacts the environment due to various industrial activities. Furthermore, plastic waste has non-biodegradable properties that make it hard to reduce its accumulation around the globe. Hence, this study aims to investigate the possibility of incorporating Polyethylene terephthalate (PET) waste as a partial replacement material of sand to improve the thermal insulation properties of cement sand brick by looking at findings of low thermal conductivity value. The study uses a PET plastic bottle that has been cut into small flakes and grind using a granulator machine to produce PET waste granules whose size is not more than 5 mm, similar to the sand size. This waste was added to other raw materials, i.e., cement and sand. The percentages of PET waste vary from 2.5%, 5%, and 7.5% by weight. This study produced two types of samples, i.e., control brick and PET waste cement sand brick. All samples undergo laboratory works involving geotechnical gradation, physical, mechanical, and thermal conductivity testing. Based on the results obtained, the optimum proportion of PET waste replacement in cement sand bricks making is 5% by its having the lowest thermal conductivity value of 0.581 W/mK and meeting the standard requirements of 3.90 MPa > 3.45 MPa (ASTM C129-11 for compressive strength), and 2,146 kg/m3 > 2,000 kg/m3 (ASTM C129-11 for normal weight non-loadbearing brick). Thus, PET plastic bottle waste can be a potential partial sand replacement material in cement sand bricks. Its potential to enhance the thermal conductivity of existing cement sand brick reduces sand consumption, solves plastic waste problems, and promotes a better environmentally-friendly construction industry.

The Performance Modeling of Modified Asbuton and Polyethylene Terephthalate (PET) Mixture Using Response Surface Methodology (RSM)

We often use the plastics daily, containing of polyethylene plastic polymers which recently can be utilized as additional material for road pavements. Several studies have attempted to find the optimum proportion of an asphalt mixture using modified Asbuton which is local bitumen abundantly deposited in Buton Island Indonesia, added with plastic waste. The optimum proportion of the asphalt mixture is influenced by many factors, such as the interactions of the material component in the asphalt mixture. To obtain the optimum proportion based a single factor, many studies employ statistical methods. This study aims to determine the optimum proportion for the asphalt mixture of the modified Asbuton with PET plastic waste by using a Response Surface Methodology (RSM). The employed RSM is the Expert Version 12 design (Stat-Ease, Inc., Minneapolis, MN, USA, 2020), in which the statistical modeling based on Box Behnken Design (BBD) and three factorial levels. The results obtained in this study show that the RSM optimization could achieve the asphalt mixtures characteristics including the stability, Marshall Quotient (MQ), Void in MIX (VIM), Void Mineral Aggregate (VMA) and density, in the level of satisfying the specification requirements of Ministry of Public Works of Indonesia. The optimum stability is at 2002.72 kg, fulfilled the minimum density of 800 kg. For the MQ, the optimal point of MQ is 500.68 kg/mm, satisfied the minimum the MQ standard minimum of 250 kg/mm. In addition, the optimal VIM is at 3.40%, satisfying the VIM specifications in the range of 3–5%. The optimal VMA response is at 21.65%, which is also satisfied the VMA specification, 15%.

Pemanfaatan FIy Ash Sebagai Substitusi Semen Dan Batu Gamping Sebagai Agregat Pada Beton

FIy Ash is a waste combustion combustion system and one of the pozzolanic mixed minerals found in Indonesia. An environmentally friendly concrete technology innovation to reduce the use of cement and river stone, namely utilizing FIy ash as a substitute for cement and limestone as an aggregate for concrete mixtures. This study aims to see the mechanical properties of concrete and the optimum proportion of FIy ash in the concrete mixture with limestone as coarse aggregate. The percentage of FIy ash used varies, namely 0%, 10%, 15%, and 20%. Concrete compressive strength testing is carried out when the concrete is 7 days, 21 days, and 28 days old with a compressive strength plan of 25 MPa. For the flexural strength and split tensile strength test, it is carried out when the concrete is 28 days old. The research used 48 cylinders 150 x 300 mm, 12 beams measuring 150 x 150 x 600 mm, carried out at the Laboratory of Civil Engineering Structures, PauIus Christian University of Indonesia, Makassar. The observation results show that the influence of FIy ash as a substitute for cement with limestone aggregate for concrete, produces concrete with compressive strength, flexural strength, and tensile strength, the maximum is 27.56 MPa, 2.50 MPa, respectively. and 4.68 MPa for normal concrete with the optimum use proportion of FIy ash 15%.

STUDY OF KINETICS MODEL OF FLAVONOID TOTAL RELEASE IN PATCH OF ANTIHYPERTENSIVE HERBS

The liquid extract of antihypertensive herbs could reduce blood pressure equivalent to Hydrochlorothiazide 25 mg based on research conducted in “Hortus Medicus” clinic, Tawangmangu, Central Java, but parameters of herbal medicine taste, design, and packaging had the lowest scores. Transdermal patch was chosen as an alternative to resolve those problems. Polymers determined the effectiveness of the active substance release from the formula. Patch was formulated from combination of hydrophilic hydroxy methylcellulose (HPMC) and carboxymethylcellulose natrium (CMC-Na) polymer which would produce a fast release profile. The objective of this research was to study the kinetics models of total flavonoid release and to study the total number of flavonoids released from the antihypertensive herbs patch for 5 hours, as well as to determine the optimum formula for observing the weight, pH and loss on drying. Herbs were infused with distilled water at 90 ° C for 15 minutes, filtered then evaporated. Release kinetics model used a modified type-5 dissolution apparatus equipment with a cellophane membrane. The optimum proportion of HPMC and CMC-Na was 220:180 mg. Patch was dark brown, circle shaped, moist and flexible. It had pH value of 7.29 ± 0.09, folding endurance of >350, and thickness of 0.64 ± 0.05 mm. The average percentage of total flavonoids released from the matrix patch was 37.23% for 5 hours. The release kinetics followed the Higuchi kinetics model with a diffusion mechanism.

Fabrication and Evaluation of Mechanical and Tribological Properties of ultra-high-molecular-weight polyethylene-based Nanocomposites Reinforced with Hydroxyapatite, Zirconia and Multi-walled Carbon Nanotubes

The unique properties of ultra-high-molecular-weight polyethylene (UHMWPE) have made composites based on this polymer the gold standard choice for articulating surfaces used in arthroplasty. However, wear debris released by prosthesis is still a major concern of the implants. In this study, we address the urgent need to revisit the current methodologies used in designing these biomaterials by fabricating UHMWPE-based nanocomposite with Hydroxyapatite (HA), Multi-walled Carbon Nanotubes (MWCNTs), and Zirconia as additives. We investigated how different combinations of these additives impact the nanocomposites' hardness, plasticity index (PI), and friction coefficient. Our results show a constant increase in hardness by increasing Zirconia. The MTT assay test and Scanning Electron Microscopy (SEM) demonstrated an increase in cell attachment and cell viability. Examining various additives' amounts, we can further explore the possibility of reaching an optimum proportion of the ingredients. Compared with other UHMWPE-based nanocomposites (UHMWPE-HA-MWCNT's), the fabricated nanocomposite shows an improvement in tribological properties.

Optimization of the Proportion of Surfactant, Co-Surfactant, and Candlenut Oil for Self-Nanoemulsifying Drug Delivery System (SNEDDS) of Secang Heartwood (Caesalpinia sappan L.) Methanolic Extract

<p class="MsoNormal" style="margin-bottom: 0.0001pt; text-align: justify; text-indent: 21.3pt; line-height: normal; background-image: initial; background-position: initial; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial;">This study aimed to determine the optimum proportion of hazelnut oil, surfactants, and cosurfactants for SNEDDS of Secang Heartwood using the simplex lattice design (SLD) method using the Design-Expert software. The SNEDDS formula was prepared using Tween 80 and Croduret 50 ss as surfactants, propylene glycol as cosurfactant, and candlenut oil based on physical stability parameters: formula transmittance (%), separation phase, and emulsification time. The optimum SNEDDS formula was compared with the predictive value [p&gt; 0.05] provided by the SLD; then extract the loading dose, accelerated stability test, analysis of particle size, and zeta potential. The optimum proportion of Tween 80-Croduret 50 ss, propylene glycol, and hazelnut oil, based on the SLD, was 62.43%; 22.57%; and 15.0%. The results showed that the transmittance was 93.2%; emulsification time was 74.67 seconds, and; separation phase was 0.89. The SLD's predictive values of the transmittance percentage, emulsification time, and separation phase were 94.98%, 78.97 seconds, 0.84, respectively. The results of the one-sample <em>t</em>-test statistical analysis showed no significant difference between the observative and predictive results. SNEDDS was found capable of loading 25.0 mg of secang heartwood methanolic extract in each system, with a particle size of 23.2 nm, a polydispersity index of 0.142, and zeta potential of +20.8 mV.</p>

Mechanical Behaviour of Normal Concrete using Fibre of Pine Tree Needle Leaves

This research was carried out to study the behaviour of concrete, specifically flexural strength, by incorporating two types of pine needle leaves (green, and brown) recycled as fibre reinforcement in the concrete. The other goal of the study is to compare the two types of fibre and determine the maximum proportion of fibre to be added in the normal concrete. OPC concrete with 0%, 1% and 2% pine needle leaves fibre (green, and brown) was prepared based on the total weight of the mixture. At an ambient temperature of 28 ± 2°C, the specimens were checked for flexural strength (FS). Laboratory test results based on short term investigation reveals that the flexural strength of concrete containing brown pine fibre (BPF) is higher than that of Green pine fibre (GPF), and also higher than normal (OPC) concrete. The optimum proportion of pine needle leaf fibre is the brown fibre (fallen leaves) to be added in the concrete as fibre is 1% by the total weight of the mixture, which gave a positive reaction from the test that was performed.

Removal of PAHs from Wastewater Using Powdered Activated Carbon: A Case Study

The aim of this study was to develop immobilized microorganism carrier for effectively degradation of petroleum hydrocarbons (PAHs), especially pyrene. Powdered activated carbon (PAC) was used to immobilize the bacterial consortium (Klebsiella pneumoniae and Pseudomonas aeruginosa) with binder CaCl2 and sodium alginate (SA) for improving mass transfer rate of the pyrene pollutants. Mass transfer properties, embedding ratio, and mechanical strength were inspected for the immobilization particles. Mechanical strength of SA beads was more influenced by proportion of SA and CaCl2 than by proportion of PAC. The optimum proportion of SA, CaCl2 and PAC were 2.5%, 2% and 0.5% for immobilization SA beads. The degradation of bacterial consortium (Pa+Kp) had the best degradation rates at 48.2% on 14 days. SA embedding immobilization by adding PAC can obviously enhanced effect of pyrene degradation because of bacterial absorption ability and nutrient permeability being improved.

Removal of PAHs from Wastewater Using Powdered Activated Carbon: A Case Study

The aim of this study was to develop immobilized microorganism carrier for effectively degradation of petroleum hydrocarbons (PAHs), especially pyrene. Powdered activated carbon (PAC) was used to immobilize the bacterial consortium (Klebsiella pneumoniae and Pseudomonas aeruginosa) with binder CaCl2 and sodium alginate (SA) for improving mass transfer rate of the pyrene pollutants. Mass transfer properties, embedding ratio, and mechanical strength were inspected for the immobilization particles. Mechanical strength of SA beads was more influenced by proportion of SA and CaCl2 than by proportion of PAC. The optimum proportion of SA, CaCl2 and PAC were 2.5%, 2% and 0.5% for immobilization SA beads. The degradation of bacterial consortium (Pa+Kp) had the best degradation rates at 48.2% on 14 days. SA embedding immobilization by adding PAC can obviously enhanced effect of pyrene degradation because of bacterial absorption ability and nutrient permeability being improved.