FRESH STATE AND MECHANICAL PROPERTIES OF ULTRA-LIGHTWEIGHT FOAMED CONCRETE INCORPORATING ALKALI TREATED BANANA FIBRE

For a Lightweight Foamed Concrete (LFC) to efficiently function as an energy-saving building material, its self-weight (density) should be reduced. However, the problem associated with a reduced density is a decline in strength. To improve the mechanical properties of LFC, this research attempts to integrate banana fibre into LFC composite with a focus on fresh and harden state properties. An Ultra-Lightweight Foamed Concrete (ULFC) with a density of 600 kg/m3 was produced with the inclusion of treated and untreated banana fibres. The volume fractions of banana fibre added into LFC were 0.00% (control specimen), 0.25%, 0.35%, 0.45% and 0.55%. In addition, an optimised batch mix of ULFC reinforced with 0.35% untreated banana fibre was produced. The batches were tested for rheological, physical, and mechanical properties. Findings reveal that the workability of ULFC composites decrease with increase in fibre addition. The compressive, flexural, and tensile strengths of the alkali-treated composites were higher than the untreated banana fibre composite. SEM micrograph reveals that defibrillation of bundle fibrils due to cleaning the surface amorphous hemicellulose, lignin and pectin of the alkali-treated fibre, leads to rough surfaces and increase surface area resulting in better interfacial adhesion of the fibre with cement matrix.

I​nfluence of Treated POME Sludge Vermicomposting on Soil Physicochemical Properties and Maize Growth Performances

Background: Transforming the abundance of palm oil mill effluent (POME) sludge into beneficial substances such as an organic amendments is vital in the recycling of waste. Vermicomposting from treated POME sludge (TPS) was evaluated on the effect of soil physicochemical properties, crop performances and to determine the best treatment effect on the biomass of the hybrid grain maize (Zea mays L.). Methods: The experimental layout was designed in a randomized complete block design (RCBD). The grain maize cultivated in Bungor series soil (Ultisol) comprising of (T1) control (NPK fertilizer), (T2) 1 kg of vermicompost, (T3) 2 kg vermicompost, (T4) 1 kg TPS and T5 (2 kg TPS) with six replications, for a period of 100 days from June to September 2019. Half of the NPK fertilizer dosage applied from the recommended practices. Result: The treatments with 50% reduction of NPK rate significantly (p less than 0.05) affected soil physicochemical properties. The dry matter production, crop performance analysis (net photosynthesis, stomata conductance and transpiration rate) and root weight density were also increased significantly using 2 kg of vermicompost treatment. Vermicompost application demonstrated the best treatment effect on soil properties and grain maize productivity. Utilization of POME sludge waste into organic amendment through vermicomposting approach would become very crucial practices to be adopted in reducing the abundance waste.

A wireless radiofrequency-powered insect-scale flapping-wing aerial vehicle

Insect-scale aerial vehicles are useful tools for communication, environmental sensing and surveying confined spaces. However, the lack of lightweight high-power-density batteries has limited the untethered flight durations of these micro aerial vehicles. Wireless power transmission using radiofrequency electromagnetic waves could potentially offer transmissivity through obstacles, wave-targeting/focusing capabilities and non-mechanical steering of the vehicles via phased-array antennas. But the use of radiofrequency power transmission has so far been limited to larger vehicles. Here we show that a wireless radiofrequency power supply can be used to drive an insect-scale flapping-wing aerial vehicle. We use a sub-gram radiofrequency power receiver with a power-to-weight density of 4,900 W kg–1, which is five times higher than that of off-the-shelf lithium polymer batteries of similar mass. With this system, we demonstrate the untethered take off of the flapping-wing micro aerial vehicle. Our RF-powered aircraft has a mass of 1.8 g and is more than 25 times lighter than previous radiofrequency-powered micro aerial vehicles.

Properties and Environmental Features of Bricks Made From Textile Waste Sludge

In recent years, there has been a lot of attention paid to the use of textile sludge waste-based products in the building industry to develop ecologically friendly construction materials. An experimental examination of the characteristics of bricks incorporating textile sludge waste and fly ash is presented in this work. In fly ash bricks, fly ash is used to replace textile sludge waste in the following proportions: For the blend percentage of cement, fly ash, and quarry dust, a 230mm × 100mm × 75mm sample size was used. For varying amounts of the components indicated previously, the findings indicate how compressive strength and water absorption fluctuate with curing age. Then we can cast bricks with various mixed proportions of cement, sludge waste, fly ash, and quarry dust using the 230mm × 100mm × 75mm specimen size. After that, the weight, compressive strength, and water absorption of textile sludge with different concentrations of fly ash bricks were compared. This inquiry is primarily concentrated on maximizing the compressive strength of newly produced bricks while limiting weight density and water absorption through extensive laboratory work. The recognition of elements influencing the diverse qualities of bricks is a clear purpose of pursuing this issue as project work.

Material Behavior of 2D Steel Lattices with Different Unit-Cell Patterns

Over the past years, two-dimensional lattices have attracted the attention of several researchers because they are lightweight compared with their full-solid counterparts, which can be used in various engineering applications. Nevertheless, since lattices are manufactured by reducing the base material, their stiffnesses then become lower. This study presents the weight efficiency of the lattices defined by relations between the elastic modulus and the weight density of the lattices. In this study, the mechanical behavior of 2D lattices is described by the in-plane elastic modulus. Experimental studies on the elastic modulus of the 2D lattices made of steel are performed. Three lattices having different unit cells, including square, body-centered, and triangular unit cells, are considered. The elastic modulus of each lattice is investigated by tensile testing. All specimens of the lattices are made of steel and manufactured by waterjet cutting. The experimental results of the elastic modulus of the lattices with the considered unit-cell patterns are validated with those obtained from finite element simulations. The results obtained in this study are also compared with the closed-form solutions founded in the literature. Moreover, the unit-cell pattern yielding the best elastic modulus for the lattice is discussed through weight efficiency.

Improved fired clay brick compressive strength by recycling wastes of blacksmiths’ workshops

This study investigates the effect of using steel filings from the waste of blacksmiths workshops on the clay bricks mixture to improve the bricks’ compressive strength. On the other hand, this process can reduce workshops’ waste by recycling it to preserve the resources and achieve sustainability. Adding steel filings to the mixture of red clay bricks was in different proportions by weight (1%, 2%, 3%, and 4%) on prototype bricks produced in a lab. Moreover, it aims to increase the effectiveness of clay bricks used in load-bearing walls, which can be used extensively in economical housing to reduce the cost if its strength increases by utilizing it in the load-bearing walls system instead of skeleton. The experimental approach was adopted to reach conclusions, as it is the appropriate approach suitable for this research. Before and after adding steel filings, many properties were tested, such as dimensions, weight, density, water absorption, and compressive strength. It is observed that on increasing the steel filings ratios by the mixture’s weight, the prototypes’ compressive strength also increases. The highest percentage of increased compressive strength occurred for the specimen with 3% steel filings by the mixture’s weight is (84%).

Utilization of Cenosphere in Manufacturing of Fly Ash Brick

Our project was built with cenosphere material and low-density brick. The cenosphere bricks may be lighter and stronger than traditional fly ash bricks. Cement is used to replace the cenosphere in fly ash bricks in the following proportions: 230mm x 100mm x 75mm sample size for blend percentage of cenosphere, fly ash, and quarry dust. The results show how compressive strength and water absorption vary with curing age for mixed proportions of the materials mentioned previously. Then we can use the 230mm x 100mm x 75mm specimen size to cast bricks with various mix proportions of cenosphere, fly ash, and quarry dust. The weight, compressive strength, and water absorption of the cenosphere with various proportions of fly ash bricks were then compared. Via comprehensive laboratory work, this investigation is primarily based on optimizing the compressive strength of newly formed bricks thus minimizing weight density and water absorption. A definitive goal of undertaking this point as project work is to recognize factors influencing the different properties of bricks.

Improving the Smoothed Complexity of FLIP for Max Cut Problems

Finding locally optimal solutions for MAX-CUT and MAX- k -CUT are well-known PLS-complete problems. An instinctive approach to finding such a locally optimum solution is the FLIP method. Even though FLIP requires exponential time in worst-case instances, it tends to terminate quickly in practical instances. To explain this discrepancy, the run-time of FLIP has been studied in the smoothed complexity framework. Etscheid and Röglin (ACM Transactions on Algorithms, 2017) showed that the smoothed complexity of FLIP for max-cut in arbitrary graphs is quasi-polynomial. Angel, Bubeck, Peres, and Wei (STOC, 2017) showed that the smoothed complexity of FLIP for max-cut in complete graphs is ( O Φ 5 n 15.1 ), where Φ is an upper bound on the random edge-weight density and Φ is the number of vertices in the input graph. While Angel, Bubeck, Peres, and Wei’s result showed the first polynomial smoothed complexity, they also conjectured that their run-time bound is far from optimal. In this work, we make substantial progress toward improving the run-time bound. We prove that the smoothed complexity of FLIP for max-cut in complete graphs is O (Φ n 7.83 ). Our results are based on a carefully chosen matrix whose rank captures the run-time of the method along with improved rank bounds for this matrix and an improved union bound based on this matrix. In addition, our techniques provide a general framework for analyzing FLIP in the smoothed framework. We illustrate this general framework by showing that the smoothed complexity of FLIP for MAX-3-CUT in complete graphs is polynomial and for MAX - k - CUT in arbitrary graphs is quasi-polynomial. We believe that our techniques should also be of interest toward showing smoothed polynomial complexity of FLIP for MAX - k - CUT in complete graphs for larger constants k .

Hydrostatic Determination of Test Weight Density and Uncertainty Evaluation by Monte Carlo Method

This paper presents the characterization of the hydrostatic weighing facility of the National Metrology Laboratory (NML) of the Philippines. The study aimed to evaluate its suitability for determination of solid density. It was used to hydrostatically measure the density of a stainless steel (OIML Class F1) test weight weighing 200 g. The measurement result obtained was 7.5827 g cm-3 ± 0.0041 g cm-3 at an approximately 95 % level of confidence. The uncertainty evaluated by the Law of Propagation of Uncertainty (LPU) according to JCGM 100:2008 (GUM) was verified by the Monte Carlo method (MCM), which gave a result of 0.0040 g cm-3. The value determined for the solid density of the sample with its associated expanded uncertainty was found to be within the tolerance interval between 7.39 g cm-3 and 8.73 g cm-3 as required in OIML R111-1 for Class F1 test weights.

Carbonized Biomass as a bonding agent for Non-Load Bearing CHB Production

One‌ ‌of‌ ‌the‌ ‌most‌ ‌prominent‌ ‌construction‌ ‌materials‌ ‌for‌ ‌walls‌ ‌in‌ ‌the‌ ‌Philippines‌ ‌is‌ ‌the‌ ‌concrete‌ ‌hollow‌ ‌blocks‌ ‌or‌ ‌CHB‌ ‌due‌ ‌to‌‌ their lower cost‌ ‌than‌ ‌other‌ ‌available‌ ‌materials‌ ‌and‌ ‌the‌ ‌ease‌ ‌of‌ ‌production‌ ‌and‌ ‌installation.‌ To manage our energy and resources, including waste, carbonized‌ ‌biomass‌ ‌as‌ ‌a‌ ‌bonding‌ ‌agent‌ ‌for‌ ‌CHB‌ ‌production was studied to ‌aid‌ ‌in‌ ‌the‌ ‌country's growing‌ ‌need‌ ‌for‌‌construction materials‌ ‌. On-site fabricated CHB with several percent of carbonized biomass (CB) as substitutes for sand (0%, 20%, and 50% CB), including commercial CHB, are subjected to volume, weight, density determination, and ultimate compressive strength test. The gathered data undergo analysis through one-way ANOVA to determine the difference among the gathered compressive strength of CHB produced with different percentages of carbonized biomass. Cost analysis was also done to determine the costs and profitability of the CHB. As a result, the CHB with carbonized biomass as bonding agent produced CHB with low density, ultimate compressive strength better than commercially available CHB (with proper curing applied), and can be more profitable with increasing the carbonized biomass content.