Zede Journal 

About: Zede Journal is an academic journal. The journal publishes majorly in the area(s): Finite element method & Expansive clay. It has an ISSN identifier of 0514-6216. Over the lifetime, 180 publications have been published receiving 311 citations.

Application of sugarcane bagasse ash as a partial cement replacement material

Abstract: Sugarcane bagasse ash is a byproduct of sugar factories found after burning sugarcane bagasse which itself is found after the extraction of all economical sugar from sugarcane. The disposal of this material is already causing environmental problems around the sugar factories. On the other hand, the boost in construction activities in the country created shortage in most of concrete making materials especially cement, resulting in an increase in price. This study examined the potential use of sugarcane bagasse ash as a partial cement replacement material. In this study, bagasse ash sample was collected from Wonji sugar factory and its chemical properties were investigated. The bagasse ash was then ground until the particles passing the 63μm sieve size reach about 85% and the specific surface area about 4716 cm 2 /gm. Ordinary Portland cement and Portland Pozzolana cement were replaced by ground bagasse ash at different percentage ratios. Normal consistency and setting time of the pastes containing Ordinary Portland cement and bagasse ash from 5% to 30% replacement were investigated. The compressive strengths of different mortars with bagasse ash addition were also investigated. Four different C-35 concrete mixes with bagasse ash replacements of 0%, 5%, 15% and 25% of the Ordinary Portland cement were prepared with water to cement ratio of 0.55 and cement content of 350kg/m 3 for the control mix. The test results indicated that up to 10% replacement of cement by bagasse ash results in better or similar concrete properties and further environmental and economical advantages can also be exploited by using bagasse ash as a partial cement replacement material. Keywords: Bagasse ash, Pozzolanic material, Normal consistency, Setting time, Compressive strength, Water penetration depth.

The use of limestone powder as an alternative cement replacement material: An experimental study

Abstract: This research paper examines the effects of partial substitution of Portland cement clinker with limestone addition on the physical and chemical properties of cement paste and hardened mortar in two ranges of blain fineness values. Laboratory tests were conducted on limestone and clinker samples before used for the intended purpose and then checked for conformity with the Ethiopian and European standards. The laboratory test results revealed that up to 15% replacement of clinker by fine limestone powder having blain fineness values in the range of 4000 to 4500 cm 2 /gm result in comparable compressive strength to similar mixes produced using 100% ordinary Portland cement. It also satisfied the standard compressive strength of high early strength of cement (42.5 MPa) as per EN 197-1 standard requirements. Furthermore, it was found that 25-35% limestone addition by weight results in slightly lesser compressive strength values than the 28 th day’s standard compressive strength requirement. Observations on the test results further indicated that increasing in fineness of the limestone filler addition in Portland cement clinker results in relative increase of rate of hydration and faster development of the early age strength while decreasing slightly the consistency and the setting times (initial and final). The loss on ignition is also observed to increase with the increase in percentage proportion of limestone filler addition where as the percentage by mass of sulphate trioxide and insoluble residue as well as soundness effect of the Portland limestone cement remain within the acceptable range. Keywords: Calcium carbonate, Compressive strength, Early strength, Limestone filler, Loss on ignition, Portland limestone cement

Assembly line balancing using simulation technique in a garment manufacturing firm

Abstract: The typical problems facing with garment manufacturing are: short product cycle for fashion articles, long production lead time, bottlenecking, and low productivity. To alleviate the problems, different types of line balancing techniques have been used for many years in the garment industry. However, garment industries which are based on manual-operations oriented system do not still gain significant results with the techniques and difficult to forecast future events when they want to change or modify the production system. The objective of this paper is to develop a simulation model which represent real production process scenarios of garment products that helps to identify the bottlenecks and enhance production system performance. The study has considered basic poloshirt to investigate and demonstrate the application of simulation technique. For this purpose, in 2009, data are collected from real system (AAYSC-Knit wear garment in Ethiopia) and different alternative systems have been considered in order to find the best one.

Stabilization of expansive soil using bagasse ash & lime

Abstract: The Expansive soil collected from Addis Ababa, Bole sub city, classified as an A-7-5 soil on the AASHTO classification was stabilized using 3% lime, 15% bagasse ash and 15% bagasse ash in combination with 3% lime by dry weight of the soil. The effect of the additives on the soil was investigated with respect to plastcity, compaction and California bearing ratio (CBR) tests.The results obtained indicate an increase in optimum moisture content (OMC) and CBR value; and a decrease in maximum dry density (MDD) and plasticity of the soil for all additives. But there was also a tremendous improvement in the CBR value when the soil is stabilized with a combination of lime and bagasse ash. This shows a potential of using bagasse ash as admixture in lime stabilized expansive soil.Keywords: Expansive soil, bagasse ash, lime, plasticity, compaction and strength characteristics

Performance Analysis of Chaotic Encryption Using a Shared Image as a Key

Abstract: Most of the secret key encryption algorithms in use today are designed based on either the feistel structure or the substitution-permutation structure. This paper focuses on data encryption technique using multi-scroll chaotic natures and a publicly shared image as a key. A key is generated from the shared image using a full period pseudo random multiplicative LCG. Then, multi-scroll chaotic attractors are generated using a hysteresis switched, second order linear system. The bits of the image of the chaotic attractors are mixed with a plaintext to obtain a ciphertext. The plaintext can be recovered from the ciphertext during the deciphering process only by mixing the cipher with a chaos generated using the same secret key. As validated by a functional, NIST randomness, and Monte Carlo simulation tests, the cipher is very much diffused and not prone to statistical or selected cipher attacks. In addition, the performance is measured and analyzed using such metrics as encryption time, encryption throughput, power consumption and compared with such existing encryption algorithms as AES and RSA. Then, the performance analysis and simulation results verify that the chaotic based data encryption algorithm is valid. Key Words: Secret key encryption, shared image, hysteresis switched second order system, multiplicative LCG, chaotic attractors, randomness.