Open Access Original Research Article

Simplified Compression Arch Action Model for R/C Beam-column Assemblages

Fouad B. A. Beshara, Ahmed A. Mahmoud, Osama O. El-Mahdy, Ahmed N. Khater

Journal of Engineering Research and Reports, Page 1-11
DOI: 10.9734/jerr/2019/v7i316969

A set of analytical equations are developed for calculating the beam-column assemblage flexure action capacity and compression arching action capacity under a middle column removal scenario. The suggested equations covered most of the main parameters affecting the assemblage behavior including seismic detailing, longitudinal reinforcement ratios, concrete confinement, and the contribution of concrete flanged slabs. The proposed analytical model for predicting the flexural and compression arching action capacities is validated with a large number of experimental results. The model provides a good estimation for 79 beam-column assemblages with several geometrical, reinforcement configurations, and material parameters. The mean values of the experimental to the theoretical ratio for calculating flexure and compression arching capacities are 1.15 and 1.16, respectively. The predictions of previous compression arch action models are found to be more conservative. Finally, the proposed model is utilized in parametric studies including all key parameters that affected resistance of the beam-column assemblages against progressive collapse.

Open Access Original Research Article

Wirebond Solution of Semiconductor IC Package through Modeling and Simulation

Frederick Ray I. Gomez, Anthony R. Moreno, Jonathan C. Pulido

Journal of Engineering Research and Reports, Page 1-10
DOI: 10.9734/jerr/2019/v7i316970

This technical paper presents a study of wirebond selection highlighting the package electrical modeling and simulation done for semiconductor integrated circuit (IC) leadframe package (hereinafter referred to as Device Z) with different wirebond configurations: Gold 2N 1.3 mil, Gold 4N 1.3 mil, Copper 1.3 mil, Copper 1.2 mil, Copper 1.1 mil and Copper 1.0 mil.  Package design, modeling and simulation are essentially important in the early stage of the package development, particularly at the package feasibility phase. 

As Device Z is previously assembled with Gold 4N 1.3 mil wirebond configuration, this technical paper focused in determining the best alternative for Gold 4N 1.3 mil in wirebonding through package modeling and simulation. Statistical analysis reinforced the study to verify the trend and to check if there is significant statistical difference in the resistance, inductance and capacitance (hereinafter referred to as RLC) performance of the device given the different wirebond configurations.  Cost analysis was crucial to determine the cost impact of using different wires.

Prioritizing the wirebond thickness and cost without sacrificing the electrical performance, Copper 1.1 mil would be the most suitable replacement for Gold 4N 1.3 mil wirebond configuration.  However, since Copper 1.1 mil is not yet available in the market, Copper 1.2 mil could be used, with better electrical parameters. In addition, Copper wire offered significant cost improvement over its Gold counterpart. Computed cost per unit of Copper 1.3 mil is just 6% of the total cost of the Gold 4N 1.3 mil – that is 94% cost savings. Ultimately, Copper wire technology offers significant cost savings and could pave the way for more businesses in the plant.

Open Access Original Research Article

Comparative Analysis of Rescaled Range Results of Normal and Abnormal Heart Sound Recordings

Lotachukwu Ibe, Tajudeen Abiola Ogunniyi Salau

Journal of Engineering Research and Reports, Page 1-7
DOI: 10.9734/jerr/2019/v7i316971

Heart acoustics can be used as an early diagnostic tool, to quickly and accurately identify medical patients who may be at risk of unfavourable cardiovascular outcomes. However, at present, there remains no universally accepted standard or technique for detecting abnormalities using Phonocardiograms. To address this, a large database containing normal and abnormal heart sound recordings of patients were studied with the rescaled range technique and the Hurst exponent, a measure of persistence for non-linear dynamic data. Using the Hurst exponent (H) as a benchmark, we compared the values of the Hurst exponent for normal heart sound recordings with that of the abnormal heart sound recordings. For this study, the recording length was limited to the first 10 seconds for all 578 distinct recordings, which were selected randomly from the database. Furthermore, two Hurst exponent values were obtained for each recording, by subjecting them to time intervals of 1 and 2 milliseconds respectively. The results from this study show that heart sound recordings are persistent (H > 0.5) for normal and abnormal heart sound recordings, with the normal recordings being slightly more persistent.

Open Access Original Research Article

Adaptive Design and Performance Evaluation of Compact Acoustic Enclosures Built with GFRP for Portable Mini-generators

Cornelius Ogbodo Anayo Agbo

Journal of Engineering Research and Reports, Page 1-11
DOI: 10.9734/jerr/2019/v7i316972

A simple, portable and effective design for enclosing portable generators to reduce the radiated noise has remained a daunting challenge to noise control advocates in many developing countries. This research aims to use an adaptive design approach to create an enclosure for minimizing portable mini-generator noise. The noise characteristics of the mini-generators was ascertained and construction of a 730 by 640 by 600 mm enclosure was accomplished by using glass fiber reinforced plastic (GFRP) to build a double walled enclosure surfacing and rock wool as the sandwiched absorbing material. The sound pressure level (SPL) around the generator before and after the application of the enclosure was measured and evaluated. The results obtained showed that the acoustic enclosure could achieve an insertion loss of up to 16 dB (A) at a distance of 1.0 m.  Also, the heat transfer characteristic of the enclosure design was put into consideration as well as the requirements of the engine air aspiration and cooling inside of the enclosure. Incorporation of fans in the acoustic enclosure design increased convectional fresh air circulation into, and discharge of the heat generated in, the enclosure, thus maintaining a safe temperature of about 40oC inside of the acoustic enclosure at the generator operating maximum load.

Open Access Original Research Article

A Comparative Study of the Basic Strength and Hydraulic Properties of Lateritic Soils Stabilized with Rice Husk Ash and Bagasse Ash

S. O. Ogundare, O. A. Oni

Journal of Engineering Research and Reports, Page 1-11
DOI: 10.9734/jerr/2019/v7i316973

The strength and hydraulic properties of lateritic soils stabilized with bagasse ash (BA) and rice husk ash (RHA) were examined in this study. The three lateritic soil samples used in the study were obtained from a borrow pit near the main waste dumpsite in Ado Ekiti, Nigeria. The BA and RHA were obtained locally from the burning of fibrous residue of sugar cane and rice husk respectively. Classification of the soils using AASTHO indicates Soil 1 to be Group A-6 soil, Soil 2 to be Group A-2-6 soil and Soil 3 to be Group A-2-7 soil. In general, the optimum moisture content of the stabilized soils increased with increased content of the admixtures-BA and RHA. The maximum dry density of the stabilized soils decreased with increase in the quantity of BA and RHA. Likewise, the saturated hydraulic conductivity of the stabilized soils decreased slightly with increased content of BA and RHA. The values of the minimum hydraulic conductivity of the stabilized soils were of the order of 10-4cm/s, which are higher than the minimum requirement of 10-7cm/s for soil liners in municipal solid waste landfills. The low pozzolanic characteristics of BA and RHA in the stabilized soils were attributed to the low content of CaO needed to produce CaOH2, which is normally needed to produce pozzolanic reaction products in the presence of water. The characteristics of the modified soils appeared to be influenced by the change in the soil matrix following mixing. Comparison of individual behaviour of BA and RHA in each stabilized soil showed very similar characteristics. It was concluded that another modifier such as cement that has a high content of CaO should be added to the stabilized soils for the full pozzolanic potentials of BA and RHA to be realised.