Open Access Original Research Article

In Situ Precipitated Calcium Carbonate in the Presence of Pulp Fibers – A Beating Study

Klaus Dölle, Bardhyl Bajrami

Journal of Engineering Research and Reports, Page 1-17
DOI: 10.9734/jerr/2021/v20i817352

The paper industry around the world is in search for new ways to decrease production costs. New approached with additives such as new developed In Situ precipitated paper fillers materials have the potential to reduce production cost and increase profit margins.

In Situ precipitated calcium carbonate filler with 20.9% and 41.7% filler material was produced in a large-scale laboratory unit using a eucalyptus pulp fiber suspension with a 1.7% fiber solids content.

Laboratory beating tests were performed with a Valley Beater and APFI Mill using pure eucalyptus pulp with no filler content as the based trial and the two-laboratory manufactured In Situ precipitated filler pulps.

Valley Beater and PFI Mill laboratory beating machines show similar differences/trends for the breaking length, tear and burst index.

EC-pulp with no filler has the highest strength for breaking length, tear and burst index. With increasing filler level breaking length, tear and burst index decrease. Filler containing pulp shows a decrease in beating time for the same beating level.  20 minutes for the Valley Beater and 15000 revolutions for the PFI mill show highest change in pulp fiber beating level sufficient for paper making operation.

Valley Beater and PFI Mill laboratory equipment operate different and an exact comparison of the beating curves is not possible. Based on the amount of pulp fiber needed for experiments the Valley Beater for large amounts and the PFI mill for smaller amounts should be selected.

The SEM pictographs of the Valley Beater and PFI Mill beating trials from 0 stage to the high beating stage at 80 minutes for the Valley beater and 60000 revolutions for the PFI Mill show similar results. No damage to the fibers is noticeable at the unbeaten level. With increasing beating level. At a magnification of 430 times the fiber structure shows an increasing dense fiber structure with less visible pores. Magnification of 2500 times reveals increasing damage to the fiber wall and fiber surface.

Open Access Original Research Article

Epoxy Fillet Height Study of Tapeless QFN Leadframe Package on Different Diebonders

E. Graycochea Jr., R. Rodriguez, F. R. Gomez

Journal of Engineering Research and Reports, Page 18-21
DOI: 10.9734/jerr/2021/v20i817353

The paper focused on the evaluation of quad-flat no-leads (QFN) device in tapeless leadframe technology on different diebonder platforms to achieve an acceptable fillet height performance. The study was narrowed down into two main machines with the objective of attaining a fillet height of less than 75 % for small die. Eventually, the fillet height requirement was achieved by both diebonder platforms, hence, these machines could be used for future works on devices with similar requirement.

Open Access Original Research Article

Derivation of Minimal Cutsets from Minimal Pathsets for a Multi-State System and Utilization of Both Sets in Checking Reliability Expressions

Ali Muhammad Ali Rushdi, Motaz Hussain Amashah

Journal of Engineering Research and Reports, Page 22-33
DOI: 10.9734/jerr/2021/v20i817354

This paper addresses two important useful extensions of binary reliability techniques to multi-state reliability techniques, namely: (a) the problem of complementation or inversion of the function of system success to that of system failure (or equivalently, of deriving the logical minimal cutsets in terms of the logical minimal paths), and (b) the associated problem of hand-checking of a symbolic reliability expression. The paper deals specifically with the reliability of a multi-state delivery network. It presents two complementation procedures, one via the application of multi-state De Morgan’s rules, and the other via the multi-state Boole-Shannon expansion. The paper also illustrates one case in which this complementation is needed, as it outlines a method for checking the reliability of the multi-state system in terms of its logical minimal paths and logical minimal cutsets.

Open Access Original Research Article

Substrate Design Augmentation for Die Placement Reference at Die Attach Process

Rennier Rodriguez, Jr. Edwin Graycochea, Frederick Ray Gomez

Journal of Engineering Research and Reports, Page 34-37
DOI: 10.9734/jerr/2021/v20i817355

Die placement reference in die attach process is one of the critical aspects in measuring the actual die placement especially for the device that has a required measurement. This paper focused on the re-design on the layout of the substrate ball grid array (BGA) package with cross fiducials at the singulation lane which are located at the corner portions of the device. The cross fiducial would serve as a reference when measuring the actual placement of the Silicon die in the package. With this improvement, the technicians and operators could now easily identify the reference based on the mount and bonding diagram requirement.

Open Access Original Research Article

Defining an Optimized Machine Process Sequence to Address Broken Wafer Phenomenon on Semiconductor Products

Jerome J. Dinglasan

Journal of Engineering Research and Reports, Page 38-44
DOI: 10.9734/jerr/2021/v20i817356

Silicon wafer as a direct material is one of the vital parts of a semiconductor product. Wastages on manufacturing plants that pulls the yield down should be addressed innovatively and accurately. This paper focused on the phenomenon of broken wafers at wafer taping process during wafer preparation. Using a wafer taper machine, silicon wafers are covered by an industrial tape as preparation for the next process. During processing and wafers are placed on wafer boat, unexpected phenomenon of broken wafers due to unwanted falling was encountered. Findings was due to the unintentional dragging of the machine’s robot arm after wafer processing. The problem is resolved through simulation and experiments using statistical analysis. As a result, an optimized machine parameter setting was defined to eliminate the said rejection. Statistical analysis was of a big help in resolving the said phenomenon and improved the process yield of the manufacturing.

Open Access Original Research Article

Study of Diebond Machine Platform on Theta Rotation Performance

Edwin M. Graycochea Jr., Rennier S. Rodriguez, Frederick Ray I. Gomez

Journal of Engineering Research and Reports, Page 45-49
DOI: 10.9734/jerr/2021/v20i817357

Theta rotation on die during diebond process is one of the critical machine responses especially for land grid array (LGA) device with tight tolerances requirement. The paper focuses on the die theta rotation tolerance capability with critical design for LGA device evaluated on two different diebond machine platforms. The evaluation was narrowed down into two main diebond machines with the objective of attaining the best performance in terms of die theta rotation tolerance capability. The study used a side-by-side comparison analysis in terms of theta rotation on the two machines and presented the effect of machine selection on the theta rotation response. Theta rotation was monitored and both machines satisfied the specification of 1 degree of maximum rotation, though diebond Machine 1 was able to produce a more stable diebonding with only around less than 0.15 degree of theta rotation variation. For future works, the selected diebond machine could be used for devices with critical requirement.

Open Access Original Research Article

Silicon Die with Integrated Epoxy for Improved Interface Adhesion

F. R. Gomez, R. Rodriguez

Journal of Engineering Research and Reports, Page 50-53
DOI: 10.9734/jerr/2021/v20i817358

Breakthroughs and innovations are constantly being developed in electronic packaging industry to address the manufacturing challenges and overcome existing assembly limitations. An augmented design of thin Silicon die is introduced to establish a robust and improved interface adhesion between the die and the die attach material during the die attach process. The wafer preparation flow is also presented. The realization of the augmented die design with integrated epoxy material would ultimately provide a robust connection and would mitigate the die attach related issues such delamination, die cracks and voids.

Open Access Original Research Article

Modification of Portable Power Tiller for Small Scale Weeding Operation

A. Zakariyah, A. M. El–Okene, U. S. Mohammed, N. Oji, I. Abubakar, J. K. Agunsoye, K. Ahmad

Journal of Engineering Research and Reports, Page 54-62
DOI: 10.9734/jerr/2021/v20i817359

Weeds are unwanted and undesirable plant that interfere with the utilization of land and water resources and adversely affect crop production. After preliminary study, it was found out that power tiller could be adopted for weeding. Therefore, the study aimed at improving its performance through modification of some major component such as: weeding blades and depth gauge.  Three sets of pairs of blade gang of four, six and eight were made from 3 mm mild steel sheet metal. The fabrication was carried out at the Department of Agricultural and Bio-Resources Engineering, Ahmadu Bello University, Zaria. The modified machine was evaluated based on weeding efficiency, field capacity, Plant Damage and Fuel consumption in the maize field during 2017/2018 irrigation season at Institute for Agricultural Research, IAR, Ahmadu Bello University, Zaria research farm. Four levels of blade types ‘B’ and three levels of weeding depth ‘D’ were considered. The field was laid in a 4×3 Randomized Complete Block Design (RCBD) at two (2) Weeks After Sowing (2WAS). DMRT was used for mean separation ran in SAS package. The results showed effects of blade types and weeding depth were significant on the weeding performance of the machine.

Open Access Original Research Article

A Novel Simplification for the Prediction of Natural Gas Compressibility Factor

OMOBOLANLE Oluwasegun Cornelious, AKINSETE Oluwatoyin Olakunle, AROMOKEYE Niyi

Journal of Engineering Research and Reports, Page 63-76
DOI: 10.9734/jerr/2021/v20i817360

The need for a simpler, effective and less expensive predictive tool for the estimation of natural gas compressibility factor cannot be exaggerated. An accurate prediction of gas compressibility factor is essential because it plays a definitive role in evaluating gas reservoir properties used in the estimation of gas reserves, custody transfer and design of surface equipment. In this present work, a novel explicit correlation and a highly sophisticated computer program were developed to accurately predict natural gas deviation factor. The research also aims to effectively capture the relationship between Pseudo-reduced temperature and pressure in relations to the Z-factor. In this study, 3972 digitized data points extracted from Standing and Katz’s Chart were regressed and analyzed using Microsoft Excel Spreadsheet, the extraction of this data was done using WebPlotDigitizer developed by Ankit Rohatgi of GitHub, Pacifica, CA, USA. The correlation was developed as a function of Pseudo-reduced temperature and pressure with tuned parameters distributed across 1.05 ≤ Tpr ≤ 3.0 and 0 < Ppr ≤ 8.0. Subsequently, the input (Tpr and Ppr values) of the feed data was used to validate the correlation and compare it with other known and published correlations. Statistical analysis of the results showed that a 99.8% agreement exists between the predicted and actual compressibility factors for the various test scenarios and case studies involving both sweet and sour gases. Also, the correlation was observed to outperform other models. Finally, the results were observed to perfectly mimic the Standing and Katz charts with an overall correlation coefficient of 99.76% and an adjusted R2 of 99.75%. The proposed correlation was subsequently used to develop a software using JavaScript. Undoubtedly, the proposed correlation and software are suitable for rapid and accurate simplification and prediction of natural gas compressibility factor.

Open Access Original Research Article

Comparative Study of Three Solar Drying Methods of Adensonia digitate L. (Baobab Leaves using Drying Kinetics and Empirical Drying Models)

S. A. Okaiyeto, Nathaniel Oji, Y. A. Unguwanrimi

Journal of Engineering Research and Reports, Page 77-85
DOI: 10.9734/jerr/2021/v20i817361

A comparative study of three drying methods of baobab leaves have been conducted and reported. Mixed mode solar drying, indirect mode solar drying and open sun drying of baobab leaves were conducted based on three drying models viz a viz Lewis,. Page and Henderson and Pabis models were employed in this research. Baobab leaves dried faster when dried under the mixed mode on-farm solar dryer. Drying time reduced considerably using the mixed mode on-farm solar dryer. Drying data were fitted into Lewis, Page and Henderson and Pabis models. Henderson and Pabis model (R2=0.9999, 0.9611, 0.9656; X2= 1.0297, 0.7931, 0.7710; RMSE= 0.5859, 0.6898, 0.6802 and MBE= -0.4.135, -0.4.231, -0.4176) gave the best prediction for the mixed mode drying). In the same way Henderson and Pabis model (R2=0.7450, 0.7699, 0.8243; X2= 1.9025, 0.4026, 0.2006; RMSE= 1.0684, 0.5181, 0.4058 and MBE= -0.8966, -0.3823, 0.2789) gave the best prediction for the indirect mode drying of baobab leaves. Effective moisture diffusivity of baobab leaves varied between -6.382 X 10-04 and -1.108 X 10-03 m2/s.

Open Access Original Research Article

Beating of Eucalyptus Pulp Fibers under Neutral and Alkaline Conditions – A Valley Beater Study

Klaus Dölle, Bardhyl Bajrami

Journal of Engineering Research and Reports, Page 86-96
DOI: 10.9734/jerr/2021/v20i817362

Beating is one of the most important and complicated processes that influences paper production and paper quality from both a process and a paper property standpoint.

With increasing costs, environmental regulations and competitiveness in the today’s global market, paper and board producers revisit existing production process to decrease production costs. New approached with additives such as new developed in-situ precipitated paper fillers materials have the potential to reduce production cost and increase profit margins.

For this research bleached eucalyptus Kraft pulp adjusted to a pH of 7.5, 11.0 and 12.3, and laboratory manufactured in-situ precipitated calcium carbonate with a filler level based on oven dry fiber content of 20.9% and 41.7% and a pH of 7.5, and commercial produced precipitated calcium carbonate filler of 10% and 20%. All pulp suspensions were beaten for 80 minutes with samples taken at the unbeaten level and 20 minutes increments.

The beating curve over 80 minutes beating time show that pulp suspensions with in-situ produced filer material have a higher dewatering ability with increasing filler content compared to the pulps with commercial PCC and different pH values.

Viscosity slightly decreases for pulp suspension with commercial and in-situ produced filler content. Pulp suspension at a pH of 12.3 showed a significant decrease in viscosity over the 80 minutes beating time, superseding the filler containing pulp suspensions.

Basis weight decreased over beating time for all pulp suspensions, which can be explained with an increased fines production during beating and lower fiber retention during handsheet forming.

The breaking length index increase for all pulp suspensions till 40 minutes of beating time for the filler containing pulp suspensions.

Tear index and burst index curves based on beating time are similar for all pulp suspensions with a maximum at 40 minutes beating for the tear index and 60 minutes beating for the burst index. High filler containing pulp suspension showed the lowest tear index.

Open Access Original Research Article

Addressing the Broken Wire Issue during the Assembly Manufacturing of QFN Leadframe Device

Raymond Albert A. Narvadez, Freddie B. Folio, Frederick Ray I. Gomez, Jonathan C. Pulido

Journal of Engineering Research and Reports, Page 97-103
DOI: 10.9734/jerr/2021/v20i817363

The integrity of the assembly wirebond process’ 2nd bond poses a big challenge for semiconductor manufacturing of quad-flat no-leads (QFN) devices, particularly on multiple wires on a lead. These devices are vulnerable to induce or obtain broken wire at heel defect. This type of defect is an abnormality in the formation of the stitch, mostly a crack or fracture seen on the facade of the stitch. Normally, it happens when there is too much vibration or transfer of ultrasonic generator (USG) power combined with high bonding force on 2nd bond. In the case of leads with common wires, broken wire at heel could also happen through excessive USG application resulting to transfer of resonance on adjacent wires. This paper presents a better understanding and analysis done to provide an adequate and appropriate solution to broken wire at heel issue.

Open Access Original Research Article

Different Vacuum Pad Design Effects with Z-Picker Assembly

Allen Jay D. Kumawit, Maria Virginia S. Buera, Mariane A. Mendoza, Frederick Ray I. Gomez

Journal of Engineering Research and Reports, Page 104-109
DOI: 10.9734/jerr/2021/v20i817364

After singulation process where the strips are being cut into single units, unit tray loading comes next. Unit tray loading is the process where the singulated units will be picked up from the table and then place it in a tray pocket. Z-picker assembly executes the pick and placing activity through vacuum suction. Vacuum pads were installed on the Z-picker’s vacuum pad holder area, and it contacts with the unit. Vacuum pads come with different design depending on dimension and configuration of the device in process. Pick and place process is prone for unit dislodge as it transfers the unit from one place to another. These unit dislodges will result to missing units and will be accounted for yield loss. In this study, the authors were driven to understand the Z-picker mechanism together with the effect of vacuum pad designs, aiming to find the best match that would lessen the occurrence of unit dislodges.

Open Access Original Research Article

Glass Die Ink Marking Media Selection for a Robust Glass Attach Process

Jerome Dinglasan, Aiza Marie Agudon, Frederick Ray Gomez

Journal of Engineering Research and Reports, Page 110-115
DOI: 10.9734/jerr/2021/v20i817365

Glass material used on a semiconductor device for isolating currents are one of the new breakthroughs of the modern world. Challenges are inevitable due to its complex characteristics and unique appearance. The study focuses on the phenomenon of reject glass die unrecognized, picked and bonded by die attach machine on good units of the semiconductor quad-flat no-leads (QFN) device in focus. This QFN device utilizes glass die as interposer on two active dice that separates the dielectric current of each die. During die attach process, machine photo recognition system failed to recognize and detect the glass die reject marking due to its unique transparent design and will be attached on good units. Thus, resulting to gross rejection and low process yield. Practical solutions to prevent the said phenomenon are simulated and determined by performing selection of variables like the contrast of the reject mark related to the product structure and compatibility through statistical analysis. The improvement drives to promote process robustness and scrap reduction that will help the manufacturing to be competitive through innovative resolutions on problems.

Open Access Original Research Article

Air Pollution Assessment of a Gas Flare Site in the Niger Delta Region

Chioma Olivia Ehumadu, Uyigue Lucky, Ndekwu Benneth Onyedikachukwu

Journal of Engineering Research and Reports, Page 116-126
DOI: 10.9734/jerr/2021/v20i817366

Aim: The aim of this research was to investigate the level of air pollutants generated from a gas flaring plant in Ogbogu and Ebocha communities of Rivers State, Port Harcourt, Nigeria.

Study design:  Seven monitoring stations were selected for Air quality monitoring, which involved measurement of basic air quality index and meteorological parameters using standard meteorological Equipment. Monitoring locations were selected with respect to the prevailing wind direction from the flare point. The following measurements were conducted;

  • Gas emission: CO, SO2, NO2, VOC, CH4, H2S, NH3
  • Meteorological: Humidity, Wind Velocity, Wind direction, Atmospheric Pressure, Heat Radiation and Smoke density.

Place and duration of study: This study was carried out in Ogba/Egbema/Ndoni Local Government Area of Rivers State. This area was chosen for this study because of the high volume of petroleum activities. Oil and gas processing, production, transportation and utilization for power generation occur daily in the area resulting in numerous cases of environmental degradation and pollution.

Methodology: A multigas Detector MSA Orion is used to monitor the different gases at 20m, 50m, 100m, 500m, and 700m. A Krestel Extech model 45112 mutli-parameter air quality equipment is used to determine the direction of wind flow and speed at a particular location.

Results: The gases flared are in decreasing order of NOx,>SOx,>CO>VOC >SMP at increasing distance. This implies that the health of the people in the study area is affected negatively especially those living very close at 20- 100m distance to the flare site since the gases are occurring at levels higher towards the allowable limits of FEPA. The quantity of carbon emitted by these flares is about 2,525,000.00 tons of carbon per day. These values portray a bad omen for the affected communities. This study recommends that gas flaring should be seen as violent action against the people and that the flared gas should be channeled to meeting the ever increasing demand for energy in the industrial sector of the economy.

Conclusion: It is safe to conclude that gas flaring not only produces excessive heat which alters the temperature of the environment, but also causes gaseous pollutants to be present in the environment and this may have adverse effects on the inhabitants and thus on the socio-economic activities of Ebocha community. The temperature of the environment returns to normal at about 450m away from the flare stack. Residential buildings should therefore be located and agricultural activities should be encouraged within this range of distance.