JES. Journal of Engineering Sciences
EISSN : 2356-8550
Published by: Zagazig University Medical Journal (10.21608)
Total articles ≅ 1,246
Latest articles in this journal
Published: 1 September 2021
JES. Journal of Engineering Sciences, Volume 49, pp 679-703; https://doi.org/10.21608/jesaun.2021.82128.1060
Moisture and stripping damages are the most prevalent cause of defects of both Hot-Mix Asphalt (HMA) and Warm-Mix Asphalt (WMA). Adhesion between aggregates and bitumen is a crucial factor that affects such defects. Various methods, such as incorporating additives, have strengthened the asphalt mixture's resistance to moisture and stripping. This paper aimed to experimentally investigate the effect of including a low-cost polymer additive (Superplast) into HMA and WMA mixtures. For this goal, a 60/70 penetration grade bitumen was used. For preparing the WMA mixtures, Showax was employed with percentages of 2, 3, 4, 5, and 6% by weight of bitumen. Polymer modified mixtures (HMA and WMA) were prepared by adding 3%, 4, and 5% of Superplast by weight of the binder. Performance characterizations of the unmodified and Superplast-modified mixtures include stiffness, moisture damage resistance, and bonding. These characteristics were evaluated via Marshall, Lottman, and Double Punching tests, respectively. Results revealed that incorporating Superplast improved the adhesion between bitumen and aggregates, which ultimately led to an increase in the stiffness and moisture resistance of both HMA and WMA. Moreover, Superplast-modified WMA mixtures exhibited the best moisture and stripping resistance performance compared to Superplast-modified HMA and other unmodified mixtures.
Published: 29 August 2021
JES. Journal of Engineering Sciences; https://doi.org/10.21608/jesaun.2021.85150.1063
The research addresses the transformations of Iraqi house designs during the period (1980-2020) represented by the cities of Baghdad and Samawah as a case study, adopting the analytical descriptive approach to study house designs, and inductive approach to reach the results. The research process was through an office and field study of the two cities, which dealt with the comparison of pre-war houses (1980-1990), during the war and siege houses (1990-2010) until now.In order to reach the house design transformations caused by the war and siege in the two cities, a comparison was made between the types of houses from both cities and in several aspects, including:• Spaces, mass and void ratio. • Direction• Internal spaces • External spaces• Facades and exterior configurationBy comparison, each city had its own housing type during the 1980s, and gradually the designs in both cities began to resemble principles and ideas in later periods due to events and large intercity migration. The research found a set of results that the events of the period studied had a significant impact on the design of the houses in the cities, where the designs were more stable at the beginning of the period studied, and then became unstable in the 1990s and early 21st century, down to the current type, which is more stable than the previous period (the period of siege).
Published: 23 August 2021
JES. Journal of Engineering Sciences; https://doi.org/10.21608/jesaun.2021.79839.1056
This research presents a cash flow construction road projects prediction model. The model based upon actual current invoices analysis and payments data of road construction projects. Initial results indicate that this simple model is best way for predicting future cash flows especially construction road projects. The main concern is to look at highway road tender projects. This investigation could be used by road authorities who manage multiple projects. It could be used for providing a forecast technique of new project payments. Latest researches from General Authority for Road, Bridges and Land Transporting (GARBLT) projects from 2003 to 2020 were analyzed. This data is used to implement mathematical models for road construction to represent monthly payment invoices for different projects types. Cost estimates of financial data were collected from 78 highway road contracts which are consist of 46 highway strengthening contracts and 32 highway overlay contracts. All collected data from field was arranged into main categories and/or subcategories according to project type and contract amount. A polynomial regression analysis for seventh degree is done for all collected data, and then regression curve is constructed. Statistically equations were performed and taken into research consideration to can provide payment curve expectation. Finally, proposed built in model by using Microsoft Excel was implemented to develop investigation results. The proposed model was named as Multi Road Projects Cash Flow Model "MRPCFM".
Published: 17 August 2021
JES. Journal of Engineering Sciences pp 704-733; https://doi.org/10.21608/jesaun.2021.80878.1058
In construction projects,reduce the cost while keeping the level of quality is an important matter, which defined as Value Engineering(VE). The main concern of VE is to search for the most effective type of works in construction projects to save project direct cost by maximizing or keeping target quality for the studied project. It is a difficult challenge to keep a balance between maximizing project quality with corresponding its minimum cost and duration at the same time. When the value-engineering process is used, each factor affecting the cost is taken into consideration all detailed studies as a specific unified factor to determine its suitable alternatives. This Paper investigates ordering the types of works in terms of effectiveness in the cost saving using the value engineering process for construction projects in Saudi Arabia. A questionnaire has been used to obtain results of only valid samples from all 205 responses, which analyzed and discussed. This study concerned with types of works in a correlation with the four main engineering categories; construction, mechanical, electrical and finishing work. The results indicate the difference effect of using value engineering between these major categories of construction engineering works. Finally, the importance score index applied to appraise the influence of the tested types of works when applying VE process on the project cost.This paper also serves as a resource and guide for construction managers, contractors, and more efficient management in the construction of Saudi projects in order to achieve a sustainable level of cost and quality.
Published: 9 August 2021
JES. Journal of Engineering Sciences, Volume 49, pp 637-661; https://doi.org/10.21608/jesaun.2021.84676.1062
The Greater Cairo suffers from several problems, such as traffic jams, which causes increasing in air pollution on one hand, and on the other hand, the congestion of public transportation with passengers all hours of the day lead to increasing in the spread of infection, especially after the world was exposed to the Corona pandemic “Covid-19” and the recommendations of the World Health Organization to adhere to social distancing to reduce the spread of infection. Bicycles are considered one of the sustainable & healthy modes of transportation, in addition of its low-cost and the positive environmental impacts of their use. Several countries have succeeded in integrating bicycles as an essential component of the urban transport network. In local level, a group of initiatives have appeared in recent years in the various governorates of Egypt, which encourage young people to use bicycles for exercise, and visiting tourist facilities, these initiatives was very popular. The research aims to develop urban suggestions for integrating bicycles into the public transportation network and facilitating their use as an alternative or intermediate means of transportation. The research uses the inductive-analytical method, which depends on studying some international experiences in the use of bicycles as a means of transportation, as well as conducting a field research to extrapolate the opinions of citizens about the obstacles and advantages of using bicycles. The research ends with urban suggestions deduced from the theoretical and field part and applying them to a part of the existing urban area in Giza Governorate. يعاني إقليم القاهرة الکبرى من عدة مشاکل أهمها الاختناقات المرورية وزيادة عدد المرکبات مما يسبب زيادة تلوث الهواء من ناتج المحروقات من جهة، ومن جهة أخرى يسبب ازدحام المواصلات العامة بالرکاب طوال ساعات اليوم إلى زيادة نسبة انتشار العدوى خاصة بعد تعرض العالم لجائحة کورونا "کوفيد-19" وتوصيات منظمة الصحة العالمية بالالتزام بالتباعد الاجتماعي للحد من انتشار العدوى. تعد الدراجات أحد وسائل النقل المستدامة لکونها من وسائل المواصلات الصحية ذات التکلفة المنخفضة إلى جانب التأثيرات البيئية الإيجابية لاستخدامها، وقد نجحت عدة دول في دمج الدراجات کعنصر أساسي في شبکة النقل في المناطق الحضرية. وقد ظهرت في السنوات الأخيرة مجموعة من المبادرات الفردية في مختلف محافظات جمهورية مصر العربية والتي تشجع الشباب على استخدام الدراجات لأغراض...
Published: 2 August 2021
JES. Journal of Engineering Sciences, Volume 49, pp 662-678; https://doi.org/10.21608/jesaun.2021.57245.1026
This article is a primary-theoretical research that investigates the effect of urban spatial structure on commuting patterns. The examined variables are the city size, centrality, concentrations of activities, urban densities, and land-uses distribution. The selection is based on the most commonly used variables in the literature. The objective is detecting the prior theoretical and empirical contributions from the old and recent studies to conclude the research gap for potential optimization. The prior research confirms that both city size and the distance from the Central Business District are positively led to longer commuting distance, time, and cost. On the contrary, most of the literature has substantiated that the decentralized and densified population, employment, and social services, as well as the mixed land-uses, would notably reduce the average commuting distance, the number of motorized trips, and total vehicles miles travelled. The effect of urban-density and land-uses mix remains unclear due to findings that conflict with the empirical results. In the high-densified and diversified districts, traffic congestions may result in longer commuting time, which offsets the decrease in the distance. Furthermore, there is a research gap detected on the effect of the spatial distribution of urban densities, concentrations, and land-uses on the commuting patterns in scale of a city. Finally, this article raises the motivation to empirically investigate these variables in further studies for the Egyptian case.
Published: 4 July 2021
JES. Journal of Engineering Sciences pp 620-636; https://doi.org/10.21608/jesaun.2021.67096.1043
Dability of limestone in their mixtures. This behavior may be attributed to the Representative samples of limestone, ilmenite, and quartz, were dry batch ground separately and in binary mixtures of limestone – ilmenite and limestone-quartz in different compositions in the ball mill. The study aimed to investigate the effect of the mixture composition on the mill product characteristics as reflected on each of the two components. The results indicated that quartz affects as a hard component more than the ilmenite as a heavy component on the grinability of quartz to transfer the kinetic energy of the grinding media to limestone component more than ilmenite, which increases the preferential comminution of limestone by quartz more than that by ilmenite.
Published: 1 July 2021
JES. Journal of Engineering Sciences pp 597-619; https://doi.org/10.21608/jesaun.2021.77902.1055
Moringa Oleifera seeds (MOS) coagulant has been used as a coagulation agent in water purification. In developing countries, usage of MOS addresses many advantages namely eco-friendly, biodegradable, available and cost-effective coagulant, resulting in a powerful alternative to chemical coagulants. This research revealed the positive effect of MOS with the aid of sponge at different operational conditions and showed a great influence in the purification efficiency without any observed clogging of sponge pores or bad smell emission. Supplementation of the sponge improved the purification efficiency in terms of turbidity and UV254 substances removal from 96% and 72% to be 99% and 93%, respectively with reduced MOS coagulant from 500 to 150 mg/L, respectively. Finally, response surface methodology (RSM) has been employed to get the optimum operational conditions for a residual turbidity value less than 1.0 NTU, which occurred at MOS dose of 250 mg/L and pH value of 6.15 after 12.17 minutes of treatment.
Published: 29 June 2021
JES. Journal of Engineering Sciences pp 577-596; https://doi.org/10.21608/jesaun.2021.69258.1044
The construction industry is considered one of the most important industries in Egypt. The majority of construction projects are known to have time delays and cost overruns. The main contribution of this study is that it is the first study of its type that identifies causes of delay and cost overrun in educational building projects with its different types (public schools, private schools, public universities, and private universities) within Egypt. The research main objective is to identify the causes of delay and cost overrun in educational building projects in Egypt and evaluate their importance by the main project stakeholders (Consultants, Contractors, and Owners). This objective was accomplished by means of an extensive literature review and a questionnaire-based survey. Forty causes of delay and cost overrun were gathered through the literature review and categorized into seven groups. The questionnaire was divided into three sections; the main section concentrated on the causes of delay and cost overrun in construction projects. Responses were gathered from 130 participants representing the key stakeholders participated in the project's construction. The analysis was conducted to determine the amount of delay and cost overrun experienced by the projects, in addition to the indices concerning the frequency of occurrence, impact on time and cost, and significance of the seven groups. As well, a ranking of the forty causes was performed to identify the most critical causes of delay and cost overrun in each type of educational building projects (public schools, private schools, public universities, and private universities).
Published: 25 June 2021
JES. Journal of Engineering Sciences pp 551-576; https://doi.org/10.21608/jesaun.2021.76842.1053
In the last decades, Aluminum foam has attracted many researchers and manufacturers due to its unique properties which find a lot of applications, especially in a lightweight structure. The current work aims to study the effect of adding calcined alumina to the melting aluminum on the final mechanical and microstructure of produced aluminum foam. Calcium carbonate was used as a foaming agent. The study reveals that calcination times/temperature have a significant effect on the final foam porosity. with increasing calcination time from 30 min to 90 min the foam density improved from 2.27 to 1.27 g/cm3, which consequently result in increase of samples porosity from 15.9 to 52.7%. also, the results from the compression test show that the variation of calcination time can be used to alter the energy absorption capacity of samples. Tested samples achieved the highest energy absorption of 128 MPa at a calcination time of 90 min. Also, the study reveals that calcination temperature has a significant effect on the final foam porosity. with increasing calcination temperature from 400 to 800°C, the foam density improved from 2.18 to 1.09 g/cm3, which consequently result in increase of samples porosity from 18.94 to 52.79%. Tested samples achieved the highest energy absorption of 325 MPa at a calcination temperature of 800°C. The increase in porosity is measured by ImageJ software, and the energy absorption test was carried out by a quasi-static compression test. These improvements produced material can be used in applications needs high energy absorption like automotive industry.