Showing papers in "Cogent engineering in 2023"

Diameter ratio and friction coefficient effect on equivalent plastic strain (PEEQ) during contact between two brass solids

Abstract: The study of contact mechanics is rapidly expanding in scope and importance. However, most studies of spherical do not spend significant time comprehensively analysing PEEQ, especially in the effect of friction coefficient and diameter ratio. This study aims to introduce comprehensive research examining diameter ratio and friction coefficient influencing equivalent plastic strain (PEEQ) during contact between two brass solids. In this study, the finite element method analysed an elastic-perfectly plastic brass material. The finite element model was two hemispheres with diameter ratios ranging from 1 to 5. In addition, the diameter in the upper hemisphere is 17.5 mm in all variations, while the bottom hemisphere follows the diameter ratio. The current study confirmed that the finite element results agreed well with the previous results’ analytical contact models. The findings also revealed that differences in ratio diameter and friction coefficient were significant to PEEQ. Therefore an increase in the coefficient of friction causes an expansion of the maximum PEEQ area for a diameter ratio of 1 and a reduction in the PEEQ maximum area for diameter ratios of 2 to 5. Expansion and contraction on the PEEQ area indicated that the contact radius widens and contracts as the coefficient of friction and diameter ratio change. Further research is required to investigate the effect of other parameters in PEEQ analysis, such as material properties and multiple cycle loading conditions. Furthermore, the practical implications of these findings may contribute to our understanding of engineering design and failure analysis.

Determination of engineering properties of onion crop required for designing an onion harvester

Abstract: The knowledge of the engineering properties of the onion bulb is a prerequisite to designing machinery for harvesting and post-harvest operations. The agronomical, mechanical, and biometric properties of the onion crop were measured for the Pusa Red variety at the harvesting stage. Onion (Allium cepa L.) seedlings of Pusa Red variety were grown at 150-mm row-to-row and 100-mm plant-to-plant spacing in sandy loam soil. The onion bulbs were obtained within 69.15 ± 7.17 mm below the ground surface with a coefficient of variation (CV) of 10.37%. The average length of onion plants was found to be 236.5 ± 35.28 mm with a CV of 14.91%. The cutting force required to cut the leaves from the onion was in the range of 45.42–105.87 N. The pulling force required to dig out the bulbs at the mean depth of 70 mm was found to be 32.33 ± 3.05 N. The shape of Pusa Red onion bulbs was found to be of prolate shape. The average values of polar diameter, equatorial diameter, and mass for the large onion bulbs were found to be 57.83 ± 5.26 mm, 46.88 ± 3.29 mm, and 65.68 ± 4.22 g, respectively, as compared to 47.44 ± 2.46 mm, 43.81 ± 3.33 mm, and 47.51 ± 7.07 g, for small onion bulbs. The average value of bulk density for the large and small onion bulbs was found to be 403 and 501.33 kg m−3, respectively. The mean value of angle of repose for small-size bulbs was obtained at 29.2°. A linear relationship was found to exist between polar and equatorial diameters as well as the mass of the bulb and polar/equatorial diameter for both large and small size onion bulbs.

How trustworthy is ChatGPT? The case of bibliometric analyses

Abstract: The introduction of the AI-powered chatbot ChatGPT by OpenAI has sparked much interest and debate among academic researchers. Commentators from different scientific disciplines have raised many concerns and issues, especially related to the ethics of using these tools in scientific writing and publications. In addition, there has been discussions about whether ChatGPT is trustworthy, effective, and useful in increasing researchers’ productivity. Therefore, in this paper, we evaluate ChatGPT’s performance on tasks related to bibliometric analysis, by comparing the output provided by the chatbot with a recently conducted bibliometric study on the same topic. The findings show that there are large discrepancies and ChatGPT’s trustworthiness is low in this particular area. Therefore, researchers should exercise caution when using ChatGPT as a tool in bibliometric studies.

Assessment of changes in climate extremes of temperature over Ethiopia

Abstract: Recently, extreme climatic events have been a major concern across the world. Assessments on various climates and geographic regions are needed to understand the uncertainties in extreme climate events’ responses to global warming. Developing countries particularly Ethiopia is highly affected by such extreme climate events due to its low adaptive capacity. The aim of this study was to investigate the trends of daily extreme temperatures indices in Ethiopia. The changes and trends in climate extremes of temperature were evaluated based on 14 indices of extreme temperatures over Ethiopia. The Mann-Kendall (MK) trend test is used to investigate the trends in the selected datasets. In the present study, three zones, which represent 34 stations, were selected based of extreme climate indices. The results of 14 extreme temperature indices showed that warm days (TX90p) and nights (TN90p) increased by 2.65 (P < 0.05) and 2.04 (P < 0.05) days/decade, respectively. The annual maximum and minimum temperatures (TXam and TNam) as well as the diurnal temperature range (DTR) were 2.68/decade, 2.04/decade and 0.62/decade, respectively. 73.5% and 26.5% of the stations show an increasing trend for (TXx and TNx), respectively. The extreme hot temperature indices (TXx, TXn, TX90, TN90 and SU) and cold temperature indices (ID, TNn, TXn, TX10P, TN10P and FD) exhibited contrasting variations over the stations. As far as spatial patterns concerned, most of the stations show significant increasing trends in northern and southeastern parts of Ethiopia. Thus, changes in climate extremes will likely increase the risk of severe extreme events and the society to become more vulnerable to the climate shocks. Generally, the findings of this study could help decision and policymakers to take immediate measures to tackle the climate change impacts.

Seasonal assessment of heavy metal contamination of groundwater in two major dumpsites in Sierra Leone

Abstract: Consumption of water contaminated with heavy metals has serious health consequences and these include hypertension, kidney disease, cancer, anaemia, brain damage, etc. However, groundwater pollution with heavy metals may occur naturally or anthropogenically as a result of water-rock interaction, dumpsite leachate, agricultural activities, or sewage percolation. Therefore, the apportionment of the specific sources of heavy metals to groundwater is vital to prevent and control its pollution to groundwater. The present work assessed thirty-four (34) groundwater samples from the vicinity of the Granvillebrook and Kingtom dumpsites, Freetown, Sierra Leone. The objective of the research was achieved by integrating geospatial, indexical, and multivariate statistical methods. The results showed that heavy metals such as Cu, Cr, Fe, and Mn exceeded the permissible levels in the majority of the groundwaters. As and Pb were below the detection level of the instrument in all the groundwaters analyzed. Seasonal variations revealed that the concentration of heavy metals is relatively higher in the dry season due to the effect of dilution. The heavy metal evaluation index and degree of contamination analyses respectively showed that 16.7 and 41.6% of the groundwaters in the Granvillebrook dumpsite are highly polluted by heavy metals. All the groundwater samples in the Kingtom dumpsites except well KW17 are unaffected by heavy metals. The principal component analysis showed that fuel combustion, brake abrasion, and discharge of municipal and industrial waste from the dumpsites are some of the anthropogenic sources that impact groundwater pollution in the study areas. The findings of this research revealed the urgent need to develop strategies to control and mitigate the occurrences of heavy metals and thus serve as a base for future research in the study areas.

In-network caching in information-centric networks for different applications: A survey

Abstract: Information-Centric Networks (ICNs) have become a promising paradigm for the future Internet instead of host-based communication. In this network, content-oriented data and in-network caching are two key properties, which have brought tremendous benefits to many challenging networks by improving the distribution and retrieval of content. The content is cached along the reversed delivery path, on-path caching and off-path caching. Generally, the existing caching approaches in Information-Centric Networks mainly consider the key characteristics of the content (to decide which content is to be cached), the network (to determine the appropriate time for caching), the nodes (to determine where content should reside), etc. This paper presents a comprehensive survey of in-network caching of ICN schemes (also known as ICN-based caching) in many network applications. Thus, a detailed analysis of the existing caching approaches in several network applications, such as MANET, VANET, IoT, and WSN, is given. This survey also provides a taxonomy for caching policies according to some feature-based approaches and highlights the trends and evaluation problems in these areas. Finally, the challenging research directions in different applications are also pointed out in this subject.

Modeling of halal supplier flexibility criteria in the food supply chain using hybrid ISM-MICMAC: A dynamic perspective

Abstract: In the context of the halal supply chain, the need for flexibility of halal suppliers is increasing along with changes in regulations, policies, markets, and technology that change dynamically. Therefore, more systematic and dynamic modeling of flexibility criteria for halal suppliers is needed to improve the quality of halal supply chain management as a whole. The purpose of this study is to identify the criteria for halal suppliers by considering flexibility in the context of a halal supply chain. In this study, modeling the criteria for the flexibility of halal suppliers is carried out using the Interpretive Structural Modeling—Matriced’ Impacts Croisés Appliquée á un Classement (ISM-MICMAC) hybrid approach and a dynamic perspective. This study resulted in 11 criteria for halal suppliers which were divided into four levels in the ISM hierarchical structure. The criteria were spread over three quadrants of the MICMAC analysis, namely independent, linkage, and dependent. The results of the ISM and MICMAC approaches are then represented in a causal loop diagram which consists of an amplifying loop and a closed loop. The reinforcing circle consists of the criteria of responsibility-service-security-trust, while the balancing circle consists of traceability and costs. Even though the flexibility criterion is not in between the two loops, the criterion still influences other halal supplier criteria. This shows that flexibility criteria have important relationships and influences in the context of halal supply chain management.

Problem based learning and design thinking methodologies for teaching renewable energy in engineering programs: Implementation in a Colombian university context

Abstract: The rapid depletion of fossil fuel reserves, population growth, and increasing environmental pollution have forced a change in the search for alternatives to produce and use energy. Currently, renewable energies (RE) have achieved more efficient advances to produce energy from non-conventional and inexhaustible sources, which can meet the basic needs of society and whose environmental impact is a door of opportunities for all. For this reason, academia has a preponderant role in ensuring that engineers are fully equipped with the necessary skills to provide feasible and contextualised solutions for this era of energy transition framed by the UN Sustainable Development Goals (SDGs). This article explores the impact on the development of the necessary skills for engineers in the renewable energy sector by tracing a route towards the acquisition of renewable energy knowledge with strategically organised work teams of undergraduate students, where two methodologies that are gaining ground in engineering education programs are applied: Problem Based Learning(PBL)and Design thinking (DT).After the validation of these techniques, it is concluded that bringing engineering students closer to real contexts related to renewable energies and above all with an objective of impact on communities, it is the right way to build knowledge in teams, in an immersive and committed way with the institution, which has developed and implemented an innovative pedagogical method based on the application of a critical educational model focused on the development of competencies, where the union of new technologies with the teaching processes on which this research is based is envisioned for the future.

Development and Testing of Solar Powered Evaporative Air-Cooling System with an Improved Performance

Abstract: This study proposes a new active direct evaporative cooling system that uses a bundle of cotton fibers as an evaporating surface and activated carbon as a moisture adsorbent. A two-stage evaporative cooling experimental setup consisting of an activated carbon adsorbent in between the cooling pad was designed, fabricated, and tested at Bahir Dar, Ethiopia. The fiber bundle (pad 1) was wetted with water and ambient air was forced through it using a fan then the air that exiting from pad 1 was forced through a bulk of activated carbon (moisture adsorbent), and then the air from the adsorbent passed through the second wetted fiber bundle (pad 2). The energy source for the fan and pump was the solar photovoltaic energy system. The average temperature drop of the cooler without the moisture adsorber was 9.33°C and with the inclusion of the moisture, the adsorber gave an additional temperature drop of 1.5°C to 4.95°C. During the hot dry season, the average relative humidity of the ambient air, pad 1 outlet, adsorbent outlet, and pad 2 outlets were 28.26%, 76.12%, 55%, and 88.2% respectively. The cooler with moisture adsorbent had a cooling capacity of 3653 W, an effectiveness of 94.25%, and a COP of 52.2. The developed solar evaporative cooling system can provide energy-efficient, sustainable, affordable cold air for different applications. The cooler could be used by small-scale farmers, wholesalers, and retailers for the cooling and storage of horticultural products to reduce the postharvest loss in fresh produces.

Flocking and formation control for a group of nonholonomic wheeled mobile robots

Abstract: The problem of flocking and formation of a group of nonholonomic wheeled mobile robot is addressed in this paper. Based on the cascade structure of the kinematic model, two kinematic controllers are proposed to achieve formation and flocking behaviors. The proposed control laws present a P and PI-like structure plus a feedforward term and do not require complex calculations. The interaction between the robots is modeled using graph theory. The performance of the proposed control laws is validated by experimental tests on a group of four differential-drive wheeled mobile robots.

Simulation of stream flows and climate trend detections using WEAP model in awash river basin

Abstract: The shrinking of water resources along with the frequent droughts plays an effective role in intensifying the water crisis. Climate change adversely affects the hydrological cycle at the basin level. These are often reflected in the water and food insecurity, frequent hydrologic extremes, frequent drought, flooding, and deteriorating ecosystem health. This study aims to calibrate and validate the stream flows in Awash River basin using a distributed hydrological Water Evaluation And Planning (WEAP) model. Mean monthly Precipitation; temperature and stream flow are used to run the model. The model was calibrated and validated using mean stream flow. The trends of climate over the study basin were also investigated using Mann Kendall trend tests. The results revealed that the value of R2 ranged from 0.73 to 0.91 during calibration periods. On the other hand, the value of Nash—Sutcliffe efficiency (NSE) is ranged from 0.65 to 0.83. However, the values of coefficient of determination (R2) during validation periods ranged from 0.54 to 0.91 and the values of Nash—Sutcliffe efficiency (NSE), ranges from 0.50 to 0.84. Thus, The results at two important parts of the main river (upstream and downstream) gauges showed good agreement between the simulated and observed stream flow. The basin receives a significant amount of water during the rainy season (June to September). The mean annual rainfall of the basin ranges from 100 to 1700 mm with great spatiotemporal variation. The annual stream flow of the Awash River basin shows a sharp decreasing trend (Z = −0.120 during the study period. Thus, the findings of this study could provide insights for concerned bodies to implement effective water resources management techniques. The study also proposed that, to ensure the sustainability of water resources, better long-term management policies are required to be implemented in the basin and to meet future downstream water needs.

A multi layer recency frequency monetary method for customer priority segmentation in online transaction

Abstract: : Customer segmentation is a critical step toward appropriately differen-tiating services to different customers. One common way of segmenting customers is by using what is called Recency, Frequency, Monetary (RFM) approach, where customers are classified based on the recency of their transactions as well as how often they purchase goods and services and how much money they spent. However, this approach is not able to fairly differentiate customers especially when it comes to the cases where old customers have decreased or stopped their purchases and the new customers just started buying. In order to overcome this, we proposed what is called Multi Layer Recency, Frequency, and Monetary (MLRFM) approach. In this approach, we divide time periods into multiple layers and the recency, frequency, and monetary values are analyzed considering these different segments. Our numerical examples show that this multi layer approach can provide a good alternative for the companies that sell products online and customers are behaving very dynamically.

Compressed earth blocks (CEB) compression tested under two earth standards

Abstract: Building with raw earth is a responsibility that translates into safe, low-impact and small carbon footprint constructions. However, beyond its current use, it is imperative to validate the different earth construction systems, starting with their components, under standards that ensure the safety of this type of constructions. In countries where construction with earth is allowed, it is verified by Standards and Technical Documents or Construction Regulations. Therefore, the objective of the research is to contrast a series of compressed earth blocks (CEB) subjected to compression tests with the Brazilian and Colombian standards, and the Mexican standards with clay soils in the region, identifying the deviations between the results and their possible causes. In the results, it was observed that the compression test procedure varies for each Standard, the Brazilian and Colombian Standards being similar, and these in turn adhere more to the construction system, while with the Mexican Standard the results are higher than the previous one since the norm requires to test the complete block.

Optimization of stirrer parameters by Taguchi method for a better ceramic particle stirring performance in the production of Aluminum Alloy Matrix Composite

Abstract: Aluminum alloy ceramic matrix composites have become widely used in a variety of sectors and will grow in the future with the growth of measures to reduce environmental pollution and the necessity to reduce the use of fossil fuels. Stir casting is the most cost-effective method for mass-producing Aluminum Alloy Matrix Composite; however, it still has certain challenges that need to optimize for its performance. The current gap is to anticipate, recognize, and strive to minimize casting flaws during the liquid phase. Taguchi method for the design of the experiment was used to optimize the stirrer parameters. The signal-to-noise (S/N) ratio (larger is better), hardness, and ultimate tensile strength were employed as response output variables. In this work, it was confirmed that the mechanical properties of aluminum alloys can be enhanced better if the method of adding SiC and SiO2 particles as ceramic reinforcements is improved. The contribution of three parameters in enhancing mechanical properties has been identified. The research proved that there is a significant relationship between the Stirrer Design and the mechanical properties. The optimal stirrer design (D5) for mixing ceramic reinforcements with melted aluminum alloy has been chosen from different designs. Mechanical properties under the effect of the most important stirring parameters have been explained. Finally, adding silicon carbide instead of silica sand enhances the mechanical properties even further.

Investigating the impact resistance of E-glass/ Polyester composite materials in variable fiber-to-matrix weight ratio composition

Abstract: E-glass/polyester composite is formed by combining E-glass fiber as reinforcement with a polyester resin matrix. These constitute materials have different properties from the composite they built. The fiber mat with 65, 55, and 35 weight percentages and a matrix with weight percentages 35, 45, and 65 have been prepared. In each composition reinforcement, the test samples are modeled using Ansys ACP—pre and fabricated using the hand-layup technique. By setting three test samples for each class of composition, a total of nine test samples are prepared. Impact tests are conducted on each test sample using an Izod impact testing machine and using Ansys explicit dynamics numerically. The maximum mechanical properties are obtained in 65 by 35 fiber-to-matrix ratios of the composite experimentally and numerically when compared with the other stated composition. Results of the numerical analysis show that good mechanical properties can be achieved using balanced and compatible reinforcement with the matrix in the composite.

Mechanical performance of cement mortar with olive pomace aggregates and olive mill wastewater: an experimental investigation

Abstract: This study investigates the potential use of olive aggregates (OA) in the production of cementitious materials as a substitute for natural sand to reduce excessive use of this resource. Two types of OA were used: OPA (olive pomace aggregates) and OPMW (OPA mixed with olive mill wastewater). The aim was to determine experimentally whether improvements in the mechanical properties of the produced lightened cement mortar could be obtained compared to the reference mortar. Laboratory tests were conducted on two series of mortar samples made by replacing 0%, 5%, 10%, and 15% of natural sand with both dry and saturated OA. The best results were observed in a mixture containing 5% of OPMW at the dry state, which had a marginal effect on the compressive strength of the produced mortar, reaching 33.50 MPa after 28 days of curing. However, microstructural analysis revealed low adhesion between the OA and the cement matrix at the interface transition zone (ITZ) after 28 days. Increasing the OA content was found to decrease the workability of the mixture while also increasing the porosity of the resulting lightened cement mortar. Additionally, the use of OA reduces ultrasonic pulse velocity and dynamic modulus of elasticity. Overall, the best results were obtained with the mixture containing 5% of OPMW at the dry state, which meets the standards for general use of building materials.

The m-polar fuzzy ELECTRE-I integrated AHP approach for selection of non-traditional machining processes

Abstract: In the literature, there are a number of decision-making strategies that can be used to choose the best NTM processes. Chen (Citation2014) introduced a novel method to handle fuzzy data that includes multipolar uncertainty, referred to as the m-polar fuzzy set (mFS) approach. The mFS method, along with other multi-criteria decision-making (MCDM) techniques, is a good way to choose between options. An illustration of such a combination is the mFS elimination and choice translating reality-I (ELECTRE-I) . A criteria weight approach is also needed to increase the accuracy of the mFS ELECTRE-I method. The mFS ELECTRE-I method and the analytical hierarchy process (AHP) criteria weight calculation method are combined in the current work. The unique thing about this method is that it can be used to solve both MCDM and MCGDM problems by combining the mFS ELECTRE-I with the AHP criteria weight method. A single-dimensional weight sensitivity analysis is performed to confirm the technique’s stability for different criterion weights for the AHP method on alternative rank performance. The results of the NTM process selection are validated by previous research findings. EDM turned out to be the best way to create machine precise holes on duralumin alloy, and ECM turned out to be the best alternative to generate the surface of revolution in stainless steel. A C++-based soft solution that uses the mFS ELECTRE-I technique to analyze various MCDM and MCGDM problems has been developed. With the soft solution, you can fix problems with selecting the FMS, the robot, and so on.

Enhancing deep learning techniques for the diagnosis of the novel coronavirus (COVID-19) using X-ray images

Abstract: Deep learning techniques combined with radiological imaging provide precision in the diagnosis of diseases that can be utilised for the classification and diagnosis of several diseases in the medical sector. Several research studies have focused on binary classification of COVID-19, and there is limited research focusing on multiclass classification of COVID-19. The purpose of this study is to develop a model that can enhance the multiclass classification of COVID-19 using raw chest X-ray images. The study involved using convolutional neural networks as the classifier. Five pre-trained deep learning models including VGG16, MobileNet, EfficientNetB0, NasNetMobile and ResNet50V2 are used to distinguish between COVID-19 infection and other lung diseases. Data Augmentation and Normalization techniques have been used to improve the models’ performance and avoid training problems. The study findings revealed that it is possible to distinguish between COVID-19 infection and other lung diseases using pre-trained deep learning models. The proposed technique successfully classifies five classes (normal, COVID-19, lung opacity, viral pneumonia, and bacterial pneumonia). It is found that NasNetMobile model outperformed the rest of the models and achieved the highest results. It achieved an overall accuracy, sensitivity, specificity and precision of 91%, 91%, 97.7% and 91%, respectively. The VGG16 model produced better results in detecting COVID-19 infection, resulting in an accuracy of 95.8%. The suggested technique is more accurate in comparison to the other newly developed techniques presented in the literature. This provides healthcare staff with a powerful tool for the diagnosis of COVID-19 based on deep learning.

Assessing the impacts of land use/land cover changes on hydrological processes in Southern Ethiopia: The SWAT model approach

Abstract: The change in land use and land cover (LULC) due to human activities is a major cause of hydrological process changes in watersheds. This study assesses the effects of LULC changes on the hydrological processes in the Bilate catchment, located in southern Ethiopia. Landsat images of 1986, 2002, and 2018 were used to classify LULC through supervised classification. The Soil and Water Assessment Tool (SWAT) evaluated the hydrological responses to LULC changes. Results indicate an increase in built-up areas (0.70%), water bodies (0.19%), cultivated land (10.54%), and barren land (1.265%) from 1986 to 2018. Conversely, the forest (8.52%) and grazing (3.18%) areas declined. An increase in water leaving the root zone (962.02 mm/year), potential evapotranspiration (593.85 mm/year), actual evapotranspiration (201.71 mm/year), and surface runoff (514.86 mm/year) was observed, while soil water content (1423.25 mm/year) decreased at the catchment level. The declining soil water content and increasing actual and potential evapotranspiration could result in a water shortage for crop production. The impact of LULC changes on hydrology provides vital knowledge for integrated LULC and water resource management. Water resource development planning must consider LULC changes to achieve sustainable development in the catchment.

Effect of different types of water soaking and re-drying on mechanical properties of glass fiber-epoxy composites

Abstract: Fiber-reinforced polymer (FRP) composites undergo different environmental conditions in the designed life span. An investigation on aging of FRPs in water helps to enhance the material’s durability. This article aims to explore the effect of different types of water soaking (viz., tap, sea, and rain water) and re-drying conditions on the tensile and flexural strengths of glass fiber-epoxy composites (GFEC). The prepared specimens are placed in the sea, tap, and rain water for 10 weeks. Some specimens are re-dried at 50°C for 5 weeks. The water uptake (%) of seawater aged specimens decreases compared to tap and rain water-aged specimens at the end of 10 weeks. Water soaking of composites has reduced the tensile and flexural strengths of GFEC by 14 to 17%. The strength of water-soaked composite specimens is partly retrieved in specimens that have been re-dried. More than 90% of the original value is retrieved for the strength of GFECs (as-made specimens). SEM analysis of the tensile specimen fracture surface reveals the causes of the specimen failure as well as the impact of water soaking, followed with re-drying.

Digi-flash pedagogy confronts new emerging technologies - Maturity level evaluation case study

Abstract: There is significant interest in emerging technologies. Universities, companies and other adopters are researching how and when these technologies should be implemented. However, this research area still lacks ways to evaluate the maturity level of the technologies and rapid experimentation concepts for testing the new technologies. This paper addresses the research gap by providing a new evaluation method and a rapid experimentation concept. This method and concept were successfully used in twenty-five Flash-projects, where five emerging digital Industry 4.0 themes evaluated.

Experimental thermophysical dependent mechanical analysis of earth bricks with Canarium schweinfurthii and Cocos nucifera bio-aggregates - A case study in Cameroon

Abstract: In order to meet sustainable development goals, global policies are strongly oriented towards the recovery of local materials such as agricultural waste. In this context, a new biosourced compressed earth brick (CEB) has been produced with bio-shell aggregates of Cocos nucifera (CN) and Canarium schweinfurthii (CS), added in equal proportions for various mixtures. The main objective is to study, on one hand, the effect of CN and CS aggregates on the mechanical behaviour and the thermo-physical properties of the CEB. On the other hand, durability of CEB was investigated in terms of hydric stability, abrasion resistance and hygro-thermo-mechanical behaviour. Mixtures were prepared using earthen material and 0, 5, 10 and 15 wt% CNCS, with 8 wt% cement CEM II-B-LL 42.5, respectively. Wet and dry compressive strengths are evaluated versus compaction pressure (2.5, 5, 7 and 10 MPa). The increase of CNCS aggregate content induced a reduction of the compressive strength in both wet a d dry situations whatever the compaction pressure. The samples with 5 wt % CNCS and 8 wt % cement, however, offered performances close to reference samples without CNCS aggregates. The reverse trend was found for thermal conductivity: thermal conductivity of the bio-sourced CEB is below 1 W·m−2·K−1 which means good insulating performances. It is noted that the modified CEB have relatively low water absorption, which contribute to a good durability. Hygro- and thermo-mechanical tests showed however a quasi-linear decrease of compressive strength when the humidity of the environment increases but also when the temperature rises. At the end, to obtain more accurate properties by prediction, some machine learning models were used.

Enhancing the success of Ghanaian public road construction projects

Abstract: The objective of this research paper is to determine the critical success factors (CSFs) influencing the success of public road construction projects from the perspective of a developing nation. A self-administered questionnaire was used to gather data on the extent to which critical success factors gathered from literature impact the success of public road construction projects from sector practitioners’ perspectives in Ghana. The data was then analysed using factor analysis. The study revealed that external environmental factors have the highest influence (46.23%) on public road construction project success, followed by project management factors (12.25%) while procurement-related factors have the least impact (6.97%). Public construction project management organisations and the government will now have a deeper understanding of CSFs that influence the success of public construction projects and use them as a guide to enhance the successful delivery of public road construction projects. Even though numerous studies have been undertaken to enhance the success of construction projects in Ghana, very little attention has been given to procurement-related factors. Thus, the study outcome will add value to sector practitioners and the Government of Ghana in the management of public road construction projects.

Attitudes of Jordanian architecture students toward scientific research: A single-institution survey-based study

Abstract: Architecture is a profession in a perpetual state of change. Thus, it is essential for students to have a solid research foundation on which they can apply their knowledge and evidence-based solutions to architectural design, to enhance the quality of the built environment. Despite the fact that students’ views and engagement in research have been receiving great attention recently, no studies have yet been conducted to assess Jordanian students’ perspectives regarding scientific research. This paper examines the attitudes of a Jordanian university’s architecture students toward scientific research. The descriptive study sampled 184 students from the College of Architecture who were asked to fill out a self-administered questionnaire. The data were both descriptively and quantitively analyzed using correlation, a Mann-Whitney U Test, and a Kruskal-Wallis Variance Test. The findings revealed that female students’ outlook on research was more optimistic than that of male students. Moreover, fifth-year students had the least favorable opinions compared to third and fourth-year students. Furthermore, participants who followed architectural channels and broadcasts had more favorable sentiments toward research than those who did not. Finally, participants with previous experience in scientific research had fewer unfavorable opinions regarding research than those who were inexperienced. In conclusion, the majority of the students who participated in this study had positive attitudes toward scientific research. However, there is still a need to promote a culture of scientific research among undergraduate students, encouraging them to engage in scientific activities and providing them with opportunities to conduct research that will contribute to the architectural scene in Jordan.

Analysis of tempering temperature and vegetable oil quenchant viscosity effect on mechanical properties of 42CrMo4 steel

Abstract: Environment is the main concern nowadays to protect the soil. Heat treatment processes used to enhance the properties of steel should not affect the environment badly. In this study, eco-friendly oil-quench specimens of 42CrMo4 steel are subjected to different tempering temperatures for about 4 hours and tested. Hardness, room temperature impact toughness, and microstructure of specimens were determined. Results showed that as the tempering temperature increased, there was an increase in impact toughness with slight decrease in the hardness. Blend oil-quench specimen, tempered at 450°C and 500°C, shows reasonably good hardness (40 and 39 Rc, respectively) and impact toughness (35 and 40 J, respectively). Response surface approach for combined optimization has given the optimized value for tempering temperature and oil viscosity as 453°C and 34.7 centistokes, respectively. Confirmation test results have shown that the regression equation developed is the best fit with percentage error less than 3%.

Tool or hassle?- Production workers evaluation of the potential of digital assistance systems on the shopfloor in shipbuilding projects

Abstract: Technology development opens up for new possibilities to facilitate the production processes through digital information systems. To optimize the systems’ value, the form, content, and medium must fit the needs of the workers. This article aims to contribute to the discussion on value, use and design of digital assistance systems for production. It presents empirical data from a case study at a Norwegian shipyard, on production workers’ perception of coordinative challenges, and the value (including content) of digital assistance systems in complex shipbuilding projects. A quantitative survey among supervisors and operators at the shop floor was conducted twice due to different circumstances at the yard. These variations in circumstances are valuable to enable an evaluation of the workers’ perception of coordinative challenges and digital solutions in different situations. The findings indicate a pronounced positive attitude towards the potential of digital systems. Moreover, the role of supervisors and operators in coordinative challenges leads to different requirements to the solutions. The results from this study will have both industrial and scientific implications, as they provide valuable insights to help develop user-friendly systems that aid both workers and the company in terms of efficiency and accurate communication.

A multicriteria decision-making approach for prioritizing renewable energy resources for sustainable electricity generation in Benin

Abstract: Benin’s rapid population, economic, and industrial growth will increase energy demand. Hence, Benin’s government is keen to increase its power capacity to meet future demand. Renewable energy sources are significant options that governments could explore when developing their sustainable energy strategies. Prioritizing energy sources for a country’s sustainable development requires a decision-making process. In this study, multicriteria decision-making (MCDM) methods are used to prioritize alternatives such as solar photovoltaic (PV), concentrated solar power (CSP), wind energy, hydropower, and bioenergy suitable for sustainable electrification in Benin. The study employed eighteen (18) criteria classified under the four pillars of sustainability (technical, social, economic, and environmental) to evaluate the alternatives. Thereafter, the criteria importance through inter-criteria correlation (CRITIC) and entropy methods, which were employed to compute criteria weights and incorporated into the evaluation based on distance from average solution (EDAS) method to rank the alternatives. The findings from the EDAS rankings show that solar PV is the optimal alternative, ranking in the first position, followed by wind energy in the second position. CSP, hydropower, and bioenergy rank in the third, fourth, and fifth positions. In addition, EDAS findings correlated fully with those of other MCDM approaches evaluated on the same decision matrix. This indicates that solar PV is Benin’s optimal technology for sustainable electricity generation. The study’s findings are critical for policymakers developing Benin’s renewable energy sector.

C. B interrupt duty reduction based controlling TRV and symmetrical breaking current

Abstract: Evaluating the rated MVA sizes of the Circuit Breaker (CB) requires calculating reactance parameters from fault analysis and synchronizing these parameters with the reference re- striking voltage. In this paper two ways are used in controlling X/R ratio of the system to reduce CB size in order to save cost on system configuration. PSS/E program was introduced to facilitate and illustrate the solution. X/R ratio and subtransient reactance were calculated to provide an approach to assess the current and duty interruption of generator buses with contributions from all other buses. The effect of reduction factors and NACD for the symmetrical component of the short circuit current is also applied in our proposed method. The obtained results proved that applying the reduction factor technique in New England system reduces the rated interruptions of C.Bs, and CB rate is also minimized in Bismayah132kV power plant from Iraqi grid utilizing effective switching which economizes choosing CB. It is concluded that the two techniques can be used successfully for designing CB ratings with a minimum cost.

Developing appropriate business model for maize shelling technologies in small holder farmers in North West Ethiopian Districts

Abstract: The aim of this paper is to identify and select an appropriate business model for the utilization of maize shelling technologies in small-scale farming practices. Though a very old practice, agriculture is still the central activity of the entire globe due the reason that it directly or indirectly affects the livelihood of the inhabitants. West Gojjam zone of the Amhara National Regional State (ANRS) in Ethiopia is among the known maize producing zones in Country for both consumption and as a cash crop. But, the problem is the high wastage of production due to post-harvest losses (PHL) due to mechanical shelling practices. Aiming to solve this PHL of maize production, at the shelling stage, assessments and discussion with the maize growing farmers and experts concerned were conducted. This paper tries to present an appropriate business model for enabling local small holder farmers get access to different maize shelling technologies. The research follows a survey-type design which provides both a quantitative and a qualitative description of operational and business variables, attitudes, or opinions of a population in the target area, and overall insight of the technology market. The current data shows that rental maize shelling service is feasible for the fragmented maize production of the West Gojjam zone, in the Amhara National Regional State of Ethiopia. Hence, a generic conceptual model has been developed based on the feedbacks of local smallholder farmers, agricultural agents, service providers and suppliers. This model shows how to select and make available appropriate maize shelling technologies that will fit the actual demand at household level. It also shows a rent-to-own approach of maize shelling service that will help the unemployed youth in the localities.