Papers by Keyword: Evaluation

Abstract: Renewable energy sources (RES) offer outstanding attributes namely environmental-friendly and reduction in the cost of Grid system. Global power firm have embraced RES in generating electrical energy. RES, notably wind energy lessens electrical power losses on the network, nevertheless, RES incorporation into the network has adverse effect on the entire network. This research bequest critical investigation and comprehensive evaluation of reverse power flow (RPF)due to the outcome of vigorous and increased RES penetration to the Electrical Power Network. Matlab/Simulink Software is employed to carry out critical investigation on eight-bus electrical power network. The Matlab simulation was carried out with and without RES connection to the electric power network. Zones are employed for potent and effective investigation and evaluation of the network. The outcome of evaluation and analysis in sub-networks and the zones were carefully compared. The result show that RPF happens at all levels of electrical power networks, though, the penetration levels are not the same. It was revealed that RPF at the zone directly linked with the RES is higher compared with other zones.

Abstract: This paper presents an assessment of system collapse causes in Nigeria’s 132-330kV Grid. Long-term monthly data of system collapse incidences (SCI) from grid’s record was analyzed using statistical analytical procedures and adapted equations. Results established that the most probable cause of SCI is transmission grid faults at 81.6%, followed by generation faults at 13.2%, and lastly, intermediate faults at 5.2%. Furthermore, probability of non-occurrence of system collapse in a month is approximately 31%, which is low and an indication of fragile grid, requiring rigorous daily system planning, monitoring and control. Furthermore, the probability of at least 1 occurrence of SCI is also 31%, which is high and an indication that the grid is not safe from possible contingency that can result in total loss of the grid. Load loss impact of SCI is rated at an annual average of 20% for partial system collapse (PSC), while load loss would be 100% for total system collapse (TSC), implying huge costs on the national grid. These analyses indicate that the transmission network of Nigeria is most susceptible to faults that leads to SCI and needs to be investigated for specific vulnerabilities that can cause system instability and failure.

Abstract: This study aims to evaluate the risks that arise in tank operations and design risk mitigation for tank operations. This research uses the Hazard and Operability Study (HAZOP) method, where HAZOP is used to explain each part of the process to determine the risk of tank operations made and the causes and consequences. The data collected includes primary data and secondary data. Primary data is obtained through observation, interviews, and questionnaire survey results. The data sample in this study was carried out on a stockpile tank construction project owned by state-owned PT Pertamina Persero. The results showed that 1) sources of danger classified as extreme were found in the risk of fire, 2) sources of danger classified as extreme were found in the risk of fire, while the source of danger classified as moderate was the queue of tank cars, 3) risk mitigation obtained in this study were 36 mitigations in the process of receiving fuel oil and 35 mitigations in the process of distributing fuel oil, and the impact of risks obtained in this study in the form of fire, material loss, environmental pollution, oil contamination, explosion, tank leakage, sparks, lightning, overpressure, queuing mobile tanks

Abstract: Transportation is a very crucial sector in supporting economic activities and regional development. Typically, the smoothness of transportation movement is influenced by the condition of transportation infrastructure, which is related to the level of accessibility, traffic performance, and road pavement conditions. To facilitate regional development and economic improvement in West Aceh Regency area, there is an interest to assess the condition of road transportation. Therefore, this research aimed to evaluate road connected to activity centers in the interior of West Aceh Regency. Among the 12 sub-districts, only 6 were situated in interior area, specifically sub-district capitals not located on national or provincial roads. Typically, national and provincial roads showed good pavement performance and quality. Also, road transportation connectivity was assessed based on accessibility, traffic performance, and pavement conditions. The data used for this exploration included information on accessibility, traffic volume, road capacity, and road pavement conditions. The result showed that the level of accessibility was currently suboptimal. Consequently, road pavement was classified as damaged, but remained in very good condition in terms of traffic performance.

Abstract: Currently, functional tests and property tests are used to evaluate cutting fluid [1]. However, the problem is that the results obtained from above tests do not always match with each other because the insert tip is under extreme pressure and high temperature in actual machining. Therefore, a new cutting fluid evaluation method based on actual machining is needed. End face cutting in lathe machining is cutting workpiece from outside to center. In this study, rotation speed was fixed. In other words, cutting speed varies with the radius of workpieces and it is considered possible to clarify the effectiveness of cutting fluid at each cutting speed in a single cut.The performance of the cutting fluid was evaluated based on acceleration of cutting tool and surface roughness of workpiece. The following results were obtained. In steel materials, the acceleration of insoluble cutting oil was highest, and burnt insert tips were observed after the end face cutting. Insoluble cutting oil used in this study has a lower viscosity and a lower boiling point than mineral oils and esters. The highest acceleration of insoluble cutting oil is considered to be due to insufficient lubricating effect because of evaporation of it. No effect of insoluble cutting oil, mineral oils or esters was obtained on surface roughness. The acceleration of undiluted solution is higher than that of diluted solution and burnt insert tips were obtained. The cooling effect of undiluted solution is low because of less water. The highest acceleration of undiluted solutions is considered to be due to insufficient lubricating effect because of evaporation of it. In A5056, surface roughness of the diluted solution was higher at low cutting speed due to lack of lubricating effect. Differences in acceleration, surface roughness and insert tip were observed for each oil type, indicating the possibility of evaluating cutting fluid performance using the method proposed in this study.

Abstract: Temu Kunci (Kaempferia pandurata Roxb.) is one of the plants from the Zingiberaceae family that contains secondary metabolites derived from flavonoids. Studies on the bioactivity of flavonoid compounds from this species have shown various biological activities such as antibacterial, antioxidant, antiviral, antitumor, antipyretic, anti-inflammatory, analgesic, and insecticidal properties. Pinostrobin (5-hydroxy-7-methoxy flavanone) (1) is the major flavonoid found in the rhizomes of this plant and has been successfully derivatized through ethylation and allylation reactions. Two compounds were obtained from the ethylation reaction, namely 5-ethoxy-7-methoxy flavanone (2) and 4'-ethoxy-6'-methoxy chalcone (3), while from the allylation reaction, 5-allyloxy-7-methoxy flavanone (4) and 6-allyl-7-methoxy flavanone (5) were obtained. Compounds 2, 3, 4, and 5 were tested for their antibacterial activity against the Gram-positive bacterium Staphylococcus aureus ATCC 25923 and the Gram-negative bacterium Escherichia coli ATCC 25922 using the agar diffusion method. The results of the inhibition zone measurements showed that compounds 2, 3, 4, and 5 were not active against S. aureus ATCC 25923 and E. coli ATCC 25922.

Abstract: Many excavations contain potsherds that have suffered from different aspects of deterioration, including salt crystallization, dirt deposition, and soot. The different stains play an important role in the deterioration of archaeological pottery, such as the disappearance of the original surface and discoloration. The present study aims to evaluate some nanoparticles in an innovative poultice form to be used to clean archaeological pottery. In this study, the nanoparticles (NPs) of titanium dioxide (TiO₂) and zinc oxide (ZnO) have been prepared at 5% and in the poultice form to be used for the cleaning process of archaeological potsherds excavated from the excavation site at Abusir. Different analytical techniques, such as transmission electron microscope (TEM), digital microscope, stereomicroscope, scanning electron microscope (SEM-EDX), X-ray diffraction (XRD), and measurement of color change have been used to characterize the studied potsherds and evaluate the cleaning process. The results of the XRD analysis showed the presence of some main minerals, such as albite, quartz, diopside, hematite, spinel and chloride salt (halite). The results of the microscopic investigation used in the evaluation process revealed that using TiO₂ NPs poultice perfectly removed soot and dust deposits from the surface, and the cleaned surface became smooth. The results of elemental analysis by (SEM-EDX) showed the effective reduction in the percentage of salts and soot from the treated potsherds by TiO₂ NPs poultice to be 3.38% and 6.68%, respectively. The measurement of color change revealed that the treated potsherds by TiO₂ NPs poultice gave the highest (ΔE*=9.41), confirming this poultice's effective role in cleaning archaeological potsherds. Based on the results of different analytical techniques used in the evaluation process, the TiO₂ NPs poultice is recommended for use in the cleaning process of archaeological pottery.

Abstract: Pyrolysis of combustible municipal solid waste (MSW) is an environmentally friendly waste to energy process that produces an ecological bio-oil with a high-energy value. However, the challenge is to obtain the desired products in considerable quantities, of good quality, and at low cost. The present work objective is to evaluate combustible MSW potential available in Morocco and their recovery in bio-oil produced by pyrolysis. An evaluation was conducted based on the MSW characterization for different Moroccan cities. It shows that Morocco has significant potential in good quality RDF, having a high calorific value and a low environmental impact. The yield of bio-oil that can be produced by pyrolysis of the dry part of municipal waste for different Moroccan cities was estimated using an appropriate model. The average total bio-oil yield estimated for each city is 45 wt%. Besides, the high calorific value fraction of bio-oil derived from Moroccan RDF will cover ~45% of the country's fuel-oil needs.

Abstract: The most of limestone objects in museums, storehouses and archaeological sites suffered from fragility and weakness which lead to the degradation of these artifacts. The present paper aims to evaluate the use of some nanolime-silica core-shell for consolidation process of these weak limestone artifacts. Two concentrations (5% and 10% w/w) were prepared for consolidating the aged limestone cubic samples. After complete drying, the cubic stones were exposed to the accelerated heat aging. The evaluation of consolidation process for the treated and aged treated samples was performed by some analytical methods such as measurement of physical properties and compressive strength. While, the investigation of surface morphology was carried out by scanning electron microscope (SEM) and measurement of contact angle. The characterization process for the prepared core-shell showed the smoothness and spherical shape of the grains with approximate size of 72 nm. The results of physical properties revealed that the treated samples with 10% of nanolime-silica core-shell gave the lowest porosity (15.57%) and water absorption (6.26%). Additionally, the treated samples with 10% concentration of nanolime-silica core-shell gave the highest values of compressive strength (21.23 Cm²/ Kg) and contact angle (122.78°). Moreover, the investigation using SEM revealed that the smoothness and good penetration for the treated sample with 10% concentration of nanolime-silica core-shell. The results of the present study revealed that the efficiency of consolidation process was maximum using 10% concentration of nanolime-silica core-shell and hence it was applied for consolidation of an archaeological limestone octagonal column, Egypt.

Abstract: The article considers the problems of diagnostics of reinforced concrete structures and creation the generalized calibration dependence for the use of ultrasonic devices. The results of the study of the influence of some factors on the results of measuring the dissemination time of ultrasonic vibrations are presented. The study was conducted using devices "Pulsar 1.1" and "Novotest IPSM-U" in compliance with regulatory requirements. Statistical processing of the obtained results (with visualization) was performed using the software package EXEL. Processing of the obtained data confirmed the multifactorial dependence of ultrasonic measurements on the concrete surface. The lack of clearly defined conditions for measurements reduces the reliability of the results. The use of ultrasonic measurements to obtain absolute values of the properties of concrete is not adequate. It is proposed to make changes to the regulations regarding the limits of application of ultrasonic measurements.