Challenge Journal Publications (TULPAR Academic Publishing)
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Mechanical, durability and solar reflectance properties of colored self‒compacting concrete
Full text linkUrbanized areas are known to have significantly higher temperatures than rural areas. The Urban Heat Island (UHI) effect is caused by surfaces such as asphalt, buildings, and other heat-absorbing surfaces that store more heat than natural vegetation. Sunlight reflecting properties of building materials are improved with different applications. The present study investigates the mechanical, durability and solar reflectance properties of the colored self-compacting concrete. SCCs containing yellow, green, and black pigments were produced and evaluated. The fresh properties were determined with the slump, L-Box and V-funnel tests. Furthermore, compressive strength, solar reflectance and magnesium sulfate resistance tests were conducted. Yellow pigment added SCC showed a great potential (with the albedo of 0.42) in terms of solar reflectance and decreasing the contribution to the urban heat island effect
Investigation of mechanical properties of steel reinforcements in reinforced concrete structures as a result of exposure to fire
Full text linkIn this study, it is aimed to investigate the properties of the most commonly used metal and alloy steel materials, which are used in our country and in the world as engineering materials, under the influence of fire of the rebar in the concrete. Inspection standard TS 708:2010 S420 quality 8 mm diameter ribbed construction iron bars for 90 minutes in resistant furnace, atmospheric environment at 600 °C, 800 °C and 1000 °C concrete inside and outside the concrete at the specified temperature fire simulation, the process was allowed to cool in air. With the protective environment created by reinforced concrete, the temperature directly affecting steel bars located outside the concrete under the same conditions, The variable properties of the sample, which are inside the concrete and outside the concrete, were evaluated comparatively. Surface images of the specimens prepared in metallography were taken at different magnifications. The tensile strength of rebar bars did not change significantly according to the environment, but the samples in the concrete showed a more ductile tendency than the samples outside the concrete. The hardness values of the steel bars in the concrete and the steel bars other than the concrete decreased as the temperature increased and this decrease was higher in the samples in the concrete
Chemical resistance of hardened mortar containing andesite and marble industry waste powder
Full text linkThe sludge generated during forming processes of marble and andesite rocks is kept in dust form after drying. Due to the high consumption of andesite and marble, the storage and health problems of these dusts arise. Therefore, reducing the environmental impacts of waste and recovering them for the economy is an important issue. For this purpose, in this work, mortar specimens were manufactured using 0%, 5%, 10%, 15% and 20% of waste marble and andesite powders separately by Portland cement. Strength properties of the samples were investigated before and after immersion to the hydrochloric acid (HCl), sodium sulfate (Na2SO4) and magnesium sulfate (MgSO4) solutions. The results indicated that partial substitution of Portland cement by andesite and marble powder up to 10% have positive influence on the mechanical properties of the mortars at ambient conditions. In addition, the andesite incorporated mortars have the better performance under the acid and sulfate environments than the other mortars. On the other hand, substitution of Portland cement by marble powder more than 5% has negative influence on the chemical resistance of the mortars
Evaluation of the lightweight foamed concrete characteristics
Full text linkThe purpose of this paper is to assess the properties of light weight foamed concrete. In this research, two phases are investigated. The first stage explored the characteristics of fresh and hardened foamed concrete using a foaming agent. The following parameters were employed in this study: foaming agent used as a volume of concrete mix by 10, 20, and 40%, fly ash used as a replacement of cement content by 10, 25, and 50%, and polypropylene fiber used with varied volume fractions of 0.5, 0.75, and 1.0%. Slump values are applied to evaluate the fresh properties. To evaluate the hardened concrete, the dry density and compressive strength at 7 and 28 days are computed. Furthermore, the 28-day tensile splitting strength and flexural strength are studied. The effect of a high temperature was evaluated. The second stage investigated the effects of polypropylene fiber on both fresh and hardened concrete. It was observed that foaming agents improve fresh characteristics while decreasing compressive strengths and dry density. Furthermore, utilizing fly ash improves the characteristics of both fresh and hardened foamed concrete. The fiber reduces the fresh characteristics while enhancing the toughened properties. Because of its low density, foamed concrete is being used for structural applications because of this study. Such as those utilized for thermal insulation, acoustic impedance, and fire breaks. Also used to create road foundations for roads built on soft soil
Comparison of ultrasound-guided genicular block vs. intrathecal morphine for postoperative analgesia in patients undergoing knee arthroplasty: A randomised prospective study
Full text linkAim: Total knee arthroplasty (TKA) is a major orthopedic surgical procedure often necessitating effective postoperative analgesia. This study aimed to compare the analgesic efficacy of ultrasound-guided genicular block (GB) and intrathecal morphine (ITM) in patients undergoing THA under spinal anesthesia.Method: A prospective, randomized, single-blind study was conducted at Ordu University Training and Research Hospital from October 1, 2022, to April 1, 2023. Eligible patients aged 18 to 90 undergoing knee surgery with spinal anesthesia were randomized into two groups: Group ITM received intrathecal morphine, while Group GB underwent ultrasound-guided triple genicular block. Pain scores, rescue opioid consumption, time to initial mobilization, and Modified Bromage Scale (MBS) scores were assessed at five time points (0, 2, 6, 12, and 24 hours) within the first 24 hours post-surgery.Results: At the 24-hour mark, cumulative tramadol consumption was significantly lower in Group ITM compared to Group GB (35.45±54.84 vs. 63.37±37.7 mg, respectively, p = 0.028). Group ITM also exhibited statistically lower Numeric Rating Scale (NRS) scores at 12 hours (p = 0.005) but had similar scores at other time points. Additionally, time to first ambulation and MBS scores were consistent across all intervals (p < 0.05).Conclusions: In patients undergoing knee arthroplasty with spinal anesthesia, those receiving ultrasound-guided genicular blocks demonstrated higher opioid consumption over a 24-hour period compared to those receiving intrathecal morphine. However, regarding postoperative pain scores, both groups exhibited similar outcomes. These findings provide valuable insights into the selection of postoperative analgesic modalities for TKA patients
Optimization of reinforced concrete beam using hybrid algorithms with multi-objective function as CO2 emission and cost
Full text linkIn this study, algorithms with two objective functions are defined considering the TS500 (2000) (Reinforced concrete structures design and construction rules) and TBDY (2018) (Turkey Building Earthquake Regulation) standards for rectangular beam design. These objective functions were determined as CO2 emission and cost. Optimizations were performed in MATLAB program using the Hybrid Algorithm of Teaching-Learning Based Optimization and Jaya Algorithm. In the case of using two objective functions, cases were created by multiplying the coefficient values found in the objective function according to the formula with the cost and CO2 emission values at different rates in order to prevent CO2 emission which is one of the biggest problems for the world. In the objective function, each rate used for CO2 and cost is implemented in a manner that increases or diminishes the impact of these values. In this way, comparisons were made between the cross-section dimensions to be formed according to not only impact rates but also the reinforcement area to be used, the CO2 emission and cost values that will arise as a result of these. Impact rates are related to cost and CO2 rate in the objective function, and the total rate is chosen as 1. Impact rates for cost are chosen as 0.1, 0.3 along with 0.5, and comparisons between the results are checked. In addition, recyclable and non-recyclable steel with different properties were used in separate analyses and the values were compared. Since the CO2 rate released by the non-recyclable steel is very high compared to the recyclable steel, the results show that the CO2 emission value is higher and this causes the objective function value to increase
Where does the praise for artificial intelligence come to an end? Tolerance for anything is not boundless
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Pericapsular nerve group (PENG) block as a sole anesthetic method for malignant soft tissue excision
Full text linkSince its first description by Philippe WH Peng in 2018, the Pericapsular Nerve Group (PENG) block, a novel regional anesthetic procedure, has been gaining in popularity. In order to provide appropriate analgesia, an ultrasound-guided local anesthetic injection around the hip joint is performed.We presented, in this case, the successful management of the PENG block for surgical anesthesia in the excision of a malignant soft tissue tumor in the proximal tibia of a 73-year-old female patient. Adequate sensory and motor blocks were obtained, allowing a 70-minute surgery without using additional analgesics. Postoperative pain scores were low, and the patient was discharged without complications
On the evaluation of lateral-torsional buckling of web-tapered cantilevers with doubly symmetric I-section
Full text linkRecently, structural engineers have tended to design stronger and lighter structures due to economic reasons, technical developments in computer-aided design, and improvements in manufacturing. The demand for designing stronger and lighter structures has led to the compulsory considering structural efficiency and stability loss at the design level. Lateral-torsional buckling (LTB) is a major stability loss for web-tapered cantilevers with doubly symmetric I-section, which are aesthetic and structurally efficient. The elastic LTB loads of these cantilevers should be calculated at the design level since the LTB may happen before bending stress reaches yield. Studies related to the LTB of cantilevers are rare and require numerical solutions since the LTB mode shape of cantilevers is complex compared to simply supported beams. The present study introduces an analytical procedure based on the energy method for calculating elastic LTB of web-tapered cantilevers with doubly-symmetric I-section in two different forms. The analytical model considers different transverse load types, positions of loads, and web tapering degrees. The analytical solutions were validated with one-dimensional finite element analysis using a beam element. Excellent accordance between results was demonstrated. The general LTB behavior of web-tapered cantilevers with doubly symmetric I-section was clarified with detailed comments based on results obtained from the presented analytical model