Search

The piping system connected with the shipboard equipment may be subjected to excessive vibration due to harmonic base excitation produced by hydrodynamic force imposed on the propeller blades interacting with the hull and by other sources. Vibration design aspects for shipboard pipework are often ignored, which may cause catastrophic fatigue failures and, consequently, leakage and spillage in the sea environment. Without dedicated design codes, the integrity of shipboard equipment against this environment loading can be ensured by testing as per test standard MIL-STD-167-1A (2005). However, in many cases, testing is not feasible and economically viable. Hence, this study develops an FE-based vibration analysis methodology based on MIL-STD-167-1A, which can be a valuable tool to optimize the testing requirement without compromising the integrity of these piping systems. The simulated model dynamic properties are validated with experimental modal testing and Harmonic response analysis result confirm that a mitigating solution option can be verified by a FE based vibration analysis to mitigate the vibration problem.

This experimental study investigated the abrasive wear behaviour of pure copper-based and multi-walled carbon nanotube (MWCNT) doped composites synthesized by the powder metallurgy technique. Composite structures were formed by reinforcing MWCNT at different ratios between 1% and 8% in 99.9% pure copper by powder metallurgy. The microstructures of the nanocomposite samples were analyzed by X-ray diffraction. Then, density and hardness measurements and abrasive wear tests were performed to determine their mechanical properties. The collected data were evaluated with scanning electron microscopy images. It has been determined that copper’s nano-sized carbon reinforcement material has a dry lubricant effect up to a specific ratio, reducing wear losses. On the contrary, wear losses increase as the MWCNT reinforcement ratio increases between 4% and 8%. The best results in lowering wear losses were obtained from the sample with 1% MWCNT reinforcement. Depending on the increase in the amount of nanomaterial reinforcement in the composite structure, it was observed that pore formation enlarges with reinforcement agglomeration. It was concluded that the dense porosity in the composite structure neglects the lubricating properties of the MWCNT reinforcement material and increases the wear losses by having a negative effect.

Recently, additive manufacturing techniques have begun to be implemented extensively in the production of implants. Ti6Al4V alloy is a material of choice for implants due to its low density and high biocompatibility. Recent research, however, has demonstrated that Ti6Al4V alloy emits long-term ions (such as Al and V) that are hazardous to health. Surface modifications, including coating, are therefore required for implants. The electrodeposition method was utilized to deposit Zn-doped TiO _2 onto the surfaces of Ti6Al4V samples, which were manufactured via the selective laser melting method. The effects of processing time, amount of TiO _2 addition, microstructure of anode materials, and resistance to wear and corrosion were investigated. The coating hardness and thickness increased with increasing processing time and TiO _2 concentration. It has been observed that the addition of TiO _2 to zinc anode coatings results in an increase in wear and a decrease in corrosion rate. It was noted that the specimens exhibiting the most significant wear also possessed the highest hardness value. The specimens were generated utilizing a graphite anode, underwent a 30-min processing time, and comprised 10 g l ^−1 of TiO _2 .

Lavandula angustifolia is an important aromatic plant and rich source of linalool. L. angustifolia and its bioactive compounds have been reported to possess several bioactivities such as antioxidant, antifungal, antibacterial and antidiabetic etc. The aim of the present study is to characterize chemical compounds present in volatile oil and ethyl acetate extract of L. angustifolia aerial parts by gas chromatography mass spectroscopy (GC-MS). The hydrodistillation of aerial parts of L. angustifolia yielded 1.56±0.27% v/w volatile oil. The GC-MS analysis of volatile oil of L. angustifolia yielded 74 chemical compounds, and lavandulyl isobutyrate (52.61%), and linalool (5.41%) were identified as major compounds. Ultrasonication was utilized for extraction of L. angustifolia using ethyl acetate as solvent and extraction yield was found to be 3.59±0.73% w/w. The GC-MS analysis of ethyl acetate extract of L. angustifolia yielded 40 chemical compounds and the major compounds were dotriacontane (8.33%), linalool (7.09%), eucalyptol (6.42%), linalyl acetate (4.69%), 1,4-cineole (4.62%), and trans-linalool oxide (4.51%). The present study explores the chemical composition of volatile oil and ethyl acetate extract of L. angustifolia.

Health care workers, especially doctors and nurses who are in direct contact with COVID-19 patients are on high-risk professions despite wearing full protective equipment. This study aimed to assess the fear and emotional stress among Iraqi dentists from getting infected with COVID-19 and also their knowledge in preventing this disease. A cross-sectional study using an online survey questionnaire consisted of 22 questions was implemented using Google Forms. The study started after gaining the agreement of the authority. The questionnaire was put out on social media; well known Iraqi dentist’s Facebook groups, and through e-mail. The study covered all the governorates of Iraq. The data were processed using SPSS. The sample was 516 dentists (216 males, and 255 females) and 218 participants were graduates, 249 postgraduates, and 49 of them were students. Results showed that, dentists who were afraid of getting infected with COVID-19 were 82%. Iraqi dentists have knowledge about the Novel COVID19 and are afraid of getting infected. Iraqi dentists need modifications in their practice to protect themselves and their patients from this pandemic.

The yield and quality traits of hyssop (Hyssopus officinalis L.) depending on the plant developmental phases were investigated under Turkey’s Eskisehir ecological conditions in 2019 and 2020. The experiment were conducted in randomized complete block design with 3 replications. The developmental stages examined were before-flowering, beginning of flowering, full flowering and after flowering stage. The effect of harvest times on examined all parameters was very significant (p ≤ 0.05). The maximum yields of fresh herb and dry leaf + flower were obtained from after-flowering stage. However, no significant difference was observed between full flowering and after-flowering period for dry leaf + flower yield. On the other hand, the essential oil content (0.93%) and essential oil yield (24.01 L ha–1) in the full flowering stage were found to be higher. The main components of hyssop essential oil were as follows: pinocamphone (38.41–41.85%), isopinocamphone (22.73–22.99%) and β-pinene (7.92–8.94%). Maximum pinocamphone content was observed in the before-flowering period. To harvesting in full flowering of hyssop plant can be a reasonable strategy in terms of high dry leaf + flower yield, essential oil content and yield.

This study was carried out for two years in order to determine the effects of mychorrizal preperate (MP) applications on nutrient contents of saplings in grafted and potted grapevine sapling production. In this study, five grapevine rootstocks (140 Ru, 110 R, 41 B, 1103 P and 5 BB) and Narince grape cultivar cuttings were used. Four commercial biological preparations Roots Deep Gel, Endo Roots, Bio-one ve Biovam were applied to grafted cuttings in plastic bags grafted cuttings in greenhouse were allowed to grow for about 2 months. The effect of MP applications on nutrient intake of saplings was determined in leaf samples taken 80-90 days after MP applications. Effect of MP on P, K, Zn, Ca, Fe and Mg content of leaves were changed in according to rootstocks and mychorrizal preparation types. MP generally had positive impact on nutrient intake. Biovam, Bio-one and Endo Roots applications were more effective in terms of nutrient intake.

Background: Children were compared to their siblings, cousins or peers regarding the eruption of their permanent teeth. Genetic and environmental factors can affect dental development and, therefore, the body mass index (BMI) could be considered as a factor that may influence dental development. Purpose: To determine any possible association between BMI and either dental caries or the eruption of permanent teeth (central incisor and molar). Methods: A cross-sectional study was completed for six-year-old school children. A total of 218 children (116 boys, 102 girls) from public elementary schools in Erbil City were entered into the study. Dental caries assessments were carried out using the WHO criteria for decayed, missing and filled primary teeth and indices (DMFT). BMI was used to classify obesity status. Results: Overall, 27.98% of the children were classified as overweight, 59.17% as normal and 12.84% as underweight. The DMFT was 5.247, while 12.39% of the children were caries-free. Conclusions: Children of normal weight had most permanent teeth erupted and a low caries index. Underweight children had fewer erupted teeth and a higher caries index. The complex relationship between body composition and oral health should be considered in paediatric patients.

Emission control regulations have been essential in reducing vehicular exhaust emissions. However, the contribution of exhaust and non-exhaust emissions to ambient particulate matter (PM) has not yet been accurately quantified due to the lack of standardized sampling and measurement methods to set regulations. The identified sources and the source profiles generated have not been comparable as none of the emission data collection techniques and the receptor models applied in the literature have produced a standard or reference method to simultaneously identify and quantify the non-exhaust emission sources. This study utilized and thoroughly characterized PM samples including 32 major and trace elements from a mixed fleet in a mountain highway tunnel atmosphere in Bolu, Türkiye. This work proposed a two-stage, simple, and robust method based on road dust enrichment factor (EF) and elemental carbon (EC) tracer methods (EFECT) for the identification and prediction of the exhaust (exh), and non-exhaust (n-exh) emissions in PM. The indicated method revealed that road dust resuspension emissions are the most significant contributor to the concentrations of crustal elements. This method was used successfully to determine the real-world elemental contributions of road dust resuspension (rdrs), emissions (em), exhaust (exh), and non-exhaust (n-exh) emission sources to the elemental concentrations in PM samples. This study provided significant insights into generating actual source profiles, source-specific emission factors, and the source apportionment results for vehicular emission sources worldwide. Considering this, PM data of any particle size fraction (PM10, PM10-2.5, and PM2.5, for example) can be used as input for the EFECT, provided that the data include the analytical results of elemental carbon in both the atmospheric PM and road dust samples having similar PM sizes.

This study was carried out in order to determine the effects of Mychorrizal Preparation (MP) applications on final take and root quality in grafted and potted grapevine sapling production. In this research, cuttings of five different Vine rootstocks (140 Ru, 110 R, 41 B, 1103 P and 5 BB) and scions of Narince grape cultivar were used. In addition, 5 commercials symbiotic mychorriza preparations (MP); Roots Deep Gel (RD), Endo Roots Soluble (ER), Myco Apply (MA), Bio-one (BO) and Biovam were applied. Scions were grafted on rootstocks by omega table grafting machine and then grafted cuttings were stored for three weeks at stratification room. The grafted cuttings were planted into polyethylene bags (12 × 20 cm size) containing 1:1 sterile perlite-peat mixture. Grafted cuttings were kept in greenhouse during 2 months for growing. After grapevine final take rates were determined, grapevine saplings were transferred to acclimatization environment. Root fresh and dry weights of grapevine saplings were detected in the first week of September. Research was designed according to completely randomized plot as three replications and as 50 grafted cuttings each plot. At the end of study, it was determined that both MP applications and rootstocks have a significant effect on final take and sapling quality. The ratios of first grade sapling varied from 21.5% to 93.3% in first year and from 10.3% to 79.3% in second year. Effects of MP applications on the total final take ratios differed depending on the rootstocks in both years. MP applications showed significant effect on total final take ratios of 110 R and 41 B in the first year, and total final take ratios of 5 BB, 41 B and 140 Ru in the second year. While the best results were obtained from MA, EN, RD applications in the first year, the highest final take ratios were in EN, RD and BO applications in the second year. The highest value on final take was obtained from 5BB rootstock, while the lowest value was recorded in 140 Ru rootstock. Effect of MP applications on the fresh and dry weight of root changed according to rootstocks.

Pressure-assisted single-point incremental forming (PA-SPIF) is one of the emerging forming techniques for sheet metals that have been the subject of rigorous research over the past two decades. Understanding of its forming mechanisms and capabilities is growing as a result. Open gaps are still present in material constitutive modelling for accurate numerical predictions and finite-element simulations as the characteristics of localised deformation behaviour in SPIF are different from those of conventional sheet metal forming. The current investigation focused on the comparison of three different material models for the finite-element analysis of PA-SPIF of cold-rolled, dual-phase steel DP600. Experimental trials using different fluid pressures showed good agreement with simulation results with discrepancies in deformed blank thickness and shape geometry predictions of 3–11% and 10–21%, respectively. Within the tested materials and range of parameters, the fracture-forming-limit diagram (FFLD) material model was identified to be of superior accord with experiments.