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A numerical technique for solving nonlinear singularly perturbed Fredholm integro-differential equations
Get PDFThis study deals with two numerical schemes for solving a class of singularly perturbed nonlinear Fredholm integro-differential equations. The nonlinear terms are linearized using the quasi -linearization technique. On the layer adapted Shishkin mesh, the numerical solution is initially calculated using the finite difference scheme for the differential part and quadrature rule for the integral part. The method proves to be first -order convergent in the discrete maximum norm. Then, using a post -processing technique we significantly enhance the accuracy from first order to second order. Further, a hybrid scheme on the nonuniform mesh is also constructed and analyzed whose solution converges uniformly, independent of the perturbation parameter and directly gives second order accuracy. Parameter uniform error estimates are demonstrated and the theoretical results are validated through some numerical tests
Prediction of Flow Behavior and Deformation Analysis of AA5754 Sheet Metal at Warm and Hot Temperatures
Get PDFThe utilization of lightweight materials such as AA5754 aluminum alloys in the inner body panel parts of vehicles has been significantly important for automotive manufacturers to minimize the high fuel consumption by reducing the overall weight. In this study, the flow behavior of AA5754 sheet metal has been discussed by conducting uniaxial tensile tests at five different temperatures (RT, 200, 250, 300, 350 degrees C) and three strain rates (0.001, 0.01, 0.05 s(-1)). Additionally, the capability of Fields and Backofen (F&B) and Voce hardening rules in describing the flow behavior of AA5754 at different temperatures and strain rates has been investigated by conducting uniaxial tensile tests in finite element analysis. It has been found that the main deformation mechanisms for the AA5754 are the strain hardening mechanism up to 250 degrees C, strain hardening and dynamic recovery mechanisms at 300 degrees C, dynamic recrystallization and strain hardening mechanisms at 350 degrees C. While the F&B hardening rule has been able to successfully capture the flow behavior of AA5754 up to 250 degrees C with a 14.36% error, its capability has significantly reduced after 250 degrees C due to its incapability of describing the effects of dynamic recovery and recrystallization. Voce hardening model has been better able to describe the flow behavior of AA5754 at all the temperature levels than F&B model due to its saturation behavior.Scientific and Technological Research Council of Turkey (TUBITAK) [120M937]; TUBITAKAcknowledgmentsThis study was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) (Project No: 120M937). The authors would like to thank TUBITAK for the financial support given to the project. The authors are grateful for the support of Mert AYGEN and Ali Baran METE, who works in NETFORM engineering firm, in licensing the software of Simufact Forming V16
Heterosis and Diallel Analysis of Yield and Yield Components of Bread Wheat F1 Generation
Get PDFIn this study, half-diallel crosses were performed using six wheat genotypes (Adana-99, Flamura-85, Masaccio, Lucilla, 1635 and 2115). This research was conducted in Kahramanmaras ecological conditions during the 2019-2020 growing season in a randomized complete block design with three replications. Heading date (HD), grain filling period (GFP), days to maturity (DM), plant height (PH), spike length (SL), grain number per spike (GNS), grain weight per spike (GWS), thousand kernel weight (TKW), grain yield per plant (GY), and chlorophyll content of flag leaf (SPAD value) traits were investigated on F1 plants and parents. When the mean values of parents and F1 generations were examined, F1 mean values were higher than the mean values of parents in heading date (134.06 days), days to maturity (164.04 days), spike length (13.31 cm), grain number per spike (51.64 units), grain weight per spike (2.11 g), thousand-grain weight (36.58 g), grain yield per plant (35.99 g), and chlorophyll content of flag leaf (49.60 SPAD), while lower in grain filling period (41.77 days) and plant height (88.80 cm). According to diallel analyses, it was found that HD, DM, GFP, PH, GWS, and SPAD traits had additive and dominant gene effects, while SL, GNS, TKW, and GY traits had significant dominant gene effects. Partial dominance was observed for HD, DM, PH, GWS, GY, and SPAD traits, while superior dominance was observed for GFP, SL, GNS, and TKW traits. The effects of general combining ability (GCA) and specific combining ability (SCA) were significant for all the traits studied. Positive average heterosis and heterobeltiosis values were determined for GNS, GWS, TKW, and GY traits. In terms of grain yield per plant, the genotypes Adana-99, Lucilla, and Masaccio were identified as potential parents for breeding programs. Combinations of 1635 × 2115, Masaccio × Lucilla, Adana-99 × Lucilla, Adana-99 × Masaccio, Adana-99 × 1635, and Flamura-85 × Lucilla were identified as promising hybrids for grain yield
Tribological and mechanical exploration of polymer-based hemp and colemanite composite as a friction material
Get PDFNatural and organic-based composite materials are widely used in many industrial applications due to their low cost, easy recyclability, economic feasibility, and ready availability. In this study, a polymer-based composite friction material consisting of Hemp-Colemanite composition (HCFCo) has been developed for the automotive sector to exhibit lower cost, environmentally friendly characteristics, and suitable friction-wear behaviors. For this purpose, three different ratios (%4, %8 and %12) of HCFCo composites were produced using a coating technique called impregnation process with a specially designed device. During the production stage, homogeneity of the composites was ensured, and then the final shape was given by the hot pressing method. Local based natural materilas frequently used for as anon-asbestos friction materails. For this reason, hemp and colomanited based composites were tested. Properties such as hardness, density, water and oil absorption, friction coefficient, and specific wear of HCFCo samples were examined. In addition, the microstructures of HCFCo composites were investigated to determine the bonding form between hemp fiber and colemanite. The results obtained revealed that the friction coefficient values decreased with an increase in temperature, while no significant change was observed in hardness and density values. Throughout the entire testing process, the friction coefficients varied between 0.14 and 0.29 on average. It was concluded that the developed fiber-reinforced composite can be reliably used in industrial applications and can contribute significantly to innovations in the literature
The change of the material class of the reinforced concrete school building examining its effect on performance
Get PDFBu çalışmada, betonarme kamu binasının performans düzeyi elastik olmayan değerlendirme yöntemi olan tek modlu statik itme analizi ile belirlenmiştir. ETABS Ultimate V.20.1.0 sonlu elemanlar programında binaya ait taşıyıcı sistem kesit bilgileri girilmiş altı adet beton sınıfı ve iki adet donatı sınıfı ile performans analiz yapılmıştır. Altı adet malzeme özelliklerine göre yapılan itme analizi sonucu yapının TBDY 2018'de istenen performans seviyesi şartlarını sağlayıp sağlamadığı incelenmiştir. SAP 2000 programı Material ayarlarından malzeme bilgileri tanımlanış, Frame Section özelliklerinden kolon, kiriş elemanları tanımlanmıştır. "Section Desinger" ayarlarından kesitlerin moment eğrilik analizleri elde edilmiş ve hinge ayarlarından kesitlerin plastik mafsal atamaları yapılmıştır. Taşıyıcı sistem elemanları etkin kesit rijitlikleri TBDY 2018 Bölüm 15'e göre tanımlanmıştır. Altı adet malzeme özelliklerine göre statik itme analizleri yapılmış ve malzeme değişiminde yapının performansının değişimi incelenmiştir. Program analizi sonucu yapının statik iki eksenli kesme kuvveti ve yapının deplasman değerleri veren statik itme eğrileri modal kapasite eğrilerine dönüşümü sağlanarak eksenleri spektral ivme ve spektral deplasman değerini veren eğrilere dönüştürülmüştür. Altı adet malzeme sınıfına göre yapı DD1 deprem düzeylerinde yapı performans noktasına ulaşıp ulaşmadığı incelenmiş Yapı performansları karşılaştırılmıştır.In this study, the performance level of the reinforced concrete public building was determined by single-mode static pushover analysis, which is an inelastic evaluation method. In the ETABS Ultimate V.20.1.0 finite element program, the structural system section information of the building was entered and performance analysis was carried out with six concrete classes and two reinforcement classes. As a result of the pushover analysis performed according to six material properties, it was examined whether the structure met the required performance level conditions in TBDY 2018. Material information was defined in the SAP 2000 program Material settings, and column and beam elements were defined from the Frame Section properties. Moment curvature analyzes of the sections were obtained from the "Section Designer" settings and plastic hinge assignments of the sections were made from the hinge settings. Effective section stiffnesses of carrier system elements are defined according to TBDY 2018 Chapter 15. Static pushover analyzes were carried out according to six material properties and the change in the performance of the structure with material change was examined. As a result of the program analysis, the static push curves, which give the static biaxial shear force of the structure and the displacement values of the structure, were transformed into modal capacity curves and their axes were transformed into curves giving the spectral acceleration and spectral displacement values. It was examined whether the building reached the building performance point at DD1 earthquake levels according to six material classes and the building performances were compared
The effects of silica and graphene nanoparticles on some physical and mechanical properties of laminated wood materials
Get PDFBu çalışmada; farklı tutkallar kullanılarak üretilen lamine ahşap malzemelerin bazı fiziksel ve mekanik özelliklerine silika (SiO2) ve grafen nanopartikülleri etkisinin belirlenmesi amaçlanmıştır. Polivinil asetat (PVAc), üre formaldehit (UF) ve epoksi (EPK) tutkallarının içerisine katman özelliklerini iyileştirmek için farklı oranlarda silika (%1 ve %2) ve grafen (%0,25 ve %0,50) nanopartikülleri eklenmiştir. Karakavak (Populusnigra) ve Avrupa kayını (Fagus sylvatica) odunlarından elde edilmiş 4 mm kalınlığındakipapel kaplamalar, modifiye edilen tutkallar kullanılarakpreslenmiş ve lamine ahşap malzemeler üretilmiştir. Lamine ahşap malzemelerin fiziksel özelliklerini belirlemek için hava kurusu yoğunluk ve boyutsal değişim (hacimsel şişme) testleri, mekanik özelliklerini belirlemek için ise yapışma direnci, eğilme direnci ve eğilmede elastikiyet modülü testleri gerçekleştirilmiştir. Çalışma sonuçlarına göre, her iki ağaç türü ile elde edilen lamine örneklerde test edilen tüm mekanik özellikler EPK tutkalında daha yüksek belirlenmiş ve bunu sırası ile UF ve PVA tutkalları izlemiştir. Ayrıca, boyutsal değişim değerleri UF ve PVA tutkallarına göre EPK tutkalında daha düşük elde edilmiştir. Silika ve grafen katkılı tutkallarla lamine edilmiş tüm örneklerde mekanik özellikler katkısız (kontrol) lamine örneklere göre artmıştır. Yapışma direnci, silika katkılı lamine örneklerde daha yüksek belirlenirken, eğilme direnci ve elastikiyet modülü grafen katkılı lamine örneklerde daha yüksek elde edilmiştir. Ayrıca, her iki nanopartikül oranındaki artış mekanik özellikler üzerinde genel olarak olumlu bir etki sağlarken, boyutsal kararlılıkta olumsuz bir etki göstermiştir.Inthisstudy; it wasaimedtodeterminethe effect of silica (SiO2) and graphenenanoparticles on somephysical and mechanicalproperties of laminatedwoodmaterialsproducedusing different glues. Silica (1% and 2%) and graphene (0.25% and 0.50%) nanoparticles were addedintopolyvinylacetate (PVAc), ureaformaldehyde (UF) and epoxy (EPK) glues at different ratiostoimprovethelayerproperties. The4 mm thickpapel veneers obtained fromblack poplar (Populusnigra) and Europeanbeech (Fagus sylvatica) woods were pressedusingmodifiedglues and laminatedwoodmaterials were produced. Air-drydensity and dimensional change (volumetricswelling) tests were performedtodeterminethephysicalproperties of thelaminatedwoodmaterials, and adhesionresistance, bendingstrength and modulus of elasticitytests were performedtodeterminethemechanicalproperties. Accordingtotheresults of thestudy, allmechanicalpropertiestested in laminatedsamples obtained withbothwood species were determinedto be higher in EPK glue, followedby UF and PVA glues, respectively. Inaddition, dimensional changevalues were obtained lower in EPK gluecomparedto UF and PVA glues. Themechanicalproperties of allsampleslaminatedwithsilica and grapheneaddedgluesincreasedcomparedtothe un-doped (control) laminatedsamples. Whiletheadhesionresistancewasdeterminedhigher in silica-addedlaminatedsamples, bendingstrength and modulus of elasticity were higher in graphene-addedlaminatedsamples. Moreover, whiletheincrease in bothnanoparticleratios had a generallypositive effect on mechanicalproperties, it showed a negative effect on dimensional stability
Hemşirelerde merhamet yorgunluğunun bakım odaklı hemşire-hasta etkileşimi ve kriz yönetimine etkisinin değerlendirilmesi
Get PDFAraştırma hemşirelerin merhamet yorgunluğu düzeylerinin bakım odaklı hemşire-hasta etkileşimi ve kriz yönetimine etkisini değerlendirmek amacıyla karma (mixed-methods) desende gerçekleştirilmiştir. Çalışmanın evrenini, Bolu İl Sağlık Müdürlüğü'ne bağlı kamu hastanelerinin acil, onkoloji, yoğun bakım ve palyatif ünitelerinde çalışan 260 hemşire oluşturmuştur. Çalışmaya katılmayı kabul eden 158 hemşire bu çalışmanın örneklemini oluşturmuş olup veriler Tanıtıcı Bilgi Formu, Merhamet Yorgunluğu Kısa Ölçeği, Bakım Odaklı Hasta-Hemşire Etkileşimi Ölçeği, Kriz Yönetimi Ölçeği ve nitel araştırmalarda veri toplama yöntemlerinden biri olan hemşirelerle bireysel derinlemesine görüşme yöntemi ile toplanmıştır. Çalışmanın nitel boyutundaki örneklemi maksimum çeşitlilik örneklemesi kullanılarak görüşülen 30 hemşire oluşturmuştur. Örneklemin genişliğine karar verirken veri doygunluğu dikkate alınmıştır. Nicel bölümün veri analizinde Kolmogorov-Smirnov, t-testi (Independent sample t-testi), Pearson korelasyon, Bonferroni, basit regresyona ve tek yönlü varyans analizi (One-Way ANOVA) kullanılmıştır. Çalışmanın nitel verilerin analiz edilmesinde ise MQXQDA 20 kullanılmıştır. MYÖ ile kriz yönetimi ve BOHHEÖ puanları arasında negatif yönde ve anlamlı bir ilişkinin olduğu bulunmuştur. Hemşireler ile yapılan görüşmelerde büyük bir çoğunluğunun merhamet yorgunluğu kavramını daha öne hiç duymadığı, merhamet yorgunluğunun yoğun çalışma koşullarında ortaya çıkabileceği ve bu kavramın hastalarla olan etkileşimi ve kriz yönetimi sürecini olumsuz etkilediği görüşlerine ulaşılmıştır. Hemşireler en zor kriz anlarını trajik olaylar, ilk ex tecrübesi, deprem, iş kazası olarak ifade etmişlerdir. Hemşireler için merhamet yorgunluğuyla başa çıkmada erişilebilir destek grupları sağlanmalı, iş yükünü azaltacak politikalar ve uygulamalar benimsenmeli, hastalarla etkili iletişim ve empati gösterme konusunda desteklenmelidir. Ayrıca, kriz yönetimi protokollerinin düzenli olarak gözden geçirilip güncellenmeleri önerilebilir.The research was conducted in a mixed-methods design to evaluate the impact of compassion fatigue levels of nurses on care-focused nurse-patient interaction and crisis management. The population of the study consisted of 260 nurses working in emergency, oncology, intensive care, and palliative care units of public hospitals affiliated with the Bolu Provincial Health Directorate. A sample of 158 nurses who agreed to participate formed the sample of this study, and data were collected through the Introductory Information Form, Compassion Fatigue Short Scale, Care-focused Nurse-Patient Interaction Scale, Crisis Management Scale, and individual in-depth interviews with nurses, which is one of the data collection methods in qualitative research. The qualitative dimension of the study consisted of 30 nurses interviewed using maximum variation sampling. Data saturation was considered in determining the sample size. In the quantitative part of the data analysis, Kolmogorov-Smirnov, t-test (Independent sample t-test), Pearson correlation, Bonferroni, simple regression, and one-way analysis of variance (One-Way ANOVA) were used. MQXQDA 20 was used for the analysis of qualitative data. A negative and significant relationship was found between compassion fatigue and crisis management and care-focused nurse-patient interaction scores. In interviews with nurses, the majority had never heard of the concept of compassion fatigue before, and it was found that compassion fatigue could arise in intense working conditions and negatively affect interaction with patients and the crisis management process. Nurses expressed the most challenging crisis moments as tragic events, first experiences, earthquakes, and workplace accidents. Accessible support groups should be provided to help nurses cope with compassion fatigue, and policies and practices to reduce workload should be adopted. Nurses should be supported in effective communication and showing empathy towards patients. Additionally, it is recommended to regularly review and update crisis management protocols
A Quest for Formant-Based Compact Nonuniform Trapezoidal Filter Banks for Speech Processing with VGG16
Get PDFIn this text, we discuss the filter banks used for speech analysis and propose a novel filter bank for speech processing applications. Filter banks are building blocks of speech processing applications. Multiple filter strategies have been proposed, including Mel, PLP, Seneff, Lyon, and Gammatone filters. MFCC is a transformed version of Mel filters and is still a state-of-the-art method for speech recognition applications. However, 40 years after their debut, time is running out to launch new structures as novel speech features. The proposed acoustic filter banks (AFB) are innovative alternatives to dethrone Mel filters, PLP filters, and MFCC features. Foundations of AFB filters are based on the formant regions of vowels and consonants. In this study, we pioneer an acoustic filter bank comprising 11 frequency regions and conduct experiments using the VGG16 model on the TIMIT and Speech Command V2 datasets. The outcomes of the study concretely indicate that MFCC, Mel, and PLP filters can effectively be replaced with novel AFB filter bank features.DAS:Data are available at the following site: https://github.com/cevparlak/AFB-Filters
Using Amino Acid-Silver Complexes Synthesized by Green Synthesis to Develop a New Antimicrobial Agent
Get PDFThe antimicrobial properties and importance of Ag+ have been known since ancient times. However, resistance has started to develop against silver ions, which are used indiscriminately and in high concentrations. Therefore, it is necessary to synthesize new and different silver complexes. In this study, five new molecules were synthesized by green synthesis from amino acids. Firstly, the antimicrobial activities of these molecules were tested with agar well diffusion assay. The result of this work is that it was revealed that the amino acid-silver complexes had very high inhibitory activity against microorganisms such as S. typhimirium, S. epidermidis, P. aeruginosa, K. pneumoniae, Y. pseudotuberculosis, P. vulgaris, E. faecalis, B. subtilis, E. cloaceae, S. aureus, E. coli, L. monocytogenes, C. albicans, and C. parapsilosis. It was found that these molecules have inhibition and bactericidal activity at low concentrations. The MIC, MBC, and MFC values were determined between 1.54-46.5 mu g/mL, 24.7-93.1 mu g/mL, and 19.0-197.0 mu g/mL, respectively. Then, to determine whether these molecules are suitable as antimicrobial agents, cytotoxic and antimutagenic activity tests were performed. The results of the cytotoxicity test showed that these molecules have no cytotoxic effect on the L929 fibroblast cells except some at higher doses (e.g. 10-100 mg/mL). In addition, cell viability stimulation was recorded at some doses below 10 mg/mL. Furthermore, these molecules showed antimutagenic activity at different concentrations 1.17-5.80 mu g/mL. The use of these synthesized molecules as antimicrobial agents in many fields such as food and pharmacology seems very promising
Exponential PID controller for effective load frequency regulation of electric power systems
Get PDFLoad frequency regulation (LFR) is an indispensable scheme in planning electrical power production to provide consumers with stable, reliable and uninterrupted power. In the face of complicated power system (PS) structures with increasing and intricate power demand, new controllers that offer not only good performance, but also easy commissioning in practice are required. To this end, this research introduces an exponential PID (EXP-PID) controller as a new control scheme to ameliorate the LFR performance of PSs. This controller is simple to design and has a nonlinear feature inherited from two tunable exponential functions, which are placed in front of the PID controller and act on the error signal and its time derivative individually. To achieve the utmost performance, the EXP-PID controller's parameters are procured by a corrected variant of the snake optimizer (co-SO). To validate the proposed control scheme, various single-/multi-area single-/multi-source PSs favored in the area are considered as test benches. A thorough comparison with the state-of-the-art approaches is performed to disclose the true efficacy of our proposal. Among the rivals, co-SO tuned EXP-PID controller, despite its simplicity, is found to render credible and promising performance in mitigating frequency and tie-line power deviations effectively. © 2024 IS