21241 research outputs found
Sort by
Production of HHO gas in the water-electrolysis unit and the influences of its introduction to CI engine along with diesel-biodiesel blends at varying injection pressures
Get PDFHydrogen has been identified as a clean and renewable energy source that has a significant potential to replace fossil fuels. The effective production of hydrogen on a commercial scale, however, presents a vital obstacle in today's world. Water splitting electrolysis, which offers high energy conversion and storage capabilities, has emerged as a promising approach for achieving the efficient hydrogen production to address this issue. This experimental research focuses on the production of hydrogen-oxygen gas through the electrolysis process. HHO gas provides promising benefits in terms of better combustion and lower emissions. Therefore, it also focuses on how best HHO gas can be utilized in diesel engines to improve the performance and to reduce the emissions. HHO gas produced at 60 L per hour through electrolysis process is mixed with air in a mixing chamber. Also, Palm munja methyl ester of 10% and diesel fuel of 90% was volumetrically blended to get B10 biodiesel. Therefore, totally four test fuels (Diesel, Diesel + HHO, B10, and B10 + HHO) were tested on a single-cylinder Kirloskar water-cooled direct injection diesel engine under different engine speeds ranging from 1447 to 1550 rpm. The engine injector pressure was varied from 200, 220, and 240 bar during the experiments with an interval of 20 bar. The engine has been modified for hydrogen and oxygen inlet at the entrance manifold 6 cm away at an angle of 30 degrees. The results shows that at 200 bar injection pressure with B10 + HHO blend exhibits better performance and released lower emissions. The perfor-mance results also show that the brake thermal efficiency was improved up to 14.16%, and the brake power was increased by 3.22%, while the brake-specific fuel consumption is reduced by 11.53%. The emission results show that CO, HC, NOx, and CO2 emissions were reduced by 20.87%, 11.47%, 1.96%, and 5.22%, respectively. Therefore, it can be concluded that B10 + HHO provides better performance and the lowest emissions compared with other blends. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.King Saud University, Riyadh, Saudi Arabia [RSP2023R42]The financial support from the Researchers Supporting Project (RSP2023R42) , King Saud University, Riyadh, Saudi Arabia is appreciated
An Optimal Hybrid Management of Electric Vehicle Fleet Charging and Load Scheduling in Active Electric Distribution System
Get PDFThis paper introduces a novel scheduling framework designed to manage the charging of electric vehicles (EVs) in a way that considers its effects on the power grid. Leveraging the Alternating Direction Method of Multipliers (ADMM), the methodology offers a significant advantage by enabling decentralized sub-problems, allowing for efficient and rapid solutions. The methodology developed as an algorithmic framework incorporates various scheduling approaches for EV charging, including demand management techniques like valley filling and peak shaving, along with real-time pricing (RTP) considerations. These strategies aim to modify individual electricity consumption patterns to reduce peak demand, ultimately enhancing energy efficiency and ensuring the stability of the power system. The results of the study highlight the crucial role of distributed optimization in improving both demand management strategies and cost objectives. The results indicated that the proposed method shows significant improvement in overall energy efficiency when compared to the state-of-the-art centralized convex optimization framework. © 1972-2012 IEEE
Analysis of bubble departure and lift-off boiling model using computational intelligence techniques and hybrid algorithms
Get PDFThe bubble departure and lift-off boiling (BDL) model was studied using computational intelligence techniques and hybrid algorithms. Quite a few studies have predicted the relationship between wall heat fluxes and wall temperature in the form of flow boiling curves. The output wall temperature is a performance indicator that depends on many operating parameters. The current study, therefore, analyses the predictability of the wall temperature in terms of operating pressure, bulk flow velocity, and wall heat flux, based on the BDL model developed by Zenginer, which included two suppression factors namely, flow-induced and subcooling factors, respectively. The soft computing techniques used for prediction were - the artificial neural network (ANN), and the Fuzzy Mamdani model, and the hybrid algorithms were adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network trained particle swarm optimization (ANN-PSO). In addition, the ANN-PSO conducted a parametric analysis to evaluate the best model configuration by considering various factors. The comparison of all four techniques showed that the ANFIS model exhibited the prediction performance for wall temperature. Moreover, the results obtained from the ANFIS model have been compared with the different flow boiling curves from the literature and observed that the curve fitted well for higher bulk flow velocities with an MSE and R2 was found to be 0.85 % and 0.9933, respectively.King Saud University, Riyadh, Saudi Arabia [RSP2023R42]The financial support from the Researchers Supporting Project (RSP2023R42) , King Saud University, Riyadh, Saudi Arabia is appreciated
Uptake and bioaccumulation of iron oxide nanoparticles (Fe3O4) in barley (Hordeum vulgare L.): effect of particle-size
Get PDFRoot-to-shoot translocation of nanoparticles (NPs) is a matter of interest due to their possible unprecedented effects on biota. Properties of NPs, such as structure, surface charge or coating, and size, determine their uptake by cells. This study investigates the size effect of iron oxide (Fe3O4) NPs on plant uptake, translocation, and physiology. For this purpose, Fe3O4 NPs having about 10 and 100 nm in average sizes (namely NP10 and NP100) were hydroponically subjected to barley (Hordeum vulgare L.) in different doses (50, 100, and 200 mg/L) at germination (5 days) and seedling (3 weeks) stages. Results revealed that particle size does not significantly influence the seedlings' growth but improves germination. The iron content in root and leaf tissues gradually increased with increasing NP10 and NP100 concentrations, revealing their root-to-shoot translocation. This result was confirmed by vibrating sample magnetometry analysis, where the magnetic signals increased with increasing NP doses. The translocation of NPs enhanced chlorophyll and carotenoid contents, suggesting their contribution to plant pigmentation. On the other hand, catalase activity and H2O2 production were higher in NP10-treated roots compared to NP100-treated ones. Besides, confocal microscopy revealed that NP10 leads to cell membrane damages. These findings showed that Fe3O4 NPs were efficiently taken up by the roots and transported to the leaves regardless of the size factor. However, small-sized Fe3O4 NPs may be more reactive due to their size properties and may cause cell stress and membrane damage. This study may help us better understand the size effect of NPs in nanoparticle-plant interaction.Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal UniversityNo Statement Availabl
The effect of transformational leadership, psychological capital and workplace well-being on task performance in healthcare professionals
Get PDFSağlık kuruluşlarının başarısı için en önemli faktör, sahip olduğu insan kaynağıdır. Sağlık kuruluşlarının insan kaynağını verimli ve etkili bir şekilde kullanabilmesi, iş yerinde beklenilen performans kriterlerine ve hedeflere ulaşabilmeyi kolaylaştırmaktadır. Sağlık kurumlarında görev performansının artması ise hızlı değişim ortamında yenilikleri yönetebilen çalışanlarla bire bir ilgilenen, yeni ve modern yönetim anlayışını merkeze alan yöneticilere bağlıdır. Ayrıca sağlık hizmetleri yoğun stres altında çalışılan, iş yükünün ağır olduğu ve çalışma saatlerinin uzayabildiği riskli çalışma ortamlarıdır. Psikososyal risklerin bulunduğu bir ortamda çalışan sağlık çalışanlarının başarısı için iş yerinde kendilerini iyi hissedebilmeleri gerekmekte ve buna özen gösterilmesi gerekmektedir. Bu araştırmanın amacı; sağlık çalışanlarında dönüşümcü liderliğin, psikolojik sermayenin, iş yerinde iyilik halinin görev performansı üzerindeki etkisini belirleyebilmektir. Araştırma, Türkiye'de Gaziantep ilinde 5 farklı hastanede görev yapan sağlık çalışanları üzerinde gerçekleştirilmiştir. Veriler 622 sağlık çalışanından gönüllülük esasına uygun olarak anket aracılığıyla toplanmıştır. Verilerin analizinde tanımlayıcı istatistikler, ölçüm modeli analizi, path (yol) analizi ve aracılık analizleri kullanılmıştır. Analizler SPSS 26 ve SmartPLS 4.0 programları yardımıyla yapılmıştır. Araştırma sonuçlarına göre sağlık kurumlarında dönüşümcü liderlik yönetim stilinin bulunması çalışanlarda psikolojik sermaye ve iş yerinde iyilik halinin yükselmesine neden olduğu ve böylelikle de görev performansında artışın sağlandığı yönde oluşudur.The most important factor for the success of healthcare institutions is their human resources. The ability of healthcare institutions to use human resources efficiently and effectively makes it easier to achieve the expected performance criteria and targets in the workplace. Increasing job performance in healthcare institutions depends on managers who deal directly with employees who can manage innovations in a fast-changing environment and who focus on the new and modern management approach. In addition, health services are risky working environments where people work under intense stress, workloads are heavy and working hours can be extended. For the success of healthcare professionals working in an environment with psychosocial risks, they need to feel good at work and care must be taken to do so. The purpose of this research; To determine the effects of transformational leadership, psychological capital, and well-being at work on task performance in healthcare professionals. The research was conducted on healthcare professionals working in 5 different hospitals in Gaziantep province of Turkey. Data were collected from 622 healthcare professionals via a survey on a voluntary basis. Descriptive statistics, measurement model analysis, path analysis and mediation analyzes were used to analyze the data. Analyzes were made with the help of SPSS 26 and SmartPLS 4.0 programs. According to the results of the research, the presence of a transformational leadership management style in healthcare institutions leads to an increase in employees' psychological capital and well-being at work, and thus an increase in task performance
Ekleşen bir son çekim edatı: TAPA>+DIVA/ +DUVA
Get PDFTürkçe, yapısına göre sınıflandırıldığında eklemeli diller grubu içerisindedir. Türkçede ekler genel olarak çekim eki ve yapım eki olarak ikiye ayrılır. Eklemeli dillerin hepsindeki ve Türk dilindeki tüm eklerin bir fonksiyonu, bir vazifesi vardır. Bu eklerin semantiğini, fonksiyonunu, etimolojisini, fonolojisini araştırmak tüm Türk dilini incelemek ve anlamak demek olduğundan oldukça önemlidir. Eklerin oluşumunda belli başlı üç yöntem vardır. Birinci yöntem iki ekin birleşerek tek bir ek hâline gelmesidir. İkinci yöntem ise ekin tek bir ortak kaynaktan gelmesidir. Yani diller arasında kelime alış-verişi yapıldığı gibi ek alış-verişi de yapılmıştır. Üçüncü yol ise daha önceden bağımsız bir sözcük olarak kullanılan kelimelerin bilinen veya bilinmeyen sebeplerle ve bir süreç dâhilinde ek hâline gelmesidir. Araştırmamızın ana amacı daha önce ayrı bir kelime iken zamanla çeşitli sebeplerle ek hâline dönüşen tapa “-e doğru” edatının tarihi ve çağdaş metinlerdeki biçimini, kullanımını, geçirdiği ses olaylarını, örnekleri ile birlikte vermektir. Tapa “-e doğru” edatının, hangi lehçelerde ekleştiği hangi lehçelerde bir edat olarak kullanılmaya devam ettiği sorusu cevaplandırılmaya çalışılmıştır. Çalışmada ilk önce tapa “-e doğru” edatının etimolojisine yer verilmiştir. Daha sonra edatın tarihi lehçelerdeki biçimlerine ve kullanım örneklerine değinilmiştir. Tarihi lehçelerden sonra ise tapa “-e doğru” edatının hangi çağdaş lehçelerde hangi biçimde yaşadığı örneklerle gösterilmeye çalışılmıştır. Çalışmada, tapa “-e doğru” edatının Batı Türkçesi dışındaki çağdaş lehçelerde kullanıldığı ve Tuva Türkçesinde de +dıva/ +dive/, +tıva/ +tive/, +duva/ +düve/, +tuva, +tüve şekliyle ekleştiği sonucuna varılmıştır
The Effect of Distant Reiki Sessions on Holistic Well-Being
Get PDFThis study investigated the effect of distant Reiki sessions on the holistic well-being of people without no acute/chronic diseases. The study was conducted between February 1 and March 31, 2022. The sample consisted of 180 healthy people living in a city in Turkey. Participants attended 20-minute distant Reiki sessions (intervention) for 4 consecutive days. Pretest data were collected using a personal information form, the Holistic Well-Being Scale (HWBS), the Positive and Negative Affect Schedule (PANAS), and the Subjective Vitality Scale (SVS). Posttest data were collected 2 days (posttest I) and 1 week after the intervention (posttest II) using the HWBS, PANAS, and SVS. There was a statistically significant difference between pretest and posttest I and II HWBS subscale scores (P < .05). There was a statistically significant difference between pretest and posttest PANAS and SVS scores (P < .05). Distant Reiki sessions improved participants' holistic well-being. They also helped them develop a positive mood, experience and perceive less sadness, and develop subjective vitality and cognitive awareness
Theoretical analysis for low voltage ride through capability in doubly-fed induction generator-based wind turbines with stator resistive hardware model
Get PDFGrid code requirements must be provided in the grid-connected operation of Doubly fed induction generator (DFIG)-based wind turbines. For this, many methods have been developed in DFIG-based wind turbines. Low voltage ride through (LVRT) capability is one of the most effective methods to meet the grid code requirement in DFIG. LVRT is the principal method used to decrease voltage dips and overcurrents caused by various symmetrical and asymmetrical faults. One of the efficient and economical methods of providing LVRT capability is Stator resistive hardware model (SRHM). This study developed the SRHM to remove oscillation that may occur during symmetrical and asymmetrical faults. In addition, stator-rotor electromotive force models in DFIG were enhanced with the aim of increasing simulation study performance, calculation, and stability in the system during various faults. In both symmetrical and asymmetrical fault operations, the results indicated that the proposed SRHM and stator-rotor electromotive force models provided dynamic stability of the system and eliminated oscillations
Borik Asit LPS ile Uyarılan Glioblastoma Hücrelerinde İnflamazom Aktivasyonunu İnhibe Eder
Get PDFAmaç: En sık görülen primer beyin tümörleri olan gliomalar, çeşitli klinik özellikler ve kötü prognoz sergiler. İnflamazom aktivasyonu, glioma gelişiminde rol oynayan, nükleotid bağlama alanı lösin açısından zengin aile pirin içeren 3 (NLRP3) gibi inflamazomlar tarafından düzenlenen, merkezi sinir sistemindeki inflamatuar mikro ortamla yakından bağlantılıdır. Ancak NLRP3'ün insan gliomasındaki rolü belirsizliğini koruyor. Bu çalışma borik asidin U87 glioblastoma hücreleri ve NLRP3 inflamazom aktivasyonu üzerindeki etkilerini araştırmaktadır. Gereç ve Yöntemler: Enzime bağlı immünosorbent analizi (ELISA) yöntemini kullanarak 24, 48 ve 72 saat boyunca çeşitli borik asit konsantrasyonlarına maruz kalan U87 hücrelerindeki hücre canlılığını, 5-bromo-2'-deoksiüridin (BrdU), NLRP3, interlökin (IL)-1?, IL-18, kaspaz 1, apoptoz indükleyici faktörü (AIF) ve sitokrom c seviyelerini değerlendirdik. Bulgular: Sonuçlarımız, 0-6,4 mM aralığında borik asit konsantrasyonlarına maruz kalmanın ardından U87 hücre canlılığında zamana ve konsantrasyona bağlı bir azalma olduğunu ortaya koydu. BrdU analizi, 24 saatlik borik asit uygulamasından sonra hücre çoğalmasının azaldığını gösterdi. Lipopolisakkarit (LPS) kullanılarak U87 hücrelerinde inflamatuar aktivasyonun uyarılması, yüksek NLRP3, IL-1?, IL-18 ve kaspaz-1 seviyeleriyle sonuçlandı. Ancak borik asit uygulaması bu etkiyi ortadan kaldırarak inflamazom aktivasyonu azalttı. Ayrıca borik asit+LPS tedavisi AIF ve sitokrom c düzeylerini indükleyerek apoptoza yol açtı. Sonuç: Bulgularımız borik asidin U87 hücrelerinde NLRP3 inflamatuar aktivasyonunu inhibe ettiğini, dolayısıyla hücre canlılığını baskıladığını gösterdi. Bu, borik asidin NLRP3 inflamatuarını engelleyerek inflamatuar mikro ortamı hafiflettiğini ve glioblastomanın ilerlemesinde potansiyel terapötik avantajlar sunduğunu göstermektedir
Anatomy-based papermaking potential of some woody plants under different ecological condtions
Get PDFThe increasing use of wood in the forest industry and reduction of forest resources have prompted the pause of wood. Wood samples of each species were collected from two different regions in Turkiye: the Kozan region, which has a Mediterranean climate, and the Yuvack region, which has a mostly oceanic climate. The species included in the study were Phillyrea latifolia (mock privet), Arbutus andrachne (greek strawberry pentine (cyprus turpentine tree), and Rhus coriaria (elm-leaved sumac). All fibers were classified as short. The longest fiber was observed for Spartium junceum (spanish broom) in Kozan. The fiber diameter was highest for Arbutus andrachne (greek strawberry tree) from Kozan, followed by Rhus coriaria (elm-leaved sumac) from Yuvack and Laurus nobilis (bay tree) from Kozan. The fiber dimensions and the relationship between them were statistically analyzed. These included the slenderness ratio, flexibility coefficient, Runkel ratio, rigidity coefficient, Luce's shape factor, F-factor, and Muhlsteph ratio. Although differences in fiber properties were detected between the two regions, it was determined that these were not enough to affect the desired properties for paper production. It was concluded that the fibers could be used in pulp, paperboard, and corrugated board production when mixed with long fibers