Sakarya University of Applied Sciences AXSIS
Not a member yet
2251 research outputs found
Sort by
Numerical and Experimental Study of Passive Pre-chamber Turbulent Jet Ignition on Wankel Engine
No full textThis study aims to increase the flame speed in the Wankel engine by using turbulent jet ignition. The Wankel engine suffers from poor exhaust emissions and high fuel consumption due to insufficient combustion speed and the inability to spread the flame throughout the shallow structured combustion chamber. With the hot turbulent flame jets obtained through the orifices, the turbulence level of the combustion chamber and the flame speed can be increased, as a result, the fuel consumption can be reduced. Various pre-chamber geometries were simulated with the Converge Studio program to determine the geometry features that can give better results. Taguchi method and ANOVA (Analysis of variance) tests were conducted to optimize the parameters and levels. Afterward, passive pre-chamber tests were conducted on a single-rotor Wankel test engine in the Istanbul Technical University Automotive Laboratory. Several load and speed operating conditions were tested, and results were compared with the base engine that has the classical spark ignition system. During the experiments, the parameters were kept constant to see the direct effect of the pre-chamber on the combustion rate. The preliminary results show that classical spark ignition engine has better specific fuel consumption and HC emissions in general. However, the turbulent jet ignition system with a passive pre-chamber has the potential to improve the Wankel engine performance at certain operating conditions. © 2024 American Institute of Physics Inc.. All rights reserved
Ultrasound Sensitive Smart Polyvinyl Alcohol/Melamine/Tannic Acid Hydrogel
No full textProblems such as hydrophilic properties of hydrogels, limited encapsulation of hydrophilic drugs, and unintended release amounts damage normal tissues and lead to overdose or repeated doses. This study investigates the development and characterization of drug carrier hydrogel formulations that can protect normal tissues. In this study, polyvinyl alcohol (PVA) hydrogel was synthesized by adding melamine (M) and tannic acid (TA) at different weight ratios to limit the hydrophilic properties of the hydrogel. In the analysis of the synthesized hydrogel, the efficiency of drug encapsulation increased from 60 to 90% as the TA content increased. The degree of swelling decreased from 73 to 63%. The contact angle increased from 10.15 degrees to 62.27 degrees, and the surface energy decreased. Drug release analysis was performed both in the presence of ultrasound (US) in a 40 kHz ultrasonic bath at 22 degrees C and without US at room temperature (22 degrees C). The drug release of Dox-loaded hydrogels was carried out in deionized water. Hydrogels release about two times more drug under ultrasound. After TA was added to the hydrogel, the drug release decreased by about 1.5 times. Successful results have been obtained with US, which is used to increase the amount of drug in the targeted area in a short time, accelerate the effect of the drug, and get faster results. The findings obtained as a result of all these characterizations and supported by FTIR provide promising contributions for controlled drug delivery systems
Effects of hippotherapy on upper extremity functions in children with cerebral palsy
No full textPurpose: The purpose of our study was to investigate the effects of hippotherapy on upper extremity functions in children with cerebral palsy (CP). Materials and Methods: The study was carried out with a quasi-hippotherapy design by evaluating the hippotherapy and control groups with pretests and posttests. Sixteen children with CP who were treated with 30 minutes of additional hippotherapy three times a week for five weeks were included in the hippotherapy group. Eleven children with CP who had conventional physiotherapy were recruited for the control group. Upper extremity functions were evaluated before and after the intervention using the Box and Block Test (BBT) and the Jebsen Taylor Hand Function Test (JTHFT). Results: There were no significant differences between the hippotherapy and control groups in terms of their baseline BBT and JTHFT scores. After 5-weeks, no statistically significant difference was found between the BBT scores of the hippotherapy and control groups. Significant increases were detected in all parameters of JTHFT in the posttest in the hippotherapy group, compared to the pretest. Moreover, in the posttest, a statistically significant difference was found between the hippotherapy and control groups in the parameters of turning over cards and picking up small objects, which subscales of JTHFT. Conclusion: In children with CP, hippotherapy provided in addition to conventional treatment was an effective practice, especially in improving fine motor skills in the hands
Effects of Different Mixture Ratios of Common Vetch and Triticale on Forage Yield and Silage Quality
No full textIn order to obtain high amounts and quality forage in legume grain mixtures, the mixture ratios must be adjusted well. Since grains are tillered due to their physiology, their ratios in roughage are different from the mixing ratios in planting. This is a factor that increases roughage yield and reduces crude protein rate and yield. In addition, in cases where grains are insufficient in terms of minerals in animal nutrition and are planted in mixtures with legumes, the rapid development and high yield effects of grains should be combined with the balanced nutrition potential of legumes in order to obtain better quality feed. In the research, which was conducted to determine the effect of vetch and triticale mixture ratios on yield and silage quality in Sakarya ecological conditions, plantings were carried out at different mixture ratios. In this study, 100% Vetch, 100% Triticale, 75% Vetch + 25% Triticale, 50% Vetch + 50% Triticale and 25% Vetch + 75% Triticale were planted in Sakarya conditions and the effect of the mixture ratios on grass yield was revealed. Additionally, silage was made from the mixtures obtained, and the effect of the applied mixture ratios on silage quality was determined. Field trials of the research were carried out in the trial areas of Sakarya University of Applied Sciences, Faculty of Agriculture. In the experiment, plant height, green and dry forage yield observations were taken. At the end of the maturation period, silage was made in 2 kilogram containers from each parcel as a silage quality criterion; silage dry matter ratio, silage pH, crude protein ratio, ADF and NDF observations were taken. By calculating the physical and sensory analysis and fleig point used to determine silage quality, the silages obtained from the mixtures were defined in detail by chemical, physical and sensory analysis and the fleig point. In the study, the highest green forage yield, hay yield, crude protein, ADF, NDF ratio and fleig point were obtained from 100% Vetch, 100% Triticale, 100% Vetch, 100% Triticale, 100% Triticale and 50% Vetch+50% Triticale mixtures, respectively. Due to the favorable outcomes in terms of forage yield and silage quality, 25% Vetch + 75% Triticale mixture ratio can be recommended to producers
Examination of the effects of innovative work behavior and leadership support on employees
No full textRepresented to be? Theories on public sphere and democracy frequently applied in Library and Information Science (LIS) are discussed in relation to the ranging notions. Findings - The analysis shows that although for all is used as an argument by both advocates and opponents of the principle of neutrality, there are different notions of who constitutes for all. In total, five ranging notions of for all are identified and presented in a typology, to serve as a framework to understand the conflicts concerning neutrality and the public library for all. Originality/value - The typology offers a new conceptual framework for understanding the nature of the conflicts and why they appear. The analysis indicates a need to discuss the use of for all in order to engage in more nuanced discussions of the democratic role of the public library. Keywords Public libraries, For all, Neutrality, Librarianship, Democracy, Public sphere, Freedom of speech Paper type Research paper Introduction This paper explores the ranging notions of a public library for all, and the related conflicts on for all and the principle of neutrality in Norway and Denmark. Descriptions of the public library often include statements that emphasize the library as an institution that empowers users by proving equal access to information (Audunson et al ., 2020) and a cornerstone o
Applicability of Metaverse in the recruitment processes in hotel businesses: A research on menagers
No full textHem eğilme de hem de eksenel basınç yükleri altında çelik yapı elemanları yanal burulma ve burkulma etkisi altında kalmaktadır. Yanal burulmalı burkulma etkisinde kalan bu elemanların yük altında olan yerlere rijitlik levhaları koyularak burkulmanın önlenmesi mümkündür. Yapılabilecek bu plaka ekleme işleminin yanı sıra çekme bölgesine koyulacak çelik donatı ve FRP donatı, ayrıca bu işlemden sonra, donatılara verilen ard germe ile I-kesitli çelik profilin yanal burulmalı burkulma davranışı farklı olacaktır. Bu çalışmada, ardgerme işleminde hangi donatı çapında ve türde FRP malzemesi kullanıldığında referans çelik kirişe en yakın veya daha fazla dayanım ve daha az yer değiştirme sağlayacağının araştırması deneysel olarak yapılmıştır. Bu amaçla I-kesitli çelik kirişlerin çekme bölgelerine ard germe verilmiş ikişer adet çelik ve FRP donatılar yerleştirilmiştir. Ф8 - Ф10 mm çapında çelik donatılar üç noktalı eğilme deneylerinde tam boyda kaynak işlemi yapılmıştır.GFRP donatılar için başlık yapılarak kaynak işlemi yapılmıştır.Dört noktalı eğilme deneylerinde de I-kesitli çelik kirişlerin çekme bölgelerine ard germe verilmiş ikişer adet çelik ve farklı türde FRP donatılar yerleştirilmiştir. Ф10 mm çapında çelik donatılar dört noktalı eğilme deneylerinde tam boyda kaynak işlemi yapılmıştır.FRP donatılar için başlık yapılarak kaynak işlemi yapılmıştır.Ard germe işleminde farklı çaplarda, uzunluklarda çelik donatılar ve FRP donatılar denenmiştir. Yapılan üç noktalı eğilme deneylerinde Ф8 - Ф10 mm çapında ard germe verilen çelik ve GFRP donatılar kullanılmıştır. Dört nokta eğilme deneylerinde ise, Ф10 mm çapında çelik ve AFRP, CFRP, GFRP ve E-CR_GFRP donatılar kullanılmıştır. Eğilme deney sonuçları elde edilen grafikler ile değerlendirilmiştir. Referans olarak kabul edilen hiçbir ardgerme işlemi uygulanmamış kirişler ile karşılaştırmaları yapılmıştır. Ayrıca donatı çapının, uzunluğunun, kullanılan FRP türünün etkisi analiz edilmiştir. Donatı türünün değişikliği ise yerdeğiştirmeye %4 azalma sağlarken çelik donatı kadar etkili olmamıştır. Üç noktalı eğilme deneyinde maksimum kuvvet GFRP_10 da,dört noktalı eğilme deneyinde ise kısa donatılı kirişte K_E-CR_GFRP,uzun donatılı kirişte U_Çelik de görülmüştür. Kısa ve uzun donatılı kirişlerde ise kısa donatılı kirişlerde şekil değiştirme de %12 azalma görülmüştür. Uzun donatılı kirişlere göre kısa donatı kullanmak şekil değiştirme de daha etkilidir. Sonuç olarak kısa donatı kullanılması uzun donatıya göre şekil değiştirmeyi azaltmıştır. Kısa donatı kullanılması uzun donatıya göre maksimum yükü arttırmıştır
The Relationship Between Environmental Taxes, Carbon Emissions and Economic Growth: An Analysis of OECD Countries; [Çevre Vergileri, Karbon Emisyonu ile Ekonomik Büyüme Arasındaki İlişki: OECD Ülkeleri Üzerine Bir Analiz]
No full textThe study examined the relationship between environmental taxes, economic growth, and carbon emissions by considering 34 OECD countries from 1995 to 2020. First, unit root tests were carried out to determine whether there is a relationship between carbon emissions, economic growth and environmental taxes. Then, the Dumitrescu Panel Granger causality test was applied. The panel quantile regression method was used depending on the relationship that emerged. According to the results, it has been determined that there is a positive relationship between environmental taxes and economic growth and a negative relationship between carbon emissions and economic growth. In addition, it can be said that while the effect of environmental taxes on economic growth is high in developing countries, this effect decreases in developed countries. © 2024, Sosyoekonomi Society. All rights reserved
Investigation of the effects of process parameters on machining quality in ultrasonic drilling
No full textSünek malzemeler arasında bulunan alüminyum ve düşük ısı iletkenliği özelliğine sahip titanyum gibi malzemelerle birlikte, kompozit malzemelerde, kırılgan metal veya metal olmayan malzemelerde, yüksek sertlik ve mukavemet özelliklerine sahip malzemelerdeki yeni gelişmeler, işlenebilirlik açısından yeni araştırmalara ihtiyaç duyulduğunu göstermektedir. Bu malzeme grupları arasındaki alüminyum ve titanyum, demir içermeyen ve hafif metaller olarak sınıflandırması nedeni ile başta havacılık, savunma sanayi ve otomotiv sektörü olmak üzere bir çok alanda tercih edilmektedir. Bu çalışmada, Ultrasonik delik delme (UDD) işleminin Al7075 ve Ti6Al4V malzemelerinin işleme performansı üzerindeki etkileri incelenmiştir. Her bir malzeme için üç farklı genlik(%60-%80-%100), iki farklı ilerleme hızı (0,06-0,12mm/dev)ve iki farklı kesme hızı (Al7075 için 30-40 m/dak, Ti6Al4V için 15-25 m/dak) olmak üzere üç ayrı parametre dikkate alınmıştır. Al7075 alüminyum alaşımı, hafifliği ve yüksek mukavemeti nedeniyle tercih edilen bir malzeme iken, Ti6Al4V titanyum alaşımı mükemmel korozyon direnci ve yüksek sıcaklık performansı sebebiyle öne çıkmaktadır. Bu iki alaşım üzerindeki delme deneyleri, malzeme özelliklerinin ve işleme parametrelerinin delik kalitesi üzerindeki etkilerini analiz etmek için gerçekleştirilmiştir. Bu deneylerin tamamı, UDD'nin katkısının daha etkili görülebilmesi için kuru delme şartlarında yapılmıştır. Al7075 için Ø5 kaplamasız HSS, Ti6Al4V için ise Ø5 kaplamasız karbür matkap ucu kullanılmıştır. Çalışmada delik kalitesi, delik çapı, dairesellik, silindiriklik, yüzey pürüzlülüğü ve çapak açısından incelenmiştir. Araştırmanın sonucu olarak, Al7075 ve Ti6Al4V alaşımlarında UDD yönteminin geleneksel delik delme (GDD) yöntemine kıyasla belirgin iyileşmeler sağladığı tespit edilmiştir. Al7075 alaşımında UDD'nin %69, Ti6Al4V alaşımında ise %59'luk bir iyileşme ile delik kalitesini artırdığı ortaya konulmuştur. Al7075 alaşımı için UDD'nin dairesellikten sapmada %40'lık bir iyileşme sağladığı, Ti6Al4V alaşımında ise %55'lik bir iyileşme elde edildiği tespit edilmiştir. Silindiriklikten sapma açısından, Al7075 için UDD'nin %34'lük bir iyileşme sağladığı, Ti6Al4V için ise %54'lük bir iyileşme elde edildiği görülmüştür. Yüzey pürüzlülüğü bağlamında, Al7075 malzemesinde yüksek genlik değerleriyle daha iyi sonuçlar elde edilirken, Ti6Al4V malzemesi için ise yüksek frekanslı ve düşük genlikli çalışmaların tercih edilmesi gerekliliği vurgulanmıştır. Son olarakta çapak yüksekliği değerlerine dayalı olarak, UDD'nin her iki alaşımda da malzemelerin işlenmesinde sırasıyla %84 ve %44'e kadar çapak yüksekliğini azalttığı belirlenmiştir. Bu çalışma, UDD'nin GDD yöntemine göre daha hassas deliklerin gerektiği yüksek kaliteli uygulamalarda Al7075 ve Ti6Al4V gibi alaşımların işlenmesinde tercih edilebilecek etkili bir yöntem olduğunu ortaya koymaktadır. İlerleme hızı ve kesme hızının optimize edilmesiyle, bu yöntemin endüstriyel uygulamalar için daha fazla tercih edilebileceği ön görülmektedir. Bu tez, ileride yapılacak araştırmalar için bir temel oluşturarak, ultrasonik delme parametrelerinin daha ayrıntılı optimize edilmesi yönünde yol gösterici olabilicektir
Acoustic and Thermal Properties of Mycelium-based Insulation Materials Produced from Desilicated Wheat Straw-Part B
No full textThe acoustic and thermal properties were determined for biodegradable insulation materials produced from desilicated wheat straws with two different fungi and three different incubation periods. Ganoderma lucidum (GL) and Pleurotus ostreatus (PO) fungi and wheat straw were exposed to fungal incubation for 10, 20, and 30 days to produce mycelium-based insulation materials. The sound absorption coefficients of mycelium-based insulation boards produced using PO fungus were higher than those produced with GL fungus. It was found that the acoustic absorption coefficients of insulation boards produced using PO fungus at 1,000 Hz were 87 to 99% according to the incubation periods. The sound transmission losses of mycelium-based insulation boards produced ranged from 46.4 to 59.7 dBa at 1000 Hz. The group of boards labeled as YP2 exhibited the lowest level of sound transmission loss, whereas GL2 revealed the highest degree of sound transmission loss at 1000 Hz. The lowest thermal conductivity coefficient was obtained in insulation boards produced with PO fungus and an incubation period of 20 days. The limiting oxygen index (LOI) value of mycelium-based insulation materials was considerably higher than the insulation boards commonly used today. Thermogravimetric analysis and derivative thermogravimetry curves of mycelium-based insulation materials were also determined. © 2024, North Carolina State University. All rights reserved
The Effect of Touch Therapy on Symptoms and Psychosocial Variables in Individuals Diagnosed With Cancer: A Systematic Review and Meta-analysis
No full textBackground: Touch therapy is used in the control of physical and psychological symptoms in cancer patients. However, its effectiveness has not been well studied. Objectives: The aim of this study was to examine the effectiveness of touch therapy intervention on symptoms and psychosocial factors for patients with cancer. Method: Four electronic databases were used to identify all experimental studies that examine the effects of touch therapy on symptoms and psychosocial factors for patients with cancer. The standardized mean differences between groups in levels of symptoms and psychosocial factors for postintervention were computed for each study. Result: The pooled results suggest that touch therapy intervention effectively reduces pain, fatigue, anxiety, and negative mood among patients with cancer postintervention. However, touch therapy intervention did not affect the quality of life and stress. Conclusion: A significant effect of touch therapy was the reduction of physical and psychological symptoms in cancer patients. Implications for practice: Touch therapy could be safely integrated into the clinical practice of patients with cancer