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Effect of grinding methods on slime dissociation characteristics and flotation kinetics of coking coal
No full textDespite extensive research on the connection between coal flotation kinetics and particle size, little is known about the shape effect. To fill this gap, this study aims not only to explore dissociation characteristics and particle shape properties resulting from the grinding of coking coal in a planetary ball mill (PBM) and a vertical shaft impact crusher (VSIC) but also to investigate their effects on flotation kinetics. Moreover, for the first time in the literature, shape, kinetic rate constant, and bubble loading capacity (hydrophobicity) properties of coking coal products ground in two different mills were compared by shape characterization, flotation kinetics, and single bubble loading tests, respectively. The findings are: (1) Compared to PBM, VSIC produced rounder-shaped particles with a better communition selectivity, (2) Since PBM's flotation rate constant values (Km) were higher than VSIC's, the particles produced by the PBM exhibit a favorable aspect ratio for faster flotation.Natural Science Foundation of Shandong Province [ZR2023QE103]; Graduate Innovation Program of China University of Mining and Technology [2024WLKXJ062]The authors gratefully acknowledge financial support from Natural Science Foundation of Shandong Province (Grant No. ZR2023QE103) and Graduate Innovation Program of China University of Mining and Technology (2024WLKXJ062)
mer-[Ni(dien)2]Cl2.H2O 2 ]Cl 2 .H 2 O and mer-[Ni(dien)2](NO3)2 2 ](NO 3 ) 2 complexes (dien= = diethylenetriamine): Synthesis, physical, computational studies , antioxidant activity, and their use as precursors for Ni/NiO nanoparticles' preparation
No full textTwo new Ni(II) complexes, mer-[Ni(dien)2]Cl2.H2O (I) and mer-[Ni(dien)2](NO3)2 (II), where dien= diethylenetriamine and mer refers to meridional coordination, have been prepared under ambient conditions. Complex (I) crystallizes in the P21/c space group of the monoclinic system, with a = 13.5000(4) & Aring;, b = 8.7170(3) & Aring;, c = 13.9430(4) & Aring;, beta = 102.091(2)degrees and V = 1604.41 & Aring;3, whereas complex (II) crystallizes in the Pbca space group of the orthorhombic system, with a = 8.8117(6) & Aring;, b = 14.0023(8) & Aring;, c = 26.7603(17)& Aring; and V = 3301.79 & Aring;3. Both structures contain the [Ni(C4H13N3)2]2+ cation, together with two chloride anions and a water molecule for (I) and two nitrate anions for (II). The metal centre is coordinated to six nitrogens of the neutral dien ligands in a slightly distorted octahedral geometry. The two compounds have been characterised by FTIR and UV-Vis spectroscopy. Their morphology and size were studied by scanning electron microscopy (SEM). The thermal behaviour of the title compounds was also investigated. Calcination of the two complexes in air yielded Ni/NiO nanoparticles. The structures of both complexes were optimised and their simulated geometric parameters and vibrational modes were discussed and correlated with the experimental data. The antioxidant potential of both complexes was evaluated using DPPH, ferric reducing power tests and phosphomolybdenum assay.Ministry of Higher Education and Scientific Research MESRS and Abbes Laghrour University of Khenchela (Algeria) [B00L01UN400120210002]BEB would like to thank Dr C. Wilson (University of Glasgow, School of Chemistry, U K) for assistance with the single crystal data collection of mer- [Ni (dien) 2] (NO 3) 2 . AD would like to acknowledge the fund of the Ministry of Higher Education and Scientific Research MESRS and Abbes Laghrour University of Khenchela (Algeria) under the project number: B00L01UN400120210002 (PRFU)
The effect of high intensity interval training on aerobic and anaerobic capacity
No full textBu çalışma, yüksek şiddetli interval antrenmanların aerobik ve anaerobik kapasiteye etkisi amaçlandı. Çalışmaya 18-25 yaş aralığında olan 24 sağlıklı birey gönüllü olarak katıldı. Gönüllüler kontrol grubu (14 kişi) ve deney grubu (10 kişi) olmak üzere iki farklı gruba ayrıldı. Deney grubuna 8 hafta boyunca, haftada 3 gün ve tek bir birim antrenmanın süresi 2 saat olacak şekilde, aşağıda ayrıntıları verilmiş olan yüksek şiddetli interval antrenman (HITT) programı uygulandı. Kontrol grubuna ise hiçbir uygulama yapılmadı ve rutin yaşantılarına devam etmeleri istendi. Çalışmaya başlamadan önce her iki gruptan da boy uzunluğu, vücut ağırlığı, vücut yağ oranı, maksimal oksijen tüketim kapasitesi (MaksVO2), solunum eşiği seviyeleri ve anaerobik güç seviyeleri tespit edildi. Deney grubuna 8 hafta boyunca uygulanacak olan antrenman programından sonra yukarıda bahsedilen ölçümler her iki gruba da tekrarladırıldı. İlk olarak çalışmada elde edilen verilerin tanımlayıcı istatistikleri yapıldı. Daha sonra verilerin normal dağılıp dağılmadığını belirlemek için Shapiro-Wilk testi, çarpıklık, basıklık, histogram, Q-Q ve P-P grafikleri kullanıldı. Verilerin normal dağılım göstermesinden dolayı antrenman öncesi ve antrenman sonrası değerlerinin karşılaştırılması için Paired-Samples T Test kullanıldı. Anlamlılık düzeyi p 0,05).Wingate test sonuçlarından maksimum güç (p 0.05). However, Wingate test results indicated significant differences in maximum power (p < 0.05) and average power (p < 0.05) between pre-test and post-test measurements. Similarly, significant differences were observed in MaksVO2 (p < 0.05) and oxygen consumption at the ventilatory threshold (p < 0.05) between pre-test and post-test values. The findings suggest that the applied HIIT protocol significantly improved both aerobic and anaerobic power values. Moreover, the rate of improvement in anaerobic power was found to be greater than the improvement in aerobic capacity
Türkiye’de Judo Başlığı ile Yapılan Lisansüstü Tezlerin İncelenmesi
No full textPurpose: The aim of this study is to examine the postgraduate thesis studies prepared with the title of judo in Turkey in terms of various variables and to provide guiding information to researchers working in the field of judo. Method: For this purpose, document analysis method, one of the qualitative research methods, was utilized in the study. Within the scope of the research, a total of 82 postgraduate theses registered in the Thesis Center of the Presidency of the Council of Higher Education (YÖKTEZ) and containing the word “judo” in the thesis title constituted the sample of the research. Theses were evaluated according to the variables of year of publication, type, university, department, institutes, method used in the research, study group, title of the advisor and gender of the thesis author, and the data obtained were expressed in numerical values and percentages. Findings: It was seen that the first postgraduate thesis written with the title of judo in Turkey was published in 1991, a total of 82 postgraduate theses, 74 of which were master's theses and 8 of which were doctoral theses, were written from this date until today, and the most postgraduate thesis was published in 2022. In the data obtained in the research, it is understood that male authors are in the majority and the theses titled judo are mostly written in Selçuk University. It was determined that the postgraduate theses were mostly written in the Department of Physical Education and Sports and under the supervision of academic staff with the title of Assistant Professor. In the theses, most of which utilized quantitative research methods, researches were conducted mostly on athlete groups and no studies were conducted especially on judo referees. Conclusion: Since Judo is a sport branch that has a long history and is popular in many countries of the world, it is thought that more postgraduate studies are necessary in this field. Although there has been an increase in the number of graduate theses in recent years, it is predicted that the increase in the number of theses, especially at the doctoral level and in foreign languages, will contribute to the field as they will be more accessible in the international arena. One of the most important issues lacking in theses on judo is research groups. Current researches to be conducted especially with samples such as administrators, referees, provincial representatives and federation employees will provide different level contributions to the field by addressing the management dimension of this sport.Amaç: Bu çalışmanın amacı Türkiye’de judo başlığı ile hazırlanan lisansüstü tez çalışmalarını çeşitli değişkenler bakımından incelemek ve judo alanında çalışma yapan araştırmacılara yol gösterici bilgiler sunabilmektir. Yöntem: Bu amaç doğrultusunda çalışmada nitel araştırma yöntemlerinden doküman incelemesi metodundan faydalanılmıştır. Araştırma kapsamında Yükseköğretim Kurulu Başkanlığı Tez Merkezinde (YÖKTEZ) kayıtlı olan ve tez adında “judo” kelimesini içeren toplam 82 adet lisansüstü tez (20.11.2024), araştırmanın örneklemini oluşturmuştur. Tezler; yayınlanma yılı, türü, yayınlandıkları üniversite, anabilim dalı, enstitüler, araştırmalarda kullanılan yöntem, çalışma grubu, danışmanın unvanı ve tez yazarının cinsiyeti değişkenlerine göre değerlendirilmiş olup elde edilen veriler sayısal değerler ve yüzdelik dilimlerle ifade edilmiştir. Bulgular: Türkiye’de judo başlığı ile yazılmış ilk lisansüstü tezin 1991 yılında yayınlandığı, bu tarihten günümüze kadar 74’ü yüksek lisans 8’i doktora olmak üzere toplam 82 adet lisansüstü tezin yazıldığı ve en fazla lisansüstü tezin 2022 yılında yayınlandığı görülmüştür. Araştırmada elde edilen verilerde erkek yazarların çoğunlukta olduğu ve judo başlıklı tezlerin en fazla Selçuk Üniversitesi bünyesinde yazıldığı anlaşılmaktadır. Lisansüstü tezlerin çoğunlukla Beden Eğitimi ve Spor Anabilim Dalında ve Dr. Öğr. Üyesi unvanlı öğretim elemanlarının danışmanlığında yazıldığı belirlenmiştir. Çoğunluğunda nicel araştırma yöntemlerinden faydalanılan tezlerde, daha çok sporcu gruplarına yönelik araştırmalar yapılmış olup özellikle judo hakemleri ile ilgili herhangi bir çalışma yapılmamıştır. Sonuç: Judo, tarihi çok eskiye dayanan ve dünyanın birçok ülkesinde popüler olan bir spor branşı olduğundan bu alanda daha fazla lisansüstü çalışma yapılmasının gerekli olduğu düşünülmektedir. Son yıllarda lisansüstü tez sayılarında artış görülse de özellikle doktora düzeyinde ve yabancı dilde yapılacak tezlerin artmasının uluslararası arenada daha fazla erişilebilirliği olacağından alana katkı sağlayacağı öngörülmektedir. Judo başlıklı tezlerde eksikliği görülen en önemli konuların başında araştırma grupları gelmektedir. Özellikle idareciler, hakemler, il temsilcileri ve federasyon çalışanları gibi örneklemlere yapılacak güncel araştırmalar bu sporun yönetim boyutunu da ele alarak alana farklı düzeyde katkılar sağlayacaktır
Effective removal of methylene blue dye from aqueous solution using Macrolepiota procera mushroom: Experimental and theoretical studies
No full textThis study investigated Macrolepiota procera mushroom biomass as a biosorbent for removing methylene blue (MB) dye from aqueous solutions. Key adsorption parameters such as pH, biosorbent dosage, and contact time were optimized, achieving a maximum adsorption capacity of 1.404 mol·kg−1 at pH 9, with 100 mg biosorbent and a temperature of 25 °C. SEM, EDX, and FT-IR analyses characterized the biosorbent's surface morphology and functional groups. Adsorption followed the Langmuir isotherm model, showing high affinity in alkaline conditions, and efficiency increased by 90.88 % with 200 mg biosorbent. Kinetic data fit Pseudo-Second and Pseudo-First Order models, and thermodynamics indicated an endothermic, spontaneous process. Recovery tests revealed ∼ 4 % retained activity after five cycles. Density Functional Theory calculations supported experimental adsorption energies, confirming chitin's role in MB binding. © 2024 Elsevier B.V.Cumhuriyet University Scientific Research Projects Commissio
Evaluation of Passive Cooling Enhancement and Thermal-Hydraulic Characteristics in Distinct Triangular Grooved Ducts Having Fins and TiO2–Water Nanofluid
No full textIn this study, transfer of heat and flow peculiarities in triangular grooved finless, double and
triple triangular grooved finned channels were searched numerically by comparing them with straight
channels. Using the Ansys-Fluent computer program, numerical analysis was performed by solving
the conservation equations under steady, two-dimensional and laminar flow conditions. To better
direct the flow to the lower surfaces of corrugated channels with constant surface temperature, the
fins were positioned between the grooves at the top surface of the duct at angles of 30°, 60°, and 90°
(θ) with the horizontal and at different heights of 4, 8, and 12 mm (z). The outcomes of the work
were examined as variations in the mean Nu number (Numcorrugated ch./Numstraight ch.), mean surface
temperature (Tsmcorrugated ch./Tsmstraight ch.) and performance evaluation criteria (PEC), taking into
account the effects of fin angles and heights. The study’s findings were checked against both the
numerical outcomes and the analytical equation of the work in the literature giving the mean
Nu number (Num), and it was determined that the outcomes were quite compatible and consistent with each other. The outcomes depicted that for Re = 1200, θ = 90°, and z = 12 mm, the (Numcorrugated ch./Numstraight ch.) ratio of TiO2–water nanofluid in the triple triangular grooved finned
channel is 4.28% higher than in the double triangular grooved finned channel. Furthermore, when the
fin height of the triple triangular corrugated channel is reduced from 12 to 4 mm for the Re = 1200 and
θ = 90°, the increase in the PEC value for the nanofluid reaches 6.02%
A study on microchip cooling performance increment by using air jet impingement with one and double rows
No full textThe impinging jet technique is a high-performance cooling technology for microchips which are basic elements of computer
systems and have high heat generation rates in small volumes. In this study, the improvement of heat transfer of the
desktop microchips used in all technological products today by air-impinging jet flow was examined. For this purpose,
numerical research was carried out on the cooling of copper plate surfaces with two different patterns, concave and
roof shaped having 1000 W/m2 constant heat flux in rectangular cross-sectional ducts by one and double air jets with
distances of Dh and 2Dh between them. Numerical analysis was performed steady and in three dimensions with the
k–ϵ turbulence model by the Ansys–Fluent program. The obtained results were compared with the numerical and experimental
results of the study in the literature and it was seen that they are determined to be compatible. The results were
presented as the mean Nu number for each of both patterned surfaces and the mean outlet temperature of the jet flow
(Tmoj) and the mean Nu number (Num) of all patterned surfaces in single and double jet channels with different distances.
Besides, pressure drop (ΔP), friction factor ( f ), thermal resistance (Rt) and thermo-hydraulic performance (THP) of concave
and roof-patterned surfaces in the channels with different jet setup configurations were analyzed. Streamline and
temperature contour distributions of the jet flow along the channel for different H/Dh ratios and jet numbers were evaluated
for both patterned surfaces. In H/Dh = 4 and at Re = 7000, the average Nu number for roof-patterned surfaces was
found to be 30.52% higher than concave patterned surfaces in the case of double jets with a distance of Dh. Rt reduction
values of the roof and concave pattern surfaces with a double jet arrangement having 2Dh distance at Re = 5000 and
H/Dh = 8 are 163.7% and 36.23% when compared to single jet, respectively
Optical rectification and second harmonic generation in different shape GaAsAlGaAs double quantum wells under electric and magnetic fields
No full textOptical rectification and second harmonic generation in different shape GaAsAlGaAs double quantum wells under electric and magnetic field
Rastgele Sinyallerin Zaman Serisi Tahmininde Rezervuar Hesaplama Yaklaşımı
No full textRastgele Sinyallerin Zaman Serisi Tahmininde Rezervuar Hesaplama Yaklaşım
