Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(77)
- Merdan, Mehmet(73)
- Duran, Celal(54)
- Ozdes, Duygu(50)
- Baltaci, Cemalettin(45)
- Kaygusuz, Abdullah(45)
- Kulakaç, Nurşen(39)
- Ashyralyyev, Charyyar(38)
- Karsli, Orhan(37)
- Demir, Selim(36)
- Öztürk, Serkan(36)
- Dokuz, Abdurrahman(35)
- Turan, Ibrahim(35)
- Araz, Onur(33)
- Kandemir, Raif(31)
- Sipahi, Ferkan(30)
- Topal, Fevzi(30)
- Kurt, Kemal(28)
- Peker, Iskender(28)
- Arslan, Mehmet(27)
- Baltacı, Cemalettin(27)
- Maden, Nafiz(27)
- Ozturk, Samet(27)
- Aydin, Aydanur(26)
- Vural, Alaaddin(26)
- Bayrakdaroglu, Serdar(25)
- Kurnaz, Muammer(25)
- Reis, Hatice Catal(25)
- Akar, Zeynep(24)
- Aydin, Faruk(24)
- Gücer, Mehmet Ali(24)
- Topal, Meryem(24)
- Yolcu, Halil(24)
- Yücel, Cem(24)
- Anaç, Halil(23)
- Kankal, Murat(23)
- Ürkek, Bayram(23)
- Aliyazicioglu, Yuksel(22)
- Günen, Mehmet Akif(22)
- Tuncer, Metin(22)
Yayınlar
- MakaleYalnız künye2010Scopus SJRQ1Investigation of abrasion resistance of cement mortar with different pozzolanic compositions and subjected to sulfated medium
Çavdar, Ahmet; Yetgin, Şükrü
The durability phenomenon for concrete, or cement mortar, has gained attention recently as one of the important mechanical properties. It can be described as concrete's resistance to the destructive influences of a medium containing acid, sulfate and/or various chemicals and mechanical effects, like abrasion. Most of the studies attempted to improve these individual properties in concrete. However, concrete can be subjected to two or more of these effects simultaneously. In this study, the mortars produced with cement samples having seven different compositions and varied with an air-entraining agent were subjected to the influence of sulfate and abrasive effects simultaneously. In this study, several examples were evaluated using samples cured for six different periods throughout one year. This study is supported by thin section and XRPD investigations, in addition to being subjected to the basic tests, such as compression, flexure and abrasion. If the most important findings obtained from the study are summarized, it is seen that a compact cement matrix is more effective against both sulfate and abrasive effects than mineral additives. The mortars subjected to coupled (sulfate and abrasive) effects show less durability if compared to ones cured in water and later abraded.
AtıfScopus31WoS27İncele - MakaleAçık Erişim2010Effect of rectangular/circular cutouts on thermal buckling load optimization of angle-ply laminated thin plates
Topal, Umut; Uzman, Ümit
This paper deals with thermal buckling load optimization of symmetrically laminated angle-ply thin plates with centrally located different cutouts subjected to a uniform temperature load rise. The optimum results are given for maximum buckling temperature and the fibre orientation is adopted as design variable. The results are obtained for the various cutout geometries such as rectangle and circle. The modified feasible direction (MFD) method is used for the optimization routine. Therefore a program based on FORTRAN is used. Finally, the effects of cutout areas, plate aspect ratios and boundary conditions on the optimum results are demonstrated.
AtıfScopus6WoS4OpenAlex5İncele - MakaleYalnız künye2010Scopus SJRQ3Comparison of stepped and smooth spillway effects on stream reaeration
Aras, Egemen; Berkun, Mehmet
The oxygen transfer at a hydraulic structure happens by self-aeration through the spillway and by flow aeration in the hydraulic jump downstream of the hydraulic structure. Spillways with their water-air controlling mechanisms are important not only for their structural properties but also for their effects on stream ecology. Spillway types also affect the efficiency of aeration. Decisions on the types of spillway should be made by taking the environmental conditions and flow rates into consideration. This paper compares the aeration efficiency of stepped and smooth spillways. Empirical correlations predicting length of the non-aerated flow region and aeration efficiency are developed. Smooth and stepped spillways cause increased dissolved oxygen (DO) concentrations at the downstream part of the channel. DO concentration changes are shown to depend on the flow types, discharge rates, tail-water depth and travelling times.
AtıfScopus22WoS14İncele - MakaleYalnız künye2010Scopus SJRQ1Stochastic finite element analysis of a cable-stayed bridge system with varying material properties
Çavdar, Özlem; Bayraktar, Alemdar; Adanur, Süleyman
Stochastic seismic finite element analysis of a cable-stayed bridge whose material properties are described by random fields is presented in this paper. The stochastic perturbation technique and Monte Carlo simulation (MCS) method are used in the analyses. A summary of MCS and perturbation based stochastic finite element dynamic analysis formulation of structural system is given. The Jindo Bridge, constructed in South Korea, is chosen as a numerical example. The Kocaeli earthquake in 1999 is considered as a ground motion. During the stochastic analysis, displacements and internal forces of the considered bridge are obtained from perturbation based stochastic finite element method (SFEM) and MCS method by changing elastic modulus and mass density as random variable. The efficiency and accuracy of the proposed SFEM algorithm are evaluated by comparison with results of MCS method. The results imply that perturbation based SFEM method gives close results to MCS method and it can be used instead of MCS method, especially, if computational cost is taken into consideration.
AtıfScopus17WoS13OpenAlex20İncele - MakaleYalnız künye2010Scopus SJRQ1Sources and petrogenesis of Jurassic granitoids in the Yusufeli area, Northeastern Turkey: Implications for pre- and post-collisional lithospheric thinning of the eastern Pontides
Dokuz, Abdurrahman; Karsli, Orhan; Chen, Bin; Uysal, Ibrahim
Small granitoids emplaced into the early Jurassic volcani-clastic succession in the Yusufeli area, northeastern Turkey, can be temporally and geochemically classified into two groups: early Jurassic low-K and late Jurassic high-K. 40Ar-39Ar hornblende analyses yielded 188.0 ± 4.3 Ma for the Dutlupi{dotless}nar intrusion, dating the subduction related rifting in the region. It comprises metaluminous to weakly peraluminous (ASI = 0.94-1.11) granodiorite and, to a lesser extent, tonalite whose K2O-poor (< 2.04 wt.%) nature and weak negative Eu anomalies (Eu/Eu* = 0.9-0.7) preclude derivation by fractional crystallization from a K-rich melt. Sr, Nd and Pb isotopic data reveal derivation by partial melting from an already cooled tholeiitic basic rocks which had mantle-like isotope signature. The Sumbated intrusion formed in the late Jurassic (153.0 ± 3.4 Ma) and consists chiefly of metaluminous (ASI = 0.84-0.99) quartz monzodiorite. Medium to high-K2O, relatively high MgO and Sr contents, flat HREE patterns without prominent Eu anomalies, slightly positive εNd(t) values (+ 1.5 to + 2.5) and low ISr ratios (0.7046-0.7056) are consistent with an origin by dehydration melting of a juvenile source, above the garnet stability field, dominated by likely K-amphibole bearing calc-alkaline mafic rocks. Geochemical data show that fractional crystallization from a Sumbated-like quartz monzodioritic magma is the fundamental process responsible for the evolved compositional range of the Keçikaya intrusion. The geochemical and geochronological data presented here indicate that the late Jurassic magmatism occurred in a post-collisional setting. Slab-breakoff, which was followed by shortly after collision, seems to be the most plausible mechanism for the generation of medium to high-K calc-alkaline rocks of the Sumbated and the Keçikaya intrusions, indicating a switch in the geodynamic setting, e.g., from pre-collision to post-collision in the middle Jurassic in the eastern Pontides.
AtıfScopus123OpenAlex122İncele - BildiriAçık Erişim2010Assessment of Turkish and class teacher candidate's attitudes towards children's literature and children's literature lesson
Ulaş, A. Halim; Kolaç, Emine; Topal, Yakup; Sevim, Oǧuzhan; Keser, H; Ozcinar, Z; Kanbul, S
Purpose of this research is to reveal class and Turkish teacher candidates' attitudes towards children's literature lesson, and works of children's literature. Study group of this research is comprised of students from Classroom Teaching and Turkish Teaching Departments of Faculty of Education of Atatürk University. Answers were sought for the level of classroom teaching and preschool teacher candidates' towards children's literature lesson, and works of children's literature, and whether there is any significant difference is seen in classroom teaching and pre-school teacher candidates' towards children's literature lesson, and works of children's literature in terms gender, and departments. Having the research conducted according to survey method (2007), "Attitude Scale towards Children's Literature, and Children's Literature Lesson", having been developed by ..., and comprised of 35 articles, was made use of. At the end of the research, it was concluded that teacher candidates had developed a positive attitude towards children's literature, and children's literature lesson, and neither gender, nor field differences had significantly affected that attitude.
AtıfOpenAlex1İncele - MakaleAçık Erişim2010Scopus SJRQ2Meibomian carcinoma of the eyelid in a Simmental cow
Gokhan, Nezihe; Sozmen, Mahmut; Ozba, Burhan; Gungor, Emine
Objective: To describe the clinical and pathomorphological features of meibomian carcinoma (MC) diagnosed in a Simmental cow. Material and methods: A 7-year-old Simmental cow was admitted to the Veterinary Surgery Clinics of Faculty of Veterinary Medicine, University of Kafkas, Kars, Turkey. The signalment and anatomical distribution were summarized and focused on pathomorphological description. Results: Macroscopically, a papillary mass, 5 × 3.5 × 7 cm in size, arising from the left lower eyelid with local spread to the upper eyelid and covering the entire globe was observed. The mass was ulcerated and hemorrhagic and applied pressure to the globe. Following sedation and local anesthesia, the mass and globe were excised. Histopathological examination revealed an MC. Conclusions: The diagnosis of MC is infrequent in veterinary literature. Complete surgical excision could be curative and histopathology is crucial for the diagnosis of MC occurring in animals.
AtıfScopus10WoS7OpenAlex9İncele - MakaleYalnız künye2010Scopus SJRQ1Exergetic performance analysis of a recirculating aquaculture system
Kucuk, Haydar; Midilli, Adnan; Özdemir, Atilla; Çakmak, Eyüp; Dincer, Ibrahim
This paper examines exergetic aspects of a Recirculation Aquaculture System (RAS) for Black Sea trout (Salmo trutta labrax) fingerling rearing at the Trabzon Central Fisheries Research Institute, Turkey. In its thermodynamic analysis, each component of the RAS is treated as a steady-state steady flow system and its exergetic efficiencies are studied. In addition, the following parameters are measured and recorded in experiments: the mass flow rates, inlet and outlet temperatures and of the system components, surrounding temperatures, and electrical work utilized by the components in the RAS. Based on these experimental data, inlet and outlet exergy values, exergy losses, and exergetic efficiencies of each component in the system are determined to assess their performance. Moreover, the overall system exergy efficiency is determined. The results show that exergy efficiencies of the system components are highly affected by varying input exergy flows as a function of the surrounding temperature and chiller's operating period.
AtıfScopus16WoS13OpenAlex26İncele - BildiriYalnız künye2009Scopus SJRQ1Mineralogy and geochemistry of dacitic rocks accompanying the Murgul (Artvin, NE Turkey) massive sulfide deposit
Sipahi, Ferkan; Sen, Cueneyt; Sadiklar, M. Burhan; Demir, Yilmaz
- MakaleYalnız künye2009Scopus SJRQ1The Effect of Local Injections in Hemiplegic Shoulder Pain A Prospective, Randomized, Controlled Study
Lakse, Emre; Gunduz, Berrin; Erhan, Belgin; Celik, Evrim Coskun
Objective: The aim of this study was to evaluate the effects of corticosteroid injections on hemiplegic shoulder pain and range of motion. Design: Fifty-two stroke patients with shoulder pain were evaluated. Thirty-eight patients who fulfilled the criteria were assigned randomly into either injection or control groups. Transcutaneous electrical nerve stimulation and therapeutic exercise program were applied to both groups for 15 sessions. The patients in the injection group were administered either intra-articular or subacromial injections of corticosteroid and local anesthetic according to their pathology. The evaluations were performed before treatment and at the first and fourth weeks of treatment. Primary follow-up parameters were passive shoulder range of motion and verbal analog scale for shoulder pain; secondary follow-up parameters were modified Barthel index, Brunnstrom upper-extremity score, and modified Ashworth scale. Results: In both groups, shoulder range of motion and shoulder pain scores showed significant improvement. When the two groups were compared, the improvement was more significant in the injection group. Barthel scores improved in both groups, and no difference was found between the groups. Brunnstrom upper-extremity and modified Ashworth scores revealed nonsignificant changes in both groups. Conclusions: Adding corticosteroid injection to conventional treatment in hemiplegic shoulder pain improved shoulder range of motion and decreased pain scores before treatment to the first and fourth weeks of treatment. Injection in hemiplegic shoulder pain is recommended in appropriate patients.
AtıfWoS27OpenAlex29İncele - BildiriYalnız künye2009Scopus SJRQ1Alteration of Late Cretaceous dacites in the Murgul Area (Artvin, KD Turkey)
Sipahi, Ferkan; Sadiklar, M. Burhan; Sen, Cueneyt; Demir, Yilmaz
- MakaleAçık Erişim2009Scopus SJRQ2U-Pb SHRIMP zircon ages, geochemical and Sr-Nd isotopic compositions of the late cretaceous I-type Sariosman pluton, Eastern Pontides, NE Turkey
Kaygusuz, Abdullah; Chen, Bin; Aslan, Zafer; Siebel, Wolfgang; Şen, Cüneyt
The petrogenesis and U-Pb SHRIMP zircon ages of the Late Cretaceous Sariosman pluton in the Eastern Pontides is investigated by means of whole-rock Sr-Nd isotope data with field, petrographic and whole-rock geochemical studies. The bulk of the I-type Sariosman pluton consists of biotite-hornblende monzogranite, with minor quantities of porphyritic hornblende-biotite monzogranite. The biotite-hornblende monzogranite contains a number of mafic microgranular enclaves (MMEs) of quartz monzodiorite composition. U-Pb zircon sensitive high-resolution ion microprobe dating (SHRIMP) dates the magma emplacement age of the biotite-hornblende monzogranite at 82.7±1.5 Ma. The rocks of the pluton show high-K calc-alkaline, metaluminous to slightly peraluminous characteristics, and are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE), thus displaying features of arc-related granitoids. Chondrite-normalised rare earth-element (REE) patterns have concave upward shapes (Lacn/Lucn= 10.1-17.4) with pronounced negative Eu anomalies (Eu/Eu*= 0.61-0.80). Initial εNd values vary between -3.0 and -4.1 and initial 87Sr/86Sr values between 0.7062 and 0.707. The MMEs are characterised by higher Mg-numbers (27-29) and lower values of both SiO2 (56-58 wt%) and aluminium saturation index (0.9-1.0), compared to the monzogranites. Fractionation of plagioclase, hornblende and Fe-Ti oxides played an important role in the evolution of the Sariosman pluton. The crystallisation temperatures of the melts ranged from 700 to 800 °C and a relatively shallow intrusion depth (~2 to 7 km) is estimated from the Al-in-hornblende geobarometry. The geochemical and isotopic compositions of the Sariosman pluton suggest an origin through dehydration melting of mafic lower crustal source rocks.
AtıfScopus50WoS48OpenAlex22TR Dizin12İncele - MakaleYalnız künye2009Scopus SJRQ1Thermal buckling load optimization of angle-ply laminated cylindrical shells
Topal, U.; Uzman, Ü.
In this study, thermal buckling load optimization of symmetrically laminated cylindrical shells subjected to uniformly distributed temperature load is investigated. The objective function is to maximize the critical temperature capacity of laminated shells and the fibre orientation is considered as design variable. The first-order shear deformation theory is used to study thermal buckling response of the laminates. The modified feasible direction method is used as optimization routine. For this purpose, a program based on FORTRAN is used for the optimization of shells. Finally, the effects of number of layers, length-to-radius ratio and boundary conditions on the optimum results are investigated.
AtıfScopus20OpenAlex16İncele - MakaleYalnız künye2009Scopus SJRQ1C2/c pyroxene phenocrysts from three potassic series in the Neogene alkaline volcanics, NE Turkey: Their crystal chemistry with petrogenetic significance as an indicator of P -T conditions
Aydin, Faruk; Thompson, Richard M.; Karsli, Orhan; Uchida, Hinako; Burt, Jason B.; Downs, Robert T.
Chemical and structural data are reported for C2/c pyroxene phenocrysts collected from three potassic series (Group A: basanite-tephrite, Group B: tephrite-phonolitic tephrite, Group C: alkaline basalt-trachybasalt) of the Neogene alkaline volcanics (NAVs) in northeastern Turkey, in order to investigate the evolution of the magmatic plumbing system and the location of magma chamber(s) with crystallization conditions. The rock series hosting the clinopyroxene phenocrysts show generally porphyritic texture and have a variable phenocryst-rich nature (20-58%), with phenocryst assemblages characterized by cpx ± ol ± plag ± foid ± amp ± bio. The clinopyroxene phenocrysts can be chemically classified as Ti- and Fe3-rich Al-diopsides for Groups A and B (ABcpxs) and Ti- and Fe3-poor Al-diopsides for Group C (Ccpxs). They have poorly variable composition, clustering in the diopside field. Structurally, the diopside groups have nearly similar a (ranging from 9.73 to 9.75 Å), Vcell (437.2-440.9 Å3), and hbetai angle values (106.01°-106.23°), but some differences in polyhedral parameters and geometries of the AB-cpxs and C-cpxs have been observed. For example, the AB-cpxs are characterized by. larger c (5.27-5.30 vs. 5.25-5.28 Å), VT (2.27-2.30 vs. 2.23-2.28 Å3), and VM2 (25.53-25.72 vs. 25.41-25.59 Å3) values and smaller b (8.87-8.88 vs. 8.88-8.91 Å) and VM1(11.49-1.63 vs. 11.64-11.83 Å3) values with respect to the C-cpxs. In addition, the AB-cpxs show higher values of VM2/VM1 (2.20-2.23) due to large VM2 and small VM1 compared to the VM2/ VM1 ratios of the C-cpxs (<2.19). Such differences in the crystal structure of the AB-cpxs and C-cpxs from the NAVs are partly related to different crystallization pressures, but mostly related to variation in melt composition and, possibly, the influence of other crystallizing mineral phases. In particular, R(M2-O1) and R(M1-O2) (i.e. bond lengths) differences in the clinopyroxenes of different groups support the presence of evolved host rocks with different alkaline character (i.e. silicaundersaturated Groups A-B and silica-saturated Group C). Based on the cpx-geothermobarometry, the crystallization pressures for the C-cpxs are lower than 4.5 kbars, but the AB-cpxs have relatively high-pressure values (5.6- 10.6 kbars), suggesting that the AB-cpxs crystallized in higher pressure environments. The relatively higher crystallization temperatures of the AB-cpxs also indicate higher cooling rates. The P-T estimates suggest that the source regions of the clinopyroxene phenocrysts from the NAVs were crustal magma chambers in a closed plumbing system at a moderate- to low-pressure regime.
AtıfScopus25WoS27OpenAlex28İncele - MakaleYalnız künye2009Scopus SJRQ4The effect of average daily gain and age at first calving on reproductive and milk production traits of brown swiss and holstein friesian cattle
Bayram, B.; Yanar, M.; Akbulut, O.
The purpose of the study was to determine the effects of average daily gain and age at first calving on the reproductive and milk production traits of Brown Swiss (BS) a.d Holstein Friesian (HF) cattle. For this purpose, daily gains and ages at first calving were divided into two groups which were below the average called as the "slow" or "early" groups and above the average named as "moderate" or "late" groups respectively. BS heifers in the moderate group reached the first insemination age and first calving age 103.7 and 101.7 days earlier (P>0.01) than these in the slow group respectively. The corresponding values for HF heifers were 37.8 and 29.5 days respectively and were not significant. While the average daily gain had negative effects on reproduction traits following the first calving, the daily gain of BS had no effect on the milk production traits in all parities. HF heifers in the moderate group had higher (P>0.05) actual (585 kg) and 305 days milk yield (324 kg) in the second parity. Early calving in both breeds resulted in a significant (P>0.05) reduction in the actual and 305-days milk yield in the first parity. Early calving caused a significant decrease (P>0.05) in the actual milk yield, 305-days milk yield, actual milk fat and 305-days milk fat yield of BS cows in the first parity. Either early or late calving in BS didn't affect on milk traits in second and third parities. The early calving in HF lowered significantly (P>0.05) the actual and 305-days milk yield in first lactation. However, late calving in HF resulted in lower actual milk yield, 305-days milk yield, actual milk fat yield and 305-days milk fat yield in third parity.
AtıfScopus15WoS12İncele - MakaleYalnız künye2009Yields and qualities of some red clover (Trifolium pratense L.) genotypes in crop improvement systems as livestock feed
Tavlas, Ayten; Yolcu, Halil; Tan, Mustafa
The objective of this study was to compare twenty-five genotypes of red clover (Trifolium pratense L.) in terms of yield (in 2000 - 2004) and quality performance (in 2000 - 2001) for animal feeding. The genotypes were evaluated for dry matter yield (DMY), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), digestible dry matter (DDM), dry matter intake (DMI), relative feed value (RFV), total digestible nutrients (TDN), net energy-lactation (NEl), net energy-maintenance (NEm) and net energy-gain (NEg) content. There were significant differences in DMY (P < 0.01), CP, ADF, NDF, DDM, DMI, RFV (P < 0.05), TDN, NEl, NEm and NEg (P < 0.01) amongst the genotypes. The Rajah cultivar had the highest DMY (13629 kg ha-1) amongst the genotypes according to five year results. While the highest CP (15.94%), NDF (50.59%), DDM (68.68%), TDN (66.50%), NEl (0.70 Mcal/1b), NEm (0.76 Mcal/1b) and NEg (0.44 Mcal/1b) were determined in the L-818 line, the lowest ADF (25.96%) was also found in the L-818 line. The highest DMI (3.16%) was observed in the Hamua cultivar. The highest RFV was determined in the Tohum Islah ecotype (156), the Hamua (155), the Orbit (154) cultivars and the L-812 (154) line. Our results showed that there were large variations in terms of yield and quality performances amongst the red clover genotypes for animal feeding. The Rajah, L-832 (selected from wild forms) and Pawera had the highest yields amongst the genotypes. The L-818, L-812 lines (selected from wild forms), Tohum Islah ecotype, Lucrun and Redwent cultivars were superior in terms of forage quality properties (low in ADF and NDF and high CP, DDM, DMI, RFV, TDN, NEl, NEm, NEg) than the other red clover genotypes.
AtıfScopus7WoS6İncele - MakaleYalnız künye2009Effects of various ages of weaning on growth performance of morkaraman lambs
Aksakal, Vecihi; Emsen, Ebru; Ozdemir, Memis; Macit, Muhlis
This study was conducted on 46 Redkaraman lambs born at the Ataturk University, Agricultural Faculty Sheep Research Farm. The lambs were weaned at different ages such as 45, 60 and 75 days. After weaning, the lambs were sent to the pasture and fed on concentrate including 15.3% crude protein in a ratio of 1.5% of live body weight for the first 6 weeks thereafter, amount of feed was increased to 2% of the live body weight in addition to pasture at the evenings. Live body weights and daily weight gaing of lambs were determined from 45 days to end of the grazing period within 14 days intervals. Live weights at 45 days for the lambs weaned at 45, 60 and 75 days were 12.20, 11.58 and 12.47 kg and at 60 days were 14.38, 14.79 and 15.40 kg and 75 days were 15.30, 16.06 and 17.28 kg. Live weights at the end of the grazing period were 34.86, 35.11 and 38.93 kg for the lambs weaned at 45, 60 and 75 days of age, respectively. The differences among the group were found significant (p<0.05) for live weights at the end of the grazing period. Daily weight gains of lambs in the groups were found as 144.5, 145.7 and 164.0 g for the end of the grazing period; 137.3, 142.6 and 160.5g for the 46 days of age and 136.5, 135.5 and 157.0 g for 61 days of age. The differences among the group were found significant (p<0.05). The results of this research indicated that there were significant (p<0.05) differences for the live weights at the end of the grazing period in Redkaraman lambs weaned at various ages, also there were significant (p<0.05) differences for daily weight gains at the end of the grazing period, 46 and 61 days of age.
AtıfScopus7WoS6İncele - MakaleYalnız künye2009Scopus SJRQ1Multiobjective optimization of laminated composite cylindrical shells for maximum frequency and buckling load
Topal, Umut
This paper deals with multiobjective optimization of laminated cylindrical shells to maximize a weighted sum of the frequency and buckling load under external load. The layer fibre orientation is used as the design variable and the multiobjective optimization is formulated as the weighted combinations of the frequency and buckling under external load. The first order shear deformation theory is used for the finite element formulation of the laminated shells. Five shell configurations with eight layers are considered as candidate designs. The modified feasible direction method (MFD) is used as optimization routine. For this purpose, a program based on FORTRAN is used for the optimization of the laminated shells. Finally, the effect of different weighting ratios, shell aspect ratio, shell thickness-to-radius ratios and boundary conditions on the optimal designs is investigated and the results are compared.
AtıfScopus64WoS56OpenAlex63İncele - MakaleYalnız künye2009Scopus SJRQ1Frequency optimization of laminated skew plates
Topal, U.; Uzman, Ü.
In this study, the frequency optimization of laminated skew plates is investigated. The objective function is to maximize the fundamental frequency of the laminated skew plates and the fiber orientation is considered as design variable. The mathematical formulation is based on the first-order shear deformation theory (FSDT) for the frequency analysis of the laminated skew plates. The modified feasible direction (MFD) method is combined with the finite element solution of laminated skew plates for optimal designs. Therefore, a program based on FORTRAN is used. Finally, the effect of skew angles, boundary conditions, aspect ratios and functionally graded materials on the optimal results is investigated and the results are compared.
AtıfScopus13WoS13OpenAlex16İncele - MakaleYalnız künye2009Chemical contents of red clover genotypes on crop improvement systems as livestock feed
Yolcu, Halil; Tavlas, Ayten; Tan, Mustafa; Gunes, Adem
A field experiment was conducted in 2000-2001 at the Research Station of East Anatolia Agricultural Research Institute in Pasinler of Erzurum province in Turkey. In this study, 25 red clovers (Trifolium pratense L.) genotypes were evaluated in terms of chemical contents for animal feeding in the 2 years results. The red clover genotypes were sown in the spring of 2000. The experiment was designed a randomized complete block with replicated 4 times. The genotypes were harvested in 50% flowering once in 2000 and 3 times in 2001. There were significant differences in N (p<0.05), Mg (p<0.05), Zn (p<0.05), Fe (p<0.05), Mn (p<0.01) and Cu (p<0.01) contents but no in Na content among the red clover genotypes. According to 2 years results, especially L-818 line and Xiashao cultivar in N; L-1881 and L-812 line in Mg; Redwent cultivar, L-77, L-l 922 lines and Lucrun cultivars in Zn; L-77 line, Redwent cultivar, L-812, L-1922 lines and Lucrun cultivar in Fe; L-79 line, Redwent cultivar and L-77 line in Mn; L-79 line, Redwent cultivar and L-77 line in Cu had higher chemical contents than the others for animal feeding. The genotypes rich in terms of chemical content can be successfully used to meet the requirement the forage quality of animal and to gain new quality red clover genotypes for animal nutrition.
AtıfScopus5WoS4İncele