Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Ashyralyev, A(8)
- Malkowsky, E(8)
- Ashyralyyev, Charyyar(7)
- Yilmaz, Ozgur(7)
- Ozdes, Duygu(6)
- Cakir, Zafer(5)
- Doğru, Bülent(5)
- Duran, Celal(5)
- Kahraman, Yakup(5)
- Arslan, Mehmet(4)
- Ashyralyev, Allaberen(4)
- Ayaydin, Hasan(4)
- Karaman, Safa(4)
- Kayacier, Ahmed(4)
- Yildirim, Mustafa(4)
- Yildiz, Salih(4)
- Yüksel, Ferhat(4)
- Aksoy, Metin(3)
- Bertan, Münevver(3)
- Cengiz, Ekrem(3)
- Doğan, Kadir Caner(3)
- Kartopu, Saffet(3)
- Kurt, Kemal(3)
- Recepoğlu, Mürşit(3)
- Sipahi, Ferkan(3)
- Temizel, Irfan(3)
- Yildiz, Emel(3)
- Yildiz, Hilal(3)
- Adanur, Hakan(2)
- Akar, Bülent(2)
- Akaryali, Enver(2)
- Akpinar, A. Sefa(2)
- Akpinar, Adem(2)
- Akyüz, Ahmet Mutlu(2)
- Ar, Ilker Murat(2)
- Arslantunali, D.(2)
- Artan, Seyfettin(2)
- Aslan, Zafer(2)
- Aydin, Faruk(2)
- Baki, Birdoğan(2)
Yayınlar
- MakaleYalnız künye2014Scopus SJRQ2Backfill and subsoil interaction effects on seismic behavior of a cantilever wall
Cakir, Tufan
The main focus of the current study is to evaluate the dynamic behavior of a cantilever retaining wall considering backfill and soil/foundation interaction effects. For this purpose, a three-dimensional finite element model (FEM) with viscous boundary is developed to investigate the seismic response of the cantilever wall. To demonstrate the validity of the FEM, analytical examinations are carried out by using modal analysis technique. The model verification is accomplished by comparing its predictions to results from analytical method with satisfactory agreement. The method is then employed to further investigate parametrically the effects of not only backfill but also soil/foundation interactions. By means of changing the soil properties, some comparisons are made on lateral displacements and stress responses. It is concluded that the lateral displacements and stresses in the wall are remarkably affected by backfill and subsoil interactions, and the dynamic behavior of the cantilever retaining wall is highly sensitive to mechanical properties of the soil material.
AtıfScopus21WoS18OpenAlex19İncele - BildiriYalnız künye2014Spatial and temporal analysis of current seismic quiescence in the east anatolian fault zone, Eastern Part of Turkey
Öztürk, S.; Sariçiçek, I.
In the scope of this study, an evaluation of recent seismic quiescence in the East Anatolian Fault Zone, eastern part of Turkey, is made by using the standard deviate Z-value. For this purpose, a statistical assessment of the spatial and temporal variations of the seismicity rate changes in the beginning of 2013is performed by using ZMAP software package. Results show that four areas with an apparently seismic quiescence may be important in the East Anatolian Fault Zone in the beginning of 2013. These anomalies are observed centered at 39.48°N-39.712°E (between Ovacik and Pülümür, Tunceli), the second one is found centered at 39.06°N-40.297°E (including Karakoçan, Sancak-Uzunpinar and Göynük fault zones), the third one is found centered at 38.55°N-38.763°E (between Malatya fault and EAFZ, north of Pötürge, Malatya) and the last one is found centered as 39.95°N-35.647°E (between Ceyhan-Yumurtalik-Karatas, Adana). The beginnings of these seismic quiescence anomalies are recently observed and nearly started in the beginning of 2007.For this reason, special attention should be given to these regions where the seismic quiescence is observed.
- KitapYalnız künye2014Handbook of research on effective marketing in contemporary globalism
Christiansen, Bryan; Yildiz, Salih; Yildiz, Emel
The 21st century has brought about many changes in the economic realm due to acceleration of globalization. The competitive landscape in numerous areas must always be reinvented to account for these changes, therefore making different marketing efforts a requirement for long-term success. The Handbook of Research on Effective Marketing in Contemporary Globalism provides readers with an understanding of the importance of marketing products and services across different cultures and languages in an era of high global competition. Intensified globalization, shifting demographics, and rapid innovations in technology and productivity solidify this publication's importance to scholar-practitioners, business executives, and undergraduate/graduate students.
AtıfScopus7OpenAlex25İncele - MakaleAçık Erişim2014Scopus SJRQ3Updated checklist of harvestmen (Arachnida: Opiliones) in Turkey
Kurt, Kemal
In this work, faunistic studies on harvestmen from Turkey are reviewed. A total of 88 species and 7 subspecies from 35 genera belonging to 7 families were determined. The distribution in Turkey and the world of these taxa is given and their distribution in the geographical regions of Turkey are presented.
AtıfScopus27WoS26OpenAlex25İncele - BildiriYalnız künye2014Performance Analysis of Linear Permanent Magnets Synchronous Motor by Scalar Control Method (v/f)
Otkun, Özcan; Doʇan, R. Özgür; Akpinar, A. Sefa
This study is conducted to improve the performance of Linear Permanent Magnet Synchronous Motor by using Scalar Control Method. To do this, open and closed loop control methods are used. The study is modeled with MATLAB / SIMULINK. Firstly, the Simulink model has been developed by using equations dq axis system of the motor. Then, a scalar control method is modeled. Thirdly, open and closed loop control forms are modeled. From these models, current, thrust force, and speed graphs were obtained. It is seen on the graphs, the motor's closed loop PID control at scalar control method provide positive results.
- MakaleAçık Erişim2014Scopus SJRQ2Geochemical make-up of oceanic peridotites from NW Turkey and the multi-stage melting history of the Tethyan upper mantle
Uysal, Ibrahim; Şen, A. Dündar; Ersoy, E. Yalçin; Dilek, Yildirim; Saka, Samet; Zaccarini, Federica; Escayola, Monica; Karsli, Orhan
We present the whole-rock and the mineral chemical data for upper mantle peridotites from the Harmanci{dotless}k region in NW Turkey and discuss their petrogenetic-tectonic origin. These peridotites are part of a Tethyan ophiolite belt occurring along the İzmir-Ankara-Ercincan suture zone in northern Turkey, and include depleted lherzolites and refractory harzburgites. The Al2O3 contents in orthopyroxene and clinopyroxene from the depleted lherzolite are high, and the Cr-number in the coexisting spinel is low falling within the abyssal field. However, the orthopyroxene and clinopyroxene in the harzburgites have lower Al2O3 contents for a given Cr-number of spinel, and plot within the lower end of the abyssal field. The whole-rock geochemical and the mineral chemistry data imply that the Harmanci{dotless}k peridotites formed by different degrees of partial melting (~%10-27) of the mantle. The depleted lherzolite samples have higher MREE and HREE abundances than the harzburgitic peridotites, showing convex-downward patterns. These peridotites represent up to ~16 % melting residue that formed during the initial seafloor spreading stage of the Northern Neotethys. On the other hand, the more refractory harzburgites represent residues after ~4-11 % hydrous partial melting of the previously depleted MOR mantle, which was metasomatized by slab-derived fluids during the early stages of subduction. The Harmanci{dotless}k peridotites, hence, represent the fragments of upper mantle rocks that formed during different stages of the tectonic evolution of the Tethyan oceanic lithosphere in Northern Neotethys. We infer that the multi-stage melting history of the Harmanci{dotless}k peridotites reflect the geochemically heterogeneous character of the Tethyan oceanic lithosphere currently exposed along the İzmir-Ankara-Erzincan suture zone.
AtıfScopus47OpenAlex45İncele - MakaleAçık Erişim2014Scopus SJRQ2R-modified crank-nicholson difference scheme for fractional parabolic pde
Ashyralyev, Allaberen; Cakir, Zafer
The second order of accuracy stable difference scheme for the numerical solution of the mixed problem for the fractional parabolic equation are presented using by r-modified Crank-Nicholson difference scheme. Stability estimate for the solution of this difference scheme is obtained. A procedure of modified Gauss elimination method is used for solving this difference scheme in the case of one-dimensional fractional parabolic partial differential equations. Numerical results for this scheme and the Crank-Nicholson scheme are compared in test examples.
AtıfScopus5WoS2OpenAlex5İncele - BildiriYalnız künye2014Imaging of the deteriorations and concrete quality of the tunnels (Zigina, Torul) with ground penetrating radar
Saricicek, Isil; Seren, Aysel; Lambot, S.; Giannopoulos, A.; Pajewski, L.; Andre, F.; Slob, E.; Craeye, C.
Ground Penetrating Radar (GPR) that give high resolution image and no damage to the researched surface, holds an important place in the use of near surface shallow researches. In this study; it is aim to investigate the fracture-crack system, the stratigraphy and the deterioration of the walls of Zigana Tunnel which is located at the way Trabzon-Gümüşhane in order to evaluate the existence of risk area leaking water out and structure contents. Furthermore, in addition to Zigana tunnel, the concrete quality of the Torul tunnel which has built recently was investigated. During examinations, GPR data were collected along totally 20 profiles at the entrance of the both sides of tunnels by using 500 MHz and 800 MHz shielded antennas. After applying data processing stages to the collected data, 2D and 3D images were acquired and interpreted.
AtıfScopus7WoS1OpenAlex5İncele - MakaleYalnız künye2014Scopus SJRQ1Microstructural, mechanical and tribological properties of Al-7Si-(0-5)Zn alloys
Alemdaǧ, Yasin; Beder, Murat
A series of Al-7Si-(0-5)Zn alloys were produced by permanent mould casting and their microstructure, mechanical and tribological properties were investigated in as-cast state. The microstructure of Al-7Si alloy consisted of α-Al dendrites surrounded by eutectic Al-Si mixture and a small amount of primary silicon particles. Addition of zinc into Al-7Si alloy resulted in the formation of α-solid solution and an increase in size and volume fraction of primary silicon particles. Moreover, these particles gathered inside interdendritic regions of the ternary Al-7Si-Zn alloys. The density, strength and hardness of Al-7Si-Zn alloys increased continuously with increasing zinc content, but their elongation to fracture and impact energy showed a reverse trend. It was also observed that zinc had no significant effect on the friction coefficient of the alloys, but their wear volume decreased with increasing zinc content up to 4%, above which the trend reversed. The wear surfaces of the alloys were characterized mainly by smearing layer with some degree of oxidation. In addition, delamination and fine scratches were observed on the worn surface. It was concluded that the addition of zinc up to 4% improves both mechanical and wear behaviour of Al-7Si alloy.
AtıfScopus48WoS41OpenAlex54İncele - BildiriYalnız künye2014Numerical solutions of linear differential-algebraic equation systems via Hartley series
Ünal, Emrah; Yalçin, Numan; Çelik, Ercan; Ashyralyev, A; Malkowsky, E
In this paper, Hartley series are presented first. Then, the operational matrix of integration together with the product and coefficient matrices are presented. They are used to transform linear differential equation systems to a set of linear algebraic equations. Finally, numerical examples are given.
- MakaleAçık Erişim2014Scopus SJRQ3Synthesis and spectral and thermal characterization of new metal-free and metallophthalocyanines: Investigation of their photophysical, photochemical, and thin film properties
Kaya, Elif Çelenk; Durmuş, Mahmut; Yanmaz, Ekrem; KantekiN, Halit
Novel tetrasubstituted metal-free (2), zinc (II) (3), cobalt (II) (4), and copper (II) (5) phthalocyanines bearing 2-phenylethanolate groups on the peripheral positions were synthesized by the cyclotetramerization reaction of the phthalonitrile derivative 1. The new compounds were characterized by a combination of IR, 1H NMR, 13 C NMR, UV-Vis, elemental analysis, and MS spectra data. The thermal stabilities of the phthalocyanine compounds were determined by thermogravimetric analysis. For metal-free (2) and zinc (3) phthalocyanines, photochemical (photodegradation and singlet oxygen quantum yields) and photophysical (fluorescence quantum yields and fluorescence lifetimes) properties were analyzed in dimethylsulfoxide (DMSO). The cobalt (4) and copper (5) phthalocyanines were not evaluated for this purpose because of their paramagnetic behavior. The metal-free (2) and zinc (3) phthalocyanines' fluorescence quenching behaviors were also investigated. The new phthalocyanine compounds' fluorescence emissions were effectively quenched by 1,4-benzoquinone in DMSO. The thin films of the cobalt phthalocyanine compound (4) were grown by electron beam evaporation technique. Crystalline CoPc (4) thin films were investigated by X-ray diffraction spectroscopy. Surface morphology of the CoPc (4) thin films was characterized by SEM.
AtıfScopus13WoS11OpenAlex15İncele - MakaleAçık Erişim2014Scopus SJRQ2High order approximation of the inverse elliptic problem with dirichlet-neumann conditions
Ashyralyyev, Charyyar
Inverse problem for the multidimensional elliptic equation with Dirichlet-Neumann conditions is considered. High order of accuracy difference schemes for the solution of inverse problem are presented. Stability, almost coercive stability and coercive stability estimates of the third and fourth orders of accuracy difference schemes for this problem are obtained. Numerical results in a two dimensional case are given.
AtıfScopus35WoS31OpenAlex35İncele - MakaleYalnız künye2014Scopus SJRQ2K-Ar dating, whole-rock and Sr-Nd isotope geochemistry of calc-alkaline volcanic rocks around the Gümüşhane area: Implications for post-collisional volcanism in the Eastern Pontides, Northeast Turkey
Aslan, Zafer; Arslan, Mehmet; Temizel, Irfan; Kaygusuz, Abdullah
Volcanic rocks from the Gümüşhane area in the southern part of the Eastern Pontides (NE Turkey) consist mainly of andesitic lava flows associated with tuffs, and rare basaltic dykes. The K-Ar whole-rock dating of these rocks range from 37.62 ± 3.33 Ma (Middle Eocene) to 30.02 ± 2.84 Ma (Early Oligocene) for the andesitic lava flows, but are 15.80 ± 1.71 Ma (Middle Miocene) for the basaltic dykes. Petrochemically, the volcanic rocks are dominantly medium-K calc-alkaline in composition and show enrichment of large ion lithophile elements, as well as depletion of high field strength elements, thus revealing that volcanic rocks evolved from a parental magmas derived from an enriched mantle source. Chondrite-normalized rare-earth element patterns of the volcanic rocks are concave upwards with low- to-medium enrichment (LaCN/LuCN = 3.39 to 12.56), thereby revealing clinopyroxene- and hornblende-dominated fractionations for andesitic-basaltic rocks and tuffs, respectively. The volcanic rocks have low initial 87Sr/86Sr ratios (0.70464 to 0.70494) and εNd(i) values (+1.11 to +3.08), with Nd-model ages (TDM) of 0.68 to 1.02 Ga, suggesting an enriched lithospheric mantle source of Proterozoic age. Trace element and isotopic data, as well as the modelling results, show that fractional crystallization and minor assimilation played an important role in the evolution of the volcanic rocks studied. The Eocene to Miocene volcanism in the region has resulted from lithospheric delamination and the associated convective thinning of the mantle, which led to the partial melting of the subduction-metasomatized lithospheric mantle.
AtıfScopus66WoS51OpenAlex64İncele - MakaleYalnız künye2014Scopus SJRQ1The effects of macro synthetic fiber reinforcement use on physical and mechanical properties of concrete
Bolat, Hakan; Şimşek, Osman; Çullu, Mustafa; Durmuş, Gökhan; Can, Ömer
Attempts to find a construction material having increased strength, ductility, toughness, and durability have led to interest in high performance fiber reinforced concrete. The use of such materials increases day by day. When the fibers are distributed in a homogeneous way and used in appropriate quantity inside the concrete, they reduce cracks, contribute to tensile strength, toughness, ductility and durability, and improve other mechanical properties. In this study, four types of concrete were produced: steel fiber (SFRC), polyester fiber (PYFRC), polypropylene fiber (PPFRC) reinforced concrete and a reference sample made of plain concrete (R1); these were then compared to one another. The ratio of fibers was used 4.25% of volume of concrete. The effects of the different types of fiber on hardened concrete were determined by conducting physical and mechanical experiments. Compressive strength, surface hardness, ultrasonic pulse velocity, carbonation, abrasion, capillarity and freeze-thaw resistance experiments were conducted on hardened concretes. SFRC had higher 12.4%, PYFRC 3.4% higher and PPFRC 4.3% lower compressive strength with respect to R1. PPFRC showed 8.04% higher compressive strength than R1 when it was determined by the surface hardness method. SFRC showed 5.4% higher compressive strength than R1 when we applied the ultrasonic pulse velocity method. In the abrasion experiment, the highest abrasion was found in SFRC with ∼0.5%, while the lowest was found in PPFRC at ∼0.18%. The highest and lowest amount of capillary water absorption was seen in R1 and PYFRC, respectively. In a carbonation experiment, SFRC was determined ∼130.8% higher than R1. It was concluded that the types of fiber used for reinforcement influenced the physical and mechanical properties of the concrete.
AtıfScopus137WoS123OpenAlex147İncele - MakaleYalnız künye2014Scopus SJRQ1LA-ICP MS zircon dating, whole-rock and Sr-Nd-Pb-O isotope geochemistry of the Camiboǧazi pluton, Eastern Pontides, NE Turkey: Implications for lithospheric mantle and lower crustal sources in arc-related I-type magmatism
Kaygusuz, Abdullah; Arslan, Mehmet; Siebel, Wolfgang; Sipahi, Ferkan; Ilbeyli, Nurdane; Temizel, Irfan
Late Cretaceous I-type plutons are widespread in the Eastern Pontides, NE Turkey. The studied Camiboǧazi pluton is a composite pluton consisting of diorite, tonalite, monzodiorite, monzonite, quartz monzonite, granite, and mafic microgranular enclaves (MMEs). Laser ablation ICP-MS U-Pb dating of zircon yielded crystallization ages of 76.21±0.79Ma, 75.65±0.50Ma, 75.04±0.83Ma, and 74.73±0.86Ma for diorite, monzodiorite, monzonite, and granite, respectively. The rocks of the pluton have I-type, high-K to shoshonitic and metaluminous character, displaying whole-rock geochemical features of arc-related granites. They are enriched in large-ion lithophile and light rare-earth elements, and depleted in high-field-strength elements. Major element variations can be attributed to fractionation of plagioclase, clinopyroxene, hornblende, and Fe-Ti oxides. The rocks show considerable variation in 87Sr/86Sr(i) (0.70498 to 0.70622), εNd(i) (-2.79 to -0.36), δ18O values (+6.3 to +11.4) and Nd model ages (TDM) (0.81Ga to 1.26Ga). Besides, they have (206Pb/204Pb)=18.44-19.09, (207Pb/204Pb)=15.64-15.69, and (208Pb/204Pb)=38.37-38.89. Although isotope signatures of the mafic microgranular enclaves (MMEs) (87Sr/86Sr(i)=0.70551 to 0.70622; εNd(i)=-2.9 to -1.23; δ18O=+8.3 to +9.7) are largely similar to the host rocks, MMEs are characterized by relatively high Mg-numbers (32-36), low contents of SiO2 (52-56wt.%) and low ASI (0.7-0.9). Estimated crystallization temperatures for the rocks of the pluton range from 735±58°C to 844±24°C and a shallow intrusion depth (<10km) is estimated from Al-in-hornblende thermobarometry. Whole-rock geochemical and isotopic data suggest magma generation by dehydration melting of an amphibolite-type lower crustal component with additional input of a subcontinental lithospheric mantle component. Furthermore, Sr-Nd isotope mixing model reveals ~30% to 40% lower crustal magma contribution to the mantle component.
AtıfScopus87WoS76OpenAlex83İncele - MakaleYalnız künye2014Smoking habits and the related sociodemographic characteristics in university students; [Üniversite öǧrencilerinin sigara İçme davrani{dotless}şlari{dotless} ve İlişkili sosyodemografik özellikleri]
Özcebe, Hilal; Doǧan, Bahar Güçiz; Inal, Ebru; Haznedaroǧlu, Dilek; Bertan, Münevver
Objectives: Smoking is an important public health issue in Turkey. This study set out to investigate the smoking prevalence among first and fourth grade university students as well as the associated socio-demographic variables. Material And Methods: A survey was carried out by the International Children's Centre (ICC) in the faculties of Science and Literature, Education and Medicine of nine Turkish Universities to determine the knowledge and life styles of the 1st and 4th grade university students in adolescence (2009). A total of 5.221 students were evaluated. Data were analysed using SPPS 16.0-9907290 statistical package program. Results: The first grade students with illiterate mothers (23.0%), those who were living alone at home (37.7%) and those who considered receiving inadequate pocket money (24.9%) had a higher level of smoking prevalence (p<0.05). The fourth grade students with illiterate mothers (34.9%), those who were living with their friends (34.0%), those who perceived their economic situation bad (37.7%) and those who considered receiving inadequate pocket money (36.3%) had a higher level of smoking prevalence (p<0.05). Conclusion: A relationship between smoking habits of university students and some socio-demographic characteristics was found. We believe that more priority should be given to health promotion interventions among university students, especially among those of low socioeconomic status. On the other hand, in order to monitor the efficacy of smoking-related interventions among young people, there is a need for early detection of young individuals who are at risk and urgent interventions should be carried out.
AtıfScopus12WoS13OpenAlex18İncele - MakaleAçık Erişim2014Scopus SJRQ4Stereotactic Excision of Additional Lesions Detected with Intraoperative Ultrasound Examination During Radiofrequency Dissecting Sealar (Habib®) Assisted Hepatic Metastasectomy: Report of 4 Cases
Altuntas, Yunus E.; Unel, Sacide; Gezen, Fazli C.; Aksakal, Nihat; Civil, Osman; Vural, Selahattin; Ozates, Mustafa; Oncel, Mustafa
Intraoperative ultrasound has been using to achieve a proper resection strategy in patients undergoing a hepatic colorectal metastasectomy. This study aims to describe and reveal the place of stereotactic metastasectomy in nonpalpable colorectal liver metastases (CLM). A chart review was initiated for all patients underwent resection for CLM between 2006 and 2011. The data concerning perioperative data and intraoperative strategy were abstracted. Among the 58 patients, who underwent a resection for CLM, 4 (6.9 %) (all men, median age 65.5, range 49-72, years) necessitated a stereotactic metastasectomy. Preoperative evaluations showed 1 (n = 1), 2 (n = 2), or 3 (n = 1) lesions, and intraoperative ultrasound (IUS) found an additional lesion in a case. Stereotactic marking was performed for nonpalpable lesions located in segments IVA, II, and VI and at the junction of segments V and VI. The margins were negative for all lesions both resected with conventional and stereotactic techniques. The examinations of the stereotactic resection materials revealed metastatic adenocarcinoma (patients n = 2), focal nodular hyperplasia (n = 1), and abnormal benign liver histology probably induced by chemotherapy (n = 1). The median (range) operation and hospitalization periods were 217.5 (150-310) minutes and 5.5 (2-9) days. No complications were observed except biliary fistula in a case, which spontaneously disappeared within 2 weeks. A patient died due to systemic disease including hepatic metastases 33 months after the liver surgery. Stereotactic metastasectomy may be feasible for the removal of nonpalpable CLM. Further evaluations are necessitated to understand the accurate place of this novel technique.
- BildiriYalnız künye2014Pid controlled line follower robot design on indoor 3D networks
Kose, Oguz; Karas, Ismail Rakip
Robots are commonly used and developed for different purposes in various areas such as research, educational, commercial, and industrial fields, also in emergency situations and space missions in today’s modern world. Robots are the machines that increasingly gain the importance with each passing day by the development of micro-electronics and micro-mechanics industry. To define a machine as a robot, it needs to have the sensors to check its environment; the mechanisms to evaluate the information received from these sensors and to transfer to the processing units. In this study, an intelligent controlled line follower robot was developed. Proportional-integral-derivative (PID) method was used for controlling. According to the information from the sensors, the method applied to the engines as Pulse Width Modulation (PWM). Online Fez Panda II embedded system board was used as the control element. This board has a 2-bit ARM 7 (Acorn RISC Machine) processor and it is suitable to.Net Micro Framework Technology. The system software was written with C# programming language in Visual Studio 2010 platform. The robot was tested on 3D indoor network, and has potential to be used for evacuation process on extraordinary sitautions in buildings. Another usage areas of this robot are factories and production lines. 3D network analyses and navigation applications could also be performed using the lines on the ground of this kind of environment.
- MakaleAçık Erişim2014Scopus SJRQ1Multiwalled CNT-pHEMA composite conduit for peripheral nerve repair
Arslantunali, D.; Budak, G.; Hasirci, V.
A nerve conduit is designed to improve peripheral nerve regeneration by providing guidance to the nerve cells. Conductivity of such guides is reported to enhance this process. In the current study, a nerve guide was constructed from poly(2-hydroxyethyl methacrylate) (pHEMA), which was loaded with multiwalled carbon nanotubes (mwCNT) to introduce conductivity. PHEMA hydrogels were designed to have a porous structure to facilitate the transportation of the compounds needed for cell nutrition and growth and also for waste removal. We showed that when loaded with relatively high concentrations of mwCNTs (6%, w/w in hydrogels), the pHEMA guide was more conductive and more hydrophobic than pristine pHEMA hydrogel. The mechanical properties of the composites were better when they carried mwCNT. Elastic modulus of 6% mwCNT loaded pHEMA was twofold higher (0.32 ± 0.06 MPa) and similar to that of the soft tissues. Electrical conductivity was significantly improved (11.4-fold) from 7 × 10-3 Ω-1.cm-1 (pHEMA) to 8.0 × 10-2 Ω-1.cm-1 (6% mwCNT loaded pHEMA). On application of electrical potential, the SHSY5Y neuroblastoma cells seeded on mwCNTs carrying pHEMA maintained their viability, whereas those on pure pHEMA could not, indicating that mwCNT helped conduct electricity and make them more suitable as nerve conduits.
AtıfScopus75WoS57OpenAlex75İncele - BildiriYalnız künye2014Note on small singular values of sequences of matrices
Ashyralyyev, Charyyar; Cakir, Zafer; Ashyralyev, A; Malkowsky, E
In this paper, some sequences of matrices for matrix pencils are considered. Properties of small singular values of these matrices are investigated. Estimates for singular values are obtained. The result of computer calculations is given.