Restoration of Strength in Polyamide Woven Glass Fiber Organosheets by Hot Pressing

Thermoplastic composite organosheets (OSs) are increasingly recognized as a viable solution for automotive and aerospace structures, offering a range of benefits including cost-effectiveness through high-rate production, lightweight design, impact resistance, formability, and recyclability. This study examines the impact response, post-impact strength evaluation, and hot-pressing repair effectiveness of woven glass fiber nylon composite OSs across varying impact energy levels. Experimental investigations involved subjecting composite specimens to impact at varying energy levels using a drop-tower test rig, followed by compression-after-impact (CAI) tests. The results underscore the exceptional damage tolerance and improved residual compressive strength of the OSs compared to traditional thermoset composites. This enhancement was primarily attributed to the matrix’s ductility, which mitigated transverse crack propagation and significantly increased the amount of absorbed energy. To mitigate impact-induced damage, a localized hot-pressing repair approach was developed. This allowed to restore the post-impact strength of the OSs to pristine levels for impact energies below 40 J and by 83.6% for higher impact energies, when OS perforation was observed. The measured levels of post-repair strength demonstrate a successful restoration of OS strength over a wide range of impact energies, and despite limitations in achieving complete strength recovery above 40 J, hot-pressing repair emerges as a promising strategy for ensuring the longevity of thermoplastic composites through repairability

Combined approach of density functional theory and quantum Monte Carlo method to electron correlation in dilute magnetic semiconductors

We present a realistic study for electronic and magnetic properties in dilute magnetic semiconductor (Ga,Mn)As. A multi-orbital Haldane-Anderson model parameterized by density-functional calculations is presented and solved with the Hirsch-Fye quantum Monte Carlo algorithm. Results well reproduce experimental results in the dilute limit. When the chemical potential is located between the top of the valence band and an impurity bound state, a long-range ferromagnetic correlations between the impurities, mediated by antiferromagnetic impurity-host couplings, are drastically developed. We observe an anisotropic character in local density of states at the impurity-bound-state energy, which is consistent with the STM measurements. The presented combined approach thus offers a firm starting point for realistic calculations of the various family of dilute magnetic semiconductors.Comment: 5 pages, 4 figure

Resmi İlköğretim Okullarında Görev Yapan Yöneticilerin Zaman Yönetimi İle İlgili Algılarının İncelenmesi,

Bu araştırma, ilköğretim okullarında çalışan yöneticilerin zaman yönetimine ilişkin algı düzeylerini tespit etmeye yöneliktir. Bu araştırma genel tarama modelinde nicel bir çalışmadır. Bu araştırmanın çalışma evrenini, İstanbul- Bağcılar, Avcılar, Esenyurt ve Bahçelievler belediye sınırları içinde bulunan 249 ilköğretim okulunda çalışan 632 müdür ve müdür yardımcısı oluşturmaktadır. Veri toplama aracı olarak araştırmacılar tarafından “zaman yönetimi” ile ilgili 5’li Likert tipinde geliştirilmiş olan 24 maddelik bir anket kullanılmıştır. Anketin Cronbach’s Alpha iç tutarlık katsayısı 0,933’tür. Anketten elde edilen veriler, SPSS 20 istatistik programı ile analiz edilmiştir. Zaman yönetimi ile ilgili açımlayıcı faktör analizi sonuçlarına göre yöneticilerin zaman yönetimi algıları dört alt boyutta toplanmıştır. Bu alt boyutlar; “zamanı planlama, zamanı değerlendirme, zaman yetersizliği ve kişisel ilişkiler” olarak isimlendirilmiştir. Faktör alt boyutları ile bağımsız değişkenler olarak cinsiyet, okulda çalışan öğretmen sayısı, mesleki deneyim, okulda geçen yöneticilik süresi ve eğitim düzeyi arasında farklılıklara bakılmıştır. Buna göre iki gruplu karşılaştırmalarda t testi, ikiden fazla bağımsız grupların karşılaştırılmasında tek yönlü ANOVA ve anlamlı değişkenler için LSD testi uygulanmıştır. Araştırma sonuçlarına göre, yöneticilerin en fazla zamanını alan konular “zamanı planlama”, en az zaman ayırdıkları konular ise, “ kişisel ilişkiler” ile ilgilidir. Bu bulgular yapılan diğer araştırma bulguları ile de desteklenmektedir

Demographic Features of Turkish Literature Audiences and Applied Analysis of the Factors Affecting Their Reading Preferences,

The purpose of this study is to determine factors affecting reading preferences in parallel with the demographic features of Turkish literature audiences. The study lasted approximately for 7 months. (N=650) individuals attended the study in total. The universe of the study is Turkey while the sample of the study is composed of 8 different provinces. These provinces are İstanbul, Ankara, İzmir, Bursa, Kocaeli, Sakarya, Trabzon and Gaziantep. A questionnaire form whose reliability and validity had been ensured before and which was composed of 5 point Likert scale was used in the study. The questionnaire form was reformed in accordance with the topic of the study, it was subjected to validity and reliability test and it was carried into main practice through taking views of experts. Data acquired from the results of main practice was analyzed by using SPSS 18.0 packet program and the value of 0.924 was acquired as Cronbach’s Alpha co-efficient. This value indicates that the measuring tool used in this study is quite reliable. The questionnaire is composed of two sections. In the first section, there are questions with regard to determine demographic features of the participants while in the second section, there are scaled questions composed of 120 items. 0.05 of significance level was taken into account among variables in terms of relations and differences. Methods such as different statistics anova, factor and hypothesis tests were applied in the analysis. Moreover, 4 different literary works were mentioned in the study so as to determine attitudes and behaviors of the participants towards literary works. Opinions of the participants were demanded about novels such as İntibah (Rebirth), Araba Sevdası (Ambition for Car), Mai ve Siyah (Blue and Black) and Çalıkuşu (The Wren). At the end of the study, it was found out that the participants followed academic publications more frequently, the use of computer and internet had an effect on reading e-book and up-to-date books were read more than those books written in a foreign or ancient language (Ottoman Turkish). Furthermore, it was determined that education and age variables of the participants had an effect on reading habits while gender, age and education variables had an effect in some reading factors

ANKOS publisher application system and its impact on the e-resource evaluation process

The Publisher Application System (PAS) is a Web-based archiving and online evaluation system developed by the Database Evaluation Group (DEG), one of the working groups formed within the Anatolian University Libraries Consortium (ANKOS). The DEG was formed in 2008 to inquire and evaluate e-resources suited to the needs of the consortium; to follow up similar consortial activities worldwide as well as developments in connection with the scientific publishing industry; and to determine, implement, and improve pricing models in accordance with the prevailing economic, legal, and academic system. Development of the PAS was essential to ensure standardization and sustainability towards a more detailed and effective analysis of e-resources qualifying for evaluation by ANKOS. The PAS played an important part not only in establishing and defining the workflow of the DEG, but also in creating an archive of both the e-resources submitted to the consortium and the applicant publishers/agents submitting these resources. This article outlines the process that started with the foundation of the DEG through the formation of the PAS as well as the present setup of the system. It is also hoped that this case study will have a positive contribution to the processes being followed by the persons and the groups engaged in similar activities.pre-prin

ANKOS publisher application system and its impact on the e-resource evaluation process

The Publisher Application System (PAS) is a Web-based archiving and online evaluation system developed by the Database Evaluation Group (DEG), one of the working groups formed within the Anatolian University Libraries Consortium (ANKOS). The DEG was formed in 2008 to inquire and evaluate e-resources suited to the needs of the consortium; to follow up similar consortial activities worldwide as well as developments in connection with the scientific publishing industry; and to determine, implement, and improve pricing models in accordance with the prevailing economic, legal, and academic system. Development of the PAS was essential to ensure standardization and sustainability towards a more detailed and effective analysis of e-resources qualifying for evaluation by ANKOS. The PAS played an important part not only in establishing and defining the workflow of the DEG, but also in creating an archive of both the e-resources submitted to the consortium and the applicant publishers/agents submitting these resources. This article outlines the process that started with the foundation of the DEG through the formation of the PAS as well as the present setup of the system. It is also hoped that this case study will have a positive contribution to the processes being followed by the persons and the groups engaged in similar activities.pre-prin

A retrospective comparison of allogeneic peripheral blood stem cell and bone marrow transplantation results from a single center: A focus on the incidence of graft-vs.-host disease and relapse

To detect the effect of the stem cell source, allogeneic peripheral blood stem cell transplantations (alloPBSCTs) performed between 1995 and 1997 from human leukocyte antigen (HLA)-identical siblings in 40 patients with acute and chronic hematological disorders were compared with a historical group of 40 patients with similar variables who had received allogeneic bone marrow transplants (alloBMTs) between 1993 and 1995. Patients in both groups were identical except that both the recipient and the donor ages were, on average, higher in the alloPBSCT group (26 vs. 36 [p = 0.005] and 27 vs. 32 [p = 0.024], respectively). Patients received similar therapy excluding posttransplant granulocyte colony-stimulating factor administration (97% in alloBMT vs. 12.5% in alloPBSCT). The median time to reach neutrophil counts >0.5×109/L and platelet counts >20×109/L was 13 and 14 days, respectively, in patients receiving alloPBSCTs compared with 19 and 27 days in patients receiving alloBMTs (p = 0.0014 and p = 0.0002). The alloPBSCT group required similar transfusions of red blood cells or platelets. The incidence of grade II-IV acute graft-vs.-host disease (aGVHD) was similar in both groups. However, chronic GVHD (cGVHD) of all grades developed in 78.1% of patients in the alloPBSCT group after a median follow-up period of 12.5 (range 0.5-34) months. In alloBMT recipients, cGVHD of all grades developed in 21.4% after a median follow-up period of 38 (range 0.5-62) months (p = 0.00001). Day 100 transplant-related mortality was also similar: 20% (8 of 40) in the alloBMT patients and 17.5% (7 of 40) in the alloPBSCT group. Although not statistically significant, a relatively higher relapse rate occurred in the alloBMT group (21.4 vs. 10.7%). The estimated disease-free survival in month 24 was 51.3% for alloBMT and 54.6% for alloPBSCT, and the estimated overall survival in month 24 was 56.1% for alloBMT and 64.6% for alloPBSCT. In conclusion, this retrospective comparison suggests that alloPBSCT from HLA-identical donors is associated with faster engraftment, fewer transfusions, and no greater incidence of aGVHD, but a high incidence of cGVHD