Two Dimensional Materials for Military Applications

This paper particularly focuses on 2D materials and their utilization in military applications. 2D and heterostructured 2D materials have great potential for military applications in developing energy storage devices, sensors, electronic devices, and weapon systems. Advanced 2D material-based sensors and detectors provide high awareness and significant opportunities to attain correct data required for planning, optimization, and decision-making, which are the main factors in the command and control processes in the military operations. High capacity sensors and detectors or energy storage can be developed not only by using 2D materials such as graphene, hexagonal boron nitride (hBN), MoS2, MoSe2, MXenes; but also by combining 2D materials to obtain heterostructures. Phototransistors, flexible thin-film transistors, IR detectors, electrodes for batteries, organic photovoltaic cells, and organic light-emitting diodes have been being developed from the 2D materials for devices that are used in weapon systems, chemical-biological warfare sensors, and detection systems. Therefore, the utilization of 2D materials is the key factor and the future of advanced sensors, weapon systems, and energy storage devices for military applications

Studieng main working components of the gas turbines and axial flow compressor and turbine designing-analyzing with the axstream software

Bu tezde gaz türbinleri donanımları (kompresör, yanma odası ve türbin) hakkında okuyucuları bilgilendirmek, gaz türbinlerinin çalışma prensiplerini teorik ve şekiller desteğinde anlatarak zihinlerde, gaz türbinlerinin çalışma sisteminin canlanması amaçlanmıştır. Bu amaca yönelik olarak verilen teorik bilgiler bir gaz türbini firması tarafından üretimi yapılmış ve halihazırda endüstride kullanılmakta olan örnek bir gaz türbininden faydanılarak, gaz türbininin ana bölümlerini (hava giriş kısmı, kompresör, yanma odası, gaz üretici türbin, güç üretici türbin) inceleyerek, gaz türbininin uygulamadaki çalışma prensipleri anlatılmıştır. Ayrıca ikinci bölümde, AxStream adlı gaz türbini kompresör ve türbin tasarım programı ile eksenel akışlı kompresör ve türbin tasarımı yapılarak, yapılan bu tasarımın analizi ile ilk bölümün dördüncü kısmında verilen teorik bilgilerin pekiştirilmesi sağlanmaya çalışılmıştır.In this thesis, it is aimed to inform readers about gas turbine equipments (compressor, combustor and turbine), and to provide understanding of working principles of gas turbines by means of theories and diagrams. In doing so, in the process of application, the working principles of gas turbines are explained through examining the main parts of gas turbines (air inlet region, compressor, combustor, gas producer turbine, power turbine) by making use of a currently used gas turbine in industry which is produced by a gas turbine firm. In addition, with the analysis of the design, in the second part, it is intended to validate the theoretical information given in fourth chapter of the first part of the thesis through designing an axial flow compressor and turbine by using AxStream, gas turbine compressor and turbine design program

Effect of Shot Peening Parameters on Surface Properties and Corrosion Resistance of 316L Stainless Steel

The present work deals with the enhancement of the surface characteristics of stainless steel 316L as a result of shot peening treatment using ceramic balls. In accordance with our own research and information available in literature, as a result of shot peening process, the shot balls can penetrate to the surface layer (permanently depositing) and modify the mechanical performance and the corrosion resistance in the products being treated in this way. Shot peening leads to a significant change to the surface hardness and topography, and consequently, to the change in corrosion behaviour dependent on the choice of processing parameters. Therefore, in this paper, steel samples were treated using two variable parameters of peening pressure (0.3 and 0.4 MPa) and peening time (30 and 60s). In the research, the reference surface were the samples subjected to mechanical polishing. The surface morphology of the samples was investigated by scanning electron microscopy (SEM). The potentiodynamic polarization tests were performed with 1 mV/s scan rate in 0.9% NalCl solution. The improved corrosion resistance (lowest current density Icorr=0.35µA/cm2 and highest corrosion potential Ecorr=-0.164V) was obtained for specimens with longer time (60s) and higher pressure of shot peening treatment (0.4MPa). Greater changes in surface roughness were observed with an increase in peening pressure than with an increase in the processing time. The treatment of the surface with ceramic shots results in an increase in the hardness of the treated surface by more than 110% (for sample 316L/0.4/60) compared to the reference surface. Moreover, an increase in average hardness values was recorded for all surfaces after shot peening (by more than 42% relative to reference samples)

Effect of AISI H13 Steel Substrate Nitriding on AlCrN, ZrN, TiSiN, and TiCrN Multilayer PVD Coatings Wear and Friction Behaviors at a Different Temperature Level

Moving components of industrial machines and tools are subjected to wear and friction. This reduces their useful life and efficiency in running conditions, particularly at high temperatures. One of the most popular solutions is to apply an appropriate surface coating to the tribocouple’s base materials. In this study, tribometer experiments were used to evaluate the tribological performance of cathodic arc physical vapor deposited (CAPVD) AlCrN, TiSiN, CrTiN, and ZrN coatings on the gas nitrided AISI H13 tool steel to explore the effects of nitriding the steel on wear and friction behavior of these coatings at ambient and elevated temperatures. The coatings characterization is split into three main parts: mechanical, morphological, and chemical characterization. Nanoindentation has been used for mechanical characterization, thin film X-ray diffraction (XRD), and an energy-dispersive X-ray spectrometer mounted on a scanning electron microscope for chemical characterization, optical profilometer, and atomic force microscopy (AFM) for morphological characterization. Significant improvements in the adhesion qualities of the coatings to the substrate were achieved as a result of nitration. Due to this circumstance, the coatings’ load-bearing capacity and high-temperature wear resistance ratings were enhanced. The wear results showed that the AISI H13 tool steel nitriding with AlCrN and ZrN layers decreased wear rates by two to three times at 700 °C

Disappearance of Biodiversity and Future of Our Foods

“I. Uluslararası Organik Tarım ve Biyoçeşitlilik Sempozyumu 27-29 Eylül Bayburt