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Smart packaging is an emerging technology that has a great potential in solving conventional food packaging problems and in meeting the evolving packaged vegetables market needs. The advantages of using such a system lies in extending the shelf life of products, ensuring the safety and the compliance of these packages while reducing the food waste; hence, lessening the negative environmental impacts. Many new concepts were developed to serve this purpose, especially in the meat and fish industry with less focus on fruits and vegetables. However, making use of these evolving technologies in packaging of vegetables will yield in many positive outcomes. In this review, we discuss the new technologies and approaches used, or have the potential to be used, in smart packaging of vegetables. We describe the technical aspects and the commercial applications of the techniques used to monitor the quality and the freshness of vegetables. Factors affecting the freshness and the spoilage of vegetables are summarized. Then, some of the technologies used in smart packaging such as sensors, indicators, and data carriers that are integrated with sensors, to monitor and provide a dynamic output about the quality and safety of the packaged produce are discussed. Comparison between various intelligent systems is provided followed by a brief review of active packaging systems. Finally, challenges, legal aspects, and limitations facing this smart packaging industry are discussed together with outlook and future improvements.

Flow and heat transfer dynamics are considered quite complex phenomenon in different enclosures. Heat transport mechanism and its improvement due to the presence of nanoscale particles is vital topic of research. Owing to the widespread importance of free convection through fluids with nanoparticle in various configuration and constraint, we have addressed in this article the natural convection nanofluid flow in a hexagon shaped enclosure with heated cylinder. Simulation has been performed in the influence of porous medium and inclined magnetic field. The physical model is translated in terms of differential systems. For solutions purpose, the finite element method is utilized. The quantities of interest include the fluid flow and heat transfer aspects. The obtained results against flow controlling parameters are offered by means of contour plots and line graphs. It is noticed that the at lower Darcy number the heat transfer rates has diminishing behavior because of the higher porosity of medium. At higher Hartman number the velocity profile tends to decrease due to resistive nature of Lorentz forces. At maximum radius of heat source, the Nusselt number and velocity profile has higher values.

Cement manufacturing is currently responsible for one of the highest levels of carbon dioxide (CO2) emissions and energy consumption in construction industry. Thus, the use of sustainable binder materials instead of cement has become a worldwide issue. Previous studies have shown that polymers are a reliable and sustainable alternative to cement in construction, while polymer concretes (PCs) are seen as the biggest alternative to conventional cement concretes in the long term. In this study, the main objective is to investigate the effects of resins, which are used as binder components in polymer concrete, on the mechanical properties of the PCs. To achieve this, ten different orthophthalic unsaturated polyester resins (OUPR) that are commonly used in construction industry are considered, and fresh concrete tests and hardened concrete tests are performed on deck plates prepared with these resins. Based on the analysis results, each resin is given a performance index. The experimental results indicate that the type of resin has a significant impact on mechanical properties of polymer concrete.

While railway vehicles are moving, a sudden change of superstructure stiffness in crossings at the starting and ending points of tunnels or bridges leads to undesired vibrations both on the track structure and in the vehicle. In this paper, simulations are performed by using a one-dimensional train-track coupled dynamic model under the condition of a light rail vehicle passed through a slab superstructure line with different stiffness values as a transition zone of the railway. The actual conditions used in Istanbul transportation are taken into account in the modelling of the track and the light metro vehicle. The model of the track consists of an Euler-Bernoulli beam resting on discrete supported rail pads, which are connected as a viscoelastic foundation to a rigid ground. The vertical vibrations are analyzed by a model in which track and 16 DOF semi-vehicle models are combined, including a dynamic wheel-rail contact. Two different controllers are designed in parallel with secondary suspensions in order to suppress vertical vibrations of the light rail vehicle resulting from the change in the dynamic conditions of the superstructure and the rail irregularity in the transition zone to increase the comfort of the passengers. For many simulation scenarios, including unloaded and fully loaded vehicle conditions at the average and maximum operational speeds, with and without track irregularities, the superiority of the fuzzy logic controller over the commonly used PID controller is shown in the time and frequency domain.

Demiryoluna bağlı titreşimler, yolcuların veya demiryolunun çevresinde yaşayan insanlar için bastırılması gereken en önemli sorunlardan biridir. Titreşimlerin öncelikle kaynakta, yani demiryolu üzerinde bastırılmaya çalışılması esastır. Bu nedenle, demiryolu üst yapı bileşenleri, titreşim yalıtımında kullanılan ray pedleri gibi çeşitli elastik elemanlar içerir. Bu çalışmada, İstanbul demiryolu trafiğinde kullanılan iki farklı demiryolu üst yapısı, demiryolu aracı çeşitli hızlarda geçerken test edildi ve tekerlek-ray etkileşiminin oluşturduğu titreşimler, yolcu konforu ve çevre ile ilgili standartlara uygun olarak karşılaştırıldı. Yayılan titreşimleri karşılaştırmak için aynı hat üzerinde yerleştirilmiş tek ve çift elastomerik tabakalara sahip demiryolu üstyapıları kullanılmıştır. Standartlara göre bazı değerlendirmeler içeren bu deneysel kıyaslama çalışmasında, bu iki demiryolu üst yapı tipinin hafif metro hatlarında titreşim yalıtımı açısından davranışları ölçüm sonuçları kullanılarak ortaya konmuştur. Sonuç olarak, üstyapıda tek katman yerine çift katmanlı elastomer kullanıldığında, hat çevresinde yaşayan insanların konfor seviyelerinde %64’e, araç içerisinde bulunan yolcuların konfor seviyelerinde ise %54 varan iyileşme gerçekleşmiştir. Ayrıca, hat çevresinde bulunan binaların güvenliği bakımından yapılan araştırmada 70 HZ’den büyük titreşimlerde anlamlı bir azalma gözlenmiş ve hatta en az 5 m mesafeye kadar konut amaçlı bina yapılabileceği sonucuna ulaşılmıştır.

The present investigation imparts the mixed convection non-linear Falkner-Skan flow and heat flux analysis of ZnO-SAE50 nanolubricant over a stationary/moving Riga-plate in presence of thermal radiation. Additionally, velocity and thermal slip boundary conditions are considered. In the current study, a micro-convection model (Patel model) is considered. The present model has great influence in significant enrichment of heat transport capability of the nanoliquids. The similar transformed nonlinear coupled governing expressions are examined numerically by the Runge-Kutta-Fehlberg integration scheme. The important outcome of the present study is that the augmented pressure gradient impedes the motion of nano-lubricant while reverse trend is attained due to the amplification of modified Hartmann number and velocity slip at the boundary. Further, the growth of thermal slip peters out the heat transfer rate from the Riga plate.

The aim of this study is to optimize the welding parameters on the mechanical properties of SAE 1021 carbon steels and Dilldur 400 (high wear resistance) and Dillimax 500 (high strength) steels joined with friction welding with Taguchi analysis method. Taguchi analysis is used as a statistical experimental design to optimize material types joined with welding parameters such as pressure of upsetting and friction rotational speed. For this purpose, the steels were joined at 1250, 1500 and 1750 rpm and at ups etting pressures of 4, 6 and 8 MPa. Tensile tests and microhardness measurements were applied to determine the mechanical properties of the joint. According to the results of analyse, it was determined that Dillidur 400-Dillimax 500 could be selected as material pair. In addition, the friction speed and upsetting pressures can be selected 1500 rpm and 6 MPa respectively. Also, according to the experimental results, maximum tensile strength was obtained at the pair of Dillidur 400- Dillimax 500 with 651 MPa. In the same material pair, the welding interface hardness value was 353 HV.