The objective of this study is to improve the efficiency of emergency departments (ED) by decreasing the overcrowding and patient waiting times. A hybrid methodology composed of a combination of lean techniques and discrete event simulation models was followed. Value stream mapping (VSM) was used as a lean technique with the aid of the ED staff. After obtaining the future state map of the ED, two discrete event simulation models were developed. By reviewing each triage process, the suggestions and proposed changes were incorporated into the future state map. There were five active process changes, each reducing lead and value added times by different amount. The usage of lean techniques can effectively reduce patient lead and value added times inside the ED, and when combined with discrete event simulation modeling, possible outcomes of the lean techniques can be tested and verified. This study contributed to the potential of lean techniques combined with simulation models in the case of reducing ED overcrowding and patient waiting times.

This study investigates the effects of post-curing temperatures on the tensile properties of hybrid basalt-jute-glass-carbon fiber-reinforced polymers (FRPs). Composite specimens were post-cured at 60 °C and 100 °C for 60 min, and their tensile behavior was assessed using a servo-hydraulic testing machine. Numerical simulations using the Abaqus software V6.14 were also conducted to compare experimental and computational results. The findings indicate that post-curing heat treatment enhances ductility due to increased polymer cross-linking, but excessive heat treatment at 100 °C negatively impacts elongation at fracture. The results revealed that specimens post-cured at 60 °C exhibited the optimal balance between strength and ductility, with increased elongation and moderate tensile strength. However, at 100 °C, while tensile strength improved in some cases, a significant decrease in elasticity and an increased risk of brittleness were observed, suggesting that extreme heat treatment may degrade polymer integrity. Natural fiber composites, particularly jute-based samples, outperformed synthetic composites in terms of elongation and overall mechanical stability. The numerical simulations provided further insights but showed discrepancies with experimental results, mainly due to fiber property variations and fabric waviness, underscoring the challenges of accurately modeling woven composites. The study highlights the importance of controlled post-curing temperatures in optimizing the mechanical performance of FRP composites, with 60 °C identified as the most effective condition for achieving a favorable balance between tensile strength, flexibility, and material durability. These findings offer valuable insights for material scientists and engineers working on the development of high-performance composite materials for structural and industrial applications.

Üretim ortamının dinamik yapısı planlanmayı güçleştirmektedir. Gelişen teknoloji ile birlikte dijital ikiz, üretim süreçlerine etkin çözümler sunabilmek amacıyla artan bir şekilde kullanılmaya başlanmıştır. Bu çalışmada, kitlesel imalat sistemlerinde üretimin planlanması amacıyla simülasyon temelli dijital ikiz ile bir çizelgeleme modeli önerilmiştir. Böylece çözümü zor olan üretim çizelgeleme problemlerine yenilikçi ve uygulanabilir bir yaklaşım önerilmesi amaçlanmıştır. Üretim hattının bir kopyası olan ve gerçek zamanlı veri ile entegre edilmiş model, hammadde stokları, üretim süreleri, hazırlık süreleri, vardiya değişimleri ve mola zamanları, bakım ve arıza kaynaklı duruşlar gibi birçok üretim parametresini dikkate almaktadır. Önerilen yaklaşımın gerçek hayat uygulamasını göstermek amacıyla, kumaş imalatı yapan bir tekstil işletmesinde üretim hattının dijital ikizi oluşturulmuş ve örgü makineleri için işlerin sıraları belirlenmiştir. Model ile her bir siparişin zamanında tamamlanma olasılığı belirlenerek risk analizi yapılabilmektedir. Böylece yüksek riske sahip siparişler yeniden çizelgelenerek olası gecikmelerden kaçınılabilmektedir.