Browsing by Subject "Experiment"

Now showing 1 - 5 of 5

Open Access
Clustering of Janus particles in an optical potential driven by hydrodynamic fluxes
(Digital Library, 2021-08-01) Callegari, Agnese; Mousavi, S. Masoumeh; Kasianiuk, Iryna; Kasyanyuk, Denis; Velu, Sabareesh K. P.; Biancofiore, Luca; Volpe, Giovanni
Self-organisation is driven by the interactions between the individual components of a system mediated by the environment, and is one of the most important strategies used by many biological systems to develop complex and functional structures. Furthermore, biologically-inspired self-organisation offers opportunities to develop the next generation of materials and devices for electronics, photonics and nanotechnology. In this work, we demonstrate experimentally that a system of Janus particles (silica microspheres half-coated with gold) aggregates into clusters in the presence of a Gaussian optical potential and disaggregates when the optical potential is switched off. We show that the underlying mechanism is the existence of a hydrodynamic flow induced by a temperature gradient generated by the light absorption at the metallic patches on the Janus particles. We also perform simulations, which agree well with the experiments and whose results permit us to clarify the underlying mechanism. The possibility of hydrodynamic-flux-induced reversible clustering may have applications in the fields of drug delivery, cargo transport, bioremediation and biopatterning.
Open Access
Message framing effects on individuals' social distancing and helping behavior during the COVID-19 pandemic
(Frontiers Media S.A., 2021-03-22) Ceylan, Melis; Hayran, C.
This research responds to urgent calls to fill knowledge gaps on COVID-19 (new coronavirus) in communicating social distancing messages to the public in the most convincing ways. The authors explore the effectiveness of framing social distancing messages around prosocial vs. self-interested appeals in driving message compliance and helping behavior. The results show that when a message emphasizes benefits for everyone in society, rather than solely for the individual, citizens find the message more persuasive to engage in social distancing, and also more motivating to help others. The results further demonstrate that the proposed effects are higher for individuals who have a lower locus of control and lower fear of coronavirus as prosocial messages lead them to feel a joint responsibility in protecting from the pandemic. Theoretical and practical implications of the results are discussed.
Open Access
Negative refraction and superlens behavior in a two-dimensional photonic crystal
(American Physical Society, 2005) Moussa, R.; Foteinopoulou, S.; Zhang, L.; Tuttle, G.; Guven, K.; Özbay, Ekmel; Soukoulis, C. M.
We experimentally and theoretically studied a left-handed structure based on a photonic crystal (PC) with a negative refractive index. The structure consists of triangular array of rectangular dielectric bars with dielectric constant 9.61. Experimental and theoretical results demonstrate the negative refraction and the superlensing phenomena in the microwave regime. The results show high transmission for our structure for a wide range of incident angles. Furthermore, surface termination within a specific cut of the structure excite surface waves at the interface between air and PC and allow the reconstruction of evanescent waves for a better focus and better transmission. The normalized average field intensity calculated in both the source and image planes shows almost the same full width at half maximum for the source and the focused beam.
Open Access
Newsvendor decisions under incomplete information: behavioural experiments on information uncertainty
(Oxford University Press, 2024-04-25) Kocabıyıkoğlu, Ayşe; Önkal, D.; Göğüş, Celile Itır; Gönül, M. Sinan
Accepted by: Aris Syntetos Exploring the effects of information uncertainty presents an extensive challenge to decision makers. This study presents a set of behavioural experiments that examine the impact of incomplete information on newsvendor decisions. Findings show that orders deviate from normative benchmarks when decision makers have incomplete information and this tendency is stronger when the demand distribution is not known. Comparison of decisions under incomplete information against behavioural benchmarks with full and no information reveal that the availability of price and cost information brings decisions significantly closer to normative levels when the underlying demand distribution is unknown. On the opposite spectrum, when demand information is available, not knowing price or cost does not lead to worse decisions. Analysing newsvendor profits under various information conditions, we find participants capture at most 84% of earnings they could have generated if they ordered the normative quantity in high-profit margin settings; the corresponding percentage is 51% in low-profit margin settings. Our results suggest decreasing uncertainty on the demand distribution has a consistently positive impact on profits, while uncertainty about cost or price does not have a significant effect. Implications of our findings on the differential impact of incomplete information are discussed via the backdrop of the prevalence of newsvendor framework across a wide range of operational decisions.
Restricted
Türkiye'nin ilk bilim merkezi: Feza Gürsey Bilim Merkezi
(Bilkent University, 2023) Okay, Duru; Çınar, Gizem; Ergün, Yağmur Ece; Gençmazlumoğlu, Perihan
Bilim merkezleri, toplumun her kesiminden insanı bilimle buluşturmayı amaçlayan kurumlardır. Bilim merkezlerinde pek çok sergi ve deney düzeneği, gelen ziyaretçilere bu amaç doğrultusunda hizmet vermektedir. Feza Gürsey Bilim Merkezi (FGBM), Türkiye’de kurulmuş olan ilk bilim merkezidir. Merkez, 23 Nisan 1993 tarihinde Ankara Büyükşehir Belediyesi (ABB) tarafından kurulmuştur. Merkezin kuruluşundaki en etkili isim, zamanın Ankara Büyükşehir Belediye Başkanı olan Murat Karayalçın’dır. Merkezin kurulma fikri ilk kez Murat Karayalçın’ın Kanada’ya olan bir iş seyahati sonrasında gündeme gelmiştir. Kanada’da bulunan Ontario Bilim Merkezi (OCS), merkezin kuruluşunun ilham kaynağı olmuştur. Ontario Bilim Merkezi, aynı zamanda Feza Gürsey Bilim Merkezine ilk deney setlerini de sağlamıştır. Bu 48 deney seti günümüzde de ziyaretçilere açıktır. Yıllar içerisinde bilim merkezi Türkiye’de interaktif eğitimin öncülerinden olmuştur. Merkez, toplumun her kesiminden ziyaretçiye uygun olacak şekilde dizayn edilmiştir. Feza Gürsey Bilim Merkezi, Türkiye’de diğer bilim merkezlerinin de kurulmasına yardım etmiş ve etmeye devam etmektedir. Merkez, günümüzde de Ankara’nın Altındağ ilçesinde bulunan Altınpark bünyesinde faaliyet göstermektedir.