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The impact of COVID-19 pandemic on tourism employees: Was it the last straw?
No full textTourism, as one of the most vulnerable industries, has survived numerous global crises with substantial negative impact on economies, communities, businesses, and individuals. Despite the circumvention of the industry after those experiences of mild and severe crises, COVID-19 pandemic has been the most serious case with deep global impact in every corner of the world leading to the explosion of academic research on a plethora of pandemic aspects. However, research offering insights on tourism and hospitality employees' experiences, is scarce in the relevant literature in spite of the chronic problems of employee retention, qualified and long-term labor force. Therefore, the aim of this study addresses at examining the experiences of hotel employees in T & uuml;rkiye during and after COVID-19, which caused sudden and deep changes in the lives following the severe decline in tourism employment and economic problems it ushered in. The data was collected through in-depth interviews with 21 individuals who formerly worked in city or resort hotels at various positions and departments. Two sensemaking perspectives were integrated to find out the consequences of the pandemic leading to the causes and factors to end working in the industry. Study findings offer important insights into pandemic-related dynamics and could support the development of effective tourism policy and practices leading to improve crisis management efforts in the tourism and hospitality industry
A heat flux model for nucleate boiling on micro-cavity surfaces
No full textThis study investigates the influence of spacing (500-1000 mu m), cavity size (100-300 mu m), and subcooling (0-10 K) on nucleate pool boiling heat transfer performance using selectively micro-caved copper surfaces. The cavity spacings (S-p approximate to S/D-b <0.4 for saturated and S/D-b <0.5 for subcooled conditions) were optimized to minimize bubble interference, while cavity sizes were chosen based on active nucleation ranges derived from theoretical calculations. Micro-drilled surfaces generally demonstrated up to 69% higher critical heat flux (CHF) and significantly improved heat transfer coefficients (HTC) up to 10.1 x 104 W/m2K compared to plain surfaces. Subcooling enhanced the condensation rates of departing bubbles near the heating surface and delayed CHF, resulting in up to 46% higher CHF compared to saturated condition and steeper boiling curves. The larger spacing (1000 mu m) reduced thermal and hydrodynamic interactions, facilitating stable bubble detachment and efficient surface rewetting. In contrast, smaller cavities (100 mu m) increased the frequency of bubble departure and HTCs, while larger cavities (300 mu m) led to premature coalescence and persistent vapor layers, reducing heat transfer performance and approximating the results of plain surfaces with slightly smaller superheats. High-speed imaging provided detailed insights into isolated bubble departure dynamics and validated empirical models, while also verifying the predictive accuracy of the proposed model. The proposed heat flux model exhibits quite satisfactory reliability, with CHF predictions for micro-drilled surfaces within +/- 15% error. These findings highlight the complex interplay of geometric and thermal parameters in boiling heat transfer and offer a robust framework for optimizing surface designs and operating conditions in high-flux boiling applications.Istanbul Teknik Üniversites
Inventory routing with heterogeneous vehicles and hazardous material backhauling
No full textEfficient coordination of distribution and backhauling is a critical challenge for many industries. This paper is motivated by a real-world case study at Hydro-Qu & eacute;bec, a large-scale utility company in North America, and introduces an inventory routing problem that integrates inventory management and vehicle routing under several operational constraints. The problem involves distributing multiple commodities to customer sites while backhauling hazardous materials to depots. The objective is to minimize delivery, collection, and inventory holding costs using a fleet of capacitated heterogeneous vehicles, while ensuring that hazardous materials are transported separately from regular delivery commodities. In each period, a customer's delivery and back-hauling can be split and satisfied by multiple vehicles. We propose a mathematical formulation, introduce valid inequalities, and solve the resulting model using a branch-and-cut algorithm. To tackle large-size instances, a two-phase decomposition matheuristic is developed. To highlight the value of split delivery and backhauling, we compare the solutions from our model with those when split delivery is prohibited and when backhauling is optimized independently. In addition, we investigate the order-up-to level policy and the case when stockout is allowed. An extensive numerical study is conducted on synthetic instances to evaluate the performance of the models and solution approaches. The heuristic algorithm solves the synthetic instances in less than two hours with an average optimality gap of less than 2%. Finally, a case study is conducted on the Hydro-Qu & eacute;bec network to demonstrate the real-world applicability of the model and quantify the benefits to the company. Our proposed model reduces the total routing costs by 21 % compared to the case where backhauling is not integrated and split delivery is not allowed.Publisher versio
Longitudinal relations between early prosocial behaviors toward parents and later prosocial and aggressive behaviors in Turkish early adolescents
No full textBecause Turkish early adolescents learn and practice many essential prosocial behaviors (i.e., helping, sharing) within the family context, it is important to examine whether early adolescents' prosocial behaviors toward parents at age 10 (Time 1) were related to their later prosocial and aggressive behaviors at age 13 (Time 3) via perceived parental psychological control at age 12 (Time 2). Participants were 355 early adolescents (M-age = 9.89 years, SD = 0.32; 51% girls) from T & uuml;rkiye at Time 1. Early adolescents reported their prosocial behaviors toward mothers and fathers at age 10, perceived maternal and paternal psychological control at age 12, and prosocial and aggressive behaviors at age 13. Mediation analyses showed that early adolescents' greater prosocial behaviors toward parents were significantly related to less perceived psychological control, which, in turn, was related to less altruistic and reactive prosocial behaviors but related to greater reactive and proactive aggressive behaviors. Importantly, these associations were robust across boys and girls, and all indirect effects were statistically significant. The findings inform theories that suggest interindividual stability in youth's levels of prosocial behavior and reciprocal relations between parenting and youth behaviors but extend such findings to a non-Western, relatively collectivist-oriented, predominantly Muslim culture.TÜBİTA