Indentation of thin elastic films glued to rigid substrate: Asymptotic solutions and effects of adhesion

Indentation of a thin elastic film attached through an interlayer to a rigid support is studied. Because the common interpretations of depth-sensing indentation tests are not applicable to such structured coatings, usually various approximating functions are employed to take into account influence of the interlayer. Contrary to the common approaches, a strict mathematical approach is applied here to study the problems under consideration assuming that the thickness of the two-layer structure is much less than characteristic dimension of the region of contact between the indenter and the coating. A simple derivation of asymptotic relations for displacements and stresses is presented. It is shown that often the leading term approximation to the non-adhesive contact problems is equivalent to contact problem for a Winkler-Fuss elastic foundation with an effective elastic constant. Because the contact between the indenter and the film at nanoscale may be greatly affected by adhesion, the adhesive problem for these bilayer coatings is studied in the framework of the JKR (Johnson, Kendall, and Roberts) theory of adhesion. Assuming the indenter shape near the tip has some deviation from its nominal shape and using the leading term approximation of the layered coatings, the explicit expressions are derived for the values of the pull-off force and for the corresponding critical contact radius of adhesive contact region

Peningkatan Aktivitas Belajar Peserta Didik dengan Menggunakan Metode Eksperimen pada Pelajaran Ipakelas IV Sdn

The problem in this research is an attempt to improve the learners' learning activities by using experimental method in natural science subjects at the fourth grade students in the Elementary School 11 Sebuduh Kembayan Sanggau. This research method is descriptive, in the Classroom Action Research, and the nature of this research is qualitative research, the research subjects are teacher and fourth grade students in the Elementary School 11 Sebuduh Kembayan Sanggau which consisted of 12 people in whole. The techniques used in this research were the technique of direct observation, documentary technique, and data collection tool were used as observation guidelines. The result based on observation by using experimental method had improved can learning activity of students. This shows that the hypothesis that stated the application of the experimental method in natural science lessons at the fourth grade students in the Elementary School 11 Sebuduh Kembayan Sanggau can improve learners' learning activities, accepted

Learning Module on Electric Motors Modeling, Control, and Testing (LM-EMMCT)

The objective of this paper is to develop and integrate a learning module on Electric Motors Modeling, Control and Testing (EMMCT) into the Electrical Engineering Technology (EET) and Mechanical Engineering Technology (MET) programs. Preparing future engineers to work in highly automated production requires proper education and training in mechatronics theory and applications. Although Engineering Technology programs at various universities offer various courses related to the controls, electrical motors, and automation, they are not including the same methods when it comes to the selection of appropriate electrical motor for a specific application in mechatronic system. MET student do have exposure to the electrical systems in the various courses that are offered at their lower division level courses. However, these methods have to be further emphasized and applied in the upper level courses as well. This paper will present one such application and a learning module that is focused on the Electric Motors Modeling, Control and Testing (EMMCT). This module can be integrated in various controls, mechatronics, robotics, senior design and capstone courses

In-plane static response of dry-joint masonry arch-pier structures

The majority of historical masonry structures include arches and vaults, constructed with or without (dry-joint) any mortar. This paper focuses on dry-joint masonry, because it is common all around the world among architectural heritage. Furthermore, even if there was a mortar in the original construction, it typically suffers from deterioration over its lifetime, often causing total loss of mortar in many of the joints. Due to large horizontal thrust that can be produced, depending on their geometry, arches are typically supported by heavy buttresses. These structures tend to be difficult to model due to their nonlinear nature and inherent discontinuity, which makes it challenging to evaluate their stability. In that context, it is necessary to have realistic numerical models to better diagnose their structural behaviour in a seismic event and, ultimately, to perform only necessary and beneficial interventions. The main goal of this paper is to assess the seismic performance of various dry-joint arch forms with different masonry pier types (i.e. monolithic and regularly coursed) subjected to incrementally increasing lateral loads proportional to the mass (pushover). To achieve this goal, a parametric study is performed on arch curvature and pier morphology. Moreover, the influence of steel tie-rod reinforcement is also examined on the proposed masonry models. These complex masonry arch systems can be simulated with discrete element modeling (DEM) approach. In this research, a commercial three-dimensional discrete element code, 3DEC, is used; in which masonry units are modeled as distinct blocks with zero tensile strength at their joints. The results reveal that pointed arches provide better seismic resistance than the circular arch form. Furthermore, implemented steel tie-rods yield significant increase in stability for the arch-pier structures, which is quantified on different arch curvatures.- (undefined

Delivery of Hands-On Technical Courses Through Real-Time Distance Learning

It is generally believed that it is too challenging to deliver technical laboratory courses using distance learning technologies. The focus of this research was to develop strategies that may be used to address these challenges. A research team composed of faculty from several universities and community colleges explored what might be needed to make these types of technical laboratory course instruction possible using distance learning technologies. The team explored delivering a microcontroller embedded systems design course through audio-visual distance learning technologies. The team\u27s research and development activities are discussed. These include focuses on the technical training equipment that had to be designed to support the course\u27s microcontroller technologies curriculum and laboratory modules, instructional support videos, and the design of an electronic server system to support this instruction. Also discussed will be the findings from the faculty of other colleges and universities who received professional development training from the research team on teaching microcontroller technology courses using distance learning technologies

The Combined Contribution of Fear and Perceived Danger of COVID-19 and Metacognitions to Anxiety Levels during the COVID-19 Pandemic.

Despite a wide base of research suggesting a major role for dysfunctional metacognitions in contributing to anxiety, their role in explaining psychological distress in the context of the COVID-19 pandemic remains unclear. In this study we investigated whether metacognitions would predict anxiety, while controlling for fear and perceived danger of COVID-19. A total of 862 individuals were included in this study. Participants completed sociodemographic questions, emotional state questions relating to COVID-19, the Metacognitions Questionnaire-30, and the Generalized Anxiety Disorder-7. Results showed that both negative beliefs about thoughts concerning uncontrollability and danger, and cognitive self-consciousness were significant predictors of anxiety beyond the fear and perceived danger of COVID-19. Future studies involving clinical populations are needed to investigate the longer-term impact of metacognitions in the maintenance and exacerbation of anxiety associated with the fear and perceived danger of COVID-19

Effects of Beta Vinasse Supplementation on Performance, Meat Quality and Ilio-Caecal Microflora in Quail Rations

The aim of this study was to evaluate the effects of Beta (?)-vinasse supplementation on the live weight (LW), live weight gain (LWG), feed intake (FI), feed conversion ratio (FCR), carcass yield, meat quality, and ilio-caecal bacteriological flora of quails. A total of 240 5-d-old Japanese (Coturnix coturnix Japonica) quails, including both males and females, were divided into 3 groups 80 quails and treated as follow: a control group (1) with 0 g ?-vinasse/ kg ration; (2) 15 g/kg ?-vinasse and (3) 30 g/kg ?-vinasse. The study lasted for 6 weeks. At the end of the experiment, supplementation with ?-vinasse did not have a significant effect on FI and FCR. Dietary supplementation with 30 g/ kg ?-vinasse significantly (P < 0.05) increased LW (21 d)and LWG (5 to 21 d). The dietary treatment of quails with different levels of ?-vinasse did not affect hot carcass weight, cold carcass weights, hot and cold carcass yields, and breast and thigh pH.The lightness (L*) and yellowness (b*) of breast values were significantly (P<0.05) increased by 30 g/kg supplementation. Different levels of ?-vinasse significantly increased Lactobacillus spp. in faeces. As a result, it was concluded that ?-vinasse (by-product obtained from molasses) can be used in quail diets as an alternative feed source that will meet the nutritional needs of the animal and have positive effects on the digestive system, especially on the intestinal health (an increase in Lactobacillus spp. counts). © 2023, Derya Yesilbag YeşilbağThe authors thank Integro for supplying the feed additive supplement

Effect of Dietary Oregano and Rosemary Essential Oil Supplementation on Growth Performance and Cecal Microbiota of Broilers

In this study, the effect of dietary supplementation of oregano and rosemary essential oils (EO) on growth performance and cecal microbiota of broilers were investigated. A total of 450 1-d-old male Ross-308 broilers were divided into 5-experimental groups (10 replicates of 9 chickens): a Control (C), fed a basal diet; four treatments, which received a basal diet supplemented with oregano and rosemary EOs individually (O, 300 mg/kg oregano EO; R, 300 mg/kg rosemary EO) and combined (OR1, 150 mg/kg oregano EO + 150 mg/kg rosemary EO; OR2, 200 mg/kg oregano EO + 200 mg/kg rosemary EO). Body weight (BW), feed intake (FI), body weight gain (BWG), feed conver-sion ratio (FCR), and cecal microbiota (coliforms, clostridia and lactobacilli) were determined weekly, and at 42 d, re-spectively. BW in R (p < 0.05) and OR2 (p < 0.001), and BWG and FCR in OR2 (p < 0.05) were significantly higher than C at 42 d, despite no difference in FI in any group during experimental period. Counts of cecal coliforms (p < 0.001) and clostridia (p < 0.01) decreased, and lactobacilli (p < 0.001) increased substantially between C and treatment groups. Results indicated that combined oregano and rosemary EO (200 mg/kg ea) supplementation significantly increased BW and BWG, improved FCR in 1-42 d, lowered coliform and clostridial, and increased lactobacilli counts suggesting a beneficial shift in cecal microbiota.Bursa Uludag Uni-versity Scientific Research Unit Grant [HDP (V) -2014/45]ACKNOWLEDGEMENT This study was funded by the Bursa Uludag Uni-versity Scientific Research Unit Grant, Project No: HDP (V) -2014/45

Expressed Willingness of STEM Teachers to Teach Engineering

Teaching engineering at the middle and high school levels has been a topic of discussion among scholars regarding the challenges it creates. One of the most critical challenges at the school level is identifying qualified teaching staff to lead engineering courses. The present study explored teachers’ willingness to lead an engineering course and the reasons behind their willingness or unwillingness to do so. The study involved 434 participants, who were enrolled in a STEM professional development program and were diverse regarding their teaching subjects, the grade levels they taught, and the locations of their schools in Turkey. In this mixed-methods study, researchers collected data at the beginning of an online professional development program. Quantitative data were analyzed descriptively, while qualitative data were analyzed with a data-driven codebook. Almost two-thirds of the participants were keen to teach an engineering course, yet differences were observed according to the subjects they taught and their professional backgrounds. Most of the mathematics teachers, the group with the highest percentage of willingness, seemed to have a holistic approach towards engineering, with half emphasizing collaboration between teachers and engineers. The study provided further insights into how initial teacher training and continuous professional development programs can be structured based on teacher expectations and needs

Getting ready for REDD+: recognition and donor-country project development dynamics in Central Africa

REDD+ (Reducing Emissions, Deforestation and forest Degradation+) is a United Nations Framework Convention for Climate Change (UNFCCC) process through which governments reduce the impacts of climate change through forest conservation in a results-based payments scheme. Distinct from international negotiations about the REDD+ framework under the UNFCCC, there are also REDD+ projects that help governments to set up the institutional architecture, plans and strategies to implement REDD+. These capacity-building projects, in the first phase of 'REDD+ readiness', involve negotiations among national and international actors in which recognition and authority claims are used by participants to influence project-level negotiations. This study analyses the project development negotiations in a World Bank-led REDD+ capacity building regional project, involving six Central African countries between 2008 and 2011. It explores how the project created a 'negotiation table' constituted of national and regional institutions recognised by the donors and governments, and how this political space, influenced by global, regional and national political agendas led to 'instances' of recognition and misrecognition – in which some negotiating parties' claims of representation were acknowledge and affirmed, while others' claims were not. Focusing on Cameroon and Gabon, this article analyses how negotiations shaped full participation by Cameroon and only partial engagement by Gabon