Numerical Simulations for Average Temperature Differential Stirling Engine

A second order mathematical model taken into account thermal losses for average temperature differential Stirling engine is developed. Dynamic simulation of the engine based on mathematical formulation is carried out under different operating and geometrical conditions to investigate the engine performance. The developed model is used to investigate the influence of geometrical and physical parameters on the performance of Stirling engine. Design optimization of Stirling engine is carried out. Finally optimal parameters have been determine

Changes in understory vegetation of a ponderosa pine forest in northern Arizona 30 years after a Wildfire

Wildland fires can cause shifts in understory species composition and production. Many studies have examined short-term changes in understory vegetation following a wildfire; however, very few long term studies are available. The objective of this study was to examine changes in understory (herb and shrub) species composition and production since the 1972 Rattle Burn wildfire on the Coconino National Forest near Flagstaff, Arizona. Understory species composition and production were originally sampled in 1972, 1974, and 1980 and were re-sampled during July and August of 2002 and 2003 on 30 plots in each of four sites: high severity burn, low severity burn, unburned site prescribed burned in 1977, and an unburned site. Repeated measures analysis was used to test for the effects of fire and time on species production. The effects of fire and time on species composition as well as species production were tested using Multi-Response Permutation Procedures (MRPP). A lingering effect of the Rattle Burn wildfire on the understory plant production and composition was revealed. Burned sites may have greater understory production as compared to unburned sites up to 30 years after a wildfire. However, species composition on burned sites is altered. A significant relationship between tree density and understory species composition and production was found for 1972, but no relationship was found for overstory parameters and understory species production and composition for 2003

The Effect of the Reciprocal Teaching Strategy on Improving the Reading Comprehension of Deaf Students

The purpose of this study was to  investigate the effectiveness of using the reciprocal teaching strategy on improving the reading comprehension of deaf students in Jordan. The reading comprehension was measured at the literal and inferential levels. The total number of deaf participants was  10 grade six students: 5 males and 5 females The students were selected from the Marka School for Hearing Challenges overseen by the Ministry of Education. The available study sample was divided into two groups: The experimental group consisting of 5 students 2 females and 3 males was taught using the Reciprocal Teaching Strategy and the control group consisting of 5 students  3 females and 2 males  was taught using the conventional strategy. The results showed that there was a statistically significant difference at the alpha level of .05 on the location and form of performance of deaf students on the posttest due to the teaching strategy. The group that  used the reciprocal teaching strategy with its two levels (literal and inferential) performed better than the group that used the conventional strategy. Also, the results showed no statistically significant difference due to gender at the alpha level of .05 on the location and form of performance on the posttest. Moreover,   the results revealed a significant difference at the alpha level of .05 on the location and form on the posttest due to the interaction between the teaching strategies and gender. Males and females who received the reciprocal teaching strategy performed significantly better than the participants who received the conventional method

Loblolly Pine Growth Response to Mid-rotational Treatments in an Eastern Texas Plantation

The effects of mid-rotational treatments (herbicide, prescribed burn, combination of herbicide and burn, and fertilization) on growth of loblolly pine were evaluated. Five replicates were established in a split-plot experimental design with fertilizer treatments as the whole-plot factor and competition control treatments as the sub-plot factor. Growth response was measured (as change in diameter, total height, and volume) at 8 months and again 4 years after treatments were applied. Mid-rotational treatments failed to enhance diameter, height, and volume growth of loblolly pine. However, a small positive response of diameter growth to fertilization was detected. Height growth was not significantly affected by any treatment 8 months after application date, while it was slightly negatively affected by herbicide and the combination of herbicide and prescribed burning 4 years after application of treatments. In this study, no substantial positive growth response to mid-rotational treatments was detected. However, loblolly growth response may vary from site to site based on differences in soil type, soil condition, and competition level. In addition, associated factors such as seedling quality and planting method may greatly influence loblolly growth response to mid-rotational treatments

The Relationship Between Perfectionism and Goal Orientation Among Gifted Students in the King Abdullah II School of Excellence

This study aimed to find out the relationship between Perfectionism and Goal Orientation among Gifted Students in the King Abdullah II School of Excellence. It also aimed at finding out if the relationship between Perfectionism and Goal Orientation is different according to the level of education and gender. To achieve the objectives of the study, Perfectionism and Goal Orientation scales were developed by the researchers. The sample of the study consisted of 184 students at seventh and eighth grades in the King Abdullah II School of Excellence. They were randomly stratified selected from the students population. The results of the study indicated that the level of Perfectionism among the gifted students was high, and the study showed that the level of the types of goal orientation was high, specifically Mastery goal oriented. The results also indicated there was no statistically significant difference at the significance level (α=0.05) in the strength of the correlation between Perfectionism and the types of goal orientation due to the level of education. The results also indicated there was no statistically significant difference at the significance level (α=0.05) in the strength of the correlation between Perfectionism and the types of Goal Orientation due to gender

The influence of length of implant on primary stability: an in vitro study using resonance frequency analysis

Primary stabilityis not sufficientin less contact area between the implant and bone, the healing process because will be disrupted due to micro-motions and fibrous tissue affects osseointegration. We implemented an in vitro experimental study of total 135 XiVE® implants were inserted in 22.5 bovine cow ribs with bone quality similar to a type IV human bone. Each rib end received a group of three different implant lengths, which were 8mm, 13mm and 15mm and had the same diameter 3.8mm. Immediately after the implant placement, its primary stability was measured using Osstell Mentor equipment. ANOVA Tukey’s honest to test the significant difference were performed for data analysis between the resonance measures of the different lengths of implants. Statistical significance was assessed at a level P< 0.05. A total of 45 implants were inserted for each length at cortical bone level. A significant difference between the three groups in favor of implant with 15mm length group (P = 0.000). Increasing dental implant length is considered to play a fundamental role in increasing dental implant primary stability, even in poor bone quality, through controlling the bone preparation process

‘This is my life style, Arabic and English’: students’ attitudes to (trans)languaging in a bilingual university context

© 2018 Informa UK Limited, trading as Taylor & Francis Group. Translanguaging is defined by Canagarajah as ‘the ability of multilingual speakers to shuttle between languages, treating the diverse languages that form their repertoire as an integrated system’. University students in our own working context have grown up in a multilingual society and study courses in both Arabic (their first language) and English (the main language of instruction). They encounter new concepts and perspectives in both languages; and when they graduate, the intention is that they will be academically and professionally prepared to use both languages in their future career. However, it is not clear how they ‘make sense of their bilingual worlds’ or whether they feel able to ‘shuttle between languages’ in a way appropriate to their future working context. The study described here focuses on two students interacting around course-related content with a peer, with a simulated workplace audience and with a research interviewer. In this paper we focus on the participants’ awareness of and attitudes towards Arabic, English and translanguaging both while engaged in the tasks and in reflection afterwards, revealing contrasting and sometimes contradictory attitudes to the deployment of their communicative repertoire

Spatial Autocorrelation and Pseudoreplication in Fire Ecology

Fire ecologists face many challenges regarding the statistical analyses of their studies. Hurlbert (1984) brought the problem of pseudoreplication to the scientific community’s attention in the mid 1980’s. Now, there is a new issue in the form of spatial autocorrelation. Spatial autocorrelation, if present, violates the traditional statistical assumption of observational independence. What, if anything, can the fire ecology community do about this new problem? An understanding of spatial autocorrelation, and knowledge of available methods used to reduce the effect of spatial autocorrelation and pseudoreplication will greatly assist fire ecology researchers

Series Solution of the Multispecies Lotka-Volterra Equations by Means of the Homotopy Analysis Method

The time evolution of the multispecies Lotka-Volterra system is investigated by the homotopy analysis method (HAM). The continuous solution for the nonlinear system is given, which provides a convenient and straightforward approach to calculate the dynamics of the system. The HAM continuous solution generated by polynomial base functions is of comparable accuracy to the purely numerical fourth-order Runge-Kutta method. The convergence theorem for the three-dimensional case is also given

E-Government Web Accessibility: WCAG 1.0 versus WCAG 2.0 Compliance

Most e-governments have traditionally used version 1.0 of the Web Content Accessibility Guidelines (WCAG) as a basis to ensure that their websites are accessible by people with disabilities. This was reflected in their design guidelines, accessibility evaluations, policy-making and legislations. Recently, WCAG 2.0 emerged as an ISO/IEC International accessibility standard that has been recommended for adoption by the W3C WAI. This paper seeks to examine if there is a need for e-governments to reassess their web accessibility conformance, in light of the latest WCAG 2.0 standard. A case study related to the 21 Dubai e-government websites is presented whereby accessibility is evaluated based on the WCAG 1.0 and WCAG 2.0 guidelines and using automated accessibility testing tools. We found that WCAG 2.0 conformance testing identified some notable accessibility issues that were not revealed by WCAG 1.0 conformance testing. Hence we recommend that egovernments should develop and update their web content and accessibility policies to conform to the latest WCAG 2.0 guidelines and success criteria. Additional implications for practice and academic research are also provided