2,444 research outputs found
Avoiding Bending in Case of Uniaxial Tension with Electromagnetic Forming
During electromagnetic forming, excessive bending of the specimen takes place due to
high velocities and inertia. We show that the excessive bending can be prevented by
optimizing the coil geometry in case of uniaxial tension. The process is simulated with
various coil geometries, and the resulting amount of bending is compared to the case of
standard Nakajima Test. The comparison shows that the bending can be minimised to
acceptable levels to be able to call the method a decent way of determining forming limits.
The results should be verified experimentally
Characterization of In-Pipe Acoustic Wave for Water Leak Detection
This paper presents experimental observations on the characteristics of the acoustic signal propagation and attenuation inside water-filled pipes. An acoustic source (exciter) is mounted on the internal pipe wall, at a fixed location, and produces a tonal sound to simulate a leak noise with controlled frequency and amplitude, under different flow conditions. A hydrophone is aligned with the pipe centerline and can be re-positioned to capture the acoustic signal at different locations. Results showed that the wave attenuation depends on the source frequency and the line pressure. High frequency signals get attenuated more with increasing distance from the source. The optimum location to place the hydrophone for capturing the acoustic signal is not at the vicinity of source location. The optimum location also depends on the frequency and line pressure. It was also observed that the attenuation of the acoustic waves is higher in more flexible pipes like PVC ones.Center for Clean Water and Clean Energy at MIT and KFUP
Health Diplomacy the Adaptation of Global Health Interventions to Local Needs in sub-Saharan Africa and Thailand: Evaluating Findings from Project Accept (HPTN 043).
Study-based global health interventions, especially those that are conducted on an international or multi-site basis, frequently require site-specific adaptations in order to (1) respond to socio-cultural differences in risk determinants, (2) to make interventions more relevant to target population needs, and (3) in recognition of 'global health diplomacy' issues. We report on the adaptations development, approval and implementation process from the Project Accept voluntary counseling and testing, community mobilization and post-test support services intervention. We reviewed all relevant documentation collected during the study intervention period (e.g. monthly progress reports; bi-annual steering committee presentations) and conducted a series of semi-structured interviews with project directors and between 12 and 23 field staff at each study site in South Africa, Zimbabwe, Thailand and Tanzania during 2009. Respondents were asked to describe (1) the adaptations development and approval process and (2) the most successful site-specific adaptations from the perspective of facilitating intervention implementation. Across sites, proposed adaptations were identified by field staff and submitted to project directors for review on a formally planned basis. The cross-site intervention sub-committee then ensured fidelity to the study protocol before approval. Successfully-implemented adaptations included: intervention delivery adaptations (e.g. development of tailored counseling messages for immigrant labour groups in South Africa) political, environmental and infrastructural adaptations (e.g. use of local community centers as VCT venues in Zimbabwe); religious adaptations (e.g. dividing clients by gender in Muslim areas of Tanzania); economic adaptations (e.g. co-provision of income generating skills classes in Zimbabwe); epidemiological adaptations (e.g. provision of 'youth-friendly' services in South Africa, Zimbabwe and Tanzania), and social adaptations (e.g. modification of terminology to local dialects in Thailand: and adjustment of service delivery schedules to suit seasonal and daily work schedules across sites). Adaptation selection, development and approval during multi-site global health research studies should be a planned process that maintains fidelity to the study protocol. The successful implementation of appropriate site-specific adaptations may have important implications for intervention implementation, from both a service uptake and a global health diplomacy perspective
Waste heat recovery from adiabatic diesel engines by exhaust-driven Brayton cycles
An evaluation of Bryton Bottoming Systems (BBS) as waste heat recovery devices for future adiabatic diesel engines in heavy duty trucks is presented. Parametric studies were performed to evaluate the influence of external and internal design parameters on BBS performance. Conceptual design and trade-off studies were undertaken to estimate the optimum configuration, size, and cost of major hardware components. The potential annual fuel savings of long-haul trucks equipped with BBS were estimated. The addition of a BBS to a turbocharged, nonaftercooled adiabatic engine would improve fuel economy by as much as 12%. In comparison with an aftercooled, turbocompound engine, the BBS-equipped turbocharged engine would offer a 4.4% fuel economy advantage. If installed in tandem with an aftercooled turbocompound engine, the BBS could effect a 7.2% fuel economy improvement. The cost of a mass-produced 38 Bhp BBS is estimated at about $6460 or 170/Bhp. Technical and economic barriers that hinder the commercial introduction of bottoming systems were identified. Related studies in the area of waste heat recovery from adiabatic diesel engines and NASA-CR-168255 (Steam Rankine) and CR-168256 (Organic Rankine)
Staff experience of harassment and stalking behaviour by patients
Staff from one National Health Service (NHS) Trust in England completed an online survey (N = 590) about their experience of intrusive behaviours from patients. These experiences were categorised into either stalking or harassment and compared in terms of staff and patient characteristics, types of intrusions, and aftermath. Overall, 150 were classified as being stalked (25.4%) and 172 harassed (29.2%). There were no differences in staff characteristics between the two groups. Staff from forensic services and nursing staff were particularly susceptible to these intrusions which took many forms. Respondents perceived a range of causes for the stalking and harassment, the most common being to gain power and control/to scare. It was rare for legal sanctions to be brought against the patient. Our findings reinforce the need for service providers to have policies supported with preventative measures, education and a robust process for addressing stalking so that these measures are embedded in practice in a way that supports staff working with patients. Furthermore, service providers should be challenged on what steps they have taken to prevent, and monitor, such behaviour
Interactive Two-Stage Stochastic fuzzy Rough Programming for Water Resources Management
This paper deals with a fuzzy programming approach for treating an interactive two-stage stochastic rough-interval water resource management. The approach has been developed by incorporating an interactive fuzzy resolution method within a rough two-stage stochastic programming framework. The approach can not only tackle dual rough intervals presented as an inexact boundary intervals that exist in the objective function and the left- and right-hand sides of the constraints that are associated with different levels of economic penalties when the promised policy targets are violated. The results indicate that a set of solutions under different feasibility degrees has been generated for planning the water resources allocation. They can help the decision makers to conduct in depth analysis of tradeoffs between economic efficiency and constraint-violation risk, as well as enable them to identify, in an interactive way, a desired compromise between satisfaction degree of the goal and feasibility of the constraints. A management example in terms of rough-intervals water resources allocation has been treated for the sake of applicability of the proposed approach
The role of social networks in students’ learning experiences
The aim of this research is to investigate the role of social networks in computer science education. The Internet shows great potential for enhancing collaboration between people and the role of social software has become increasingly relevant in recent years. This research focuses on analyzing the role that social networks play in students’ learning experiences. The construction of students’ social networks, the evolution of these networks, and their effects on the students’ learning experience in a university environment are examined
Effect of different growing nutrient solutions on Azolla pinnata productivity under Egyptian conditions
A field experiment was conducted from 24 June to 31 December, 2023 in a private farm (30° 22’ 01.0” N and 31° 36’ 26.1” E), Egypt, to test the effects of two nutrient solutions compared with farmer practice on Azolla pinnata fresh biomass, tissue-chemical constituents, tissue-NPK concentrations and the amount of water applied and its water productivity. Results showed that average fresh yields were 54.9, 44.1, and 40.9 t/ha/month respectively for nutrient solution A, solution B and farmer practice. Average Azolla pinnata fresh yield during summer season was higher than that recorded during autumn season. In Azolla's tissues, average Total Carbohydrates (TC) values were 32.3, 31.4, and 32.7%, average Total Fiber (TF) contents were 15.9, 15.7, and 15.8%, average AA values were 14.0, 12.6, and 13.1%, and average Crude Protein (CP) values were 14.0, 12.6, and 13.1% for solution A, solution B and farmer practice treatments, respectively. Average tissue-N values were 2.41, 2.21, and 2.14%, tissue-P values were 0.54, 0.40, and 0.40%, and average tissue-K values were 1.22, 1.21, and 1.25% for the same respective treatments. Total amounts of applied water during the growing period was 4071 m3/ha and average water productivity values were 96.4, 80.4, and 73.6 kg fresh yield/m3 for the three respective treatments. It could be concluded that, the multiple contents of growing nutrient solution significantly increase Azolla pinnata biomass. It also increased the chemical constituents of the plant, tissue-NPK, and water productivity. Ponded water contains macro- and micro-nutrients and can be used to irrigate other crops in the farm.
Keywords: Azolla pinnata, biomass, chemical constituents, tissue-NPK, water productivit
Productivity of date palm as affected by irrigation in a sandy soil
A field experiment was conducted on drip irrigated date palm trees (Barhi var.) in a private farm during the 2020 and 2021 seasons to evaluate the effect of five irrigation treatments (120, 100, 80, and 60% ETo and farmer practice) on amounts of applied irrigation water (AIW), consumptive use (CU), date yield and its components, fruit quality, water use efficiency (WUE), water productivity (WP), consumed electric energy, net income, a local date crop coefficient (Kc) and yield response factor (Ky). Results revealed that, average ETo values varied between 1.26 mm/day in December and 9.85 mm/day in July. The 2–year average AIW values were 17 377, 14 546, 11 715, 8 885 and 24 680 m3/ha for the 120, 100, 80 and 60% ETo treatments and farmer practice, respectively. Highest and lowest fruit yields of 39.2 and 15.2 t/ha were recorded for the 120% and 60% ETo treatments, respectively. The WP values of the same treatments were 2.27 and 1.23 kg fruits/m3. Seasonal average Kc value of 0.74 is obtained for the 120% ETo treatment. The Ky value of 1.187 is obtained for the Barhi variety. The lowest consumed energy (64.7%) and highest net income (31.8%) were recorded for 60% and 120% ETo treatments compared with farmer practice.
Keywords: Applied water, water consumption, water use efficiency, water productivity, crop coefficient, yield response factor, energy saving, net incom
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