• Title/Summary/Keyword: primary energy use

Search Result 236, Processing Time 0.026 seconds

Development and evaluation of continuing education course in renal nutrition

  • Karavetian, Mirey;Rizk, Rana
    • Nutrition Research and Practice
    • /
    • v.10 no.1
    • /
    • pp.99-107
    • /
    • 2016
  • BACKGROUND/OBJECTIVE: Competent renal dietitians are crucial for better patient compliance and clinical outcomes, specifically in critical settings. The aim of this study was to develop and evaluate an evidence-based course in renal dietetics for dietitians working in health care systems where dietetic specialization is absent. SUBJECTS/METHODS: Fifteen licensed dietitians working with hemodialysis patients in Lebanon were randomly recruited to participate in the course. The latter was developed by the study's primary investigator, according to evidence-based practice guidelines, and focused on all aspects of renal nutrition. Total course duration was 28 hours spread over a 2 month period. Dietitians' knowledge in renal nutrition was tested pre- and post-training through a 23-item questionnaire; the total score was expressed in percentage (< 60% score indicated insufficient knowledge). Paired-samples t test was used for statistical analysis. RESULTS: Overall knowledge of the dietitians significantly improved post-training and reached satisfactory levels (pre: $38.75{\pm}17.20%$, post: $62.08{\pm}21.85%$). Sub-analysis of the change in the knowledge showed significant and satisfactory improvement only in 3 topics: 1) correct body weight use in calculations, 2) energy estimation method and 3) phosphorus management. Knowledge in the fluid management significantly improved but did not achieve a satisfactory level. CONCLUSION: The course significantly improved dietitians' knowledge in renal nutrition. If adopted as part of the continuing education of dietitians in countries that lack dietetic specializations, it may serve the first step towards improving health care practice.

Numerical investigation on the flexural links of eccentrically braced frames with web openings

  • Erfani, S.;Vakili, A.;Akrami, V.
    • Steel and Composite Structures
    • /
    • v.39 no.2
    • /
    • pp.171-188
    • /
    • 2021
  • Plastic deformation of link beams in eccentrically braced frames is the primary dissipating source of seismic energy. Despite the excellent compatibility with the architectural designs, previous researches indicate the deficiency of flexural yielding links compared to the shear yielding ones because of their localized plastic deformation. Previous investigations have shown that implementing web openings in beams could be an efficient method to improve the seismic performance of moment-resisting connections. Accordingly, this research investigates the use of flexural links with stiffened and un-stiffened web openings to eliminate localized plasticity at the ends of the link. For this purpose, the numerical models are generated in finite element software "Abaqus" and verified against experimental data gathered from other studies. Models are subjected to cyclic displacement history to evaluate their behavior. Failure of the numerical models under cyclic loading is simulated using a micromechanical based damage model known as Cyclic Void Growth Model (CVGM). The elastic stiffness and the strength-based and CVGM-based inelastic rotation capacity of the links are compared to evaluate the studied models' seismic response. The results of this investigation indicate that some of the flexural links with edge stiffened web openings show increased inelastic rotation capacity compared to an un-perforated link.

Numerical investigation on the flexural links of eccentrically braced frames with web openings

  • Erfani, S.;Vakili, A.;Akrami, V.
    • Steel and Composite Structures
    • /
    • v.44 no.2
    • /
    • pp.183-198
    • /
    • 2022
  • Plastic deformation of link beams in eccentrically braced frames is the primary dissipating source of seismic energy. Despite the excellent compatibility with the architectural designs, previous researches indicate the deficiency of flexural yielding links compared to the shear yielding ones because of their localized plastic deformation. Previous investigations have shown that implementing web openings in beams could be an efficient method to improve the seismic performance of moment-resisting connections. Accordingly, this research investigates the use of flexural links with stiffened and un-stiffened web openings to eliminate localized plasticity at the ends of the link. For this purpose, the numerical models are generated in finite element software "Abaqus" and verified against experimental data gathered from other studies. Models are subjected to cyclic displacement history to evaluate their behavior. Failure of the numerical models under cyclic loading is simulated using a micromechanical based damage model known as Cyclic Void Growth Model (CVGM). The elastic stiffness and the strength-based and CVGM-based inelastic rotation capacity of the links are compared to evaluate the studied models' seismic response. The results of this investigation indicate that some of the flexural links with edge stiffened web openings show increased inelastic rotation capacity compared to an un-perforated link.

The Need for Weight Optimization by Design of Rolling Stock Vehicles

  • Ainoussa, Amar
    • International Journal of Railway
    • /
    • v.2 no.3
    • /
    • pp.124-126
    • /
    • 2009
  • Energy savings can be achieved with optimum energy consumptions, brake energy regeneration, efficient energy storage (onboard, line side), and primarily with light weight vehicles. Over the last few years, the rolling stock industry has experienced a marked increase in eco-awareness and needs for lower life cycle energy consumption costs. For rolling stock vehicle designers and engineers, weight has always been a critical design parameter. It is often specified directly or indirectly as contractual requirements. These requirements are usually expressed in terms of specified axle load limits, braking deceleration levels and/or demands for optimum energy consumptions. The contractual requirements for lower weights are becoming increasingly more stringent. Light weight vehicles with optimized strength to weight ratios are achievable through proven design processes. The primary driving processes consist of: $\bullet$ material selection to best contribute to the intended functionality and performance $\bullet$ design and design optimization to secure the intended functionality and performance $\bullet$ weight control processes to deliver the intended functionality and performance Aluminium has become the material of choice for modern light weight bodyshells. Steel sub-structures and in particular high strength steels are also used where high strength - high elongation characteristics out way the use of aluminium. With the improved characteristics and responses of composites against tire and smoke, small and large composite materials made components are also found in greater quantities in today's railway vehicles. Full scale hybrid composite rolling stock vehicles are being developed and tested. While an "overdesigned" bodyshell may be deemed as acceptable from a structural point of view, it can, in reality, be a weight saving missed opportunity. The conventional pass/fail structural criteria and existing passenger payload definitions promote conservative designs but they do not necessarily imply optimum lightweight designs. The weight to strength design optimization should be a fundamental design driving factor rather than a feeble post design activity. It should be more than a belated attempt to mitigate against contractual weight penalties. The weight control process must be rigorous, responsible, with achievable goals and above all must be integral to the design process. It should not be a mere tabulation of weights for the sole-purpose of predicting the axle loads and wheel balances compliance. The present paper explores and discusses the topics quoted above with a view to strengthen the recommendations and needs for the weight optimization by design approach as a pro-active design activity for the rolling stock industry at large.

  • PDF

A Numerical Study on a High-Temperature Air Combustion Burner for a Compact Fuel-Cell Reformer (연료전기용 컴팩트형 개질기의 고성능화를 위한 고온 공기 연소 기술의 적용에 관한 연구)

  • Lee, Kyoung-Ho;Kwon, Oh-Chae
    • Journal of Hydrogen and New Energy
    • /
    • v.16 no.3
    • /
    • pp.229-237
    • /
    • 2005
  • A new burner configuration for a compact fuel-cell reformer with a high-temperature air combustion concept was numerically studied. The burner was designed for a 40 $Nm^3/hr$ hydrogen-generated reformer using natural gas-steam reforming method. In order to satisfy the primary requirements for designing a reformer burner (uniform distribution of temperature along the fuel processor walls and minimum heat losses from the reformer), the features of the present burner configuration included 1) a self-regenerative burner for an exhaust-gas-recirculation to apply for the high-temperature air combustion concept, and 2) an annular-type shield for protecting direct contact of flame with the processor walls. For the injection velocities of the recirculated gas of 0.6-2.4 m/s, the recirculated gas temperature of 1000 K, and the recirculated oxygen mole fraction of 4%, the temperature distributions along the processor walls were found uniform within 100 K variation. Thus, the present burner configuration satisfied the requirement for reducing temperature gradients along the processor walls, and consequently demonstrated that the high-temperature air combustion concept could be applied to the practical fuel reformers for use of fuel cells. The uniformity of temperature distribution is enhanced as the amount of the recirculated gas increases.

Experimental study on all-bolted joint in modularized prefabricated steel structure

  • Wu, Zhanjing;Tao, Zhong;Liu, Bei;Zuo, Heng
    • Structural Engineering and Mechanics
    • /
    • v.73 no.6
    • /
    • pp.613-620
    • /
    • 2020
  • The research study is focuses on a form of all-bolted joint with the external ring stiffening plate in the prefabricated steel structure. The components are bolted at site after being fabricated in the factory. Six specimens were tested under cyclic loading, and the effects of column axial compression ratio, concrete-filled column, beam flange sub plate, beam web angle cleats, and spliced column on the failure mode, hysteretic behavior and ductility of the joints were analyzed. The results shown that the proposed all-bolted joint with external ring stiffening plate performed high bearing capability, stable inflexibility degradation, high ductility and plump hysteretic curve. The primary failure modes were bucking at beam end, cracking at the variable section of the external ring stiffening plate, and finally welds fracturing between external ring stiffening plate and column wall. The bearing capability of the joints reduced with the axial compression ratio increased. The use of concrete-filled steel tube column can increase the bearing capability of joints. The existence of the beam flange sub plate, and beam web angle cleat improves the energy dissipation, ductility, bearing capacity and original rigidity of the joint, but also increase the stress concentration at the variable section of the external reinforcing ring plate. The proposed joints with spliced column also performed desirable integrity, large bearing capacity, initial stiffness and energy dissipation capacity for engineering application by reasonable design.

Changes in Plant Species on a Grass Roof over Time (초지지붕에서의 시간경과에 따른 식생변화)

  • Lee, Young-Moo
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.34 no.6 s.119
    • /
    • pp.39-53
    • /
    • 2007
  • Unlike conventional roof landscaping, where various kinds of plants and structures are employed, a grass roof is a roof on which herbaceous plants are grown in planting medium and which is not accessed or maintained, mainly because it doesn't have sufficient load capacity to support a regular roof garden. They are mostly built on existing roofs, whether flat slab or gabled. Planting on roofs has numerous advantages, such as creating a biotope, purifying urban air, adding moisture to the atmosphere, storing rain water, preventing flash floods, reducing energy use for heating and air conditioning, enhancing the urban landscape and providing relaxation to the city dwellers, not to mention the alleviation of global warming by absorbing $CO_2$. In addition to the general merits of roof planting, the grass roof has its own unique qualities. Only herbaceous species are planted on the roof, resulting in light weight which allows roofs of existing buildings to be planted without structural reinforcement. The species chosen are mostly short, tough perennials that don't need to be maintained. These conditions provide an ideal situation where massive planting can be done in urban areas where roofs are often the only and definitely the largest space available to be planted. If roofs are planted on a massive scale they can play a significant role in alleviating global warming, heat island effects and energy shortages. Despite the advantages of grass roofs, there are some problems. The most significant problem is the invasion of neighboring plants. They may be brought in with the planting medium, by birds or by wind. These plants have little aesthetic value comparing to the chosen species and are usually taller. Eventually they dominate and prevail over the original species. The intended planting design disappears and the roof comes to look wild. Since the primary value of a grass roof is ecological, a change in attitude towards what constitutes beauty on the roofscape is necessary. Instead of keeping the roof neat through constant maintenance, people must learn that the wild grass with bird's nests on their roof is more beautiful as it is.

A Numerical Study of the 2-D Cold Flow for a Qubec City Stoker Incinerator (큐벡시 스토커 소각로 2차원 비반응 유동장 수치해석)

  • 박지영;송은영;장동순
    • Journal of Energy Engineering
    • /
    • v.2 no.3
    • /
    • pp.268-275
    • /
    • 1993
  • A series of parametric investigations are performed in order to resolve the flow characteristic of a Quebec city stoker incinerator. The parameters considered in this study are five internal configurations of the Quebec city stoker itself and its modified ones, primary air velocity, the injection velocity and angle of the secondary air, and the reduction of the stoker exit area. A control-volume based finite-difference method by Patankar together with the power-law scheme is employed for discretization. The resolution of the pressure-velocity coupling is made by the use of SIMPLEC algorithm. The standard, two equation, k-$\varepsilon$ model is incorporated for the closure of turbulence. The size of recirculation region, turbulent viscosity, the mass fraction of the secondary air and pressure drop are calculated in order to analyze the characteristics of flow field. The results are physically acceptable and discussed in detail. The flow field of the Quebec city stoker shows the strong recirculation zone together with the high turbulence intensity over the upper part of the incinerator.

  • PDF

Nutritional Assessment of Menu Plan Prepared according to the Target Pattern - Menu Prepared by Home Economics Teachers and Middle-School Girls - (권장식사패턴을 활용하여 작성된 식단계획의 영양평가 - 가정과 교사와 여중생이 작성한 식단계획 -)

  • Kim, A-Rom;Kim, Mi-Jeong;Kim, Young-Nam
    • Korean Journal of Community Nutrition
    • /
    • v.16 no.3
    • /
    • pp.375-385
    • /
    • 2011
  • The nutritional balance of the menu plans prepared according to the target pattern was examined. Total of 81 home economics teachers throughout the nation and 161 3rd-grade middle-school girls in Chungnam area participated. The data was collected by questionnaire and analyzed by using SPSS WIN 12.0. Although both teacher and student groups had fairly good knowledge on preparing menu plans related concepts, they rarely make use any menu planning currently. More than 85% of menu plans investigated exceeded their energy goal in the target pattern. The energy contribution ratios of carbohydrate: protein: fat were 56.1%: 17.4%: 26.5% in teachers' menu plan and 55.1%: 17.2%: 27.7% in students' menu plan. The NAR of the protein, phosphorous, iron, zinc, vitamin A and C, thiamin, riboflavin, niacin, B6 was 1 or near 1. But in case of calcium, 56.5% of the menu plan prepared by the students was less than 1, and in case of folate 75.3% of teachers', and 85.1% of students' were less than NAR 1. The MAR of the 12 nutrients examined were 0.98, 0.97, and the DVS were 51, 49 for menu plan prepared by teachers and students, respectively.

Review of Methods for Measurement of Ecological Energy Conversion Rate by Herbivores in Offshore and Adjacent Sea (연근해 생물 잠재생산력 추정을 위한 Herbivores 단계의 에너지 전환 효율의 추정 방법에 관한 고찰)

  • KIM Yong-Sool
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.24 no.4
    • /
    • pp.266-271
    • /
    • 1991
  • Probably herbivorous fishes were visibility main body as aquatic substantial production in offshore and adjacent sea. It is a major problem to estimation of energy conversion rate by hervivores from primary production when to be measurement for potential productivity of herbivores as above meaning according to deductive method. This was deal with review of I index, with mean transfer efficiency from food in seawater to food in gut be eaten by a particular species. Yet $K_i$ was not settled with an established theory. In this review coefficients of food selection or electivity indices suggested by two Russian biologists, Ivlev and Sorygin, (r-p) /(r+p) and (r/p) were understand unsuitable to use with the transfer efficiency $K_i$. But CCOS that is one of community resemblance chord is suggested to be possible with someone a treatment, as (CCOS)$\times$(Filtering rate).

  • PDF