bluuebunny/crossref_metadata_2025 huggingface dataset:
Achievement-Related Perceptions of Children with Learning Disabilities and Normal Achievement
Authors: Bear George G. , Minke Kathleen M. , Griffin Shaunna M. , Deemer Sandra A.
Published: December 2008

Self-perceptions of teacher feedback, social comparison of reading competence, reading satisfaction, and general self-worth were assessed among third and sixth graders with learning disabilities and normal achievement ( n = 247). Relations among these variables and mean differences were examined within and across grades. As predicted, in both grades teacher feedback was the most common criterion children used to judge their academic performance. In both achievement groups, perceived teacher feedback and reading satisfaction were less favorable among sixth than third graders. Hierarchical regression analyses showed that perceived teacher feedback was the best predictor of reading satisfaction; however, in sixth grade, social comparison also contributed significantly to the prediction. The importance of perceived feedback also was demonstrated in the relation to self-worth, which was generally positive among both achievement groups and within each grade. Through its relation to reading satisfaction, perceived teacher feedback contributed significantly to prediction of self-worth. Developmental differences and classroom factors that may explain these findings are discussed.
Very-Low-Birthweight Infants at Seven Years
Authors: Farel Anita M. , Hooper Stephen R. , Teplin Stuart W. , Henry Marianna M. , Kraybill Ernest N.
Published: December 2008

To determine whether history of chronic lung disease (CLD) in children born at very low birthweight (VLBW) confers additional risk for impaired health, growth, and neurodevelopment, 17 VLBW children born in 1984 who had CLD (requiring supplemental oxygen more than 30 days after birth) in infancy and 28 VLBW children who did not have CLD were assessed at age 7 years. Assessments included a medical history, standard physical and neurological examinations, pulmonary-function tests, and tests of neuropsychological and psychoeducational functioning. Health status did not differ between the groups. In contrast, children with CLD did not perform as well in neuropsychological and psychoeducational assessments. Although CLD confers little added risk to health, it seems to add significantly to risks for poor school performance that are known to be associated with very low birthweight.
Inclusion or Pull-Out
Authors: Klingner Janette Kettmann , Vaughn Sharon , Shay Schumm Jeanne , Cohen Patricia , Forgan James W.
Published: December 2008

The purpose of this study was to better understand students' perceptions of and preferences for inclusion or pull-out service delivery models. Thirty-two students with and without learning disabilities who had participated in both models during the past 2 or 3 years were interviewed individually. Key questions assessed their perceptions of which model was most conducive to academic learning and which was most likely to yield social benefits, and the reasons for their beliefs. Results indicated that students' views varied. Overall, more children identified pull-out as the model of choice, but many children were confident that inclusion was meeting their academic and social needs. We interpret the results of this study as providing support for maintaining a continuum of service delivery options and for considering the placement of each child individually, based on his or her unique needs.
Mediators of the Risk for Problem Behavior in Children with Language Learning Disabilities
Authors: Vallance Denise D. , Cummings Richard L. , Humphries Tom
Published: December 2008

A developmental-organizational perspective was employed to explore underlying risk for problem behavior in children with language learning disabilities. The independent and relative influences of social discourse and social skills on problem behavior were examined in 50 children with language learning disabilities (LLD) and 50 control children (children without LLD) aged 8 to 12 years. Hierarchical regression analyses revealed that when examined independently, both impaired social discourse skill and poor social skills accounted for the negative effect of LLD status on children's problem behavior. When social discourse and social skills were examined simultaneously in relation to problem behavior, social discourse no longer retained its predictive value. This result suggests that children's impaired social interactional functioning is central to the development of behavioral symptomatology. However, the importance of social discourse cannot be overlooked, given the significant correlation between social discourse and social skills ratings. Though these results are correlational in nature, it is argued that the impaired communicative competence of some children with LLD may contribute to poor social skills that ultimately manifest themselves as more clinical problem behaviors characterized by internalizing and externalizing symptomatology. Finally, differences were confirmed in social discourse performance, social skills, and problem behaviors between the children with LLD and the control group children. Findings emphasize the importance of the routine assessment and monitoring of broader social discourse skills, in addition to social competence, in children with LLD.
Special Education in Russia
Authors: Malofeev Nikolai N.
Published: December 2008

Tracing the history of special education services in Russia from its beginnings in the early nineteenth century through the rapid expansion of both private and government-supported programs and institutions until the restrictive Soviet period provides both understanding and appreciation of current Russian special education services and institutions. Theoretical principles guiding special education formulated by L. Vygotsky, and sources outside the USSR, were officially suppressed, as were testing and statistical data on handicapped individuals. Official mandates to bring students with handicaps up to state-approved standards resulted in the development of creative, effective approaches. The framework of special education changed little until the breakdown of the USSR. The new Russian Federation ratified UN resolutions protecting the rights of children. Categorical language is a recent development, and terms such as defective, retarded and pedologist are gradually being replaced. The final decade of this century is witnessing rapid change at the initiation of the Ministry of Education that is beginning to produce needed reform. One of the major initiatives is to provide LD specialists in all schools so that students will not need to be a great distance from home to receive needed services.
What Follow-Up Studies Say About Postschool Life for Young Men and Women with Learning Disabilities
Authors: Levine Phyllis , Nourse Steven W.
Published: December 2008

Follow-up studies examining the outcomes for children and youth with learning disabilities who attended special education have appeared in the literature for decades. As American society becomes more technologically advanced and competitive, postsecondary school opportunities and subsequent employment choices that are meaningful and provide a livable wage teeter out of the reach of young people with learning disabilities. Follow-up study investigators seek to understand how to better prepare youth to meet these challenges by studying their long-term outcomes. The authors review data from 13 frequently referenced follow-up studies regarding postschool outcomes, postsecondary education, and employment, with attention to gender differences, for youth with learning disabilities who were served by and graduated from special education programs nationwide. They take a critical look at contradictions in the findings and discuss five methodological issues that seem to influence the conduct and interpretation of follow-up studies: aggregating data across disability categories; combining data on graduates who have been out of school for unequal periods of time; ignoring the issues of missing data, participant attrition, and incomplete data sets; combining data from different informants; and using nonequivalent databases to make comparisons to a population with no disabilities. The authors provide recommendations for conducting follow-up research on the long-term quality of life of children and youth with disabilities and their families.
The National Learning Disabilities Postsecondary Data Bank
Authors: Vogel Susan A. , Leonard Faith , Scales William , Hayeslip Peggy , Hermansen Jane , Donnells Linda
Published: December 2008

A survey was developed to assess support services, procedures, policies, the proportion of students with learning disabilities (LD), and the factors that affect differences in proportion in a nationally representative sample of postsecondary institutions (PSIs). The factors investigated included general characteristics about the PSI, such as size of the student body and type of PSI. The specific characteristics investigated in regard to LD were admissions procedures, year of initiation of LD support services, type and location of support services, eligibility criteria for services and accommodations, the number of students with LD, and demographic and diagnostic information available. In this article, descriptive data regarding the services, practices, policies, procedures, and proportions are provided. The findings indicated that the proportion of students with LD ranged from .5% to almost 10%. The factors that had a significant impact on the proportion of students with LD were size of the student body, the type of institution, the institution's Carnegie classification, and whether the institution offered graduate degree programs. These findings and their implications are discussed.
Longitudinal Research in Learning Disabilities
Authors: Raskind Marshall H. , Gerber Paul J. , Goldberg Roberta J. , Higgins Eleanor L. , Herman Kenneth L.
Published: December 2008

In June of 1995 an international symposium on longitudinal research in learning disabilities (LD) was held in Missillac, France. The purpose of the symposium was to bring together an international panel of experts in this area to promote international dialogue on longitudinal research in LD, define and develop guidelines for conducting such research, identify problems inherent in this type of research and methods to alleviate them, and establish research priorities. This article synthesizes and highlights the information that emerged from individual presentations and ensuing discussions. Generic considerations regarding longitudinal research are presented; however, particular emphasis is given to the confluence of longitudinal research and learning disabilities.
Behavioral and Emotional Problems of Students with Learning Disabilities, Serious Emotional Disturbance, or Both Conditions
Authors: Handwerk Michael L. , Marshall Richard M.
Published: December 2008

This study investigates the behavioral and emotional problems of children with learning disabilities (LD), serious emotional disturbance (SED), and LD/SED, using the Teacher Report Form (TRF) and Child Behavior Checklist (CBCL). The sample consisted of 217 students with LD, 72 with SED, and 68 with SED/LD, ages 6 to 18 (mean age = 11.5). The students with SED were rated more impaired than the students with LD on all TRF scales except Attention Problems, and on three of the eight CBCL syndrome scales. The children with LD differed from those with SED mainly in terms of severity of problems, not with respect to type of problem. It is concluded that students with co-morbid LD and SED are underidentified and underserved in special education systems.
The Consequences of Negative Scaffolding for Students Who Learn Slowly—-A Commentary on C. Addison Stone's “The Metaphor of Scaffolding
Authors: Biemiller Andrew , Meichenbaum Donald
Published: December 2008

In this commentary, we discuss the outcomes of effective scaffolding, the processes by which successful scaffolding works, and consider implications for children with learning disabilities or below-average academic progress. Scaffolding aims at transferring responsibility for task accomplishment from a competent person to a learner. In the context of children with educational problems, we explicate our view that current practices in many schools may result in a kind of reverse-scaffolding, preventing rather than encouraging transfer of responsibility for tasks.
What Happens During Instruction
Authors: Scruggs Thomas E. , Mastropieri Margo A.
Published: December 2008

This article provides a response to Stone's review and analysis of the scaffolding metaphor as it is applied to research applications for students with learning disabilities. We propose that, to advance the field of instructional research with students with learning disabilities, all available literature should be used when interpreting findings for instructional procedures for students with learning disabilities. Only when all of the intervention research literature in learning disabilities is examined can reliable conclusions be drawn regarding the efficacy of instructional procedures.
Investigating Reading Disabilities Using the Rauding Diagnostic System
Authors: Carver Ronald P. , Clark Susan W.
Published: December 2008

Should a measure of intelligence be replaced by a measure of listening in discrepancy definitions of reading disability? This question was answered using a newly developed diagnostic system, which is based on “rauding” theory and a causal model of reading achievement. In Study 1, diagnostic results were analyzed from 122 students in Grades 3 through 7 who took, via computer, a battery of tests called the Computer Assisted Reading Diagnosis (CARD). In Study 2, 44 university students were given the CARD. In Study 3, the CARD was administered to 128 students in reading improvement classes at a suburban community college. From the results, it was concluded that the rauding diagnostic system consistently diagnoses disabilities in listening, decoding, and naming speed when they are theoretically needed to explain accuracy and rate disabilities of children and adults who are poor readers. It was recommended that (a) general intelligence, fluid intelligence, or IQ not be used to measure potential or to diagnose reading disabilities; (b) listening not be used to measure potential; (c) verbal knowledge aptitude, pronunciation aptitude, and cognitive speed aptitude be used to measure potential; and (d) the new rauding diagnostic system replace the system of diagnosing dyslexics, hyperlexics, and garden-variety poor readers.
A Validation of the Role of Preschool Phonological and Orthographic Skills in the Prediction of Reading
Authors: Badian Nathlie A.
Published: December 2008

Two cohorts of children were followed to determine whether tests of phonological awareness (Syllable Tapping), orthographic processing (Visual Matching), and serial naming speed (RAN Objects), added to a preschool battery, would improve prediction of reading. The major predictors of first-grade reading and spelling were preschool letter naming and sentence memory for both cohorts, but the orthographic and serial naming tasks added a small amount of additional variance. Sentence memory accounted for the most variance in second-grade reading for both cohorts, and Visual Matching made contributions to reading and spelling for each cohort. Sentence memory, Visual Matching, and color naming together yielded an 87% to 90% hit rate in predicting which individual children would be good or poor readers. The orthographic and serial naming speed tasks are useful additions to a preschool predictive battery, but recommendations are that alternative preschool phonological tasks, not based on syllable recognition, should be used to predict reading.
The Performance of Students with Disabilities in a Norm-Referenced, Statewide Standardized Testing Program
Authors: Gronna Sarah S. , Jenkins Amelia A. , Chin-Chance Selvin A.
Published: December 2008

Hawaii uses the Stanford Achievement Test, 8th Edition (Stanford 8), to assess the academic performance of students in Grades 3, 6, 8, and 10. Three longitudinal cohorts were analyzed for achievement performance among Grades 3 to 6, 6 to 8, and 8 to 10. ANOVAs indicated significant differences in overall performance between nondisabled students and three high-incidence categories of students with disabilities (specific learning disability, emotional impairment, and mild mental retardation). Local subgroup norms were developed on the basis of Stanford 8 reading and mathematics results from 1992 to 1996 to supplement the national norms and provide an additional means of comparison to evaluate performance for these categories. The longitudinal cohorts of students with disabilities made greater gains in achievement from third to sixth grade than their national counterparts and cohort of nondisabled students in Hawaii. Between 8th and 10th grade, students with learning disabilities and emotional impairments made gains equal to or greater than their national counterparts.
Prospective Study of Tobacco Smoking and Substance Dependencies Among Samples of ADHD and Non-ADHD Participants
Authors: Lambert Nadine M. , Hartsough Carolyn S.
Published: December 2008

This study focused on an audience at high risk for heavy use of licit and illicit substances: young adults who as children had attention-deficit/hyperactivity disorder (ADHD). The participants in this study were part of a longitudinal study of the life histories of 492 children, one third of whom were identified as hyperactive in 1974 and whose childhood symptom ratings and medical histories were used to establish Diagnostic and Statistical Manual of Mental Disorders (3rd ed., revised; DSM-III-R) ADHD diagnoses (American Psychiatric Association, 1987). The objectives of the study centered on describing (a) developmental history of tobacco use among ADHD and non-ADHD participants in a longitudinal sample, (b) the characteristic adult patterns of tobacco use from early adolescence through early adulthood, and (c) the relationship between ADHD status and tobacco and substance dependence outcomes. Adult data were obtained for 81% of the original 492 participants (77% of the ADHD and 86% of the controls). Lifetime and current tobacco use were assessed from child, adolescent, and adult data, yielding eight measures of smoking status. The study showed that participants with and without ADHD did not differ in age of initiation to smoking, but there was a significant difference in the age they began smoking regularly. By age 17, 46% of all participants with ADHD, as contrasted with 24% of the age-mate controls, reported smoking cigarettes daily. In adulthood, the proportion of participants with ADHD who were current smokers (42%) continued to exceed that of the age-mate controls (26%). Among current adult smokers, 35% with ADHD smoked daily as compared to 16% of the age-mate controls. There were significantly different lifetime tobacco dependence rates—40% compared to 19% for age-mate controls. The rates for cocaine dependence were 21% for participants with ADHD and 10% for age-mate controls. We reported a significant difference in rates of daily smoking and tobacco dependence for those with ADHD who had used stimulant medication in childhood in contrast to controls. Results were interpreted to support a possible link between ADHD treatment histories and levels of tobacco smoking and tobacco dependence in adulthood.
Self-Management as a Strategy to Improve the Classroom Behavior of Adolescents with ADHD
Authors: Shapiro Edward S. , DuPaul George J. , Bradley-Klug Kathy L.
Published: December 2008

This article reports on the application of a self-management strategy for improving the classroom behavior of students with attention-deficit/hyperactivity disorder (ADHD). Based on the work of Rhode, Morgan, and Young (1983), the intervention focuses on teaching students to systematically rate their own behavior according to the rating of their teacher. Although, historically, self-management strategies based on cognitive control have not been found to be effective for students with ADHD, strategies based on contingency management have not been widely reported in the literature. A description of the intervention and two case study illustrations are provided. Potential limitations and implications for research in using this strategy are discussed.
The Irvine Paraprof essional Program
Authors: Kotkin Ronald
Published: December 2008

The Irvine Paraprofessional Program (IPP) looks promising for serving elementary-school children with attention-deficit/hyperactivity disorder (ADHD) in the general education classroom. This article describes the components of the IPP, preliminary research studies that support its efficacy, and the benefits of the model. The IPP is a 12–week intensive intervention that includes (a) direct intervention to children with ADHD by specially trained paraprofessionals, (b) teacher consultation by the school psychologist on the use of effective classroom management strategies, (c) school-based reinforcement, and (d) social skills training. Preliminary studies suggest that paraprofessionals can effect positive changes in children with ADHD that can be maintained by the teacher once the paraprofessional is removed from the classroom. The purpose of this article is to provide a description of the IPP as an effective model for serving children with ADHD in the general education classroom.
Differentiating Attention-Deficit/Hyperactivity Disorder From Pervasive Developmental Disorder Not Otherwise Specified
Authors: Roeyers Herbert , Keymeulen Heidi , Buysse Ann
Published: December 2008

This study investigated early clinical differences between children with a diagnosis of pervasive developmental disorder not otherwise specified (PDD-NOS) and children with attention-deficit/hyperactivity disorder (ADHD). Differential diagnoses between the two disorders is often difficult in infancy or early childhood. Twenty-seven children with PDD-NOS were matched with 27 children with ADHD as to IQ and chronological age. Their parents were retrospectively questioned on pre-, peri-, and postnatal complications and on atypical or delayed development of the children between 0 and 4 years of age. This exploratory study revealed almost no differences between both groups with respect to pregnancy or birth complications. The results suggest that differences between the two groups become more pronounced and specific with growing age. Consequently, this investigation offers sufficient guidelines for more specific research with larger samples.
Predictors of Job Stress Among Staff in Juvenile Correctional Facilities
Authors: Wells James B. , Minor Kevin I. , Angel Earl , Matz Adam K. , Amato Nick
Published: December 2008

There have been relatively few studies of job stress among staff of juvenile correctional facilities. The Job Stress subscale of the Prison Social Climate Survey, which has been used extensively in studies of adult facility staff, was completed by 443 staff (72.1% of those surveyed) working in residential placement facilities and group homes operated by the Kentucky Department of Juvenile Justice. Job stress scores were regressed on a wide range of potential predictors. The significant predictor variables were all related to the work environment; background variables had no predictive utility. Lower staff stress was predicted by organizational satisfaction and commitment, job satisfaction, and sense of personal efficacy. Staff who perceived less danger in the work environment and those who did not supervise other staff reported lower stress. Implications of the findings for policy and practice are discussed.
Analysis of parameters affecting the internal environment of a naturally ventilated auditorium
Authors: Clancy E.M. , Howarth A.T.
Published: December 2008

A programme of work involving the measurement of ventilation rates, air velocities and temperatures has been completed within a naturally ventilated auditorium in the Queens Building, De Montfort University. Measurements have been recorded for 'winter', 'mid-season' and 'summer' conditions, and average occupancy levels. Measurements carried out in 'winter' and 'mid-season' indicate that the predominant ventilation driving force is the stack effect. However, current control settings of fresh air inlets allow too great a free area to be produced, which causes high room air velocities with associated low temperatures, resulting in high discomfort levels for occupants seated in line with external openings. Results for 'summer' external conditions on particular dates indicate that ventilation rates are driven largely by wind-induced effects, which can be much higher than buoyancy-driven flows. Internal ceiling and wall surface temperatures show little variations with time, owing to the heavyweight nature of the building structure and its exposed areas.
Survey of available data for pressure loss coefficients, ζ, for elbows and tees of pipework
Authors: Koch P.
Published: December 2008

Although numerous data are available for pressure loss factors for ductwork components, the factors for pipework components have not received the same attention. Gross simplifications and contradictions are found in surveys of available published data from the USA, Britain and continental Europe. Some is repeated from research conducted nearly 70 years ago and extrapolated into areas that were not investigated. It was first necessary to disregard that which is least reliable so as to be able to select what might be considered the most reliable. It is regrettable that it is inevitably necessary to discard data published specifically with the intention of helping engineers; it is hoped that no offence is caused. For laminar flow, data were found that had not appeared in any simplified guide. For turbulent flow, there is a case to be made for a re-investigation of the pressure loss factors that occur with standard manufactured components, since some of the best data are taken from generalised work on larger dimensions artificially roughened to simulate pipework. The only data considered as reliable for tees concern tees made of malleable iron. Until further information is available, it is suggested that this will need to be used also for fittings of other materials. Although data for pipe elbows are size dependent, those for tees are not.
Application of univariate search methods to the determination of HVAC plant capacity
Authors: Hanby V.I. , Angelov P.P.
Published: December 2008

For nearly a century, the sizing of building heating and cooling systems has been carried out by calculation procedures based on matching the output of the plant to a peak load design figure. The design conditions are normally based on historical records of weather data and give a probabilistic 'worst case' scenario. These calculations, although often regarded as a routine stage in the design process, are critical in the sense that they affect the overall efficiency and energy consumption of the plant, the installed cost and the space occupied within the building. It is argued in this paper that advances in the simulation of the dynamic thermal performance of buildings and HVAC plant afford an opportunity to change the basis of F-mnc plant sizing procedures from the load calculation to an assessment of the ability of the plant to meet an installed performance specification. Two potential performance specifications are identified in this paper and an example zone/HVAC plant model is used to illustrate how performance-based sizing might work. Simulations have been run for conditions in the UK and in Hong Kong. Plant sizes determined by simulation have so far been smaller than those given by the conventional sizing calculation procedures.
Ventilation strategy, energy use and CO2 emissions in dwellings -a theoretical approach
Authors: Lowe R.J.
Published: December 2008

An equation is developed for predicting the combined effect of naturally and mechanically induced air flows in buildings and solved by a combination of analytical and iterative methods. The resulting two-dimensional formulation, implemented as a simple computer program, allows rapid, hourly simulation of infiltration in domestic-scale buildings with a range of ventilation strategies. This implementation is used to compare energy use and carbon dioxide emissions for three ventilation strategies—natural ventilation, mechanical extract and balanced, whole-house mechanical ventilation— as a function of dwelling airtightness. This exercise confirms the need for airtightness if the benefits from balanced mechanical ventilation with heat recovery are to be maximised.
Assessment of practical applications of outdoor air economiser in Hong Kong
Authors: Yiu J C M , Wang S.W. , Yik F W H
Published: December 2008

In Hong Kong, it is usually thought that the use of an economiser is not beneficial. Comparative studies on outdoor air conditions in urban, suburban and rural areas show that use of economisers in suburban areas is feasible. The potential for use of economisers in suburban and rural areas is significantly higher than that in urban areas, and might be higher than that claimed on the basis of Hong Kong weather data reported by the Hong Kong Observatory. An in-situ monitoring exercise on an enthalpy-based economiser in a building shows that over 40% reduction in refrigeration load is achieved in the entire winter period (over 10% in a year) in a suburban area. The use of partial and total free cooling does not cause humidity problem but improves the indoor air quality.
Low-order model for the simulation of a building and its heating system
Authors: Gouda M.M. , Danaher S. , Underwood C.P.
Published: December 2008

Signifirant progress has been made in recent years on the development of modular and generic simulation programs for investigating the thermal behaviour of buildings and associated HVAC plant and controls. However, many of these programs are inflexible for the specific analysis of HVAC plant and control systems over short time scales. The nature of this inflexibility is discussed and a remedy is sought through the development of a low-order lumped-capacity thermal model of a building space. This is expressed as a linear time-invariant state-space description. A non-linear dynamic model of a hot water heating system with feedback control has been added and results under open-loop conditions are presented. The model has the advantage of simplicity and computational efficiency. Results are compared with field-monitored data obtained from a building in use and an excellent agreement between the two is demonstrated, though this comparison is restricted to a north-facing building space with high thermal capacity.
Enhanced performance of air-cooled chillers using evaporative cooling
Authors: Huan Zhang , Shijun You , Hongxing Yang , Jianlei Niu
Published: December 2008

This paper reports the test and analysis results of an evaporative air cooler filled with corrugated holed aluminium foil. The design and performance parameters of the cooler, e.g. the characteristics of air flow through the cooler and the effectiveness of evaporative cooling, are presented using mathematical equations and figures. The new combination of air coolers and chillers is also analysed. The calculations show that the new combination has achieved a 39% increase in the coefficient of performance (cop) of air-cooled chillers in the hot and dry area of China.
Zone modelling of high-lift pressure relief valves
Authors: Francis J.
Published: December 2008

The lift attained by automatic spring-loaded pressure relief valves depends upon spring selection and upon the variation in hydrodynamic thrust on the moving parts. Accurate prediction of the latter is difficult, requiring analysis of the complex multidimensional flow beneath the disc. A simple zonal model is suggested that enables designers to identify key geometric and dynamic parameters. Comparison is made between model predictions and published experimental data. Limitations are also considered and work to improve the general use of the model in product development is identified.
Stability analysis for a VAV test rig
Authors: Mei Li , Levermore G.J.
Published: December 2008

A stability analysis for a simple VAV test rig is presented. The test rig is described by a series of non-linear mathematical models. For this system, the well-known stability analysis for linear systems cannot be applied directly. As a result, this paper presents two new approaches for the analysis of the closed-loop stability of the non-linear VAV test rig. The first approach is based on a non-linear empirical model simulation. In this approach, different operating points of the supply fan PI control are applied and the stable regions of the model are obtained and compared with the results from experiments. The boundary lines of the stability region are given in terms of the proportional gain kp and the integral gain ki of the PI controller. The results are reasonably accurate. The second approach uses a linearised model with Lyapunov's method for non-linear systems, and the stability is analysed at selected fan operating points. Again, a stability region is obtained in terms of kp and ki. This region can be used for the selection of stable control and can help in commissioning. Although the linear model with Lyapunov's method gives results that are less accurate than those of the non-linear model, the former is more flexible and quicker in use, despite being more complex in derivation. Further refinement of the linear model in the future may well yield more accurate results.
Modelling ventilation—Source, not conductance
Authors: Davies M.G.
Published: December 2008

The inappropriateness of modelling ventilation in a building as a conductance is demonstrated. A correct formulation in terms of a quasi heat source is given.
Comparison of variable pitch fans and variable speed fans in a variable air volume system
Authors: Johnson C.M.
Published: December 2008

The paper describes a study of variable pitch and variable speed fans in temperature controlled and constant pressure controlled VAV systems using computer simulated building models and weather data.
Cold bridging at corners: Surface temperature and condensation risk
Authors: Oreszczyn T.
Published: December 2008

This paper describes theoretical modelling and experimental measurements of the wall temperatures in the corners of buildings. A dimensionless cold bridge temperature (DCBT) is proposed as a parameter to characterise cold bridges. A simple resistance model is suggested as an improved method for calculating cold bridge temperatures in corners. This model shows reasonable agreement with both finite-element modelling and measured data. Theoretical studies suggest that an increased internal surface resistance at the comer results in a substantial increase in cold bridging. During transient conditions the DCBT can vary by 50%. The impact of external corners on the risk of mould growth is discussed. Mean internal relative humidities lower than the normally accepted value of 70% are suggested for rooms with significant cold bridges.
Estimation of ground-reflected radiation for the United Kingdom
Authors: Saluja G.S. , Muneer T.
Published: December 2008

The estimation of ground-reflected radiation is reviewed. Using published data, albedo-related monthly maps for the snow season in the United Kingdom are presented. Albedo values for different dominant surfaces during the snow-free period and for the snow season are recommended. Use of the proposed straightforward procedure should improve the estimation of ground-reflected radiation on inclined and vertical surfaces.
Algorithms for estimating hourly solar irradiation on slopes
Authors: Muneer T.
Published: December 2008

Solar radiation intensity on vertical walls and sloped surfaces is required in air conditioning plant design for buildings. This Note gives a comprehensive account of simple and 'user-friendly' algorithms for determining the sun's position, and then estimating hourly solar irradiation on a surface of given orientation and tilt.
Energy savings from sealed double and heat reflecting glazing units
Authors: Rayment R.
Published: December 2008

Results are presented on the comparative energy consumption of houses with single, double and heat reflecting glazing. The experiments were carried out in the BRE 'matched house pairs with simulated occupany' described. Under the given environmental conditions the main results show a saving in space heating consumption of 9% (±2%) for double glazing and 10% (±2%) for heat reflecting glazing compared with single glazing. Theoretical energy balance calculations using the thermal properties of the houses and the measured mean seasonal weather data and internal temperatures give approximately the same savings as measured. Using this energy balance to extrapolate to larger glazing areas shows that the energy requirements increase for single glazing but decrease for double and heat reflecting glazing. The predicted savings substantially support the Building Regulations Approved Document L2/3. Reducing curtain closing times increases the energy requirements significantly for single glazing but has only a small effect for double and heat reflecting glazing.
Hot water usage patterns in dwellings: Measurement by non-intrusive instruments
Authors: Pimbert S.L. , Peat B.J.
Published: December 2008

An instrument has been developed to measure hot water usage patterns in occupied dwellings. The instrument consists of a flowmeter inserted into a rubber nozzle which is push-fitted into the supply pipe to the hot water cylinder. It has been used successfully in nine homes having different occupancy patterns.
Intraregional temperature variation and the Audit Commission yardstick
Authors: Penman J.M.
Published: December 2008

The Note reviews the Audit Commission's normalised performance indicator yardsticks for the assessment of the energy performance of local authority buildings against a national standard. Using empirical data, it is argued that the Commission's procedure does not take account of intraregional (as opposed to inter-regional) temperature variations, and a method for appropriate correction is detailed.
Refrigeration and heat pump designs: Optimising for meat-processing plants
Authors: Bowater F.J.
Published: December 2008

The services requirements for meat processing plants include refrigeration, hot water and team. The by-products section generates a large amount of waste heat. These systems are usually designed piecemeal and in isolation by specialists. The paper aims to integrate and systematise plant design to meet the energy requirement in an optimal way, taking into account all usable sources of waste heat.
Novel room temperature control
Authors: Peat B.J.
Published: December 2008

This paper investigates, theoretically, a novel type of room temperature control for a wet domestic heating system based solely on the monitoring of system flow and return temperatures. The proposed controller would be sited at the boiler and include a user adjustment to set room temperature. Feedback from the house would be provided by the water returning from the radiators, eliminating the need for a conventional room thermostat. A theoretical derivation is provided, giving system flow temperature as a function of room temperature and instantaneous system differential, followed by some practical considerations for the proposed controller.
Thermal responses of sprinkler heads
Authors: Chow W.K. , Ho P.L.
Published: December 2008

The paper reports the construction of a heated wind tunnel for studying thermal responses of sprinkler heads. The design of the tunnel is similar to the one developed at the Fire Research Station, United Kingdom. Two tests were carried out with it, a plunge and a ramp test, to investigate the thermal responses of a liquid-in-glass sprinkler head which is commonly used in Hong Kong. A brief review of the thermal response of sprinkler heads is presented. Experimental results are then reported and particularly, those giving comparative values for the different defined time constants of the sprinkler heads are discussed. The measured result on the thermal characteristics of a sprinkler head is found to be similar to those in the literature.
Hot water services for a modern hospital ward unit
Authors: Corless D.K.
Published: December 2008

A study of hot water service requirements for a modern hospital ward unit has attempted to quantify the excess provided by existing guidelines and to explain how this situation has evolved. The current guidelines are based on a statistical study carried out over twenty five years ago. This time scale, together with the present adoption by the National Health Service of a standard hospital design layout, and also changes in nursing and management practices, suggest that a review of this study is long overdue. The fieldwork was carried out at the Countess of Chester 'Nucleus' General Hospital.
Psychrometry: Use of standard charts for non-standard air pressures
Authors: Berry I J G
Published: December 2008

The applicability of psychrometric charts is normally limited by their dependence on particular air pressures. This Note demonstrates a method of allowing for pressure variation when using a standard psychrometric chart. Despite the approximations involved, good accuracy is obtained for pressures from 70 to 110 kPa.
Building control systems: Fuzzy rule-based approach to performance assessment
Authors: Dexter A.L. , Trewhella D.W.
Published: December 2008

A simple case study (the water temperature control loop of a fan-coil unit) is used to demonstrate a semi-qualitative approach to assessing the performance of building control systems. The reasons for the diversity of opinion are considered, and possible methods of evaluating the performance are discussed. Five performance criteria are defined, including one that can be used as a simple indicator of reliability and maintenance costs. Sets of linguistic rules, that are based on expert opinion, are then used to relate the behaviour of the control system to the opinions of the various interest groups. Results are presented that demonstrate the way in which the tuning of the controller affects the different aspects of its overall performance. The paper provides a simple introduction to the use of fuzzy sets in a building services application and illustrates both the highly subjective nature of the evaluation process and the difficulties of assessing the overall performance of a building control system in a realistic manner. It is concluded that any practical method of evaluation must be capable of incorporating qualitative opinion and resolving conflicting points of view.
Solar radiation model for Europe
Authors: Muneer T.
Published: December 2008

This study is concerned with the evaluation of the isotropic and four anisotropic solar radiation models for inclined surfaces. The evaluation procedure was split in two stages— abbreviated and detailed analysis. Physical reasoning was used in the abbreviated analysis to demonstrate the shortcomings of the older models, while detailed evaluation was carried out for the newer models, using at least one-year's measured hourly data from each of five European sites. Plots displaying the hourly estimated radiation against measured values have been prepared along with computation of the mean bias error and the root mean square error for each slope/ azimuth. The isotropic model has been found to perform very poorly and in view of its impact on the thermal energy and daylight related calculations it is not recommended for further use. In this work further refinements have been suggested for the treatment of the background sky-diffuse radiance. The newer models including the presently proposed one have shown good agreement with the measurements.
Mineral fibre filled cavity wall: Hygrothermal properties
Authors: Simpson A. , O'Connor D.E. , Stuckest A.D.
Published: December 2008

An experimental study of the heat and moisture transfer processes in an insulated cavity wall was carried out under controlled steady-state winter conditions applicable to the UK, in a wall laboratory at Salford University. The overall test area of each wall, between the indoor and outdoor climatic chambers was 3 m x 3 m. The principal objective was to study the thermal performance of the wall and the effect of moisture. Other objectives were to locate regions of interstitial condensation and compare with theoretical predictions, and to compare the actual performance with that predicted. In the cavity wall filled with mineral fibre, moisture was found to have a negligible effect on the thermal conductivity of the insulant and a small but predictable effect on the concrete block inner leaf. The variations in thermal conductivity of the concrete could be explained in terms of the moisture content profile, which in turn could be explained, to a large extent, by the hygroscopic moisture present under the prevailing relative humidity distribution. Under 'wet' conditions, where interstitial condensation is predicted to occur, saturation conditions were detected and these were found to be restricted to the brick/insulant. The measurements support the current theory that condensation tends to be restricted to the interface. Measurements of relative humidity in the cavity were broadly in line with those predicted by current theoretical models. The overall measured thermal performance was in line with normally accepted values.
Airflow through modulated louvre systems
Authors: Yakubu G.S. , Sharples S.
Published: December 2008

Whilst the use of louvres for the control of solar radiation and daylight has been extensively studied, their impact on airflow through window openings seems to be relatively poorly researched. An experimental study has been carried out to investigate the airflow characteristics through a system of modulated louvres. The pressure flow characteristics across a full-scale louvre system were measured. Airflow models were developed for different louvre inclinations using quadratic relationships of the form ΔP = AQ 2 + BQ and compared to the power law expression of the form ΔP = aQ". The changes to airflow at various angles of louvre inclination for a range of pressure differences were also evaluated.
Measurements of heat losses from an insulated domestic hot water cylinder
Authors: Simpson A. , Castles G.
Published: December 2008

The paper provides data for heat losses from exposed pipes, plugs, thermostat cap and base of an insulated domestic hot water cylinder (capacity 120 litres), and examines their influence, and the effect of air movement, on standing heat loss performance as prescribed by standard methods such as BS699. Results show that under 'still air' conditions heat losses from exposed areas are 17% of the total loss. This figure is likely to increase for higher levels of insulation, and decrease for larger cylinder sizes. The experimental data compare favourably with standard theoretical models and data given in the CIBSE Guide. The standing heat loss is sensitive to changes in air velocity, increasing by almost 7% in the range 0.1 to 0.3 m s-1, in reasonable agreement with predictions. The pipework is responsible for the majority of the heat losses from the cylinder appendages, and is shown to be particularly sensitive to air movement.