bluuebunny/crossref_metadata_2025 huggingface dataset:
Pseudo-Random Pressure Pulses Used to Determine the Shape of Reflected Waves from an Opening
Authors: Reed E. W. , Ali M. A. , Gill K. F.
Published: November 2015

This work forms part of a study into reflection behaviour within a duct directed towards the understanding of the problems associated with metering pulsating gas flows.

A novel application of correlation analysis is used to predict the shape of the reflected wave from an opening of finite thickness. The incident wave is in the form of a pseudo-random binary sequence pressure pulse sequence which enables incident and reflected waves to be distinguished one from the other.

It is shown that for waves of small amplitude, reflections do not occur in like shape to that of the incident wave. These shapes are influenced by both the amplitude of the incident wave and the geometry of the opening. It is believed that this technique makes an original contribution to the study of reflection behaviour and the use of correlation analysis.
Research and Prediction;
Authors:   HRH The Prince Philip Duke of Edinburgh
Published: November 2015

The inaugural Hartley Lecture was given by HRH The Prince Philip, Duke of Edinburgh, KG, KT, OM, at the Wellcome Lecture Hall of The Royal Society, London, on Tuesday, 21 May, 1974. This Lecture was founded in honour of the late Sir Harold Hartley, GCVO, CH, CBE, MC, FRS, jointly by The Institute of Measurement and Control, The Institution of Chemical Engineers and The Royal Society.
The Measurement of Pulsating Gas Flow Velocities Using Pseudorandom Pressure Pulses
Authors: Reed E. W. , Ali M. A. , Gill K. F.
Published: November 2015

Demonstrated is an experimental means of measuring the mean flow velocity of a pulsating gas flow without the use of pipe constrictions. Small pseudo random binary sequence pressure pulses are injected into the flow. Correlation techniques are used to determine the velocity of propagation of these pulses from which the mean gas flow velocity can be calculated. The method is shown to be especially effective for high-velocity pulsating flows where measuring techniques at the present time are inadequate.
Trade Cycling in UK Industry
Authors: Lunt S. T.
Published: November 2015

This paper was largely written in 1971, intended primarily for an audience who might not be familiar with some of the principles and concepts of process control systems, but it was not possible to offer it for publication at that time. Apart from minor changes, mainly to delete confidential information, it is now presented in its original form.
Needs in Flow Measurement
Authors: Spencer E. A.
Published: November 2015

Revised version of a paper first presented at SYMFLO ′72, an International Symposium on Flow Measurement held by the Manchester Section of The Institute of Measurement and Control on 19–21 April, 1972.
Control Valve Movement Limitations — An Essay in Practical Control Engineering
Authors: Martin E. N.
Published: November 2015

All control systems are subject to constraints on both the magnitude of the corrections and the rate at which they can be applied to a process, and violation of these constraints, in response to severe disturbances, then leads to a deterioration in control performance just when it is most unwelcome.

An attempt is therefore made to explain these effects in simple terms, and it is shown that a change in controller configuration could provide a complete solution. Because this cannot be generally applied, however, the use of a design criterion taking account of the rate constraint, and of high speed valve actuators as a means of economising in capital cost, are discussed with examples.
The Potential of Power Fluidics for Plant Protection
Authors: Grant J. , Marshall V. C.
Published: November 2015

The possibility of using Direct Flow Control (DFC) to avoid catastrophic accidents due to containment breaches in chemical plant is discussed. Recommendations are made for locating fluidic elements, and the effectiveness of simple DFC protection is analysed. More powerful methods of protection are outlined using spin diversion and the complementary properties of fluidic and conventional valves are exploited.
Advances in Temperature Measurement Devices Using Fluidic Resistor Circuits
Authors: Schneider D.
Published: November 2015

The different temperature behaviour of fluidic form and laminar resistors can be used to construct pressure divider circuits with temperature dependent output pressure. The temperature sensitivities of four pressure dividers can be compared by using a graphical method. The influence of supply pressure fluctuations can be reduced essentially if two pressure dividers are combined to a DC bridge circuit.
Computer Aided Dynamical System Analysis and Control for Undergraduate Courses
Authors: McCorkell C. , Wilson N.
Published: November 2015

Dynamical system analysis is included in undergraduate courses in the Northern Ireland Polytechnic, as part of a presentation of general engineering methodology and more particularly, accompanied by synthesis techniques, in control options at final year honours level.

Such is the extent of the computational requirement, necessary for a non-trivial treatment, that steps have been taken to introduce computer usage where possible. Included is information on the initial stage of a project undertaken to provide for the computational needs of undergraduates involved in dynamical problems in the laboratory.
Reliability of Large Systems
Authors: Hunns D. M.
Published: November 2015

Modern plants and processes can involve the accumulation of unnatural concentrations of hostile substances in high energy situations. The safe storage of the ingredients and products of these processes, the controlled disposal of waste and the successful harnessing of the reaction energies are all problems which tax our technological resources. There is now sufficient evidence from recent years to demonstrate the potential of fault situations to cause vast economic losses in terms of plant damage and loss of production, to cause loss of life and injury to numbers of operators and in some cases to cause the effects of the catastrophe to extend far beyond the bounds of the factory fence. The need to objectively measure and regulate reliability has now long since been clear and has stimulated the growth of a formalised methodology of reliability assessment which finds expression in quantitative terms.

This quantitative component of assessment offers an analogue scale of performance estimation. By this means alternative design strategies can be decisively compared and the reliability spectrum of the component-sections (at any chosen hierarchical level) of a system can be derived. Also the reliability performance of a system may be assessed with respect to some quoted target criterion. Such a target criterion may be derived in reference to plant economics, plant safety or both. Thus a definitive means of gauging the adequacy of the reliability of systems is provided which is increasingly of value as the scales of our technological activities grow. The ability to regulate the reliability of plant to satisfy explicitly derived performance requirements clearly places a valuable and reassuring tool in the hands of the designer. Not only does the tool enable the correct level of reliability to be designed into a system (which is itself cost effective) but also provides a sufficient break-down of performance constituents to enable the most cost effective means of achieving this level to be found.
Definition of a Complex Domain Adjoint for Use in Optimal Control Problems
Authors: Grimble M. J.
Published: November 2015

A complex frequency version of the time domain adjoint operator for a linear time-invariant system is obtained. A very simple relationship is shown to exist between this operator and the system transfer function matrix. A simple method of simulating the adjoint system is described.
Control, Measurement and Design Aspects of Low-Speed Magnetically Suspended Vehicles
Authors: Sinha P. K.
Published: November 2015

The possibility of overcoming wheel friction, wear and vibration by contactless suspension for passenger-carrying vehicles is currently being investigated throughout the world. Of the several forms of magnetic suspension proposed, the one using attraction force generated between controlled direct-current (DC) electromagnets mounted on the vehicle chassis and a ferromagnetic guideway offers a desirable combination of design simplicity and operational flexibility. This paper presents an overview of the various control and design aspects of controlled DC electromagnetic suspension systems for low-speed (up to 70 km/h) urban application. The control requirements of the DC suspension system are evaluated in this paper through ride and track-clearance characteristics for a single-degree of freedom suspension system travelling along a guideway with random roughness. Operation and performance of some of the transducers compatible with the DC suspension system have been considered, and design features of lift magnets and power amplifiers discussed with a view to evaluating their suitability for transport system application.
A Silt-Salinity-Depth Profiling Instrument
Authors: Shepherd I. E.
Published: November 2015

The planning of new port facilities in muddy estuaries often calls for the acquisition of velocity, salinity and suspended solids data throughout the length of the estuary at several stages of the tidal cycle. The tidal regime in most estuaries causes periodic scour, transport in suspension, and deposition of fine grained sediments. Interaction of the tidal and fluvial flows may generate a pattern of saline stratification and longitudinal density currents which are important in determining the zones of maximum siltation in the navigation channel. Each estuary has a unique tidal current-salinity-sediment transport regime.

It is a major exercise to organise the simultaneous measurement of these variables from a series of stationary barges or boats, especially if the salinity and sediment transport patterns depend on the occurrence of particular combinations of tides and fluvial flows. Because the measurement of salinity and suspended solids by conventional sampling techniques is a slow process, a profiling instrument has been developed at the Hydraulics Research Station, which permits measurements to be made rapidly from a high speed launch at several sites during substantially identical tidal states. This paper describes the design of the transducers used for salinity and suspended solids measurements, and how they have been incorporated into a simple low cost system for rapid indications of the results.
Vibration Monitoring for Rotating Machinery
Authors: Hitchen I. R.
Published: November 2015

This article has been produced as a guide for instrument personnel involved in specifying and/or maintaining vibration monitoring equipment. The information has been gathered by the author from many sources during his initiation into the subject. The topic is only based on two measurement techniques — non-contact proximity probes and contact accelerometers — there are many other techniques available (velocity transducers, ultrasonics, for example).
The Positioning of Control Valves in Digital Control Systems
Authors: Hinkins A. J. , Malcolm J. M. , Little R. I.
Published: November 2015

The history of valve positioning systems on process control loops is reviewed. The advent of single loop micro-processor based controllers makes possible an improved functional layout for such systems, which has previously found application on direct digital control systems. If this new layout should find support within the industry, then some form of national co-ordination of the development of interface standards would be desirable.
Hygrometry
Authors: Riemer W. , Röss R.
Published: November 2015

To meet the many different requirements of gas humidity and water vapour measurement, a wide variety of measurement techniques has been developed. The criteria for deciding which technique to use are the range of concentration, the accuracy of measurement required, the sensitivity, and the pressure or even the corrosiveness of the gas sample. For measuring traces of moisture, sensors are used in which the admittance of an arrangement of electrodes changes with the partial pressure of the water vapour. Another method measures desorption due to Joule heat after absorption of the water by phosphorus pentoxide. Devices for measuring high humidities are equipped with capacitive, temperature-controlled sensing elements which measure the dew point. For special application, units have been developed which make use of the dielectric absorption of microwaves by the water.

For hygrometrical problems requiring a high degree of accuracy, good discrimination and continuous measurement, a method is discussed below which uses the absorption of IR radiation by molecules in gaseous phase: Non-Dispersive Infra-Red Analysis.
Micro-Computer Control for Low Cost Automation
Authors: Leung T. P. , Chick W. K.
Published: November 2015

The article describes through a prototype example how pneumatic actuators for machine control in ‘low cost automation’ can be implemented with a micro-computer. Hardware and software developments are described for both sequential and combinational control of one or more machines on a time-sharing basis. The micro-computer used is an Intel 8085 with 2K PROM's and 1K RAM's. An eight bit microprocessor is chosen because of the requirement to do time-sharing work. Some problems due to noise interference and interfacing between micro-computer and pneumatic actuators are discussed with possible solutions presented.
Intrinsic Safety Rules OK for Process Instrumentation (Part 1)
Authors: Hutcheon I. C.
Published: November 2015

The technique of intrinsic safety was originated in England for mine signalling, following a serious Welsh mine disaster in 1913. The first surface certificate was issued in 1936 and the first formal standard in 1945, but it was not until the 1960s that the technique came into its own, with the advent of semiconductors. Now intrinsic safety has become the predominant solution in Europe for process measurement and control in hazardous locations, and is seriously challenging the flameproof approach in North America. This paper outlines the development of the technique, its application rules, and some typical applications of shunt-diode safety barriers and intrinsically safe “interface units”.
A Wavelength Multiplexed Optical Shaft Encoder
Authors: Dakin J. P. , Liddicoat T. J.
Published: November 2015

A wavelength multiplexed optical shaft encoder using a single optical fibre as the transmission medium between the transducer and the read-out unit is described. A ten bit system has been constructed, giving 0.1% resolution over 360 of arc. It is believed that this is the largest number of channels to date to be wavelength multiplexed into a single fibre waveguide.
Measurement and Control Problems of a Multinational Pharmaceutical Manufacturer
Authors: Smith Ray
Published: November 2015

Although making specific reference to pharmaceutical production the problems and principles described apply to a wide variety of industries, and may therefore be of general interest. In the spirit of technology transfer the paper is deliberately written in ‘mid-Atlantic’ English.

The author is a specialist engineer within the Project Unit of a major UK-based pharmaceutical company, which operates a broadly decentralised management structure. The views expressed are his own and do not necessarily represent those of the company.
Selecting a Control Valve for a Given Service
Authors: Orr H , Papoutsis N
Published: November 2015

The final year studies of BEng Instrumentation and Control Engineering at Teesside Polytechnic includes project work undertaken by an individual student and supervised by a member of staff. ‘Selecting a control valve for a given service’ formed part of the project carried out by N Papoutsis who graduated in June 1984, supervised by H Orr, Senior Lecturer in Control Engineering.
An Introduction to Kalman Filters
Authors: Dean G C
Published: November 2015

Kalman filters are a powerful tool for reducing the effects of noise in measurements. This paper gives a no-nonsense introduction to the subject for people with A-level maths. The basic ideas of getting better estimates from many measurements are simply introduced. Thereafter, the basics are gradually developed, using worked examples, to a full Kalman filter. Wherever possible, variations, simplifications, and applications are given in the hope that the reader will be encouraged to use Kalman filter techniques
Computer Aided Identification of an Air Heating System
Authors: Mercer R M , Mailey S G
Published: November 2015

A system testing and identification package has been developed on an HP1000 minicomputer. The package contains components to allow the user to synthesise test signals, conduct tests on on-line systems, spectral analyse system responses and derive frequency responses and s-domain transfer functions. The package is illustrated by consideration of its application to the identification of a simple air heating system exhibiting significant transport delay.
The Durham MEng Degree Course — An Innovation in Postgraduate Education
Authors: Holgate M J
Published: November 2015

MEng Courses — A clarification for readers of the following article: The Engineering Council defines MEng Degree courses in its Sartor document as follows: ‘It is Council policy that degree courses in engineering accredited in relation to stage 1 of the Chartered Engineer Section of the register should be designated as Bachelor of Engineering (BEng) or if appropriately extended as Master of Engineering (MEng). The Council disapproves of and will strongly discourage, the use of these titles for other courses.’ The Engineering Council further defines MEng as ‘an extended course’ and recommends that selection to an ‘extended’ degree course should include assessment during the first two years of an accredited ‘enhanced’ degree course and performance at an interview.

The Durham MEng Course (as well as some other similar courses at various Universities) is a very good course but is essentially a one year postgraduate Course and therefore runs counter in concept to the stated policy of the Engineering Council. This explanation is given to avoid any confusion which may be engendered in the mind of the reader.
Ultrasonics Advance at Mach 1
Authors: Beard Keith
Published: November 2015

This paper discusses recent developments in ultrasonic level measurement technology.
The Application of On-Line Expert Systems to Supervisory Process Control
Authors: Foster Howard M , Meadowcroft Simon R
Published: November 2015

The use of computers in the process industry is set to increase. However, the implementation of conventional computer technology is not adequate for executing the complex supervisory tasks.

This paper speculates upon the use of on-line expert systems which have been developed for working in non-linear, non-algorithmic problem domains. Expert systems for supervisory control are explored, and the potential benefits for optimisation and improved accuracy of control are outlined.

The complexity and multi-tasking nature of real-time supervisory control points to an expert system structure which is distributed. A modular expert system design is proposed and the potential benefits for the approach are evaluated.
Monitoring and Controlling the Public Telephone Network
Authors: Leakey D M
Published: November 2015

The telephone network is a complex system of switching and transmission equipment to enable any of tens and internationally hundreds of millions of telephones to be interconnected in virtually any combination. To ensure optimum performance various performance criteria have to be agreed and then monitored and controlled. This network management function has to be effective in the presence of rapid modernisation where new generations of equipment have to interwork with older generations in a manner not directly evident to the customer.
Trends in the Development of Gas Sensors
Authors: Jones T A
Published: November 2015

Recent developments in various types of gas sensing devices are examined and the advantages and disadvantages of currently available sensors in relation to the various application areas are summarized. Possible directions of future development are identified and discussed. The trends in the ways that sensors are utilized and the possible impact of new developments in a number of application areas are considered.
The Single European Act — 1992: Implications for Measurement and Control
Authors: Cornish Derek
Published: November 2015

The 31 December 1992 completion of the internal market as envisaged in the Single European Act will have far-reaching consequences for all Europe, as member-states, companies, employers, employees and as individuals. Not all the consequences can be foreseen, but progress is being achieved at an ever faster pace. The estimated economic gains of £140 billion or more and the creation of millions of new jobs are powerful incentives!

What will be the impact on instrumentation, measurement and control? This introductory article by the President is the first of a series to be published in Measurement and Control, each being written from a different viewpoint. They will address the issues involved and seek to highlight the evolving situations.
Mass Flow Measurement — A State of the Art Review
Authors: Medlock R S , Furness R A
Published: November 2015

The paper presents a detailed and comprehensive review of the techniques of mass flow measurement and the present state of knowledge and experience. The techniques are classified under three main headings: Direct, Thermal, and Indirect. Special attention is given to Coriolis types since these are the meters which are generating considerable interest in the field of flow measurement. Areas addressed include tube materials, design changes and the problems of verifying installed performance.

Applications are covered only superficially and a section is included on the various committees looking at the possibilities of producing Coriolis meter standards. A brief reference is made to mass flow techniques for solids. Finally an assessment is made of future applications and possible trends in metering developments.
Moisture Measurement during Biscuit Manufacture
Authors: Leach K G
Published: November 2015

Final moisture content of baked products is an important quality parameter which affects shelf life. Standard laboratory methods of measuring moisture content require skilled personnel to perform the analysis which can take upwards of an hour. Other off-line ‘quick’ methods are sensitive to initial settings and operator performance. These off-line methods also involve the operators in sample selection, transport and preparation, a procedure that can be a prime source of additional errors.

A requirement exists for a rapid online measurement technique capable of close performance to the reference methods of moisture determination. This paper describes the application of an instrument employing infra-red back-scatter techniques to work effectively online for the measurement of moisture content in discrete biscuit products.
An Ada-Based On-Line Computer System for AGR Power Stations
Authors: Clarke R , Humphries F
Published: November 2015

Nuclear Electric have commissioned Ferranti International to develop a replacement system for their on-line computer systems in earlier AGR power stations. This system represents a step forward both in software and performance and takes advantage of investment made for military use in the Ada Language, CASE tools and a high-performance real-time relational database.
Tensile Creep and Creep Rupture of Continuous Strand Mat Polypropylene Composites
Authors: Little R. E. , Mitchell W. J. , Mallick P. K.
Published: November 2015

This paper describes an experimental study on the tensile creep behavior of a random continuous fiber mat reinforced polypropylene composite, commercially known as Azdel. A special experimental setup was designed and used to conduct these creep tests at 75 and 100°C with stress levels ranging from 30 to 60 percent of the tensile strength of Azdel. The test duration was 3,000 hours or the time to creep rupture response, whichever occurred first. A straight line on a semi-log plot adequately described the relationship between the imposed stress and the creep rupture response time for the range of stress levels studied. Moreover, the estimated secondary creep rate was inversely related to the observed creep rupture response time.
Neurotransmitter Control of Secretion
Authors: Baum B. J.
Published: November 2015

It is very well established that the principal control of salivary secretion is derived from autonomic innervation. Transmission of a neural signal to a salivary gland acinar cell occurs chemically via neurotransmitters, the first messengers of a secretory response. Neurotransmitters bind to specific cell surface receptor proteins, an event which activates precise transduction mechanisms which then transfer the neural signal to the inside of the cell. There are two major transduction mechanisms operative in salivary gland acinar cells. One involves the generation of cAMP, the other involves the breakdown of plasma membrane polyphosphoinositides. For both mechanisms, the appropriate stimulated receptor activates a second plasma membrane protein, termed an N (or G) protein. The N protein requires GTP to activate an enzyme (adenylate cyclase or phospholipase C), which then catalyzes the formation of a second messenger (cAMP and inositol trisphosphate/diacylglycerol, respectively). This action provides the intracellular signal for secretory events (protein, fluid, electrolyte secretion) to begin.
Use of Human Minor Salivary Glands in Basic and Applied Secretion Research
Authors: Izutsu K.T. , Schubert M.M. , Truelove E.L. , Johnson D.E.
Published: November 2015

Previous findings from studies utilizing human labial and palatine minor salivary glands are reviewed. These studies took histopathological, biochemical, and ultrastructural approaches, and focused on control and diseased glands. Disease-oriented summarizations are used, and control results are discussed in the context of disease-related findings. Findings are reviewed separately for electrolytes, macromolecules, and ultrastructure. In control subjects, minor gland salivary electrolyte concentrations are dependent on flow rate, and this dependence may be altered by diseases such as cystic fibrosis as-well as by inflammatory situations such as graft-versus-host disease. There is also evidence that salivary electrolyte secretion processes are not similar in labial and palatine minor glands. Studies of salivary macromolecular composition are reviewed for control subjects and for patients with graft-versus-host disease and Sjögren's syndrome. The findings indicate that the macromolecular contents of labial and palatine gland saliva are similar, but that both are significantly different from that for major gland saliva. Finally, studies attempting to measure disease-related changes in intracellular composition are reviewed. It is concluded that the minor salivary glands are important models for the study of exocrine gland physiology and pathophysiology in man.
Chemical Events During Tooth Dissolution
Authors: Ingram G.S.
Published: November 2015

Information on chemical changes during enamel dissolution has been collected from investigations on hydroxyapatite solubility, enamel solubility, artificial lesion formation, and natural caries.

Although hydroxyapatite and enamel will ultimately dissolve in acid or during caries, compositional changes also occur. Most notably, there is a preferential dissolution of calcium, both from hydroxyapatite and from enamel, and of carbonate and magnesium from enamel. Root dentin yields substantial amounts of magnesium on acid attack Fluoride may be involved in surface zone formation during attack, but an additional theory of coupled diffusion is described.

Calcium-deficient mineral is produced during an acid attack, and this has lattice parameters and solubility behavior different from those of stoichiometric material. The interaction of fluoride produces a more stable lattice, resisting dissolution and favoring accretion, and tending to counteract the effects of carbonate and magnesium in forming mineral. The provision of fluoride, albeit at low levels, in plaque fluid is seen as being important in maintaining the net integrity of the tooth. More information is also needed on the role of the organic phase in tooth structures during caries and acid attack.
In vitro Studies on the Effects of Fluoride on De- and Remineralization
Authors: Cate J.M. Ten
Published: November 2015

The recent literature extensively describes the role of ambient fluoride in the de- and remineralization of dental enamel. Fluoride in sub-ppm concentrations is effective in promoting mineral deposition and inhibiting mineral dissolution. The latter phenomenon is most likely attributable to the concomitant precipitation of a fluoride-rich mineral phase which inhibits further dissolution. These fundamental processes result in an inhibition of enamel demineralization and an enhancement of enamel lesion remineralization. Alternatively, fluoride may also induce the ‘arrestment’ of enamel lesions. For the in vivo patterns and the effects of caries-preventive substances to be studied, de- and remineralization can best be examined with a pH-cycling system in which the pH depressions occurring in the oral environment are mimicked in a laboratory model. Such an approach has proved useful in developing optimal fluoride schemes which can be tested in animal, intraoral, and clinical studies.
Nature and Mechanisms of Dental Fluorosis in Animals
Authors: Richards A.
Published: November 2015

Recent studies of dental fluorosis in animals have been reviewed. The aim was to describe studies which have provided information which may be relevant to explaining the mechanisms involved in human dental fluorosis.

Studies on rats, sheep, and pigs have provided details of dosage regimens which produce lesions which resemble those described in human fluorosis. In the pig and rat, the plasma fluoride concentrations associated with these dental lesions are of the same order of magnitude as those which may occur in man.

Three different kinds of studies in different species have shown that fluoride affects processes occurring during enamel maturation. One study on rats has indicated that fluoride may reduce matrix removal during maturation by an effect on enamel proteases. Many studies have demonstrated accumulation of fluoride in secretory enamel and that fluoride concentrations in maturation enamel are lower than in secretory enamel. This phenomenon had previously been explained by the binding of fluoride to enamel proteins, but recent studies indicate that such binding does not occur. The hypothesis that enamel fluorosis might be caused by general effects of fluoride on calcium metabolism has not been supported by more recent studies. It was concluded that, although the mechanisms involved in dental fluorosis remain obscure, recent animal studies do seem to have provided new information which may prove to be important for our understanding of mechanisms whereby fluoride causes dental fluorosis in man.
Dental Caries in Developing Countries in Relation to the Appropriate Use of Fluoride
Authors: Manji F. , Fejerskov O.
Published: November 2015

Although it is widely believed that caries prevalence in developing countries is increasing rapidly, a review of studies from Africa and China provides equivocal evidence. Data from child and adult populations indicate that the disease is almost ubiquitous but with a slow rate of progression. Theoretically, administration of fluoride in such populations should result in reducing caries progression rates, but too little is known about the magnitude of the effect, and therefore about the cost-effectiveness of different methods of fluoride administration. The lack of a developed infrastructure and of trained personnel in many developing countries limits the applicability of many strategies. Methods of fluoride administration that minimize systemic exposure are to be recommended where affordable or practical. In the light of economic constraints and slow caries lesion progression rates, however, improvements in oral hygiene practices may be the most important method of controlling the disease whether or not fluoride is available or accessible.
Clinical Evidence of the Role of Pre-eruptive Fluoride in Caries Prevention
Authors: Thylstrup A.
Published: November 2015

Recent clinical and laboratory evidence has suggested that systemic fluoride plays a more minor role in caries inhibition than was previously believed. This paper reviews clinical data on water fluoridation, the topical administration of fluorides, and fluoride supplements in the light of more recent understanding of the disease dental caries. Due to reduced functional usage, erupting teeth tend to accumulate plaque which has cariogenic potential. For this reason, the period from tooth emergence to the establishment of interproximal contact and full occlusion is the most critical for caries initiation. Analyses of clinical data indicate that maximum protection against caries is obtained when teeth erupt into an environment with low concentrations of ionic fluoride. The similarity in caries reductions obtained in water fluoridation studies and long-term studies with topically administered fluoride regimens, including fluoride-containing dentifrices, indicates that the pre-eruptive effect of fluoride is of borderline significance relative to the more significant post-eruptive effect. Water fluoridation and topical fluoride programs are thus important measures for the control of caries at the community level. For the individual, topical application of fluoride is seen as an integral part of caries treatment aimed at arresting progressive caries. Fluoride application is thus considered a supportive therapy, in conjunction with cariogenic plaque control. Daily use of fluoridated dentifrices from tooth eruption is more efficacious than daily use of fluoride supplements from birth.
Critical Evaluation of the Composition and Use of Topical Fluorides, with Emphasis on the Role of Calcium Fluoride in Caries Inhibition
Authors: Rølla G. , Saxegaard E.
Published: November 2015

There is evidence that a major part of the fluoride which is retained on teeth during topical application is calcium fluoride or calcium fluoride-like, and that this material is relatively stable in the mouth. This is due to surface adsorption of phosphate (HPO42–) ions onto the calcium fluoride surface. Calcium fluoride releases fluoride during caries challenges due to reduced concentration of HPO42–at acid pH. Normally, the fluoride released from calcium fluoride during caries challenges is subsequently built into hydroxyfluorapatite through dissolution/re-precipitation reactions.

It appears likely that the formation of calcium fluoride from topical application agents should be increased and not reduced, as believed in the past. Increased deposition of calcium fluoride can be achieved with increased reaction time between fluoride and enamel, reduced pH of the solution, increased concentration, or pre-treatment with calcium. A reduction in pH of the agents is probably the most practical approach to increase the deposition of calcium fluoride during topical application, and clinical data support this contention. Calcium fluorides with various dissolution rates are formed during different procedures of topical application with fluoride, presumably due to incorporation of phosphate into the calcium fluoride crystals.
Cross-Lagged Relationships among Adolescent Problem Drug Use, Delinquent Behavior, and Emotional Distress
Authors: Van T. Bui Khanh , Ellickson Phyllis L. , Bell Robert M.
Published: November 2015

This study examines the cross-lagged relationships among problem drug use, delinquent behavior, and emotional distress in a sample of 3,458 adolescents from California and Oregon. The analyses used data collected from participants in grades 10 and 12 (or equivalent). Structural equation modeling with latent variables showed strong cross-sectional correlations among these problems, strong stability effects for all three problems, and only one cross-lagged effect (greater frequency of delinquent behavior at grade 10 led to greater problem drug use at grade 12). Multisample analyses by ethnicity (Asian, Black, Latino, and White) showed that the cross-lagged effect was not statistically different in these four groups. The results suggest that curbing delinquent behavior might contribute to the prevention of problem drug use.
Personality, Environment, and Problem Drug Use
Authors: Curran Geoffrey M. , White Helene R. , Hansell Stephen
Published: November 2015

We tested a theoretical model that posited direct and Interactive relationships between personality and environment as predictive of problem drug use. Hierarchical regression analyses were performed on data from a nonclinical sample of males and females first tested in adolescence and followed into young adulthood. In main effects analyses, cross-sectional models for marijuana and a composite of “harder” drugs strongly supported our theoretical perspective: several environmental and personality variables significantly predicted concurrent problem use. Longitudinal analyses produced mixed results, with either smaller numbers of significant personality/environment predictors or personality predictors dropping out completely. Peer drug use and depression best predicted problem “hard” drug use, while motivations to use with others and disinhibition best predicted problem marijuana use. Personality/peer group interactions were significant both cross-sectionally and longitudinally, indicating that membership in a problem-using social network enhanced the predictive ability of, or helped bring to fruition, several personality predisposers.
Context Dissonance in Tobacco Education Literature
Authors: Shevalier Rae
Published: November 2015

Tobacco education has gained widespread popular and political support and Is incorporated into many public schools' curricula. However, evaluation studies indicate that such programs do not decrease adolescents' smoking rates because program content is often dissonant with adolescents' interpretations of smoking. This study uses social constructionism and content analysis to explore tobacco education literature used in an alternative high school for at-risk youths. Findings indicate that the content's construction of smoking and cessation is dissonant with adolescents' subcultural social contexts. Dissonance-generating elements include decontextualization of smoking; suggested alternatives that are Improbable in adolescents' social contexts; and image biases that reflect stereotypes of age, class, and gender. The conclusion suggests ways to eliminate context dissonance in order to increase adolescents' receptivity to intervention efforts.
Injection Drug Use and Unprotected Sex among Institutionalized Drug Users in China
Authors: Li Xiaoming , Stanton Bonita , Zhou Yong
Published: November 2015

The current study was designed to examine injection drug use practices (injecting drugs and needle sharing) and unprotected sexual behaviors (multiple sexual partners, failure to use a condom) among drug users in China. Data were obtained from 833 institutionalized drug users in southwest China. More than two-thirds of the sample reported frequent intravenous or intramuscular drug-injection. Among injection drug users (IDUs), 78% shared needles. Compared to non-IDUs, IDUs who also shared needles had significantly higher rates of having multiple sexual partners (73% versus 54%, p<.001) and of never having used a condom (71% versus 56%, p<.01). The data in this study suggest that IDUs comprise a high-risk population for HIV infection in China and underscore the urgency for preventing injection drug use and unprotected sexual practices among drug users in China.
Questioning Sex: Drug-Using Women and Heterosexual Relations
Authors: Mulia Nina
Published: November 2015

Historically, views of sexuality have been used to marginalize poor women, women of color, and colonized women. The concept of deviant sexuality remains discernible today in scientific and popular responses to drug addiction and the AIDS epidemic that essentialize low-income, drug-using women as disease vectors and dangerous mothers. Using data from in-depth qualitative interviews with 28 women, this paper brings to light the perspectives and experiences of these materially and culturally marginalized women—speaking on, interrogating, and analyzing heterosexual relations. This paper finds that commodified (“deviant”) sexual relations are not homogeneous; that some intimate (“normative”) relations incorporate sex as a form of reciprocity; and suggests that these varied forms of exchange are not confined to poor and drug-using women but are consonant with dominant cultural practices. Ultimately the presence and form of exchange are conditioned by women's (and men's) positioning within economic systems and cultural norms delineating gender and sexuality.
Client Gender and the Implementation of Jail-Based Therapeutic Community Programs
Authors: Bouffard Jeffrey A. , Taxman Faye S.
Published: November 2015

Using a structured observation methodology, the researchers examined the degree to which the content of a set of therapeutic community (TC) programs for jail detainees varied based on the gender of the participants. The observation technique allowed the researchers to examine the theoretical orientation of the program, the therapeutic tools used in the treatment programs, and the content of individual sessions. The four programs had mixed success in providing gender-specific services as suggested by previous research on the treatment needs of women. While the implementation of these four programs did vary according to client gender, these variations did not always represent the delivery of appropriate gender-specific treatment. Overall, men's treatment sessions focused on motivation building and relapse prevention, and women's meetings focused on aftercare planning and spirituality. Furthermore, the sessions for males used more structured therapeutic techniques, while the females' meetings were less structured. The authors suggest that a more comprehensive therapeutic approach, combining pro-social value reinforcement and specific skill development, might be more successful in addressing the multiple and complex needs facing women in residential substance abuse treatment, as identified in previous research.
Magic Mint, The Internet, and Peer Associations: A Test Of Social Learning Theory Using Patterns of Salvia Divinorum Use
Authors: Lee Miller Bryan , Stogner John M. , Khey David N. , Akers Ronald L. , Boman John , Griffin O. Hayden
Published: November 2015

As new drugs are introduced into the market, it becomes the role of policy makers to assess the dangers associated with each drug and its potential to be misused by the populace. The focus of this research is to better understand how young adults learn about a new drug and subsequently engage in its use. Salvia divinorum is a plant species whose leaves contain psychoactive components. Its recreational use among teenagers and young adults has received increased media and policy attention. Several states have taken the initiative to ban this substance. Despite this legal action, little is known about why this substance has gained in popularity and what factors contribute to its use. Akers’ social learning theory offers one explanation for why individuals experiment with drugs. We employ a sample of college students from a large public university to test Akers’ propositions, finding support for his theory.
The Bitter and/or Better Medicine of Drug Abuse
Authors: Yolles Stanley F.
Published: November 2015

In the current profile of the use and abuse of illicit drugs, there is evidence that most individuals within the population are involved in some facet of the “drug problem,” either directly or indirectly. There is further evidence that the problem itself has become a political issue, as well as projected solutions to the problem. Simultaneously, as medical and other health professionals search for answers to effective treatment of minors whose legal status is changing, there is evidence that a significant number of young people have become “turned off” by drugs and are seeking alternate pursuits. As a result, the quest for “alternatives to drug abuse” is an increasing concern among various communities of interest throughout the United States.
The Heroin Problem: Policy Alternatives in Dealing with Heroin Use
Authors: Marks Robert E.
Published: November 2015

The paper examines the social and private aspects of heroin use in the U.S. today and attempts to estimate the associated costs, both society's and the individual user's. Possible goals of any government policy are discussed. Twelve possible policy alternatives are examined, eight dealing with the demand for heroin, and four dealing with its supply. These alternatives are compared using a rough cost-benefit analysis in terms of costs and benefits to society at large. A more detailed comparison is made of therapeutic communities, methadone maintenance, and the British experience of prescription heroin maintenance as alternatives. The conclusion is reached that to minimize social cost while containing the spread of heroin usage a scheme of prescription heroin should be implemented; but if the spread of usage is seen as benign, the best policy is to sell the drug freely to any adult as alcohol is today.
Planning for the Development of Comprehensive Community Alcoholism Services: Organizational Approaches
Authors: Beigel Allan
Published: November 2015

A comprehensive community alcoholism program can become viable regardless of the manner in which it is formed, the agencies that may be involved and the number of different sub-systems of service that need to be developed only if there is an effective cohesion of these elements. In this paper, the third in a series on alcoholism planning (1, 2), the advantages and disadvantages of four different approaches to the organization of “comprehensive” (all necessary services) community-based alcoholism services are presented. The selection of a specific concept of organization will depend upon the kinds of agencies involved, the existing services and their relationships and the particular individuals involved in the planning process. These approaches are as follows 1) the “governmental approach”; 2) the “single community agency approach”; 3) the “consortium model approach”; and 4) the “for profit approach”.

Regardless of which approach is chosen, there are certain substantive issues that transcend any and all of these organizational approaches. Without paying attention to them, those involved in planning will undermine their own ability to successfully implement the chosen organizational approach. Substantive underlying issues discussed include community boards, traditional versus non-traditional approaches to the delivery of alcoholism services, pre-program planning, continuity of care and funding. A “comprehensive” community alcoholism program which includes all services necessary for the information of a total treatment system, must become viable regardless of how it is formed or the number of agencies involved. Unless these multiple elements are integrated, service delivery will be inadequate. Consequently, the development of an administrative structure requires clearly defined lines of communication and responsibility between care-giving agencies, institutions and the community. Effective service delivery and continuity of care are directly related to the administrative structure.

The specific concept of administrative organization selected will depend upon the kinds of agencies involved, existing services and their relationships and those individuals involved in the planning process.