bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined Conduction, Natural Convection, and Radiation Heat Transfer in an Electronic Chassis
Authors: Smith T. F. , Beckermann C. , Weber S. W.
Published: April 2008

A numerical study of the combined heat transfer by conduction, natural convection, and radiation in a sealed electronic package is reported. The goal of the study is to investigate the importance of the various heat transfer modes, the effectiveness of different heat transfer paths, and the impact of a number of design changes on the overall thermal performance of a typical electronic package. The package consists of an enclosure containing three printed circuit boards on which are mounted various heat-generating electronic components. Heat transfer processes at both small (i.e., inside a component) and large (i.e., the package) scales as well as all heat transfer modes are included simultaneously in the numerical model. Both one and two-dimensional radiation is considered. Results are presented in terms of streamline and isotherm plots and average temperatures and heat transfer rates. Overall, the numerical data show favorable agreement with available empirical data. One significant conclusion is that natural convection inside the enclosure has only a minor effect on the heat transfer in the present system.
Constriction Resistance in Rectangular Bodies
Authors: Krane Matthew John M.
Published: April 2008

Steady conduction equations are solved for two and three-dimensional rectangular bodies with a constant temperature sink and heat applied over a portion of the opposite face. The solutions, with previously published solutions to similar bodies with convective boundary conditions at the sink, are presented as dimensionless resistances in such a way that a designer can easily use them to predict the effect of constriction of flux lines on the overall resistance of the bodies.
Effects of Peeling Stresses in Bimaterial Assembly
Authors: Mirman Ilya B.
Published: April 2008

Peeling stress is experimentally shown to be an important factor for delamination in thermally mismatched bimaterial assembly. Strips of the plastic ULTEM-1000 and nickel alloy Kovar were attached with Devcon 14200 epoxy, and the temperature was raised from the stress-free curing temperature for one set of samples, and lowered for another set of samples, resulting in interfacial stresses. The samples that delaminated had the highest peeling stress.
Heat Transfer in Wire Bonding Process
Authors: Jog M. A. , Cohen I. M. , Ayyaswamy P. S.
Published: April 2008

We have analyzed an electric discharge between wire and planar electrodes with wire diameter and current densities that are typically used in upscaled experimental simulations of the wire bonding process employed in microelectronic manufacturing. A set of continuum conservation equations has been solved to obtain the variation of electric potential, temperature distributions, and the electrode heat fluxes. Results indicate that the main body of the discharge is quasineutral bounded by space charge sheaths at both electrodes. Strong electric fields are concentrated in the electrode sheaths. The heat flux to the wire is sharply peaked near the wire tip but on the plane it decays slowly away from the discharge axis. The model studied here may be used to establish optimum discharge parameters for wire bonding.
Use of a Two-Dimensional Simulation Model in the Thermal Analysis of a Multi-Board Electronic Module
Authors: Beckermann C. , Smith T. F. , Pospichal B.
Published: April 2008

A study is reported of heat transfer and air flow in an electronic module consisting of an array of narrowly spaced vertical circuit boards with highly-protruding components contained in a naturally vented chassis. A two-dimensional simulation model is developed that accounts for heat transfer by conduction, convection, and radiation, and sensitivity studies are performed. Experiments are conducted using a specially constructed test module. Comparisons with the experiments reveal the need to calibrate the model by selecting an effective component height that represents the drag properties of the actual three-dimensional component geometry. The need to account in the model for heat losses in the depth direction is also discussed. The importance of accurate thermophysical properties and of multi-dimensional radiation is shown. Good agreement with measured velocities and local board temperatures is obtained over a wide range of power levels, and it is concluded that the calibrated model is capable of representing the thermal behavior of the present module.
Bending and Twisting of 60Sn40Pb Solder Interconnects With Creep
Authors: Lau John H.
Published: April 2008

An exact analysis is presented for the creep deformation of a thin-walled circular solder cylinder under the actions of bending and twisting moments. Dimensionless interaction curves and charts which relate the variables, interconnect geometry, solder material properties, bending moment, twisting moment, curvature rate, and twist rate are also provided for engineering practice convenience.
Experimental Analysis of Thermal Cycling Fatigue of Four-Layered FR4 Printed Wiring Boards
Authors: Pan Tsung-Yu , Cooper Ronald R. , Blair Howard D. , Whalen Thomas J. , Nicholson John M.
Published: April 2008

Long-term reliability of electronic packaging has become a greater challenge as a result of ever increasing power requirements and the decreasing size of electronic packages. In this study, the effects of three variables on plated-through hole (PTH) design have been investigated on the thermal cycling fatigue lives in four-layered printed wiring boards (PWB’s). These three variables were evaluated at two levels each: (a) hole size (0.030 and 0.040 in.), (b) internal pad (presence or absence), and (c) epoxy-plugged holes (plugged or unplugged). The electrical resistance was measured on 40 test boards with 23 design of 8 daisy-chain PTH nets each. Full factorial analysis and analysis of variance indicate that all three factors had significant influence on PTH fatigue life, but no two-factor or three-factor interactions were found. Metallurgical analysis reveals that the failure mechanism is barrel cracking near the internal pad. This mechanism has been illustrated by a finite element analysis in this study and correlated by a SEM stereoimaging analysis in the literature. The increase of electrical resistance with thermal cycles correlates well with an analytical barrel crack model. The crack length in each net at specific cycles is calculated, but fails to match predictions from a fracture mechanics model.
Local PWB and Component Bowing of an Assembly Subjected to a Bending Moment
Authors: Barker D. B. , Sidharth
Published: April 2008

An analytical model is developed for determining the bowing of a component mounted on a printed wiring board (PWB) that is subjected to a bending moment. The model assumes a uniform elastic attach, between the component and the board. The elastic attach is assumed to transmit axial forces and restrain cross-sections of the component against rotation. The closed form solution to the beam equations directly determines the bowing of the component and the board. The solution is then used for computing the forces and moments, and hence, stresses in the leads that can occur in static or vibrational loading of a PWB/component assembly. The present analysis applies to electronic components with uniformly distributed leads in an array format, such as some PGA components, or to the class of components with parallel rows of leads such as a DIP or a SOIC. To demonstrate the solution and whether or not the rotational stiffness of the component leads needs to be considered, three different types of packages are analyzed.
Forward‐planning intensity‐modulated radiotherapy technique for prostate cancer
Authors: Metwaly Mohamed , Awaad Awaad Mousa , El‐Sayed El‐Sayed Mahmoud , Sallam Abdel Sattar Mohamed
Published: April 2008

In this study, we present an intensity‐modulated radiotherapy technique based on forward planning dose calculations to provide a concave dose distribution to the prostate and seminal vesicles by means of modified dynamic arc therapy (M‐DAT). Dynamic arcs (350 degrees) conforming to the beam's eye view of the prostate and seminal vesicles while shielding the rectum, combined with two lateral oblique conformal fields (15 degrees with respect to laterals) fitting the prostate only, were applied to deliver doses of 78 Gy and 61.23 Gy in 39 fractions to the prostate and seminal vesicles respectively. Dynamic wedges (45 degrees of thick end, anteriorly oriented) were used with conformal beams to adjust the dose homogeneity to the prostate, although in some cases, hard wedges (30 degrees of thick part, inferiorly oriented) were used with arcs to adjust the dose coverage to the seminal vesicles. The M‐DAT was applied to 10 patients in supine and 10 patients in prone positioning to determine the proper patient positioning for optimum protection of the rectum. The M‐DAT was compared with the simplified intensity‐modulated arc therapy (SIMAT) technique, composed of three phases of bilateral dynamic arcs. The mean rectal dose in M‐DAT for prone patients was Gy; in M‐DAT and SIMAT for supine patients, it was Gy and Gy respectively. The doses to 15%, 25%, 35%, and 50% of the rectum volume in M‐DAT for prone patients were Gy, Gy, Gy, and Gy respectively. These values were lower than those in M‐DAT and in SIMAT for supine patients by 7.7%, 18.2%, 22.4%, and 28.5% and by 25.0%, 32.1%, 34.9%, and 41.9% of the prescribed dose (78 Gy) respectively. Ion chamber measurements showed good agreement of the calculated and measured isocentric dose (maximum deviation of 3.5%). Accuracy of the dose distribution calculation was evaluated by film dosimetry using a gamma index, allowing 3% dose variation and 4 mm distance to agreement as the individual acceptance criteria in prostate and seminal vesicle levels alike for all supine and prone patients. We found that fewer than 10% of the pixels in the dose distribution of the calculated area of failed the acceptance criteria. These pixels were observed mainly in the low‐dose regions, particularly at the level of the seminal vesicles.

In conclusion, the single‐phase M‐DAT technique with patients in the prone position was found to provide the intended coverage of the prescribed doses to the prostate and seminal vesicles with improved protection for the rectum. Accordingly, M‐DAT has replaced non‐modulated conformal radiotherapy or SIMAT as the standard treatment for prostate cancer in our department.

PACS number: 87.53.Tf
Three‐dimensional quantitative dose reduction analysis in MammoSite balloon by Monte Carlo calculations
Authors: Zhang Zhengdong , Parsai E. Ishmael , Feldmeier John J.
Published: April 2008

Current treatment planning systems (TPSs) for partial breast irradiation using the MammoSite brachytherapy applicator (Cytyc Corporation, Marlborough, MA) often neglect the effect of inhomogeneity, leading to potential inaccuracies in dose distributions. Previous publications either have studied only a planar dose perturbation along the bisector of the source or have paid little attention to the anisotropy effect of the system. In the present study, we investigated the attenuation‐corrected radial dose and anisotropy functions in a form parallel to the updated American Association of Physicists in Medicine TG‐43 formalism. This work quantitatively delineates the inaccuracies in dose distributions in three‐dimensional space. Monte Carlo N‐particle transport code simulations in coupled photon–electron transport were used to quantify the changes in dose deposition and distribution caused by the increased attenuation coefficient of iodine‐based contrast solution. The source geometry was that of the VariSource wire model VS2000 (Varian Medical Systems, Palo Alto, CA). The concentration of the iodine‐based solution was varied from 5% to 25% by volume, a range recommended by the balloon's manufacturer. Balloon diameters of 4, 5, and 6 cm were simulated. Dose rates at the typical prescription line (1 cm away from the balloon surface) were determined for various polar angles. The computations showed that the dose rate reduction throughout the entire region of interest ranged from 0.64% for the smallest balloon diameter and contrast concentration to 6.17% for the largest balloon diameter and contrast concentration. The corrected radial dose function has a predominant influence on dose reduction, but the corrected anisotropy functions explain only the effect at the MammoSite system poles. By applying the corrected radial dose and anisotropy functions to TPSs, the attenuation effect can be reduced to the minimum.

PACS number: 87.53.‐j
Clinical assessment and characterization of a dual‐tube kilovoltage X‐ray localization system in the radiotherapy treatment room
Authors: Lee Sung‐Woo , Jin Jian‐Yue , Guan Huaiqun , Martin Flavious , Kim Jae Ho , Yin Fang‐Fang
Published: April 2008

Although flat‐panel kilovoltage X‐ray imaging devices have been well tested for clinical use in diagnostic radiology, their use as a part of an image‐guided radiation therapy (IGRT) system in a treatment room is new and requires systematic assessment.

We used the Novalis IGRT system (BrainLAB, Feldkirchen, Germany) for the present study. The system consists of two floor‐mounted kilovoltage X‐ray tubes projecting obliquely onto two flat‐panel detectors mounted on the ceiling. The system can automatically fuse two‐dimensional localization images with three‐dimensional simulation computed tomography images to provide positioning guidance. We evaluated these system parameters:

Overall performance of the IGRT system, including isocenter correlation between the IGRT system and the linear accelerator (LINAC)

Image quality of the system

Exposure received by patients for a pair of images

Linearity, uniformity, and repeatability of the system

The Novalis system uses a daily isocenter calibration procedure to ensure consistency of isocenters between the IGRT and the LINAC systems. The localization accuracy was about 1 mm. We measured the relative modulation transfer function (RMTF) to quantify the spatial resolution of the imaging device, with being 0.7 – 0.9 line pairs per millimeter. The maximal exposure of an image was 95 mR. We derived an empirical relationship between the exposure and the X‐ray technical settings. The other parameters of the system were quantitatively measured and generally met the requirements.

The IGRT system is safe and reliable for clinical use as a target localization device. The measured data can be used as a benchmark for a quality assurance procedure.

PACS number: 87.56‐v
The medical student global health experience: professionalism and ethical implications
Authors: Shah S , Wu T
Published: April 2008

Medical student and resident participation in global health experiences (GHEs) has significantly increased over the last decade. In response to growing student interest and the proven impact of such experiences on the education and career decisions of resident physicians, many medical schools have begun to establish programmes dedicated to global health education. For the innumerable benefits of GHEs, it is important to note that medical students have the potential to do more harm than good in these settings when they exceed their actual capabilities as physicians-in-training. While medical training programmes are beginning to provide students with the knowledge to put their GHEs in context, they must remember that they also bear the responsibility of training their students in a framework to approach these experiences in a principled and professional way. It is necessary that these institutions provide adequate and formalised preparation for both clinicalandethical challenges of working in resource-poor settings. This paper outlines potential benefits and risks of GHEs and delineates recommendations to some of the current issues.
Human rights and bioethics
Authors: Barilan Y M , Brusa M
Published: April 2008

In the first part of this article we survey the concept of human rights from a philosophical perspective and especially in relation to the “right to healthcare”. It is argued that regardless of meta-ethical debates on the nature of rights, the ethos and language of moral deliberation associated with human rights is indispensable to any ethics that places the victim and the sufferer in its centre.

In the second part we discuss the rise of the “right to privacy”, particularly in the USA, as an attempt to make the element of personal free will dominate over the element of basic human interest within the structure of rights and when different rights seem to conflict.

We conclude by discussing the relationship of human rights with moral values beyond the realm of rights, mainly human dignity, free will, human rationality and response to basic human needs.
Normalized behavior of clay under irregular cyclic loading
Authors: Vucetic Mladen
Published: April 2008

A systematic analysis of the undrained stress–strain behavior of clay under irregular cyclic simple shear loading is presented. Seven specimens of an offshore clay consolidated to overconsolidation ratios of 1, 2, and 4 were subjected to different combinations of variable and nonsymmetric cyclic amplitudes using the Norwegian Geotechnical Institute (NGI) direct simple shear device. The test results show that (1) the behavior under such loads is influenced by several different factors, (2) among these factors the loading history and cyclic stiffness degradation are predominant, and (3) the irregular cyclic loading stress–strain curves can be described quite well by five rules that incorporate only these two factors. Four out of these five rules are the extensions of two original and two extended Masing rules to the behaviour of cyclically degrading clay. The fifth rule is new. The effects of the S-shaping of the stress–strain curves and the rate of loading on the applicability of the rules are also discussed. The stress–strain curves are presented in the normalized form with respect to the vertical effective consolidation stress. In this form they show quantitatively the same trends, indicating that such normalization is applicable to irregular cyclic loading. Key words: clay, earthquake loading, laboratory test, ocean soil, overconsolidation, simple shear test, soil dynamics, strain rate effect, repeated loading.
Monitoring well into abandoned deep-well disposal formations at Sarnia, Ontario
Authors: Raven K. G. , Lafleur D. W. , Sweezey R. A.
Published: April 2008

A 300 m deep monitoring well was completed to the Detroit River Group of formations in Sarnia, Ontario, to evaluate the potential near-surface impacts resulting from previous deep injection of industrial waste. Detailed logging, testing, and sampling were performed to evaluate the vertical distribution of industrial waste and to determine hydraulic conductivity and hydraulic head in the disposal horizon and in the confining formations. Results of hydraulic testing indicate the hydraulic conductivity of the disposal formation is 2 × 10−9 to 2 × 10−7 m/s and that of most of the confining shale and limestone formations is less than 1 × 10−10 m/s. Analyses of groundwater samples and results from other studies show that industrial waste, characterized by elevated phenol concentrations, is present in a 10 m horizon in the Lucas dolomite disposal formation at 192 m depth. Waste is also likely present within 2–3 m thick, high-permeability limestone layers at 74 and 123 m depth in the confining units of the Hamilton Group. Because of the generally low vertical hydraulic conductivity of the confining formations, waste in the permeable limestone layers was likely introduced via poorly constructed disposal wells, cavern storage wells, or abandoned oil and gas wells. The hydraulic conductivity and hydraulic head data indicate the high pressures resulting from injection into the disposal formation have dissipated. The head within the zone of residual contamination in the disposal formation is now 8 m below the level of the St. Clair River. The hydraulic data and chemical composition of the injected waste show that the discharges of tarry liquids on the bottom of the St. Clair River in 1984 and 1985 were not caused by upward migration of injected waste. Key words: deep-well disposal, pressurized waste injection, industrial waste, Sarnia.
Soil classification using the cone penetration test
Authors: Robertson P. K.
Published: April 2008

Several charts exist for evaluating soil type from electric cone penetration test (CPT) data. A new system is proposed based on normalized CPT data. The new charts are based on extensive data available from published and unpublished experience worldwide. The new charts are evaluated using data from a 300 m deep borehole with wire-line CPT. Good agreement was obtained between samples and the CPT data using the new normalized charts. Recommendations are provided concerning the location at which to measure pore pressures during cone penetration. Key words: soil classification, cone penetration test, in situ, case history.
ARITHMETIC OF THE SPLITTING FIELD OF ALEXANDER POLYNOMIAL
Authors: KOMATSU TORU
Published: April 2008

In this paper, we study the arithmetic of the minimal splitting field of the Alexander polynomial of a knot and present two kinds of infinite families of knots, one being a family of knots which satisfy Heilbronn conjecture and the other a family of counterexamples to the conjecture.
SIMILARITY INDICES OF AMPHICHEIRAL KNOTS AND TANGLES
Authors: JEONG MYEONG-JU , PARK CHAN-YOUNG
Published: April 2008

Whether Vassiliev invariants can distinguish all knots or not is a well-known open problem which is equivalent to the question whether the similarity index of any two different knots is finite or not.

Let T and S be two tangles which are n-similar for some natural number n and let the closure [Formula: see text] of T be well-defined. Let T* and S* be the mirror images of T and S respectively. Then we show that for any prime number p, [Formula: see text] mod p for any integral Vassiliev invariant v of degree ≤ np. We also show that [Formula: see text] for any Vassiliev invariant w of degree ≤ n if n is odd. Therefore, if an amphicheiral knot can be distinguished from a trivial knot by a Vassiliev invariant, then it has an even triviality index.

From these, we get some necessary conditions for a knot invariant to be a Vassiliev invariant and get a method to detect the similarity index of two knots or tangles.
DIFFERENCE AND DIFFERENTIAL EQUATIONS FOR THE COLORED JONES FUNCTION
Authors: GAROUFALIDIS STAVROS
Published: April 2008

The colored Jones function of a knot is a sequence of Laurent polynomials. It was shown by Le and the author that such sequences are q-holonomic, that is, they satisfy linear q-difference equations with coefficients Laurent polynomials in q and qn. We show from first principles that q-holonomic sequences give rise to modules over a q-Weyl ring. Frohman–Gelca–LoFaro have identified the latter ring with the ring of even functions of the quantum torus, and with the Kauffman bracket skein module of the torus. Via this identification, we study relations among the orthogonal, peripheral and recursion ideal of the colored Jones function, introduced by the above mentioned authors. In the second part of the paper, we convert the linear q-difference equations of the colored Jones function in terms of a hierarchy of linear ordinary differential equations for its loop expansion. This conversion is a version of the WKB method, and may shed some information on the problem of asymptotics of the colored Jones function of a knot.
NONLINEAR EFFECTS IN OPTICAL FIBERS: LIMITATIONS AND POSSIBILITIES
Authors: FERREIRA MÁRIO F. S.
Published: April 2008

Nonlinear effects in optical fibers impose different limitations on the communications link, and an understanding of such effects is almost a prerequisite for actual lightwave-system designers. On the other hand, they offer a variety of possibilities for all-optical signal processing, amplification and regeneration. The nonlinear effects are enhanced dramatically, and new phenomena are observed in the so-called photonic crystal fibers. In this paper, we review the effects — both detrimental and potentially beneficial — of optical nonlinearities in conventional and in photonic crystal fibers.
ROLE OF HYSTERESIS ON THE MODE-SHIFT CHARACTERISTICS OF INJECTION LOCKING A LASER DIODE
Authors: NAKKEERAN K. , WAI P. K. A. , XU L. , LUI L. F. K. , TAM H. Y.
Published: April 2008

Using Lang's equation for the dynamics of injection locking of a laser diode, we show that the hysteresis property of the excess carrier density has direct influence on the mode-shift characteristics, which makes the shift of the slave laser mode to be different from the frequency detune of the external master laser signal within the locking range of the slave laser. The theoretical prediction is experimentally confirmed by the measurement of the mode-shift of an injection locked Fabry-Perot laser diode.
SOMATIC EVOLUTION OF CANCER
Authors: VINCENT THOMAS L. , GATENBY ROBERT A.
Published: April 2008

Human carcinogenesis may be thought of as Darwinian evolution of cells within the body (somatic evolution). As such, it may be modeled using evolutionary game theory. Winners in this game proliferate while losers become extinct. Here evolutionary dynamics are proposed that model the rate of somatic evolution. The speed at which somatic evolution proceeds determines whether a clinically significant cancer will emerge in the lifetime of the individual. The underlying model has an associated adaptive landscape that illustrates the evolutionary potential of cells due to the selection forces and microenvironment. Normal cells have a novel adaptive landscape that permits both coexistence and invasion of mutant phenotypes. A mutant cellular population does not initially form a malignancy because of constraints resulting in limited growth and nonlethal coexistence. However this coexistence deforms the local adaptive landscape resulting in the potential for evolution to drive the mutant cells to an unoccupied fitness peak resulting in an evasive cancer. There are two factors that determine this evolutionary potential. The first factor involves a relaxation of proliferation constraints and the second involves an increase in nutrients thereby removing a barrier allowing the mutant cells to climb to an adaptive peak. One unfortunate consequence of the cancer reaching this peak is that it starts producing acid that further contributes to the demise of the normal cells.
Adaptive Framework for Collisions in RFID Tag Identification
Authors: Piramuthu Selwyn
Published: April 2008

Radio Frequency Identification (RFID) is promising, as a technique, to enable tracking of essential information about objects as they pass through supply chains. Information thus tracked can be utilised to efficiently operate the supply chain. Effective management of the supply chain translates to huge competitive advantage for the firms involved. Among several issues that impede seamless integration of RFID tags in a supply chain, one of the problems encountered while reading RFID tags is that of collision, which occurs when multiple tags transmit data to the same receiver slot. Data loss due to collision necessitates re-transmission of lost data. We consider this problem when Framed Slotted ALOHA protocol is used. Using machine learning, we adaptively configure the number of slots per frame to reduce the number of collisions while improving throughput.
Knowledge Management in Business Schools
Authors: Ranjan Jayanthi
Published: April 2008

Business schools have been using information for years to improve the efficiency of academic services and effectiveness of academic programs. As more trustees, administrators, faculty, parents, students have begun to seek better outcomes, not surprisingly these schools are investing in technology. But these schools are finding that technology implementation does not necessarily improve decision-making nor does it necessarily improve outcomes and decision-making. This paves the way to recognise the urgent need for Knowledge Management (KM) which is a key asset.

A big and major crucial feature of business schools is that they are made up of a number of nested systems. In analytical terms, this can also be described as levels or units. These levels range from faculty, student, research, administration, academics and placement. The reports in business schools are numerous as the requirement of reports from level to level is difficult. Analytical needs differ, but are present at every level of the system. A robust KM system must reflect the information needs of all levels. In particular, data must be gathered at all levels to the user in a fine-grained manner. This paper explores the application KM to business schools and in particular in support of the sharing of knowledge resources. This paper considers the critical role played by the "sharing of knowledge resources" in one of top business schools, Test Business School — TBS (pseudonym is used to mask the institution name) in India.
Residual Strength: Does BS 5930 Help or Hinder?
Authors: Hawkins A. B. , Privett K. D.
Published: April 2008

BS 5930 offers little assistance to engineers wishing to use residual strength parameters in slope stability analysis. It wrongly suggests the ring shear gives lower parameters than the shear box.

BS 5930 does not mention the fact that the residual strength is stress dependent, hence the failure envelope is curved and the parameters must be assessed using an appropriate effective normal stress. For this reason the correlation charts relating
ϕ
′

R

to plasticity index or clay content need replacing with a series of charts in which these properties are plotted against
ϕ
′

R

values obtained at a number of effective normal stress loadings. Even then such correlations should be treated with caution.
A Critical Review of Section 8 (BS 5930)—Soil and Rock Description
Authors: Norbury D. R. , Child G. H. , Spink T. W.
Published: April 2008

BS 5930 proposes fundamental changes to current practice in the description of soils and rocks. The paper reviews these changes and suggests alternative proposals which provide a workable reconciliation between the aims of the new Code and current practical soil and rock description. The main changes made by the Code and the authors' recommendations are:

The distinction between fine soil and coarse soil solely on grading is rejected in favour of description according to engineering behaviour.

The distinction between silt and clay solely on the basis of the A-line is supplemented with additional terms for borderline cases.

Simplification and extension of terminology for description of secondary constituents of mixed soils.

Rejection of proposed weathering classification for rocks as inapplicable, in favour of current practice.

Clarification of rock nomenclature to conform with geological conventions.

The changes to current practice made by BS 5930 are considered to be a retrograde step and could lead to confusion and errors. The paper also considers the process of sample description and attempts to clarify the definition of terms employed in fracture logging of rock core.

The paper calls for a revision and reissue of Section 8 of the new Code.
Aspects of geology in planning
Authors: Bell F. G. , Cripps J. C. , Culshaw M. G. , O'Hara M.
Published: April 2008

The planning of man’s environment is a complex operation which requires the interaction of many disciplines. Generally speaking, the physical development of society occurs by the implementation of a series of separate, but converging, aims which may be expressed in terms of, for instance, improvements to living conditions, public health or mobility. A development plan usually attempts to achieve these aims at minimum financial cost while reconciling many conflicting influences.

So far as the use of land is concerned, since some land is inherently more suitable for some purposes than for others, there are clear cost implications in implementing a particular development plan and savings may be possible if the ground conditions are considered at an early stage. However, problems often arise with quantifying this cost due to a lack of appreciation of all the effects of a plan, including unexpected and undesirable ones.

Since many natural systems pose threats to society, they should be taken into account during planning. The monetary costs may be less tangible, but security of life, disruption to production and destruction of property all reduce the well-being of society. Whether the causative hazards are the result of either planned or unplanned changes to the environment, or due to natural processes, they can only be successfully predicted or avoided if their mode of interaction with human activities is understood.

In this paper the opportunity is taken to explore some of the more important geological factors which may significantly influence the planned use of land. Both natural and man-made geological hazards are considered. In addition, attention is given to the sources and interpretation of geological information in the context of planning.
Thematic geological mapping as an essential tool in land-use planning
Authors: Brook D. , Marker B. R.
Published: April 2008

There are many competing requirements for the use of land in the densely populated British Isles. Options are constrained by existing development, economics, the need to safeguard the environment and to reclaim damaged land, and the pressure for urban renewal. Land use planners attempt to balance the various issues and requirements and to identify the best possible solution. Geology, geotechnics, geomorphology, hydrogeology and related sciences can provide essential information on additional constraints to development (such as land instability, poor foundation conditions, active erosion and deposition, likelihood of land or water contamination, flooding and seismicity) and resources for development (including mineral and water resources, usable underground space and good foundation conditions). Recognition of these factors permits safer, more cost-effective planning and development and allows rational decisions to be taken on the exploitation or sterilization of the Earth’s resources. However, few planners and administrators have any training in these relevant sciences. Thematic geology mapping provides an important means of communicating facts and interpretations to planners but only if the results are presented in ways which can be readily understood and appreciated by non-specialists. The communication gap can only be bridged if earth scientists and planners cooperate in designing methods of map presentation.
Quaternary engineering geology
Authors: Fookes P. G.
Published: April 2008

The geological and geomorphological effects on the Earth’s surface during the Quaternary have been both extensive and profound. An attempt has been made to simplify and summarize these effects by considering the principal agencies at work during the Quaternary: plate tectonics, rapidly rising sea levels, rapidly falling sea levels, rapidly cooling climates and rapidly warming climates.

The resulting series of major glacial and interglacial episodes have had far-reaching consequences for the engineering characteristics of the Earth’s surface. In attempting to summarize these major omissions will have been inevitable and errors will have occurred due to compression of the subject and its interpretation in a simplified manner. Table 2 summarizes the approach of the paper in itemising the principal Quaternary events, causes and effects, consequences to landscape and inferences to engineering. Each of the six events has been developed into larger tables and accompanied by some discussion and examples. The principal consequences of the events for engineering have been the production of glacial and periglacial soils,over large areas of the northern and southern hemispheres; changes in the sediment patterns on the coasts, the continental shelves and in river systems; and the development of weathering profiles of very variable type and distribution leading to development of in situ residual soils of many different engineering characteristics.

The major shifts in climate associated with these events have led to migration of various surface forms which are now being exposed or covered by the present regime, leading to many active slope processes with potential instability for engineering projects and unexpected distribution of materials.

The continuing events of plate tectonics which precedes the Quaternary by a long period of geological time explain the distribution of earthquake systems, growing coastlines and mountains, and the pattern of volcanic areas with their own suites of rock and soil of significance for the engineer.
Development of a regional model for the Devensian Glaciation of County Durham for use in the assessment of sand and gravel resources
Authors: Stevens P.F. , Morey A.J. , Sanders M.K. , Mallett S.H.
Published: April 2008

The sand and gravel resources of County Durham are mainly of Quaternary age, predominantly dating from the latter part of the Devensian stage of the Pleistocene and are the result of a complex pattern of glacial recession. A recent study predicted the distribution of drift deposits from a model based on published information, limited field observations and the analysis of approximately 6000 items of subsurface information; predominantly borehole records. This model, which describes the sequence of events during the Devensian glaciation of the area and infers palaeogeographical changes was an essential element in the assessment of the nature and distribution of granular Sediments and the prediction of mineral quality. The assessment identified 178 km
2
of potential resource, in both outcrop and subcrop, 53 km
2
of which had not been previously shown on published maps and plans.
Highway embankment construction across the Strathearn buried Valley
Authors: Cochrane G. A. , Carter P. G.
Published: April 2008

Improvements to the trunk road network around Perth during the early 1980–s involved construction of two new routes crossing the River Earn. Embankments were constructed across lower Strathearn to carry the M90 Edinburgh to Perth motorway and the A9 Stirling to Perth trunk road. Thick Quaternary deposits laid down under conditions of varying climate and sea level occupy the Earn Valley in this area. The nature and extent of these deposits dictated the Engineering Solutions which were adopted for the highway construction.

In this area the Earn Valley is deeply incised into rockhead. Investigations indicated that late glacial “arctic” clays and post glacial organic “carse” clay infilled the buried Valley to depths in excess of 30m and 60m at the A9 and M90 sites respectively. Efforts were made at the site investigation stage to detErmine the anticipated behaviour of these weak and compressible subsoils under embankment loading. Particular attention was given to assessing design parameters for embankment stability and settlement in relation to soil structure, in situ permeability, effective shear strength and pore water response.

The greater problems were encountered at the M90 where embankments of up to 13m in height were designed to prevent shear failure in the foundation subsoils and accommodate Settlements of up to 1.5m within the construction programme. Ground Engineering techniques employed on the various sections of both schemes included the use of stability berms, stage construction, controlled rate of filling and installation of band drains. Extensive use was made of soils Instrumentation to monitor pore pressures, horizontal deflections and Settlements and to control the rate of earthmoving operations to a predetermined construction procedure.
Periglacial discontinuities in Eocene clays near Denham, Buckinghamshire
Authors: Spink T. W.
Published: April 2008

In the investigation for part of the M25 motorway near Denham, Buckinghamshire, several types of sheared and unsheared discontinuities were found within the Eocene London Clay and Reading Beds clays which are considered to have formed under Pleistocene periglacial conditions. These consisted of two types of low angle, near-surface solifluction shears with associated discontinuous, random accommodation shears. These overlay and truncated high angle shears believed to have formed by collapse on thawing of the top of the permafrost. Deeper, low angle shears of two types, one continuous, subhorizontal and planar, the other discontinuous, random and undulose, are tentatively attributed to shearing at the base of a permafrost layer at a thawing front. Subvertical, unsheared discontinuities are considered to be contraction cracks.
Study of the effect of excavation technique on rock slope stability and slope maintenance costs at two locations in Scotland
Authors: Ross D. G. , Reeves G. M.
Published: April 2008

Rock excavations at two localities in Scotland have been examined to establish the relationship between the technique of excavation and stability in the final face. Maintenance data have also been collected and whole life costs for different techniques of excavation calculated and compared. The results indicate that the instability induced into the face by the technique of excavation has added considerably to the maintenance costs. Pre-splitting is advocated as a method of minimizing
remedial and maintenance costs when blasting is necessary.
Educational issues in environmental geological engineering
Authors: Toll D. G.
Published: April 2008

The educational implications of introducing environmental issues into engineering geology courses are discussed. It is suggested that there is a need for specialist courses in environmental geological engineering specifically designed for engineering geologists who intend to work in the environmental field. Such courses should introduce the various issues related to air, water and ground pollution; noise and vibration. The courses also need to deal with environmental planning issues such as risk assessment, hazard evaluation and the appropriate legislation. However, it is argued that the main focus of these courses should be the disposal or treatment of waste and the investigation and remediation of contaminated land and groundwater.
Rock slope hazard assessment: a new approach
Authors: McMillan P. , Matheson G. D.
Published: April 2008

Uncontrolled bulk blasting and the application of ‘standard’ designs have left a legacy of many unstable highway rock slopes, some of which are potentially hazardous. Effective management of these slopes requires knowledge of their location and the risk posed to the road user. Existing rock slope stability assessment and risk evaluation systems use various approaches to data collection, and different scales and nomenclature for results. In addition, these assessments are usually undertaken on a reactive basis, prompted by rockfalls. As a consequence road users may be exposed to risk before problems are addressed, comparison of results is very difficult, budgetary problems arise as incidents are largely unforeseen, and prioritization of funds is impossible.

As a result of a research programme undertaken for the Scottish Office Industry Department (SOID) National Roads Directorate, a new, proactive approach to identifying and classifying rock slope hazards has been developed. Application of this new approach is likely to improve risk management of hazardous rock slopes.

The first stage of this approach derives a rock slope hazard index from rapid, standardized field data collection. This is used to classify rock slopes into four categories depending on the requirement for future action. The second stage derives a rock slope hazard rating from detailed field surveys. The rating is a measure of the risk of a vehicle incident being caused by rockfall.

The results of a field trial of the rock slope hazard index, carried out on a section of trunk road in the Scottish Highlands, are described.
Time of deformation in the Caledonide Orogen of Britain and Ireland
Authors: Powell D. , Phillips W.E.A.
Published: April 2008

Considerable problems attach to any attempt to define precisely the timing of such geological events as deformation. The biostratigraphical evidence may be imperfect or lacking, the isotopic evidence may be imprecise or conflicting, and where both lines of evidence are available, disagreement over definition of the Geological time scale creates problems of wider correlation. The last situation is exempslified by the English Lake District wherein the biostratigraphical and isotopic data appear to be reliable and compatible but the isotopic data conflict with some recently published time scales. Of particular importance to the present study are disagreements over the ages of the Lower Palaeozoic period boundaries. Estimates for the Devonian-Silurian boundary vary from 400 to 412 Ma (Odin 1982, cf McKerrowetal. in press); the Silurian-Ordovician boundary 418 to 438 Ma (Odin 1982, cf Harland et al. 1982); the Ordovician-Cambrian boundary 495 to 513 Ma (Odin 1982, cf McKerrow et al. in press); and the Camsbrian-Vendian boundary 530 to 590 Ma (Odin 1982, cf Harland
et al
. 1982). Such differences evidently become critical where comparisons of timing based only on biostratigraphic evidence are made with those based solely on isotopic data. Particular difficulties also arise from the problems involved in determining the biostratigraphic base of the Devonian within rocks of Old Red Sandstone facies.

Throughout this work reference has been made to the Special Reports of the Geological Society of London numbers 1, 2, 3, 6, 7, 8 and 10, which provide summaries of the lithostratigraphic and biostratigraphic record in Britain and
A review of Palaeozoic palaeomagnetic data from Europe and their palaeogeographical implications
Authors: Torsvik Trond H. , Smethurst Mark A. , Briden James C. , Sturt Bryan A.
Published: April 2008

Recent palaeomagnetic studies on Devonian and Carboniferous rocks have resulted in a time re-calibration of the Apparent Polar Wander Path (APWP) for Europe, and revision of the shape of the APWP for North America. Differences between previously published versions of these paths are now much reduced. The APWP for southern Britain is different from those for North America and Armorica, thus southern Britain is believed to have been an isolated block within the pre-Hercynian ocean. New continental reconstructions are presented to take account of these conclusions. A lack of sufficient reliable palaeomagnetic data from Baltica make its position on the map uncertain, and hence the significance of the Tornquist Sea between Baltica and Palaeo-Europe remains incompletely understood.
Palaeobiogeography of Middle Palaeozoic organic-walled phytoplankton
Authors: Colbath G. Kent
Published: April 2008

Potential advantages to the use of Palaeozoic organic-walled phytoplankton over other fossil groups are their presence in large numbers in small samples (particularly cores) and their partial independence from lithofacies. Reasons why this potential has not been fully realized are discussed, and the history of study is briefly reviewed. The 'latitude parallel' distribution model proposed for Silurian phytoplankton does not hold up when plotted on a more recent plate reconstruction, although some important insights are forthcoming. Ordovician microfloras appear broadly consistent with proposed plate models, and the diachronous distribution of the genusFrankeacan be explained by combining the plate model with a restricted, high southern latitude distribution. Ten Frasnian microfloras are compared in detail using G. G. Simpson's Index and cluster analysis. Microfloras from Brazil, Ghana and Algeria cluster together, distinct from outlying areas, while the Carnarvon Basin microflora in Australia is considered relatively endemic. The Frasnian phytoplankton data support a plate reconstruction in which a large seaway separated Africa and South America from North America and Europe.