IS-78: LonWorks® goes into hazardous areas

This paper introduces LonWorks technology, intrinsic safety and how the two are combined in the IS-78 physical channel which enables networks to be taken into hazardous areas. The capabilities of the physical channel are described, together with some applications in which it has been used.     

NJTxtr—A Computer Program Based on LASER to Monitor Asphalt Segregation

Abstract: This paper describes the research funded by the New Jersey Department of Transportation to develop an automated technology to monitor segregation during construction of hot-mix asphalt concrete pavements. A Laser-based system was used to measure surface texture and to detect segregation. Two segregated test sections and a control test section were tested to evaluate the applicability of Laser texture method to detect and quantify segregation. Laser texture data were gathered from all three sections. Ratios of texture in segregated areas to that in nonsegregated areas were set as the basis for detection of different levels of segregation. By combining the level of segregation and extent of segregation, an AREA index was developed to determine the acceptability of a pavement section. Based on AREA index, pay adjustment factors were proposed to reduce the payment to account for loss of pavement life due to segregation. Further remedial actions were proposed to correct segregated pavement sections with acceptable AREA index. Based on the above concepts, Windows-based computer program NJTxtr was developed to detect and quantify segregation. This computer program uses the Laser-equipment-collected pavement texture data and determines whether the pavement section is acceptable or unacceptable based on the level of segregation within a pavement section, and provides bonus or penalties to the contractor. The paper describes a novel technology using laser and associated software for construction quality control of asphalt concrete pavements. The proposed methodology was applied to detect segregation in an interstate highway section in New Jersey, and this section was repaved based on visual observation and recommendation from this study.     

The use of small angle neutron scattering with contrast matching and variable adsorbate partial pressures in the study of porosity in activated carbons

The porosity of a typical activated carbon is investigated with small angle neutron scattering (SANS), using the contrast matching technique, by changing the hydrogen/deuterium content of the absorbed liquid (toluene) to extract the carbon density at different scattering vector (Q) values and by measuring the p/p₀ dependence of the SANS, using fully deuterated toluene. The contrast matching data shows that the apparent density is Q-dependent, either because of pores opening near the carbon surface during the activation processor or changes in D-toluene density in nanoscale pores. For each p/p₀ value, evaluation of the Porod Invariant yields the fraction of empty pores. Hence, comparison with the adsorption isotherm, shows that the fully dry powder undergoes densification when liquid is added. An algebraic function is developed to fit the SANS signal at each p/p₀ value hence yielding the effective Kelvin radii of the liquid surfaces as a function of p/p₀. These values, when compared with the Kelvin equation, show that the resultant surface tension value is accurate for the larger pores but tends to increase for small (nanoscale) pores. The resultant pore size distribution is less model-dependent than for the traditional methods of analyzing the adsorption isotherms.     

Macroporous calcium phosphate ceramic implants for sustained drug delivery

Limited blood circulation to the skeletal tissue is a major cause of reduced therapeutic effects seen with drugs administered by conventional systemic ways. To resolve this issue and obtain a sufficiently high local concentration to induce therapeutic effects, several implanted drug delivery systems have been developed for hard tissues using biomaterials.We have designed a drug delivery device based on hydroxylapatite (HA) and tested it in vitro using metronidazol and chloramphenicol as model compounds. Porous HA ceramics were prepared with two different shapes (cylindrical and spherical). Known amounts of drugs were introduced inside a drilled hole and sealed with wax. The ceramics were then suspended in stirred distilled water in closed polypropylene vials. Drug release was observed during several weeks.A mathematical model used to describe drug release from HA was elaborated based on the expressions of Fick's laws. The experimental kinetic results could be related to ceramic constitution and to drug localization.     

An efficient file structure for document retrieval in the automatedoffice environment

A file system tailored to the general needs of the office environment is proposed. This system supports large numbers of a wide variety of documents and inexact fuzzy queries on the documents. The file system is based on a multilevel file structure that combines and extends multikey extendible hashing and signature files to create a document-retrieval system that is more time efficient than other previously proposed systems and is also space efficient     

Synthesis of calcium hydroxyapatite from calcium carbonate and different orthophosphate sources: A comparative study

The synthesis of calcium hydroxyapatite (Ca-HA) starting from calcium carbonate and different orthophosphate sources, including orthophosphoric acid, potassium, sodium and ammonium dihydrogen orthophosphates, was investigated under ambient conditions. The reaction started with calcium carbonate dissolution in an acid medium, followed by rapid precipitation of calcium cations with orthophosphate species to form calcium phosphate based particles which were in the size range of 0.4–1 μm. These particles then agglomerated into much larger ones, up to 350 μm in diameter (aggregates). These aggregates possessed an unstable porous structure which was responsible for the porosity of the final products. The highest specific surface area and pore volume were obtained with potassium dihydrogen orthophosphate. On the other hand, orthophosphoric acid led to the highest dissolution of calcium carbonate and the complete precipitation of orthophosphate species. Under ambient conditions, calcium phosphate based solid products of low crystallinity were formed. Different intermediates were identified and a reaction pathway proposed.     

Ethnography,ethnomethodology and the problem of generalisation in design

This paper discusses the relationship between sociological theory and method, ethnomethodology and design. It argues that social science theoretical and methodological interests cannot form a basis for interdisciplinarity. Much of the argument about the relevance of ethnography for design, and more specifically about ethnomethodological enquiry, has been cast firstly as problems of method and secondly in terms of the problem of generalisation. We argue that in both instances the problem is miscast. Drawing on the arguments of Wittgenstein and Winch, we suggest that forms of generalisation are to be found in ethnomethodological enquiry and that they may be useful in design-related enquiry. We further suggest, however, that they are not the forms to be found in explanatory social science.     

Thaumatin-like protein in kiwifruit

A 21-kDa protein extracted from woody tissue underlying the pedicel of kiwifruit (Actinidia deliciosa var deliciosa [A Chev] Liang and Ferguson) was purified to homogeneity by cation exchange, gel filtration, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) on a 15% gel and electro-transfer onto a polyvinylidene difluoride (PVDF) membrane, followed by excision of the band of interest. Amino terminal sequence analysis of this band revealed a high degree of homology with basic endochitinase (EC 3.2.1.14) in orange and thaumatin-like proteins in tobacco, barley, maize and tomato. This is the first record of a thaumatin-like protein in a subtropical berryfruit. Potential implications of this finding and the need for future research are discussed. © 1999 Society of Chemical Industry     

Arterial and pulmonary arterial concentrations of the enantiomers of bupivacaine after epidural injection in elderly patients

Bupivacaine HCl is a 50:50 racemic mixture of the levo [S(-)] and dex [R(+)] enantiomers. The R(+) enantiomer exhibits greater cardiac tissue binding and toxicity. To determine whether the lung exhibits selective uptake of one of the enantiomers of bupivacaine, we measured pulmonary artery and radial artery blood concentrations of the two enantiomers after a lumbar epidural injection of 20 mL of 0.75% bupivacaine in 10 elderly patients undergoing one-stage bilateral total knee arthroplasty. Significantly lower concentrations of R(+) than S(-) were noted in both pulmonary artery and arterial blood. Both enantiomers were absorbed by the lung to a similar extent within the first 5 min after epidural injection (extraction ratio approximately equal to 0.1 or 10%). Mean time of maximal concentration (Tmax) was 6 min. In 3 of the 10 patients, Tmax occurred in 1-3 min. We conclude that the lung absorbs both the R(+) and S(-) enantiomers of bupivacaine to a similar extent after epidural injection and that this is of doubtful clinical significance. This study also suggests that peak concentrations of bupivacaine may occur earlier after epidural injection in certain elderly patients than previously believed. Implications: In the first 5 min after epidural injection, approximately 10% of the local anesthetic bupivacaine was absorbed by the lung. Absorption of the two enantiomers (mirror images) of bupivacaine were similar. Lung absorption of bupivacaine is unlikely to influence local anesthetic toxicity.     

Clinical variability of target volume description in conformal radiotherapy planning

PURPOSE: The pivotal step in radiation planning is delineation of the target volume and production of a treatment plan to encompass this. This study assesses the variation of physicians in creation of these volumes. METHODS AND MATERIALS: Three radiologists and eight radiation oncologists outlined the gross tumour volume (GTV) on the planning CT scans of four cases with T3 bladder cancer. In addition, the radiation oncologists (RO) created a planning target volume according to a set protocol for all cases. Volumes were produced and comparison of these volumes and the position of the isocenters were analysed. In addition, the margins allowed were measured and compared. RESULTS: There was a maximum variation ratio (largest to smallest volume outlined) of the GTV in the four cases of 1.74 among radiologists and 3.74 among oncologists. There was a significant difference (p = 0.01) in mean GTV between RO and the radiologists. The mean GTV of the RO exceeded the radiologists by a factor of 1.29 with a mean difference of 13.4 cm3. The variation ratio in PTV among oncologists ranged from 1.25 to 3.33. There was no significant difference in mean PTV values between the two groups of ROs divided by specialization in uro-oncology. The mean variation in location of the isocenter from the centroid of the radiologists' volume in the four cases was from 2.6 to 5.7 mm. There was, however, a wide range of values from 1.4 mm to 24.1 mm. Median margin per case ranged from 14.7 to 18.7 mm. Minimum margins allowed in each case varied from minus 7 mm to 9 mm. CONCLUSION: This study demonstrates significant interphysician variability in producing target volumes and radiation plans for conformal radiotherapy. The scale of this difference is clearly of significance, with up to 3-fold variation in volumes delineated by clinicians. The factors leading to these differences will be further addressed. The existence of such variability, however, clearly needs to be accepted as a factor in the overall uncertainty analysis in conformal radiotherapy planning.