Public Works Services Research Articles

In vitro effects of steroidal saponins fromYucca schidigera extract on rumen microbial protein synthesis and ruminal fermentation

In a first experiment, ground alfalfa hay and rolled barley grain were incubated in buffered ruminal fluid with and without Yucca schidigera extract (YE, 0 or 10 mg ml−1). Gas and total VFA production from barley grain were increased (P < 0.05) by YE during the first 10 h of incubation; from alfalfa hay, these were reduced (P < 0.001) throughout the 24 h. Yucca extract reduced (P < 0.001) acetate/propionate ratios and ammonia concentrations, irrespective of substrate. In a second experiment, ground barley grain was incubated in a buffered suspension of mixed ruminal microbes obtained by low-speed centrifugation of ruminal fluid. Steroidal saponins (SAP) isolated from YE were included at 0, 15, 75 or 225 µg ml−1. Microbial incorporation of 15N was increased (P < 0.05) by 15 µg SAP ml−1 but decreased (P < 0.05) by 225 µg SAP ml−1. Gas and VFA production peaked with 75 µg SAP ml−1 and were elevated (P < 0.05) relative to control in the presence of 75 µg SAP ml−1. Microbial protein synthesis was increased (P < 0.05) by SAP at 15 µg ml−1 and reduced (P < 0.05) by the higher concentrations. Acetate/propionate ratios were linearly reduced by SAP from 8 to 24 h incubation (P < 0.01). The effects of SAP on digestive microbes were less pronounced (P < 0.05) with barley grain digestion than with alfalfa. A YE × diet interaction was recorded. The biological activity of YE was shown to be attributable to its SAP and to be diet-dependent. © 2000 Society of Chemical Industry. Contributions of Y Wang, T A McAllister, L J Yanke and Z Xu © Minister of Public Works and Government Services Canada 2000

Étude de la pénétrabilité du coulis de ciment microfin sous pression dans les structures de maçonnerie dégradées à caractère historique : effet d'un agent colloïdal

Several masonry structures, built over the past centuries, have to be restored to ensure their structural integrity and their conservation. Important research and development projects have been initiated by Public Works and Government Services Canada to rehabilitate some of these structures, such as the Rideau canal locks, by using a cement-based grouting technique. By following grouting pressures and flow rates, the stability of the structure is protected and the efficiency to fill openings is assured by using microfine cement-based grouts with admixtures. However, cement grout penetration cannot be observed with precision during the injection. The project described in this paper presents the grouting treatment of a Rideau canal lock sill wall that had to be demolished and reconstructed. The penetration of two different grout mixes was observed by removing the front row of blocks, piece by piece. A second phase of this study was conducted in the laboratory to compare the penetration of different grouts in a reconstructed granular material which simulated the lock's interior walls.Key words: restoration, masonry, grouting, groutability, cement grout, colloidal agent.

Public Works Delivery Systems in North America

One of the 1998 International PublicWorks Congress and Exposition’s workshops focused on the methods of delivery currently used to provide public works services in North America. This article examines three public works delivery systems: traditional model, privatization in general, and managed competition. The three perspectives are intended to provide insight into actual methods, advantages and disadvantages, and trends of each approach based on experience rather than theory.

Seasonal cyclic pituitary and testicular activities in rams

Adult rams were subjected to various photoregimes for more than 4 years to determine whether pituitary and testicular activities are inherently cyclic. Adult rams (three treatment groups, each with 12 rams) of the Arcott breeds were housed in environmental rooms kept at 15°C and exposed to short days (8 h of light and 16 h of darkness) for 1 year to dissipate the possible influence of normal environmental changes. The rams were then exposed to long days (16 h of light and 8 h of darkness) for 3 months to induce testicular regression. Subsequently, rams in Treatment Group 1 were exposed to short days for 39 months. Rams in the other treatment groups were exposed either to alternating 4-month periods of short days and long days for 16 months followed by 21 months of short days (Treatment Group 2), or to alternating 4 month periods of short days and 2 month periods of long days for 12 months followed by 4 months of short days, and then a reversal in daylength to 21 months of long days (Treatment Group 3). Exposure to the fixed daylength photoregime was followed with a change in daylength to test the retention of photosensitivity in the rams. Scrotal circumference and serum concentrations of follicle stimulating hormone (FSH), testosterone and prolactin were measured every 2 weeks throughout the study. In the rams exposed to short days only (Treatment Group 1), no cyclic change in hormone levels or scrotal size was apparent; FSH levels, testosterone levels and scrotal size all rose significantly early in the 39 months period and remained above basal levels. In the rams of Treatment Groups 2 and 3, the changes in the photoperiod cycles induced rhythmic pituitary and testicular activities which persisted for the first year of constant daylength, faded or disappeared thereafter. Prolactin levels in each treatment depended on the light regime, with levels being depressed or elevated during short or long days, respectively ( P < 0.01). All rams responded to the final change in photoperiod with an appropriate increase or decrease in the pituitary and testicular activities. These observations indicate that persistent memory of previous photoperiod change accounts for the `apparently spontaneous' rhythms in pituitary and testicular activities in the short term, but the decline of the regular changes as the memory fades does not support the existence of inherent cyclicity in reproductive functions in rams of the Arcott breeds. 5 Authors: G.A. Langford, L.M. Sanford, G.J. Marcus and J.N.B. Shrestha. For the Department of Agriculture and Agri-Food Canada, Government of Canada, © Minister of Public Works and Government Services Canada (1998). 5

Effects of proanthocyanidins, dehulling and removal of pericarp on digestion of barley grain by ruminal micro-organisms

The effects of proanthocyanidins (PA), dehulling, and removal of the pericarp on the rate and extent of barley digestion by ruminal micro-organisms were studied using a control barley (cv Harrington) and three PA-free barley lines (Caminant, Ca504316 and Ca802711). Each barley was studied in five preparations: whole grain (W); dehulled kernels (DH); kernels with pericarp removed (DP); dry-rolled grain (DR), and the pericarp-testa fraction (PT) produced during preparation of DP. Vanillin-HCl staining and chemical analysis confirmed that PA were present only in the Harrington barley, and localised in the pericarp-testa layer. Whole kernels, DH and DP were incubated with diluted ruminal fluid in vitro, and all five preparations were incubated in situ (nylon bag technique). Harrington DR and all four PT fractions were also incubated in vitro in the presence (0.074% w/v) and absence of polyethylene glycol (PEG), which specifically binds PA. The four barleys did not differ in in vitro dry matter disappearance (DMD) or gas production from W, DH or DP preparations, nor in in situ DMD rates from W, DH or DP (P > 0.05). In vitro DMD and gas production among PT fractions from the four barleys were also similar (P > 0.05), as were in vitro DMD from PEG-present and PEG-absent DR Harrington. With Harrington PT, in vitro ammonia concentrations were higher (P < 0.05) with PEG than without. For each barley line, in vitro DMD rates were highest (P < 0.01) with DP, followed by DH, and then by W (P < 0.01). In in situ incubations also, DMD rates and effective degradabilities of DR samples exceeded (P < 0.05) those of DH samples. It was concluded that the presence of proanthocyanidins did not affect ruminal digestion of barley grain, and that abrasive milling to breach the hull and pericarp may be a promising method by which to regulate the rate of barley digestion in the rumen. © Minister of Public Works and Government Services Canada 1999

Sharing of Public Works Services by Small Towns

Many federal initiatives now being considered are aimed at increasing the fiscal responsibilities of local and county governments in providing public works services. However, the feasibility of providing the necessary mix of public works in small towns is not easily accomplished, and there is a need to assess and evaluate the efficiency of the delivery of these services when they are offered. A method advocated to increase small town and rural county government efficiency in delivering such services is to share them with other towns, cities, and counties. A survey of Iowa communities was conducted to assess and analyze the extent of public works/services provision and sharing. The fundamental hypothesis is that the propensity to share services is a function of community size, which results in cost efficiencies in service provision. The results of the survey did not confirm this hypothesis. It may be that service sharing is more likely a function of organizational and institutional processes.

Labor-Management Cooperation—City of Portland, Maine

Portland, Maine had a traditional bargaining relationship. It now has one of the most complete programs of service-focused labor management cooperation of any place in the country. A broad range of city services, including an emerging effort in public safety are now run this way, with workers and their union leaders, managers and elected officials all benefitting from and praising the new relationship. Portland made this radical transformation without a crisis of fiscal pressure. New leadership in the city manager's office and responsive leadership in key bargaining units led to an experiment on the building of Hadlock Field. A partnership between the department head and the president of the AFSCME local led the project. Instead of contracting out to meet a short deadline and employ skills that didn't seem to exist, the parties worked out a special set of arrangements and via cross-training, teamwork and dedication completed the stadium in seven months, millions under the expected budget. From the pride and satisfaction of this joint effort, Portland, AFSCME and other key units worked to create a new participative relationship across the full range of city services. The effort has produced major cost savings and service improvements, has strengthened both the management and the union and has produced a far less adversarial bargaining relationship. In one innovation, separate services were split up and reorganized into district teams, providing customer-oriented public works services in areas that match city council districts. Cross training and new responsibilities have resulted in new opportunities and pay raises, yet have saved time and money. The piece, co-authored by union and management leaders from Portland, illustrates the breadth and depth of what they have achieved without a crisis as the initiating factor.

Frost Durability Testing of Stone Masonry Mortars: Restoring the Canadian Parliament Buildings

Restoration of historic masonry is not only a matter of removing failing stone or mortar and replacing it with new. It is necessary to maintain the historic fabric of the structure and ensure that any intervention is reversible. It is also very important to ensure that the repointing effort has a high degree of durability. In much of northern North America and Europe, freeze-thaw durability is key to long-term service life. This is a particular challenge in climatic regions where winter thaws can result in temperature swings from -200C to '+5C and back to -200C in less than 24 hours. Driving rain is often associated with this type of weather pattern. Mortar failure in a single season is not uncommon under these severe climatic conditions. Ottawa, Canada, is in this type of region. Accelerated testing for frost durability of masonry is not a standard test. ASTM C-666 [1], which was developed for freeze-thaw durability testing of concrete, is commonly used for testing mortar; this is an unrealistic test. The durability of masonry is a complex interaction of the mortar and masonry unit. Recognizing this, the National Research Council of Canada (NRCC), Institute for Research in Construction (IRC) developed a frost durability test for masonry [2]. The development of the test was in direct response to the need of Public Works and Government Services Canada (PWGSC) to produce a guideline for specifying for the current, largescale restoration of the buildings that make up the Parliamentary Precinct of Canada's capital city, Ottawa. The results reported in this paper represents the 1994-95 test program of an ongoing investigation. Two phases of mixing were conducted. The first phase investigated a broad range of mix designs and the second a refinement of the favorable mix designs. A companion paper in this issue by Suter et al describes the mechanical testing protocols and details the results. The purpose of this paper is to describe the approach and outcome of frost durability testing of mortars and to discuss those physical properties that appear to relate to freeze-thaw durability. The work was conducted under the umbrella of the Masonry Retrofit Project, which is a strategic research focus of the Institute for Research in Construction.

Modelling Concepts For The Risk-cost Assessment Model Firecam'" And Its Application To A Canadian Government Office Building

To support the introduction of performance-based building regulations in Canada in the year 2001, the National Research Council of Canada (NRC) is developing a computer fire risk cost assessment model that can be used to assess both the expected risk to life to the occupants and the expected costs of fire protection and fire losses in a building. The computer model that is being developed at NRC is called FiRECAMTM (Fire Risk evaluation and Cost Assessment Model). This paper provides a description of the modeling concepts of FiRECAMTM and the results of its application to a six-storey Canadian federal government office building where the existing fire protection systems were being re-evaluated to see how they could be upgraded to meet the current building code requirements. The project was a collaboration between NRC and Public Works and Government Services Canada (PWGSC) which owns the building. The objective was to determine whether all the required upgrades were necessary. The results showed that one of the required upgrades, closing the stair vents, was not necessary, meaning a saving of $37,000 (Canadian).

"The Promise of Progress: Public Works and the Way We Live in North Carolina"

In the spring of 1984, the North Museum of History, a section of the state's Division of Archives and History, presented an exhibit, Works: Building a Better Life, which traveled to Charlotte's science and nature museum, Discovery Place, in May 1985. exhibit was retitled The Promise of Progress: Public Works and the Way We Live in North Carolina to reflect the use of artifacts pertaining to North and the social and humanistic concerns emanating from the technological advances represented by public works. addition of a five-part lecture series to accompany the exhibit and to provide the public with an appropriate national and historical context for the display was a major feature of the Charlotte exhibition. speakers were David R. Goldfield, Ruth S. Cowan, Joel A. Tarr, Jon C. Teaford, and Blaine A. Brownell. lecture topics coincided with the major themes of the exhibit-water and waste, transportation, and household technology. basic objectives of the exhibit were to define public works clearly for the museum visitor, to underscore our reliance on and investment in public works services, and to raise the visitor's awareness of those people in the field of public works-the ditchdigger as well as the engineer-who have dramatically improved the quality of life in our communities. More than 30,000 people were expected to visit the exhibit, part of a larger, permanent, hands-on science and technology museum. Approximately three-quarters of these visitors were schoolchildren, and the panels and the exhibit design were aimed particularly at them.

CORROSION‐RESISTANT PIPES AND SURFACES

There were several stands of interest to readers of CORROSION TECHNOLOGY at the Public Works and Municipal Services Exhibition, held in London last month. A number of firms were concerned with the production of pipes, corrosion‐resistant surfaces and sealing materials.

Public Works and Municipal Services Congress and Exhibition

Public Works and Municipal Services Congress and Exhibition

Public Works and Engineering Services on a Public Service Basis

Public Works and Engineering Services on a Public Service Basis