A multiple regression assessment of the biomineral urease activity from urine drainpipes of California public restrooms

Clogging and odor is strongly associated with ureolytic biomineralization in waterless and low-flow urinal drainage systems in high usage settings. These blockages continue to hinder widespread waterless and low-flow urinal adoption due to subsequent high maintenance requirements and hygiene concerns. Through field observations, hypothesis testing, and multiple regression analysis, this study attempts to characterize, for the first time, the ureolytic activity of the biomineralization found in alternative technologies located at 9 State-owned restrooms. Multiple regression analysis (n = 55, df = 4, R2 = 0.665) suggests that intrasystem sampling location ($$ \hat{\upbeta} $$ β ̂ = 1.23, p < 0.001), annual users per rest area ($$ \hat{\upbeta} $$ β ̂ = 0.5, p = 0.004), and the volatile solids to total solids mass fraction ($$ \hat{\upbeta} $$ β ̂ = 0.59, p = 0.003), are statistically significant influencers of the ureolytic activity of biomineral samples (p < 0.05). Conversely, ureC gene abundance (p = 0.551), urinal type (p = 0.521) and sampling season (p = 0.956) are not significant predictors of biomineral ureolytic activity. We conclude that high concentrations of the urease alpha subunit, ureC, which can be interpreted as proxy measure of a strong, potentially ureolytic community, does not necessarily mean that the gene is being expressed. Future studies should assess ureC transcriptional activity to measure gene expression rather than gene abundance to assess the relationship between environmental conditions, their role in transcription, and urease activities. In sum, this study presents a method to characterize biomineral ureolysis. This study establishes baseline values for future ureolytic inhibition treatment studies that seek to improve the usability of urine collection and related source separation technologies.

Approach to Nav Aids System on Islands

Offshore business is gradually moving from traditional Well Head Platforms to the concept of Artificial Drill Islands and use of renewable energy sources. Navigational Aids design for artificial drilling islands has unique challenges due to vast periphery. This paper highlights all such challenges along with recommendations for a reliable and cost effective solution. Clients as well as FEED/EPC Contractors can benefit from the experience shared in this paper. The trend over the last decade has been to develop Navigation Aids that minimize maintenance requirements whilst maintaining stable and satisfactory performance. Although, Navigation Aids are automated there is still a need for regular visual inspections as there is always the risk of vandalism, ship impact or damage during significant storm events. Navigational Aids System shall be in strict compliance with International Association of Lighthouse Authorities (IALA) Guidelines. In addition to usual Visual & Audible Navigations Aids, artificial islands require break water lanterns (both red & green type). Also, number of Navigational Aids is much more than those required for a typical offshore platform. Requirement of interfaces with remote ends need to be clearly defined as these have impact on the design and ultimate cost. GSM monitoring and control system, GPS synchronization & AIS remote monitoring shall be considered. Cabling over the Island periphery is neither reliable nor cost effective solution. Standalone solar power based Navigational Aids Skids with all control and monitoring facilities can be more suitable solution. Considering that Island Contractor provides few Navigational Aids before the mobilization of EPC Contractor, it is essential to coordinate the Navigational Aids design aspects to ensure synergy in terms of compatibility.

Kincardine Bridge – An engineering triumph 85 years on

When construction of Kincardine Bridge was completed in 1936, it was the longest road bridge in Scotland and the largest swing-span bridge in Europe. 85 years on, the Historic Environment Scotland Category A listed bridge remains in service and carries approximately 12,000 vehicles daily across the Forth Estuary. On occasions when the Queensferry Crossing and Forth Road Bridge are closed simultaneously, the Kincardine Bridge offers the shortest available diversion route across the estuary for unrestricted traffic. A 2019 principal inspection highlighted deterioration to some structural elements and in 2020 DMRB bridge assessment standards were revised. As a result, a quantitative assessment was undertaken to provide confidence that the bridge remains safe for use and fit for purpose and to inform future maintenance requirements. This paper focuses on the multitude of structural forms that comprise the overall bridge and how they: - have comparably performed relating to durability over the past 85 years - have been quantitatively assessed - have comparably withstood present-day traffic loading criteria - will be maintained in future.

Design Guideline for Hydropower Plants Using One or Multiple Archimedes Screws

The Archimedes/Archimedean screw generator (ASG) is a fish-friendly hydropower technology that could operate under a wide range of flow heads and flow rates and generate power from almost any flow, even wastewater. The simplicity and low maintenance requirements and costs make ASGs suitable even for remote or developing areas. However, there are no general and easy-to-use guidelines for designing Archimedes screw power plants. Therefore, this study addresses this important concern by offering a simple method for quick rough estimations of the number and geometry of Archimedes screws in considering the installation site properties, river flow characteristics, and technical considerations. Moreover, it updates the newest analytical method of designing ASGs by introducing an easier graphical approach that not only covers standard designs but also simplifies custom designs. Besides, a list of currently installed and operating industrial multi-Archimedes screw hydropower plants are provided to review and explore the common design properties between different manufacturers. On top of that, this study helps to improve one of the biggest burdens of small projects, the unscalable initial investigation costs, by enabling everyone to evaluate the possibilities of a green and renewable Archimedes screw hydropower generation where a flow is available.

Techno-Economic Assessment of an Air-Multiple PCM Active Storage Unit for Free Cooling Application

A latent energy storage (LES) unit is presented in this paper for free space cooling and ventilation application. The unit includes multiple phase change materials (PCM) to advance the thermal performance of common LES units. It is composed by metallic rectangular panels containing commercial paraffins with melting temperatures ranging among 20 °C and 25 °C and surrounded by air channels. The average cooling load of the unit corresponds to approximately 1 kW over 8 h. It fulfils the peak ventilation cooling load during summer of an office building in Portugal. The study provides a techno-economic analysis and the environmental benefits of the LES technology compared to a traditional air conditioning (AC) unit for the cooling and ventilation of an office building. During daytime, the air-multiple PCM unit allows reducing the energy consumption by nearly 200 kWh. The full charging of the PMs during nighttime, requires significant energy consumption due to the high air flowrate demand for full solidification. The competitiveness of such units can be achieved by introducing fins into the panels, allowing double the energy savings. In an overall perspective, the unit presents several benefits such as lower initial cost and reduced maintenance requirements (non-use of refrigerants and batteries) that also allows better personal health issues when related to traditional ACs.

A Century of Use of SOLOMIT Thermal Insulation Panels

This article traces the century-old history of using a thermal and acoustic insulation panel called SOLOMIT. It presents some of Sergei Nicolajewitsch Tchayeff’s patents, on the basis of which production and installation took place. The survey section provides examples of the use of this building component in Australia, Czechoslovakia, France, Germany, the Netherlands, Poland, Russia, the Soviet Union and Spain. It pays attention to applications in the 1950s and 1960s in collectivized agriculture in Czechoslovakia. It also presents the results of measuring the thermal conductivity of a panel sample, which was obtained during the reconstruction of a cottage built in the 1950s and 1960s of the 20th century. Even today, SOLOMIT finds its application all over the world, mainly due to its thermal insulation and acoustic properties and other features, such as low maintenance requirements, attractive appearance and structure and cost-effectiveness.

Development of Condition Assessment Index of Ballast Track Using Ground-Penetrating Radar (GPR)

The condition of the ballast is a critical factor affecting the riding quality and the performance of a track. Fouled ballast can accelerate track irregularities, which results in frequent ballast maintenance requirements. Severe fouling of the ballast can lead to track instability, an uncomfortable ride and, in the worst case, a derailment. In this regard, maintenance engineers perform routine track inspections to assess current and future ballast conditions. GPR has been used to assess the thickness and fouling levels of ballast. However, there are no potent procedures or specifications with which to determine the level of fouling. This research aims to develop a GPR analysis method capable of evaluating ballast fouling levels. Four ballast boxes were constructed with various levels of fouling. GPR testing was conducted using a GSSI (Geophysical Survey Systems, Inc.) device (400, 900, 1600 MHz), and a KRRI (Korea Railroad Research Institute) GPR device (500 MHz), which was developed for ballast tracks. The dielectric permittivity, scattering of the depth (thickness) values, signal strength at the ballast boundary, and area of the frequency spectrum were compared against the fouling level. The results show that as the fouling level increases, the former two variables increase while the latter two decrease. On the basis of these observations, a new integrated parameter, called a ballast condition scoring index (BCSI), is suggested. The BCSI was verified using field data. The results show that the BCSI has a strong correlation with the fouling level of the ballast and can be used as a fouling-level-indicating parameter.

Investigating Factors Influencing Consumer Adoption of Low-input Turfgrasses

Important financial savings, along with reductions in environmental impact, can be achieved by planting lawns with low-input turfgrass species. Drawing on data from an online survey, this article provides empirical evidence on the factors that influence consumers’ willingness to adopt low-input turfgrasses. We group consumers into two segments: Willing Adopters and Reluctant Homeowners. Regardless of segment, consumers who regard maintenance requirements as more important were more willing to adopt low-input turfgrasses, whereas those who placed a higher value on appearance, were more unlikely to change to a low-input turfgrass, especially for Reluctant Homeowners. We categorized the barriers to adoption as follows: 1) Promotion, 2) Benefits and Accessibility, 3) Peer Effect, 4) Sample, and 5) Information. Our models predict that consumers’ willingness to adopt low-input turfgrass can be significantly increased if the identified barriers are removed. Based on our study, suppliers/retailers should adopt heterogeneous and multiple marketing strategies, such as promoting through multiple channels, informing and advising the public on proper information, providing photos or exhibiting in-store samples, triggering communication between different types of consumers, and providing incentives and improving accessibility, to target different consumer groups.

A Novel Tripod Concept for Onshore Wind Turbine Towers

A wind turbine tower assembly is presented, consisting of a lower “tripod section” and an upper tubular steel section, aiming at enabling very tall hub heights for optimum exploitation of the wind potential. The foundation consists of sets of piles connected at their top by a common pile cap below each tripod leg. The concept can be applied for the realization of new or the upgrade of existing wind turbine towers. It is adjustable to both onshore and offshore towers, but emphasis is directed towards overcoming the stricter onshore transportability constraints. For that purpose, pre-welded individual tripod parts are transported and are then bolted together during erection, contrary to fully pre-welded tripods that have been used in offshore towers. Alternative constructional details of the tripod joints are therefore proposed that address the fabrication, transportability, on-site erection and maintenance requirements and can meet structural performance criteria. The main structural features are demonstrated by means of a typical case study comprising a 180-m-tall tower, consisting of a 120-m-tall tubular superstructure on top of a 60-m-tall tripod substructure. Realistic cross-sections are calculated, leading to weight and cost estimations, thus demonstrating the feasibility and competitiveness of the concept.

Numerical Simulation of Two-Stage Variable Geometry Turbine

The modern internal combustion engine (ICE) has to meet several requirements. It has to be reliable with the reduced emission of pollutant gasses and low maintenance requirements. What is more, it has to be efficient both at low-load and high-load operating conditions. For this purpose, a variable turbine geometry (VTG) turbocharger is used to provide proper engine acceleration of exhaust gases at low-load operating conditions. Such a solution is also efficient at high-load engine operating conditions. In this paper, the result of an unsteady, three-dimensional (3D) simulation of the variable two-stage turbine system is discussed. Three different VTG positions were considered for those simulations, along with three different turbine speeds. The turbine inlet was modeled as six equally placed exhaust pipes for each cylinder to eliminate the interference of pressure waves. The flow field at the outlet of the 1st stage nozzle vane and 2nd stage rotor was investigated. The simulations showed that the variable technologies significantly improve the efficiency of the two-stage turbine system. The highest overall efficiency of the two-stage system was achieved at 60,000 rpm and 11o VTG position.