Search Results (92)

Drinking water biofilm ecosystems harbor complex and dynamic prokaryotic and eukaryotic microbial communities. However, little is known about the impact of copper corrosion on microbial community functions in metabolisms and resistance. This study was conducted to evaluate the impact of upstream Cu pipe materials on downstream viable community structures, pathogen populations, and metatranscriptomic responses of the microbial communities in drinking water biofilms. Randomly transcribed cDNA was generated and sequenced from downstream biofilm samples of either unplasticized polyvinylchloride (PVC) or Cu coupons. Diverse viable microbial organisms with enriched pathogen-like organisms and opportunistic pathogens were active in those biofilm samples. Cu-influenced tubing biofilms had a greater upregulation of genes associated with potassium (K) metabolic pathways (i.e., K-homeostasis, K-transporting ATPase, and transcriptional attenuator), and a major component of the cell wall of mycobacteria (mycolic acids) compared to tubing biofilms downstream of PVC. Other upregulated genes on Cu influenced biofilms included those associated with stress responses (various oxidative resistance genes), biofilm formation, and resistance to toxic compounds. Downregulated genes included those associated with membrane proteins responsible for ion interactions with potassium; respiration–electron-donating reactions; RNA metabolism in eukaryotes; nitrogen metabolism; virulence, disease, and defense; and antibiotic resistance genes. When combined with our previous identification of biofilm community differences, our studies reveal how microbial biofilms adapt to Cu plumbing conditions by fine-tuning gene expression, altering metabolic pathways, and optimizing their structural organization. This study offers new insights into how copper pipe materials affect the development and composition of biofilms in premise plumbing. Specifically, it highlights copper’s role in inhibiting the growth of many microbes while also contributing to the resistance of some microbes within the drinking water biofilm community. Full article

The accurate detection and mapping of subsurface utilities are critical for ensuring safety and efficiency in excavation and construction projects. Among various technologies, Ground-Penetrating Radar (GPR) has been widely used for locating underground infrastructure due to its non-destructive nature and ability to detect both metallic and non-metallic materials. However, many GPR systems struggle to meet the practical depth requirements in real-world conditions, especially when identifying non-metallic facilities such as PVC and PE pipes. In South Korea, the legal regulations require underground utility locators to meet specific accuracy standards, including a minimum detectable depth of 3 m. These regulations also mandate periodic performance testing of surveying equipment at authorized inspection centers. Despite this, most GPR systems tested at the official performance evaluation site at Sungkyunkwan University demonstrated limited effectiveness, with an average detection range of only 1.5 m. This study evaluates the performance of a handheld All Materials Locator (AML) device developed by SubSurface Instruments, Inc., (Janesville, WI, USA) which uses ultra-high radio frequencies to detect subsurface density variations. Experimental results from both the certified test facility and field conditions indicate that the AML meets South Korea’s legal requirements for minimum depth and accuracy, by successfully identifying a wide range of subsurface utilities including non-metallic materials. The findings suggest that the AML is a viable alternative to conventional GPR systems for utility detection in regulated environments. Full article

Penetration points on walls must include firestop measures to prevent the spread of fire. Countries worldwide have established standardized testing protocols for firestop methods, and firestop products must pass relevant tests before they can be used in buildings. In the present study, a simple method was developed to enhance the smoke leakage performance and fire resistance of existing polyvinyl chloride (PVC) pipes passing through walls. Two sets of smoke leakage tests were performed, followed by two sets of fire tests. The smoke leakage tests were nondestructive and thus did not damage the specimens; consequently, the same specimens could be used in the smoke leakage and fire tests. The results of the smoke leakage tests indicate that the method using PVC pipes wrapped with galvanized steel sleeves outperforms the method without such wrapping. Moreover, the results of the fire tests suggest that galvanized steel sleeves considerably improve thermal insulation and safety. This finding is explained as follows: PVC pipes may burn and break apart at high temperatures, compromising fire compartmentation. A galvanized steel sleeve can retain a burning, broken pipe piece, thereby preventing injuries and stopping the detached pipe from continuing to burn on the ground. Full article

Sea level rise is an escalating threat to saltmarsh ecosystems as increased inundation can lead to decreased biomass, lowered productivity, and plant death. Another potential stressor is elevated nitrogen often brought into coastal regions via freshwater diversions. Nitrogen has a controversial impact on belowground biomass, potentially affecting saltmarsh stability. In this study, we examined the effects of inundation and nitrogen on common saltmarsh plants (Spartina alterniflora and Spartina patens) placed within two marsh organs (a collection of PVC pipes at different levels, the varied elevation levels expose the plants to different inundation amounts) located in the Pascagoula River, Mississippi, USA, with six rows and eight replicates in each row. We randomly fertilized four replicates in each row with 25 g/m² of NH4⁺-N every two-three weeks during the growing season in 2021 and 2022. We concurrently collected vegetative traits such as plant height and leaf count to better understand strategies saltmarshes utilize to maximize survival or growth. We harvested half of the vegetation in Year 1 and the remaining in Year 2 to evaluate the impact of inundation and nitrogen on above- and belowground biomass at different temporal scales. We developed Bayesian models that show inundation had a largely positive impact on S. alterniflora and a mostly negative impact S. patens, suggesting that S. alterniflora will adapt better to increasing inundation than S. patens. Additionally, fertilized plants from both species had higher aboveground biomass than non-fertilized plants for both years, with nitrogen addition only showing impact on belowground biomass in the long term. Our results highlight the importance of long-term study to facilitate more-informed restoration and conservation efforts in coastal wetlands while accounting for climate change and sea level rise. Full article

We describe an experiment in which we employ a radiofrequency sensor to measure pH changes in a liquid solution. The experiment is novel in a few ways. First, the sensor does not have contact with the liquid but rather detects the change from the outside of a PVC pipe. Second, the change is detected using a Linear Discriminant Analysis model using values from an inverse Fourier transform of the frequency data as its features. We believe this to be the first use of Fourier analysis in contactless pH measurement using radio frequencies. Full article

Accurately measuring the discharge in partially full pipe flow is both difficult and demanding. In this regard, a new meter sensor using microwave technology has been evaluated for determining partially full pipe discharge across a range of flow depths. A range of experiments with smooth PVC pipes of two different pipe diameters (101.6 and 152.4 mm) at two different pipe slopes (1° and 2°) were carried out under turbulent (Reynolds numbers = (0.27–3.25) × 10⁵) and supercritical flows with Froude numbers F_r in the range of 1.5 ≤ F_r ≤ 3.6. Our results showed that when combining the microwave sensor readings with either the Chezy equation or Manning’s law, reliable discharge predictions were found compared to the measured discharge across all experiments. The range of R² values obtained from the plots of predicted versus measured discharge were all greater than 97%, indicating an accuracy allowing the meter to be used in commercial applications. Full article

Earth–Air Heat Exchange (EAHE) systems are an eco-friendly and energy-efficient technology as pre-heating or pre-cooling systems in civil buildings. Technically, the performance of the EAHE system is influenced by properties associated with the technology. In this paper, the focus is placed on the properties covered by the published literature to understand how they impact the efficiency of these systems. The review scrutinizes the implication of pipe properties such as the material type (steel, Polyvinyl Chloride [PVC], concrete, or high-density polyethylene), diameter and length, and depth in the context of modern building design and energy conservation. Other properties considered in this work are air velocity and the bonding of pipes with the soil. The EAHE systems’ performance is not significantly influenced by the pipe material, unlike the pipe length and diameter. It is reported that longer pipes enhance the cooling output in the EAHE system. The pipe length positively correlates with the in-pipe air temperature. An increment in the pipe diameter led to a drop in the in-pipe air temperature. An indicative report states that an increasing air flow velocity can lead to thermal losses from pipes to their surrounding soil. The addition of sand below and above the pipe enhances the thermal conductivity, just as an increase in the moisture content of the soil will contribute. There are attempts to use additives, construction waste, graphite, and fly ash as a backfill material, but with opposing economic feasibility. Construction waste could help the EAHE system to improve by 80%. A combination of graphite and fly ash as a backfill material is cost-effective. Research on the pipe material type and standards development are limited. Overall, the pipe material type and length to adopt for an EAHE system are based on the funds’ availability for the construction. Full article

The plastic profile of construction waste is varied and complex, particularly when compared to other waste streams such as timber, concrete, metals, and plasterboard. There are fewer incentives for recycling this low-density, low-value waste stream. Plastic waste generated by construction activities remains poorly characterised, obstructing efforts to optimise reduction, reuse, and recycling practices. To understand its types and sources, and better address plastic waste management, this study audited plastic waste produced across six new-build construction sites in Auckland, New Zealand. A total of 7.2 tonnes of plastic construction waste was collected on-site and audited. Plastics were separated, weighed, and categorised by function and construction stage. Polymer type was determined using Fourier transform infrared (FTIR) spectroscopy. In total, 62% of plastic waste was diverted from landfill through reuse or recycling. On average, 0.61 kg of plastic was generated per m² of construction. Soft plastics were the most generated by mass (33%), followed by PVC and HDPE pipes (22%), shrink wrap (12%), and expanded polystyrene (5%). The majority of plastic waste was generated in the final stages of the projects. The authors recommend the separation of soft plastic, pipes, shrink wrap, and polystyrene on construction sites, particularly towards the finishing stages of construction. Full article

An ultrafiltration (UF) installation was used to separate the actual wastewater from a car wash. Following these studies, the plant was washed several times; however, severe membrane fouling was observed during the filtration of sterile deionised (DI) water. As a result, the permeate flux decreased by more than 50% after 5 h of the UF process. The source of the fouling was the release of deposits, particularly bacteria, from the surfaces of plant elements such as pipes and pumps. The paper presents the effectiveness of biofilm removal from the surface of the equipment during a cyclically repeated washing process. Chemical washing was carried out using acid solutions and alkaline cleaning solutions containing NaOH (pH = 11.5–12). After installation cleaning, the filtration tests were carried out using DI water as a feed. It was determined how biofouling, which develops under these conditions, reduces permeate flux. Despite 3 h of installation washing, there was a 50% reduction in flux after 10 h of UF. Repeating the installation wash (4 h) resulted in a similar decrease in flux after 4 days of UF. Stabilisation of the flux at a level of 500 LMH was achieved after an additional 5 h of washing, including application of hot (323–333 K) alkaline cleaning solutions. The number of bacteria in the biofilm collected from the surface of the membranes, the pump inlet and the surface of the polyvinyl chloride (PVC) hoses forming the pipeline was also investigated. Despite repeated chemical cleaning, the number of bacteria on the pump and hose surfaces was 50–100 CFU/cm². Studies were carried out to determine which bacterial species survived the chemical cleaning of the installation. Gram-positive and Gram-negative bacteria were determined, and taxonomic characteristics of the isolated bacteria were identified. Full article

The scouring and sedimentation of wharf bank slopes significantly impact port safety and efficiency. To overcome the limitations of existing monitoring technologies in real-time capability, adaptability, and precision, this study introduces an innovative device based on distributed fiber optic sensing technology. By analyzing changes in the temperature gradient at the water–soil interface, the device enables dynamic monitoring of the results of scouring and sedimentation processes. It employs a modular design, integrating a linear heat source with fiber optic temperature sensing to capture high-resolution changes. Laboratory experiments evaluated variables such as heating duration, pipe material, pipe diameter, and fiber winding pitch. Results show optimal performance with a 20-min heating duration, with PVC sensors offering higher sensitivity and steel sensors providing greater stability. This study presents a high-precision, real-time solution for monitoring wharf bank slopes, offering insights for equipment optimization and engineering applications. Full article

This work presents an imaging testing system (software and hardware) that can generate repeatable images through a stabilized port in the soil for processes known to change with time. The system includes (i) a stabilized port in the ground made of standard PVC pipe, with sections lined with a borosilicate glass tube, and (ii) a digital imaging instrument to survey the optically transparent portion of the stabilized port. The instrument uses a probe containing a digital camera and two light sources, one using white lights and one using ultraviolet (UV) lights (365 nm). The main instrument controls the probe using a cable within the stabilized port to take overlapping pictures of the soil under the different light sources. Two examples are provided, one to document the distribution of soil and groundwater contaminants known as non-aqueous phase liquids (NAPL, which include petroleum) at variable water saturation levels and a second one to monitor the growth of a plant over a 2-week interval. In both examples, the system successfully identified critical changes in soil processes and showed a resolution of approximately 15 µm (in the order of the thickness of a human hair), demonstrating the potential for repeated imaging of soil processes known to experience temporal changes. Both examples are illustrative, as additional applications might be possible. The novelty of this system lies in its ability to generate repeated measurements at larger depths than the current shallow systems installed by hand. Full article

The aim of this research is to investigate the performance of indoor amorphous photovoltaic systems with PVC water cooling and compare them with those using heatsink cooling. The amorphous approach used in this study involves water flowing through a PVC pipe and a heatsink cooler. The circular heatsink that was used has fins all around it. The water flow through the pipe is pumped from the reservoir to the PVC pipe. The study found that a PVC water flow-based active cooling system is the most effective at preserving thermal stability and improving the performance of amorphous PV modules under high light intensity circumstances, providing insights for future advancements. Full article

Crystallization-induced blockages in tunnel drainage systems pose significant challenges to their functionality and longevity. To address this issue, this study proposes a novel adaptive drainage pipe designed to prevent crystallization. By constructing an indoor experimental model for anti-crystallization tests, combined with scanning electron microscopy (SEM) and molecular dynamics simulations, this study investigates the mechanism and effectiveness of the proposed system. The findings reveal that flexible PVC pipes in dynamic flow and expansion states significantly reduce crystallization compared to conventional PVC pipes. Among tested materials, EVA and TPU demonstrate superior crystallization resistance, with EVA exhibiting the lowest crystallization accumulation (7.13 g/m). Molecular dynamics simulations further elucidated the influence of material properties on the diffusion coefficient and binding energy of calcium carbonate crystals, with EVA showing the lowest binding energy with calcium carbonate at 135.11 kcal/mol, ultimately confirming EVA as the optimal material for crystallization prevention. These results offer new strategies and valuable references for managing crystallization in tunnel drainage systems. Full article

The impact of enrichment on stress reduction in zebrafish (Danio rerio) exposed to a novel environment was assessed. Four control shoals (CTRL) and five treated shoals (TRT), each with eight fish, were observed; in TRT tanks, a PVC pipe was included (three-way tube, 11.7 × 4 cm) as enrichment for 90 days. Subsequently, fish were moved to a new tank for a shoaling test, and behavior was evaluated over periods of 0′–5′ and 5′–10′. Cortisol dissolved in water was measured before and after the test. No differences were found between the two groups in distance moved, swimming speed, or shoal acceleration. Both groups reduced interindividual distance in the second phase of the test (CTRL: t = 8.977, p ≤ 0.0001; TRT: t = 8.247, p ≤ 0.0001), though TRT fish maintained greater spacing (t = 2.292, p ≤ 0.05). TRT fish spent more time without contact during both phases (first: t = 2.645, p ≤ 0.05; second: t = 3.134, p ≤ 0.01), while CTRL fish reduced this time in the second phase (t = 2.991, p ≤ 0.05). Cortisol rose significantly in CTRL after the test (t = 2.452, p ≤ 0.05) but not in TRT fish. These results suggest that environmental enrichment mitigates stress, as seen by reduced cohesiveness and cortisol in TRT fish. Full article

In the study of structural materials, the analysis of fracture and deformation resistance plays an important role, particularly in materials widely used in the construction industry, such as poly(vinyl chloride) (PVC). PVC is a popular material used, among others, in the manufacture of window profiles, doors, pipes, and many other structural components. The aim of this research was to define the influence of the degree of milling of the glass-fibre-reinforced composite on the strength of the window frame welds, and in the next step, to propose new welding parameters to obtain sufficient strength properties that allow reducing the cost of the technological welding operation. During the tests, it was found that the average failure load of the composite samples was highest at a milling depth of 1 mm and lowest at 6 mm. Up to a depth of 1 mm, the values of destructive loads show an increasing trend, while above this depth, a decreasing trend. A clear reduction in strength was observed when milling to a depth of 1.5 mm, which is related to material discontinuity and the lack of a visible weld joint caused by milling too deep. The differences in average failure loads between the samples of 0 mm, 0.5 mm, and 1 mm milling are minimal. Full article