Non-Symmetrical Direct Extrusion—Analytical Modelling, Numerical Simulation and Experiment

The article presents the original technology of the extrusion of hollow curved pipes. The curvature radius of pipe axis was obtained directly during extrusion by eccentric alignment of the annular calibration gap of the extrusion die. Theoretical relationships describing the radius of curvature of the extruded part as a function of the eccentricity e of position of the annular calibration gap in the die were developed. A die with replaceable inserts with eccentricity e equal to 1, 2, 3, 5, 7 mm was designed and fabricated. Experimental tests were carried out to extrude lead pipes with an outer diameter of 20 mm and an inner diameter of 18 mm. Measurements of the radii of the curvature of the extruded pipes were consistent with the values calculated from the developed theoretical relationships. Numerical modelling of the proposed method of extrusion in a finite element-based QForm 3D program was carried out. The finite element method (FEM) numerical calculations were carried out for lead. Numerical simulations and experimental studies have shown that, by changing the value of the eccentric gap, the radius of curvature of the extruded pipe can be controlled.

Childhood Lead Exposure and Cognitive Functioning Among Older Adults: Evidence From the Health and Retirement Study

Many children born in the early 20th century were exposed to water-borne lead, a neurotoxin that negatively impacts brain development. While lead exposure has been linked to poor cognition among children and young adults, no population-level research has examined the long-term implications of lead exposure for cognitive functioning in later life. Our study is the first to address this gap by utilizing novel data linkages between the 1940 U.S. Census and the Health and Retirement Study (HRS). Our sample includes respondents who were under age 17 (born 1924-1940) by the time of the decennial enumeration on April 1, 1940. Given that the dominant source of lead exposure was water during this period, we assessed lead exposure by using water chemistry and piping material data for each HRS respondent’s city of residence in 1940. Late-life cognitive functioning for HRS participants (observed 1998-2016) was measured using the Telephone Interview for Cognitive Status. We find that lead exposure during childhood is significantly and negatively associated with cognitive functioning in later life. HRS participants who lived in cities with lead pipes and acidic or alkaline water—the conditions required for lead to leech into municipal water—showed lower levels of cognitive functioning decades later as compared to other participants. This association persisted net of race, gender, childhood socioeconomic status and childhood health. However, the association was largely accounted for by adjusting for educational attainment. This implies that childhood lead exposure impacts later-life cognition via its effect on educational attainment.

Worth a Closer Look: Raman Spectra of Lead-Pipe Scale

The identification and characterization of lead-bearing and associated minerals in scales on lead pipes are essential to understanding and predicting the mobilization of lead into drinking water. Despite its long-recognized usefulness in the unambiguous identification of crystalline and amorphous solids, distinguishing between polymorphic phases, and rapid and non-destructive analysis on the micrometer spatial scale, the Raman spectroscopy (RS) technique has been applied only occasionally in the analysis of scales in lead service lines (LSLs). This article illustrates multiple applications of RS not just for the identification of phases, but also compositional and structural characterization of scale materials in harvested lead pipes and experimental pipe-loop/recirculation systems. RS is shown to be a sensitive monitor of these characteristics through analyses on cross-sections of lead pipes, raw interior pipe walls, particulates captured in filters, and scrapings from pipes. RS proves to be especially sensitive to the state of crystallinity of scale phases (important to their solubility) and to the specific chemistry of phases precipitated upon the introduction of orthophosphate to the water system. It can be used effectively alone as well as in conjunction with more standard analytical techniques. By means of fiber-optic probes, RS has potential for in situ, real-time analysis within water-filled pipes.

Examining the Lead Exposure and its Effects among U.S Children

According to the United States Environmental Protection Agency (2019), lead is anelement that is naturally found on the surface of the earth. Lead is also harmful to humans,especially young children. Similarly, the CDC (2021) has reported that lead naturally occurs in the environment such as soil, air, and water. However, it is also commonly found in older homes. This is especially true with lower socioeconomic communities’ housing. Lead exposure commonly comes from old lead pipes, faucets, and plumbing fixtures. In addition to water contamination, nearly 23 million houses have lead-based paint hazards in the United States (Egan et al., 2021). Egan and his colleagues also found that there are more than 3.6 millionhouseholds with children younger than six years old living in these lead-filled homes. More than 6 million housing units still have lead water pipes in the United States.

Examining the Lead Exposure and its Effects among U.S Children

According to the United States Environmental Protection Agency (2019), lead is an element that is naturally found on the surface of the earth. Lead is also harmful to humans, especially young children. Similarly, the CDC (2021) has reported that lead naturally occurs in the environment such as soil, air, and water. However, it is also commonly found in older homes. This is especially true with lower socioeconomic communities’ housing. Lead exposure commonly comes from old lead pipes, faucets, and plumbing fixtures. In addition to water contamination, nearly 23 million houses have lead-based paint hazards in the United States (Egan et al., 2021). Egan and his colleagues also found that there are more than 3.6 million households with children younger than six years old living in these lead-filled homes. More than 6 million housing units still have lead water pipes in the United States (Dignam et al., 2019).

Research to Move Toward Evidence-Based Recommendations for Lead Service Line Disclosure Policies in Home Buying and Home Renting Scenarios

Lead service lines (LSLs)—lead pipes connecting the water main under the street to a building’s plumbing—contribute an estimated 50% to 75% of lead in tap water when they are present. Although Congress banned lead in plumbing materials in 1986, over 6 million LSLs remain in homes across the United States today. This paper summarizes three different home buying or renting scenario-based experimental studies used to evaluate disclosure styles, to assess if these influenced respondents’ perceived risk of the LSL in a home, and their willingness to act. In renting scenarios, having landlords disclose the presence of an LSL, but also provide water test results showing lead levels below the EPA’s lead action level resulted in lower levels of perceived risk, and of willingness to act. In seller-disclosure home buying scenarios, levels of perceived risk and willingness to act were consistently high, and three different disclosure styles did not differentially influence those outcomes. In home inspector-disclosure home buying scenarios, levels of perceived risk and willingness to act were high, but having explicit recommendations to replace LSLs and/or information about risk did not further influence those outcomes. In some cases, including the specific recommendations backfired. Implications for policy and regulation are discussed.