The World Health Organisation (WHO) presents an upper limit for lead in drinking water of 10 parts per billion ppb. Typically, to reach this level of sensitivity, expensive metrology is required. To ...increase the sensitivity range of low-cost devices, this paper explores the prospects of using a volume reduction technique of a boiled water sample doped with Lead-210 (
210
Pb), as a means to increase the solute’s concentration.
210
Pb is a radioactive lead isotope and its concentration in a water sample can be measured with e.g. High Purity Germanium (HPGe) detectors at the Boulby Underground Germanium Suite. Concentrations close to the WHO limit have not been examined. This paper presents a measurement of the volume reduction technique retaining
99
±
(
9
)
% of
210
Pb starting from a concentration of
1.9
×
10
-
6
ppb before reduction and resulting in
2.63
×
10
-
4
ppb after reduction. This work also applies the volume reduction technique to London tap water and reports the radioassay results from gamma counting in HPGe detectors. Among other radio-isotopes,
40
K,
210
Pb,
131
I and
177
Lu were identified at measured concentrations of
2.83
×
10
3
ppb,
2.55
×
10
-
7
ppb,
5.06
×
10
-
10
ppb and
5.84
×
10
-
10
ppb in the London tap water sample. This technique retained
90
±
50
%
of
40
K. Stable lead was inferred from the same water sample at a measured concentration of 0.012 ppb, prior to reduction.
The
γ
-ray flux inside
La Guadalupe
mine, the selected site for the construction of the underground laboratory LABChico in Mexico, is reported for energies below 3 MeV. Data were recorded with a ...0.669 kg thallium-activated sodium iodide (NaI) crystal detector deployed for 3.6 hr. The detector response was calculated via Monte Carlo simulations with GEANT4 and validated against point-like calibration sources, and the
γ
-ray spectrum was extracted using an unfolding technique. The
γ
-ray flux above 250 keV and below 3 MeV is 0.1768
γ
/cm
2
/s. The two most intense
γ
-rays in the natural radioactive background,
40
K and
208
Tl, were identified. The flux measured for these isotopes is 0.0363 ± 0.0020
γ
/cm
2
/s and 0.0016 ± 0.0005
γ
/cm
2
/s, respectively. A
γ
-ray spectrometry analysis of rock samples showed 674.0 ± 2.0 Bq/kg, 24.0 ± 0.1 Bq/kg, and 17.7 ± 0.2 Bq/kg, of
40
K,
232
Th, and
238
U, respectively. These results are compared with deep underground facilities such as SURF, SNOLAB, Boulby, Modane, and Gran Sasso, with differences observed mainly due to the rock composition. Geotechnical studies of the mine and its rock composition are also reported.
Phase velocity of a surface acoustic wave (SAW) varies when the electric field associated with the wave interacts with a conductive material located above the propagation plane. In this paper, we ...propose a general method to approximate the scattering matrix when the conductive structure has a specific geometry. This structure has reflective properties of SAW. As an example, we considered a previously reported SAW-MEMS microaccelerometer which mainly consists of a slotted beam. By applying this method, we obtained the relationship between acceleration and the reflection and transmission coefficients. The dynamic of the slotted beam was studied using the finite element method (FEM). It was observed that relatively small variations in the size of the microstructure could cause significant changes in the reflection and transmission coefficients. We also show that the slotted beam acts as an acoustic wave bandpass filter, and its response is similar to that of reflective gratings, but with linear phase.
The World Health Organisation (WHO) presents an upper limit for lead in drinking water of 10 parts per billion ppb. Typically, to reach this level of sensitivity, expensive metrology is required. To ...increase the sensitivity of low cost devices, this paper explores the prospects of using a volume reduction technique of a boiled water sample doped with Lead-210 (\(^{210}Pb\)), as a means to increase the solute's concentration. \(^{210}\)Pb is a radioactive lead isotope and its concentration in a water sample can be measured with e.g. High Purity Germanium (HPGe) detectors at the Boulby Underground Germanium Suite. Concentrations close to the WHO limit have not been examined. This paper presents a measurement of the volume reduction technique retaining \(99\pm(9)\%\) of \(^{210}\)Pb starting from a concentration of \(1.9\times10^{-6}\) ppb before reduction and resulting in \(2.63\times10^{-4}\) ppb after reduction. This work also applies the volume reduction technique to London tap water and reports the radioassay results from gamma counting in HPGe detectors. Among other radio-isotopes, \(^{40}\)K, \(^{210}\)Pb, \(^{131}\)I and \(^{177}\)Lu were identified at measured concentrations of \(2.83\times10^{3}\) ppb, \(2.55\times10^{-7}\) ppb, \(5.06\times10^{-10}\) ppb and \(5.84\times10^{-10}\) ppb in the London tap water sample. This technique retained \(90\pm50\%\) of \(^{40}\)K. Stable lead was inferred from the same water sample at a measured concentration of 0.012 ppb, prior to reduction.
This paper reports on the development of a novel CMOS device employing lead-sensing bacteria to assay lead in drinking water. The objective of the PlomBOX project is to develop a low-cost sensor ...({\pounds}10) which can expedite access to on-demand assay methods and thus help mitigate lead intake through contaminated drinking water. The project follows three development paths: a) Certain bacteria can fluoresce or change colour when in the presence of lead. A genetically modified strain of Escherichia coli sensitive to lead concentrations up to 10 ppb is being developed. This constitutes the biosensor that fluoresces in proportion to the presence of lead. b) Bacteria response is imaged using a microprocessor (ESP32) with a camera module. This constitutes the optical metrology component of the PlomBOX. c) Data acquisition and control of the PlomBOX is achieved through a Bluetooth connection with the PlomApp, a custom-developed mobile phone application. Data are sent from the PlomApp to a database where a bespoke automated analysis software provides a result of the lead concentration in a sample of water. This paper reports on the instrumentation challenges of developing the electronics for the PlomBOX and on the first prototype.
This article reports the characterization of two High Purity Germanium detectors performed by extracting and comparing their efficiencies using experimental data and Monte Carlo simulations. The ...efficiencies were calculated for pointlike \(\gamma\)-ray sources as well as for extended calibration sources. Characteristics of the detectors such as energy linearity, energy resolution, and full energy peak efficiencies are reported from measurements performed on surface laboratories. The detectors will be deployed in a \(\gamma\)-ray assay facility that will be located in the first underground laboratory in Mexico, Laboratorio Subterráneo de Mineral del Chico (LABChico), in the Comarca Minera UNESCO Global Geopark
Several animal models of right ventricle hypertension (RVH) have been produced through pulmonary artery banding with linen, tygon or teflon. Nevertheless few devices attempting a progressive, step by ...step graduated chronic development of RVH have been reported. The present study describes the results in our animal model of chronic RVH.
We designed a software programmed to obtain hemodynamic data and installed a small occlusive hydraulic device (OHD) at the pulmonary artery trunk producing a raise in the right ventricular systolic pressure (RVSP); this pressure can be modified externally through the OHD. We studied 12 healthy mongrel dogs (18 to 28 kg of weight) in the course of 6 months. Hemodynamic measurements were performed at different RVSP at two months intervals; (Baseline, 40 mmHg and 60 mmHg).
The software was useful to analyze several hemodynamic variables at each RVSP. At 60 mmHg, the end diastolic pressure of the right ventricle (RVEDP) increased from 4.2 +/- 0.4 mmHg to 13.2 +/- 1.1 mmHg, p < 0.000, accompanied with a fall in cardiac output adjusted to the dogs weight from 0.16 +/- 0.03 L/min/kg to 0.09 +/- 0.01 L/min/kg, p > 0.000. Also an increase of the end diastolic pressure of the left ventricle (LVEDP) from 7.4 +/- 0.8 mmHg to 16.3 +/- 2.8 mmHg, p < 0.000, was observed. RVSP was maintained in chronic condition and the intraclass correlation coefficient was 0.83, P < 0.005.
Right ventricular chronic hypertension is created. The device is useful and reliable to maintain chronic increments of RVSP. The software permits a versatile analysis.
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