TB122: Comparison of Alpha- and Beta-Carotene Content of Supermarket vs Roadside Stand Produce in Maine

A study was conducted to determine the alpha- and beta-carotene content of supermarket vs roadside stand produce using high-performance liquid chromatography (HPLC). The fruits and vegetables were obtained from a major local supermarket chain and three roadside stands in Dixmont, Etna and Charleston, ME. Thirteen vegetables and one fruit were sampled during a ten-week period between July and September of 1985. Significant differences at the 0.05 level were observed between supermarket and roadside stand produce for only Swiss chard and green peppers with roadside stands having higher beta-carotene levels in both instances. Alpha-carotene was shown to be nonsignificant among sources at the 0.05 level in all cases.https://digitalcommons.library.umaine.edu/aes_techbulletin/1082/thumbnail.jp

Quantum Spin Excitations through the metal-to-insulator crossover in YBa2Cu3O6+yY Ba_2 Cu_3 O_{6+y}

We use inelastic neutron scattering to study the temperature dependence of the spin excitations of a detwinned superconducting YBa$_2$Cu$_3$O$_{6.45}$ ($T_c=48$ K). In contrast to earlier work on YBa$_2$Cu$_3$O$_{6.5}$ ($T_c=58$ K), where the prominent features in the magnetic spectra consist of a sharp collective magnetic excitation termed ``resonance'' and a large ($\hbar\omega\approx 15$ meV) superconducting spin gap, we find that the spin excitations in YBa$_2$Cu$_3$O$_{6.45}$ are gapless and have a much broader resonance. Our detailed mapping of magnetic scattering along the $a^\ast$/$b^\ast$-axis directions at different energies reveals that spin excitations are unisotropic and consistent with the ``hourglass''-like dispersion along the $a^\ast$-axis direction near the resonance, but they are isotropic at lower energies. Since a fundamental change in the low-temperature normal state of YBa$_2$Cu$_3$O$_{6+y}$ when superconductivity is suppressed takes place at $y\sim0.5$ with a metal-to-insulator crossover (MIC), where the ground state transforms from a metallic to an insulating-like phase, our results suggest a clear connection between the large change in spin excitations and the MIC. The resonance therefore is a fundamental feature of metallic ground state superconductors and a consequence of high-$T_c$ superconductivity.Comment: 9 pages, 7 figures, accepted by Phys. Rev.

Removal of the finite-distance source effect on the Applebaum array

The effect of a finite-distance signal source on the performance of an Applebaum array has been studied extensively in the literature. It has been concluded that unless the Applebaum array is focused at the exact source location, the degradation of the output signal-to-noise ratio (SNR) becomes unacceptable. The automatic focusing technique (AFT), developed for long-wavelength imaging systems using nonadaptive linear arrays, is extended here to focus adaptive arrays such as the Applebaum type. Thereafter, the far-field steering vector is used successfully to form a beam approaching the desired signal while suppressing the interferences. Substantial improvements in data processing have been achieved through the use of a partial convolution in the frequency domain. It is also demonstrated that the AFT can be used when the signal source range lies in the beginning of the Fresnel region of a nonadaptive linear array with negligible loss in the output SN

Removal of the finite-distance source effect on the Applebaum array

The effect of a finite-distance signal source on the performance of an Applebaum array has been studied extensively in the literature. It has been concluded that unless the Applebaum array is focused at the exact source location, the degradation of the output signal-to-noise ratio (SNR) becomes unacceptable. The automatic focusing technique (AFT), developed for long-wavelength imaging systems using nonadaptive linear arrays, is extended here to focus adaptive arrays such as the Applebaum type. Thereafter, the far-field steering vector is used successfully to form a beam approaching the desired signal while suppressing the interferences. Substantial improvements in data processing have been achieved through the use of a partial convolution in the frequency domain. It is also demonstrated that the AFT can be used when the signal source range lies in the beginning of the Fresnel region of a nonadaptive linear array with negligible loss in the output SN

Internet of Things Based Monitoring System of Leaks in Water Supply Networks Using Pressure-Based Model

Leaks in water distribution networks impose several impacts on economy, freshwater resources, water quality, health and safety. Fast leak detection and reparation is a key for lowering its negative impacts and associated costs with conventional detection techniques. This study has been used a pressure-based model to detect leaks events and its coordinates based on pressure and flow measurements. Pressure and flow data for systems that having leaks in their structure were analyzed and compared with data generated from non-leaking systems using EPANET software packages. An extension package of EPANET software (EpanetWaterGen) has been used as it has the advantage of its ability to better simulate leaks. The results show the ability of the model to detect leaks in a small and large water distribution networks with uncertainty level associated with low pressure change. The developed leak detection model utilizes pressure and flow sensors and enables the network managers and administrators to optimally place the sensors in a manner to increase efficiency and optimize cost. The system allows operators to detect leak location and volume of lost water, thus enabling a better and more efficient response to leaks, such that the network managers can address and respond to most urgent leaks and optimize the time end efforts of technical and maintenance personnel

Internet of Things Based Monitoring System of Leaks in Water Supply Networks Using Pressure-Based Model

Leaks in water distribution networks impose several impacts on economy, freshwater resources, water quality, health and safety. Fast leak detection and reparation is a key for lowering its negative impacts and associated costs with conventional detection techniques. This study has been used a pressure-based model to detect leaks events and its coordinates based on pressure and flow measurements. Pressure and flow data for systems that having leaks in their structure were analyzed and compared with data generated from non-leaking systems using EPANET software packages. An extension package of EPANET software (EpanetWaterGen) has been used as it has the advantage of its ability to better simulate leaks. The results show the ability of the model to detect leaks in a small and large water distribution networks with uncertainty level associated with low pressure change. The developed leak detection model utilizes pressure and flow sensors and enables the network managers and administrators to optimally place the sensors in a manner to increase efficiency and optimize cost. The system allows operators to detect leak location and volume of lost water, thus enabling a better and more efficient response to leaks, such that the network managers can address and respond to most urgent leaks and optimize the time end efforts of technical and maintenance personnel

The evolution of antiferromagnetic susceptibility to uniaxial pressure in Ba(Fe{1-x}Co{x})2As2

Neutron diffraction measurements are presented measuring the responses of both magnetic and structural order parameters of parent and lightly Co-doped Ba(Fe{1-x}Co{x})2As2 under the application of uniaxial pressure. We find that the uniaxial pressure induces a thermal shift in the onset of antiferromagnetic order that grows as a percentage of T_N as Co-doping is increased and the superconducting phase is approached. Additionally, as uniaxial pressure is increased within parent and lightly-doped Ba(Fe{1-x}Co{x})2As2 on the first order side of the tricritical point, we observe a decoupling between the onsets of the orthorhombic structural distortion and antiferromagnetism. Our findings place needed constraints on models exploring the nematic susceptibility of the bilayer pnictides in the tetragonal, paramagnetic regime.Comment: 10 pages, 7 figure

Magnetic properties of LaFe1-xCrxO3 and Fe2-2xCr2xO3 mixed oxides

Mixed oxides with formula LaFe1-xCrxO3 and Fe2-2xCr2xO3, where 0≤x≤1, are studied. The samples have been prepared using solid state reaction technique in air. The X-ray diffraction spectra indicated that the samples crystallize in a corundum phase with space group ( R3c ) for Fe2-2xCr2xO3 and in the perovskite structure for LaFe1-xCrxO3. Many techniques have been used to explore the magnetic properties of the systems. High field, ZFC and FC magnetization vs. temperature, d.c. susceptibility and Mössbauer spectroscopy were carried out. High temperature magnetic susceptibility measurements and high field magnetic magnetization (H ≤ 20 T) show that the behavior of the susceptibility and the magnetization are complex. Mössbauer spectra of the solid solutions have been measured at 4.2 K and in the temperature range 77 K to 300 K. The shapes of spectra are unusual, showing strong relaxation phenomena in a wide temperature range as recently observed for many frustrated systems. The results are discussed by establishing the existence of various magnetic structures, inducing intermediate magnetic phases between the antiferromagnetic and the paramagnetic states. Preliminary magnetic phase diagrams of the systems have been established.Mixed oxides with formula LaFe1-xCrxO3 and Fe2-2xCr2xO3, where 0≤x≤1, are studied. The samples have been prepared using solid state reaction technique in air. The X-ray diffraction spectra indicated that the samples crystallize in a corundum phase with space group ( R3c ) for Fe2-2xCr2xO3 and in the perovskite structure for LaFe1-xCrxO3. Many techniques have been used to explore the magnetic properties of the systems. High field, ZFC and FC magnetization vs. temperature, d.c. susceptibility and Mössbauer spectroscopy were carried out. High temperature magnetic susceptibility measurements and high field magnetic magnetization (H ≤ 20 T) show that the behavior of the susceptibility and the magnetization are complex. Mössbauer spectra of the solid solutions have been measured at 4.2 K and in the temperature range 77 K to 300 K. The shapes of spectra are unusual, showing strong relaxation phenomena in a wide temperature range as recently observed for many frustrated systems. The results are discussed by establishing the existence of various magnetic structures, inducing intermediate magnetic phases between the antiferromagnetic and the paramagnetic states. Preliminary magnetic phase diagrams of the systems have been established