Impedances of electrochemically impregnated nickel electrodes as functions of potential, KOH concentration, and impregnation method

Impedances of fifteen electrodes form each of the four U.S. manufactures were measured at 0.200 V vs. the Hg/HgO reference electrode. This corresponds to a voltage of 1.145 for a Ni/H2 cell. Measurements were also made of a representative sample of these at 0.44 V. At the higher voltage, the impedances were small and very similar, but at the lower voltage there were major differences between manufacturers. Electrodes from the same manufacturers showed only small differences. The impedances of electrodes from two manufacturers were considerably different in 26 percent KOH from those in 31 percent KOH. These preliminary results seen to correlate with the limited data from earlier life testing of cells from these manufacturers. The impedances of cells being tested for Space Station Freedom are being followed, and more impendance measurements of electrodes are being performed as functions of manufacturer, voltage, electrolyte concentration, and cycle history in hopes of finding better correlations of impedance with life

Changes in impedance of Ni electrodes upon standing and cycling

Impedances of Ni electrodes vary with many factors including voltage, cycling, and manufacturer. However, results from Ni/H2 cells being tested for Space Station Freedom show that consistent results are obtained within a group of cells from the same manufacturer if the cells are cycled and stored in the same manner. Impedance changes with storage and cycling are being investigated. Impedances are low in the fully charged state but rise abruptly by several orders of magnitude at a voltage corresponding to a very low state-of-charge. After standing for several months, this increase occurred at a higher voltage, consistent with an increase in structural order during storage which hinders diffusion of protons and reduces high rate capacity. Early measurements on the effects of cycling on Ni/H2 cells being tested for Space Station Freedom show differences between cells from different manufacturers

Impedances of Li/SO2 cells retrieved from the Long Duration Exposure Facility (LDEF satellite) and comparison with cells stored terrestrially

Impedances were measured on several Li/SO2 cells retrieved from the Long Duration Exposure Facility (LDEF) satellite. These cells were used to power instruments and recorders and had all been partially or fully discharged. Impedances were also measured on several cells that were stored in cold storage since manufacture. Unfortunately, none of the cells stored terrestrially had undergone any discharge, whereas all of the cells on the satellite were at least partially discharged early in the mission and then remained on orbit for about 5 years further. It has been observed by others that storage of an Li/SO2 cell after partial discharge, increases the resistance and thickness of the passive film on the Li electrode, as indicated by an increase in the time for recovery of voltage when a load is applied (voltage lag), or in some cases by an inability of a cell to sustain a normal current after such storage. Since the cells stored terrestrially were not discharged in the same manner as the LDEF cells, a direct comparison cannot be made. Thus, the effects of the space environment cannot be separated from the effects of storage after partial discharge. It is believed that the increases in impedance in the LDEF cells are largely due to the storage upon partial discharge rather than the effects of the space environment

Changes in impedance of Ni/Cd cells with voltage and cycle life

Impedances of aerospace design Super Ni/Cd cells are being measured as functions of voltage and number of cycles. The cells have been cycled over 4400 cycles to date. Analysis of the impedance data has been made using a number of equivalent circuits. The model giving the best fit over the whole range of voltage has a parallel circuit of a kinetic resistance and a constant phase element in series with the ohmic resistance. The values for the circuit elements have been treated as empirical parameters, and no attempt has been made as yet to correlate them with physical and chemical changes in the electrode. No significant changes have been seen as yet with the exception of a decrease in kinetic resistance at low states of charge in the first 500 cycles

Impedance studies of Ni/Cd and Ni/H cells using the cell case as reference electrode

Many impedance studies were carried out on Ni electrodes and Ni/Cd and Ni/H batteries. In order for impedance to become a diagnostic tool, accurate and reproducible measurements must be made, and some way of separating the contributions of the individual electrodes must be found. Using the PAR and the Solartron impedance equipment, studies have found that consistent measurements can be made if the cells or electrodes are equilibrated at the voltage of interest. In the charged state, equilibration times required are short, on the order of a few hours or less, but the equilibration time required becomes progessively longer as the voltage is lowered. The cell case can be used as a reference electrode during impedance measurements. The voltage of the case with respect to the electrodes is unimportant provided that it does not change appreciably during the course of the measurement. Measurements were made with several uncycled Ni/Cd cells, one from a lot which was known to have faulty Cd electrodes and another from a lot which showed excellent cycle life and presumably had good Cd electrodes. The impedances of the Ni electrodes vs. the case were similar, while the impedance of the poor Cd electrodes vs. the case. A 50 AH Ni/H cell was also investigated. After subtraction of the ohmic resistances, the sums of the impedances of the individual electrodes were very close to the impedance of the total cell. This indicates that the method is valid for examining the characteristics of the individual electrodes in situ

Impedance studies of Ni/Cd and Ni/H2 cells using the cell case as a reference electrode

Impedance measurements have been made on several Ni/Cd and Ni/H2 flightweight cells using the case as a reference electrode. For these measurements the voltage of the case with respect to the anode or cathode is unimportant provided that it remains stable during the measurement of the impedance. In the cells measured so far, the voltages of the cell cases with respect to the individual electrodes differ from cell to cell even at the same overall cell voltage, but they remains stable with time. The measurements can thus be used to separate the cell impedance into the contributions of each electrode, allowing improved diagnosis of cell problems

Divided by a lack of common language? - a qualitative study exploring the use of language by health professionals treating back pain

Background: The importance of using a common language when communicating to others about back pain is acknowledged in the literature. There are broadly three areas where difficulties in communication about back pain arise. Firstly, patients seeking information from health care professionals can experience difficulties understanding them and the medical literature; secondly, misunderstandings among health professionals concerning terminology can arise. Thirdly, the lack of standardised definitions for back pain terms can make comparison of research studies problematic. This study aims to explore the meanings and issues surrounding the use of existing medical terms for back pain from the perspective of health care professionals, lay people who have consulted health care practitioners for back pain and lay people who have not seen a health care professional regarding back pain. \ud \ud Methods: A series of focus groups were used to explore participants' understanding. A purposive sampling approach was used to achieve a sample which included general practitioners, chiropractors, osteopaths, physiotherapists, and lay people. Focus groups were facilitated by an independent professional qualitative researcher. They were audio taped and full transcripts of each focus group underwent line by line analysis, identifying concepts and coded. Constant comparison was used to allow each item to be checked or compared against the rest of the data \ud \ud Results: Lay participants understood the majority of the terms explored in the group differently to the health professionals. The terms, as understood by the lay participants, can be split into three broad categories. Firstly, terms which were not understood or were misconstrued and which had inadvertent negative connotations or implications. Secondly, terms which were not understood or were misconstrued, but without this leading to negative emotional responses. Thirdly, terms which were understood by lay participants as the health professionals stated they intended them to be understood. \ud \ud Conclusion: Few of the existing medical terms were understood and accepted by lay participants in the way discussed and expected by health professionals. Misunderstandings, unintended meanings and negative emotional responses to terms were common within the study focus groups

Expressive Arts Therapy for Healing Gang Trauma: A Community Engagement

Many ex-gang members have experienced trauma. The purpose of this thesis is to explore the benefits of arts-based programs for rehabilitating gang members who have experienced trauma. The literature reviewed explores arts-based programs for those who have been incarcerated and those who have experienced trauma. The author was part of a community engagement with a gang-rehabilitation program in Los Angeles. The author participated in Music, Art and Drama based programs with ex-gang members. This experience further demonstrated the benefits of the expressive arts being used as a tool for treating trauma, especially in a community of people who have participated in gang life