Frequency response in short thermocouple wires

Theoretical expressions are derived for the steady state frequency response of a thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for a nonuniform wire with unequal material properties and wire diameters across the junction. The amplitude ratio at low frequency omega approaches 0 agrees with the results of Scadron and Warshawsky (1952) for a steady state temperature distribution. Moreover, the frequency response for a nonuniform wire in the limit of infinite length l approaches infinity is shown to reduce to a simple expression that is analogous to the classic first order solution for a thermocouple wire with uniform properties. Theoretical expressions are also derived for the steady state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire and a two material wire with unequal material properties across the junction. For the case of a one material supported wire, an exact solution is derived which compares favorably with an approximate expression that only matches temperatures at the support junction. Moreover, for the case of a two material supported wire, an analytical expression is derived that closely correlates numerical results. Experimental measurements are made for the steady state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 pct. with the theoretical predictions of Forney and Fralick (1991). This is accomplished by choosing a natural frequency omega sub n for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at low frequencies but decrease the natural frequency of the wire. The phase angle data are also distorted for imperfect junctions

Living with HIV after Release from Prison: An Evaluation of the Long-term Health of Formerly Incarcerated Individuals who used Michigan’s Community Reentry Service

In 2003, Michigan implemented a reentry service to assist HIV-infected people incarcerated in state prisons in linking to HIV medical care immediately upon their release. We examined whether formerly incarcerated people were linked to care successfully, remained in care, and were in good health 3 years after their date of release. In all, 190 people used the service over the 5 years following its inception. Only a minority of those who were alive and not reincarcerated at the time of the evaluation engaged consistently with medical care. Unsurprisingly given low rates of engagement in care, 3 years after their release only 27% had achieved viral suppression. Concerted efforts to support formerly incarcerated HIV-infected individuals’ engagement in care over the long term are urgently needed

Mutations of penicillin acylase residue B71 extend substrate specificity by decreasing steric constraints for substrate binding

Two mutant forms of penicillin acylase from Escherichia coli strains, selected using directed evolution for the ability to use glutaryl-L-leucine for growth [Forney, Wong and Ferber (1989) Appl. Environ. Microbiol. 55, 2550-2555], are changed within one codon, replacing the B-chain residue Phe(B71) with either Cys or Leu. Increases of up to a factor of ten in k(cat)/K-m values for substrates possessing a phenylacetyl leaving group are consistent with a decrease in K-s. Values of k(cat/)K(m) for glutaryl-L-leucine are increased at least 100-fold. A decrease in k(cat)/K-m for the CySB71 mutant with increased pH is consistent with binding of the uncharged glutaryl group. The mutant proteins are more resistant to urea denaturation monitored by protein fluorescence, to inactivation in the presence of substrate either in the presence of urea or at high pH, and to heat inactivation. The crystal structure of the Leu(B71) mutant protein, solved to 2 X resolution, shows a flip of the side chain of Phe(B256) into the periphery of the catalytic centre, associated with loss of the pi-stacking interactions between Phe(B256) and Phe(B71). Molecular modelling demonstrates that glutaryl-L-leucine may bind with the uncharged glutaryl group in the S-1 subsite of either the wild-type or the Leu(B71) mutant but with greater potential freedom of rotation of the substrate leucine moiety in the complex with the mutant protein. This implies a smaller decrease in the conformational entropy of the substrate on binding to the mutant proteins and consequently greater catalytic activity

Three-wire Thermocouple: Frequency Response in Constant Flow

Theory and experimental measurements are compared with a novel three-wire thermocouple. Signals from three wires of unequal diameters arc recorded from the thermocouple suspended in constant flow with a periodic temperature fluctuation. It is demonstrated that the reconstructed signal from the three-wire thermocouple requires no compensation for omega less than or equal to 5(sub omega1), where omega, is the natural frequency of the smaller wire. The latter result represents a significant improvement compared to previous work with two-wire thermocouples. A correction factor has also been derived to account for wires of arbitrary diameter

Frequency response of a thermocouple wire: Effects of axial conduction

Theoretical expressions are derived for the steady-state frequency response of a thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a uniform thermocouple wire and a nonuniform wire with unequal material properties and wire diameters across the junction. For the case of a uniform wire, the amplitude ratio and phase angle compare favorably with the series solution of Scadron and Warshawsky (1952) except near the ends of the wire. For the case of a non-uniform wire, the amplitude ratio at low frequency omega yields 0 agrees with the results of Scadron and Warshawsky for a steady-state temperature distribution. Moreover, the frequency response for a non-uniform wire in the limit of infinite length l yields infinity is shown to reduce to a simple expression that is analogous to the classic first order solution for a thermocouple wire with uniform properties

Multiwire Thermocouples in Reversing Flow

Measurements are recorded for multiwire thermocouples consisting of either two or three wires of unequal diameters. Signals from the multiwire probe are recorded for a reversing gas flow with both a periodic temperature and time constant fluctuation. It is demonstrated that the reconstructed signal from the multiwire thermocouple requires no compensation provided omega/omega(sub 1) less than 2.3 for two wires or omega/omega(sub 1) less than 3.6 for three wires where omega(sub 1) (= 2(pi)f) is the natural frequency of the smaller wire based on the maximum gas velocity. The latter results were possible provided Fourier transformed data from the wires were used and knowledge of the gas velocity phase angle was available

Measurement of frequency response in short thermocouple wires

Experimental measurements are made for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 percent with the theoretical predictions of Fralick and Forney (1991). This is accomplished by choosing a natural frequency omega(sub n) for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at low frequencies but decreas the natural frequency of the wire. The phase angle data are also distorted for imperfect junctions

The influence of leadership behaviors and hospitality culture on the perception of internal service quality delivered in hotels

Service is an important aspect of the hotel industry, especially to the customer (Large & König, 2009). However, more importantly, customer service starts internally with how employees perceive they are being served (Kang et al., 2002). Improving internal service quality (can improve the overall performance of an organization. Researchers state that internal service quality can be influenced by the organizational culture and the leadership within an organization. The purpose of this research was to examine the relationship between specific leadership behaviors as defined by Posner and Kouzes (1988) and the influence the defined behaviors have on the perception of organizational culture within a hotel, referred to as hospitality culture in this research, and internal service quality as perceived by hotel employees. The sample consisted of employees at a Western New York Management company with midscale and upper-midscale hotels. Three separate measurement tools were selected to comprise the questions for the survey: (a) the INTSERVQUAL, (b) the Hospitality Culture Scale, and (c) the Leadership Practices Inventory. Data were analyzed using descriptive statistics, analysis of variance, and multiple regression to answer the five research questions and their corresponding hypotheses. The results of this study demonstrated that the hospitality culture and specific leadership behaviors model the way and inspired a shared vision influence how employees perceive how they are supported by their managers/supervisors. Implications of this study can assist managers in planning and development of internal service quality management and strategies

Frequency response of a supported thermocouple wire: Effects of axial conduction

Theoretical expressions are derived for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire and a two material wire with unequal material properties across the junction. For the case of a one material supported wire, an exact solution is derived which compares favorably with an approximate expression that only matches temperatures at the support junction. Moreover, for the case of a two material supported wire, an analytical expression is derived that closely correlates numerical results. Experimental data were taken with a type K supported thermocouple. The test thermocouple was constructed with dimensions to demonstrate the effects of axial heat conduction assuming constant physical properties across the junction