The development of a novel large area building integrated solar collector for pool heating

Unglazed solar collectors have often been used a means of providing low cost heating to swimming pools. However, these systems are typically polymer style “mats” that are laid on top of a roof, often leading to poor aesthetics due to their lack of integration with the building itself. This study charts the development of a novel large area unglazed building integrated solar pool heating system (BIT), based on long run sheet metal roofing, from its initial conceptualisation through to its implementation. It discusses the design of the building integrated solar collector modules, the assessment of their performance through theoretical modelling and experimental validation. Subsequently, it shows the scaling of laboratory scale testing to a large area array through modelling and discusses the performance of the system in the “as-built” configuration. In doing this, it provides a succinct illustration of the design process for the development of the University of Waikato’s building integrated pool heating system

The purification and characterisation of novel dipeptidyl peptidase IV-like activity from bovine serum

The discovery of a potentially novel proline-specific peptidase from bovine serum is presented which is capable of cleaving the dipeptidyl peptidase IV (DPIV) substrate Gly-Pro-MCA. The enzyme was isolated and purified with the use of Phenyl Sepharose Hydrophobic Interaction, Sephacryl S300 Gel Filtration, and Q-Sephacryl Anion Exchange, producing an overall purification factor of 257. SDS PAGE resulted in a monomeric molecular mass of 158 kDa while Size Exclusion Chromatography generated a native molecular mass of 328 kDa. The enzyme remained active over a broad pH range with a distinct preference for a neutral pH range of 7-8.5. Chromatofocusing and Isoelectric Focusing revealed the enzyme’s isoelectric point to be 4.74. DPIV-like activity was not inhibited by serine protease inhibitors but was by the metallo-protease inhibitors, the phenanthrolines. The enzyme was also partially inhibited by Bestatin. Substrate Specificity studies proved that the enzyme is capable of sequential cleavage of bovine β- Casomorphin and Substance P. The peptidase cleaved the standard DPIV substrate, Gly-Pro-MCA with a KM of 38.4 μM, while Lys-Pro-MCA was hydrolysed with a KM of 103 μM. The DPIV- like activity was specifically inhibited by both Diprotin A and B, non-competitively, generating a Ki of 1.4x10-4 M for both inhibitors. Ile-Thiazolidide and Ile-Pyrrolidide both inhibited competitively with an inhibition constant of 3.7x10-7 M and 7.5x10-7 M respectively. It is concluded that bovine serum DPIV-like activity share many biochemical properties with DPIV and DPIV-like enzymes but not exclusively, suggesting that the purified peptidase may play an important novel role in bioactive oligopeptide degradation

Modelling Molecular Motors as Folding-Unfolding Cycles

We propose a model for motor proteins based on a hierarchical Hamiltonian that we have previously introduced to describe protein folding. The proposed motor model has high efficiency and is consistent with a linear load-velocity response. The main improvement with respect to previous models is that this description suggests a connection between folding and function of allosteric proteins.Comment: 5 pages RevTeX, 2 Postscript figures, replaced due to LaTeX proble

Currents, Torques, and Polarization Factors in Magnetic Tunnel Junctions

Application of Bardeen's tunneling theory to magnetic tunnel junctions having a general degree of atomic disorder reveals the close relationship between magneto-conduction and voltage-driven pseudo-torque, as well as the thickness dependence of tunnel-polarization factors. Among the results: 1) The torque generally varies as sin theta at constant applied voltage. 2) Whenever polarization factors are well defined, the voltage-driven torque on each moment is uniquely proportional to the polarization factor of the other magnet. 3) At finite applied voltage, this relation predicts significant voltage-asymmetry in the torque. For one sign of voltage the torque remains substantial even when the magnetoconductance is greatly diminished. 4) A broadly defined junction model, called ideal middle, allows for atomic disorder within the magnets and F/I interface regions. In this model, the spin dependence of a state-weighting factor proportional to the sum over general state index of evaluated within the (e.g. vacuum) barrier generalizes the local state density in previous theories of the tunnel-polarization factor. 5) For small applied voltage, tunnel-polarization factors remain legitimate up to first order in the inverse thickness of the ideal middle. An algebraic formula describes the first-order corrections to polarization factors in terms of newly defined lateral auto-correllation scales.Comment: This version no. 3 is thoroughly revised for clarity. Just a few notations and equations are changed, and references completed. No change in results. 17 pages including 4 figure

Performance of building integrated solar hot water systems

The integration of solar energy systems into buildings has been the subject of considerable commercial and academic research, particularly building integrated photovoltaics. However, the integration of solar hot water systems into roofing systems has had far less attention. This paper presents the theoretical and experimental results of a novel building integrated solar hot water system developed using existing long run roofing materials.This work shows that it is possible to achieve effective integration that maintains the aesthetics of the building and also provides useful thermal energy. The results of an unglazed 108m2 swimming pool heater and 8m2 glazed domestic hot water systems are presented.The experimental results show that the glazed system performs close to the theoretical model and is an effective provider of hot water in certain climates. However it was also found that for larger scale building integrated solar water heating systems, special attention must be paid to the configuration and arrangement of the collectors in order to minimise problems with respect to flow distribution and its effect on collector and system efficiency.<br /

Stochastic lattice models for the dynamics of linear polymers

Linear polymers are represented as chains of hopping reptons and their motion is described as a stochastic process on a lattice. This admittedly crude approximation still catches essential physics of polymer motion, i.e. the universal properties as function of polymer length. More than the static properties, the dynamics depends on the rules of motion. Small changes in the hopping probabilities can result in different universal behavior. In particular the cross-over between Rouse dynamics and reptation is controlled by the types and strength of the hoppings that are allowed. The properties are analyzed using a calculational scheme based on an analogy with one-dimensional spin systems. It leads to accurate data for intermediately long polymers. These are extrapolated to arbitrarily long polymers, by means of finite-size-scaling analysis. Exponents and cross-over functions for the renewal time and the diffusion coefficient are discussed for various types of motion.Comment: 60 pages, 19 figure

Military nurses caring for the enemy

Purpose: This phenomenological study described the lived experience and aftermath of U.S. military nurses assigned enemy detainees during Operation Iraqi Freedom/Operation Enduring Freedom. Two themes emerged: Insurgent Assignments (subthemes included identification of and interactions with insurgents; training, precautions, and ethical issues, thoughts and feelings, coping, and meanings of insurgent care) and The Aftermath (subthemes were mental, emotional, personal, professional, and positive). Conclusions: Insurgent assignments caused ethical dilemmas and challenged theoretical constructs related to caring. Formal training is needed to prepare nurses for the practicalities of and responses to insurgent assignments. This work is the dissertation manuscript of Sharon Thompson, completed by faculty members in the School of Nursing at The University of Texas at Tyler. A final, published version of this article can be viewed at: https://doi.org/10.20467/1091-5710-18.2.6