The validity of weighted scoring evaluation techniques applied to design: studies in the appraisal of heating, ventilating and air conditioning systems for office buildings.

The common weighted scoring evaluation technique is presented by the design methods literature and by many practical guides as being an appropriate method for appraising different design solutions, however there are few critical assessments of the assumptions inherent in the method and no serious attempts to evaluate the validity of the technique as applied in a design context. This thesis presents a series of empirical studies and theoretical reviews which examine, in a logical sequence, aspects of the validity of weighted scoring techniques in the context of early stage heating, ventilating and air conditioning (HVAC) system design for office buildings. The nature of the HVAC design process is investigated, and in parallel with this a theoretical critique of the weighted scoring method as described in the design methods literature is conducted. It is found that the common approach to weighted scoring is invalid, raising concern over the indiscriminate use of such decision aids. However, a theoretically correct interpretation known as Multi-Attribute Value Theory (MAVT) is possible. It is also found that the method is not applicable to the selection of HVAC systems in general, but may be considered reasonably valid in more restricted tasks such as air conditioning system selection for a specific area in a building. While the MAVT models developed are judged to be reasonably valid, it is argued that their usefulness is debatable. If all the information on which to base the decision is available and the decision maker is reasonably skilled then MAVT will only improve decision making at the margin where the penalty for a wrong decision is less significant

Pensions and the Labor Market

Employers typically view their investment in pension plans as a means of providing retirement income for their workers. Economists, on the other hand, view pension programs as a way to increase workplace productivity. Dorsey, Cornwell and Macpherson explore the theoretical and empirical basis for this perspective and, in the process, offer a complete and up-to-date discussion on the productivity theory of pensions.https://research.upjohn.org/up_press/1067/thumbnail.jp

Pensions and Productivity

Employers typically view their investment in pension plans as a means of providing retirement income for their workers. Economists, on the other hand, view pension programs as a way to increase workplace productivity. Dorsey, Cornwell and Macpherson explore the theoretical and empirical basis for this perspective and, in the process, offer a complete and up-to-date discussion on the productivity theory of pensions.https://research.upjohn.org/up_press/1067/thumbnail.jp

Cardiovascular effects of serotonergic agents

Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter which exerts its cardiovascular effects predominantly by interaction with specific 5-HT1 and 5- HT2 receptors. The effects of serotonergic agents differ between in vivo and in vitro preparations and display wide inter-species variation. It is therefore impossible to extrapolate results from animal or in vitro studies to the clinical situation. The role of these two receptors has therefore been studied in patients with suspected coronary artery disease using 3 different 5-HT1 agonists and ketanserin, a 5-HT2 antagonist. Sumatriptan and naratriptan, 5-HT1B/D receptor agonists, vasoconstrict the systemic and pulmonary circulations. Sumatriptan-induced vasoconstriction appears more pronounced in the pulmonary circulation suggesting a greater density of 5-HT1 receptors in the pulmonary compared to the systemic circulation. Although left ventricular end diastolic pressure and pulmonary artery wedge pressure rose after sumatriptan, there was no change in peak rate of left ventricular pressure rise, indicating the absence of a negative inotropic action. Naratriptan, an analogue of sumatriptan, displayed no significant effect on coronary artery diameter, a finding previously noted with sumatriptan. Eletriptan, a selective 5-HT1D agonist with less 5-HT1B activity, had little vasoconstrictor effect on the systemic, pulmonary or coronary circulation perhaps suggesting that the 5-HT1B receptor subtype mediates vasoconstriction. The effect of sumatriptan on systolic time intervals and forearm blood flow was also assessed. The results suggest that STI's are of potential use in the non-invasive assessment of 5-HT1 agonists. No significant effect on forearm blood flow was observed but plasma noradrenaline levels fell after subcutaneous sumatriptan. Ketanserin, a 5-HT2 antagonist, acted as a vasodilator in the systemic and pulmonary circulation but failed to vasodilate the coronary arteries, presumably because the patients in this study had stable angina without platelet activation and therefore had low circulating levels of serotonin

Enhanced Ballistic Transport of Charge Carriers in Alloyed and K-Passivated Alloyed Perovskites Thin Films

Hybrid organic-inorganic perovskites show remarkable charge transport properties despite their deposition via low-temperature solution phase methods. It has recently been shown that this includes the ballistic transport of charges following photoexcitation, with ballistic transport lengths as large as 150 nm measured in MAPI3 films, which is almost twice the value report for GaAs. Here we explore the ballistic transport regime in high performance triple cation and K passivated triple cation perovskite films, using femtosecond transient absorption microscopy which allows us to image carrier motion with 10 fs temporal resolution and 10 nm spatial precision. We observe ballistic transport lengths of 160 and 220 nm respectively in triple cation and K passivated triple cation perovskite films. We propose that the ballistic transport is limited by nanoscale trap clusters at grain boundaries and interfaces, which can be passivated via chemical treatments to enhance the ballistic transport length, which implies that further enhancements are possible as passivation methods are improved.EPSR

A porphyrin-centred fullerene tetramer containing an N@C60 substituent

An N@C60-containing C60 tetramer was synthesized by quadruple 1,3-dipolar cycloaddition (Prato) reaction. This molecule demonstrates the N@C60 qubit’s ability to form covalently linked arrays. Furthermore, it provides a promising scaffold with which to measure multiple qubit–qubit interactions; which must be well characterized for a functioning quantum information processing architecture

Triple oxygen isotopic composition of the high-³He/⁴He mantle

Measurements of Xe isotope ratios in ocean island basalts (OIB) suggest that Earth’s mantle accreted heterogeneously, and that compositional remnants of accretion are sampled by modern, high-3He/4He OIB associated with the Icelandic and Samoan plumes. If so, the high-3He/4He source may also have a distinct oxygen isotopic composition from the rest of the mantle. Here, we test if the major elements of the high-3He/4He source preserve any evidence of heterogeneous accretion using measurements of three oxygen isotopes on olivine from a variety of high-3He/4He OIB locations. To high precision, the Δ17O value of high-3He/4He olivines from Hawaii, Pitcairn, Baffin Island and Samoa, are indistinguishable from bulk mantle olivine (Δ17OBulk Mantle − Δ17OHigh 3He/4He olivine = −0.002 ± 0.004 (2 × SEM)‰). Thus, there is no resolvable oxygen isotope evidence for heterogeneous accretion in the high-3He/4He source. Modelling of mixing processes indicates that if an early-forming, oxygen-isotope distinct mantle did exist, either the anomaly was extremely small, or the anomaly was homogenised away by later mantle convection. The δ18O values of olivine with the highest 3He/4He ratios from a variety of OIB locations have a relatively uniform composition (∼5‰). This composition is intermediate to values associated with the depleted MORB mantle and the average mantle. Similarly, δ18O values of olivine from high-3He/4He OIB correlate with radiogenic isotope ratios of He, Sr, and Nd. Combined, this suggests that magmatic oxygen is sourced from the same mantle as other, more incompatible elements and that the intermediate δ18O value is a feature of the high-3He/4He mantle source. The processes responsible for the δ18O signature of high-3He/4He mantle are not certain, but δ18O–87Sr/86Sr correlations indicate that it may be connected to a predominance of a HIMU-like (high U/Pb) component or other moderate δ18O components recycled into the high-3He/4He source

Wideband corrugated feedhorns, for radar, communications, radiometry and quasi-optics

This work was supported in part by Engineering and Physical Sciences Research Council, U.K., under Grant EP/R013705/1, and in part by IAA Funding.A wide variety of desirable antenna beam patterns can be synthesized by optimal excitation and phasing of the HE11 and HE12 modes in scalar corrugated feedhorns. However, the bandwidth of such two-mode horns is often limited by modal dispersion. In this paper we introduce a class of low dispersion, two-mode feedhorns that can operate, in some cases, over operating bandwidths of 40-50%. We provide example designs that include horns with high coupling efficiency to: 1) a pure HE11 mode for single-mode excitation of corrugated pipe transmission lines; 2) a LG00 and LG02 combination for radiometry, with narrow beams; 3) a pure Laguerre Gaussian LG00 mode for quasi-optical instrumentation with constant phase centers; 4) a constant gain antenna for uniform illumination with frequency; 5) Airy patterns or “top hat” patterns for radar or communications applications, designed to maximize aperture efficiencies when used with larger reflect or lens antennas. More generally, we show methods to generate and phase multiple HE1n modes, to synthesize symmetric output beams at any desired frequency or gain.Publisher PDFPeer reviewe