Gain measurements of standard electromagnetic horns in the kappa and kappa alpha bands

Gain measurements of standard electromagnetic horn antennas for use in calibrating millimeter wave, parabolic radio telescope

Write from the Heart: An Interview with Brian Wrixon, a Poet from Canada

Brian Wrixon, a poet, was born in 1946 in Toronto, Canada. He graduated from Laurentian University in Canada with a degree in Classical Studies, and is a former faculty member, online curriculum design consultant and program coordinator at Mohawk College in Hamilton, Ontario. His working career in the financial services business spanned forty years. He has contributed his poems to numerous collections of poetry. Apart from this, as a poet, he has written Poetry in Motion Volumes 1 & 2 (2011), Confessions of a Would-Be Poet (2011), Heartbeats, Footsteps & Musings (2012), Doors (2013), Down to the Sea in Words (2013), The Moving Finger Writes (2013), Sculptured Words (2013), A tisket, a tasket, poems in a Basket (2013), It’s a Sign of the Times (2013), Nightmares & Dreams (with Rollie Mukherjee) (2013),Shoot From the Hip: Memories of a Small Town (2013), A Return Ticket: Memories of Leaving a Small Town (2013), My Passage to India (2014), A Look at Yesterday (with Robert Vincent) (2014), Our Town Revisited (with Robert Vincent) (2014) and Desperate Freedom: a Play in Four Acts (2014). Apart from composing a good number of poems, he has edited many anthologies of poems and operates as a publisher as well. In addition to writing and publishing numerous poetry and prose works of his own, he has been instrumental in assisting hundreds of young and emerging authors from around the world get published, either personally or as contributors to group anthologies

A rigorous exposition of the LEMMA method for analog and mixed-signal testing.

The linear error-mechanism modeling technique is an effective tool for testing analog and mixed-signal devices which minimizes the number of measurements required to characterize the static transfer function of a circuit by determining a small number of parameters of a linear error model and then predicting the entire response error. This work focuses on optimizing the linear error-mechanism model algorithm (LEMMA), introducing novel refinements which are shown to improve its performance significantly. We outline the implementation of the algorithm in a tutorial manner, paying due consideration to the underlying theory where required

Addressing car dependency in Cape Town: Reviewing how the Citys mobility and spatial frameworks can transcend car-oriented urbanism

This dissertation presents research conducted by Wrixon Mpanang'ombe titled ‘Addressing car dependency in Cape Town: Reviewing how the city's mobility and spatial frameworks can transcend car-oriented urbanism'. The research stems from a background of the need to address problems associated with the dominance of cars in cities. The problems include carbon emissions contributing to climate change, road safety issues, pollution and other public health challenges, but also inequitable accessibility favouring private car users, among many other problems. Also, the research is motivated by and in response to the argument by Newman and Kenworthy (2015) that cities are experiencing an end to car dependency. However, since this argument is made based on Global North contexts, researching what an end to car dependency might imply for Southern cities is very relevant. Therefore, this research situates in Cape Town to explore how the City of Cape Town is currently dealing with the issue of transitioning away from car dependency and caroriented urbanism. The research explores this by deploying an analysis of the discourse around issues addressing car dependency and car-oriented urbanism in the City's key transport and spatial planning frameworks. The frameworks were analysed through a series of assessment criteria that were derived from the literature review. Three main gaps emerged through the research: (1) the reluctance to call out car dependency as a major transport problem in the city, (2) the focus on costs for low-income groups in the City's transport planning objectives while overlooking the car dependency in medium- and high-income groups, and (3) the inadequate spatial alignment of plans with the varying urban fabrics (i.e., based on Newman's and Kenworthy's (2015) theory of urban fabrics) and therefore not positioned to leverage the potential of rejuvenating urban fabrics as a pathway toward ending car dependency. The research further suggests that to address these gaps, the key frameworks should be repositioned to explicitly name car dependency as a major problem for the urban mobility system, but also the various urban fabrics should be mapped and aligned with the City's transport and spatial plans and land use policies

Soil radium, soil gas radon and indoor radon empirical relationships to assist in post-closure impact assessment related to near-surface radioactive waste disposal

Least squares (LS), Theil’s (TS) and weighted total least squares (WTLS) regression analysis methods are used to develop empirical relationships between radium in the ground, radon in soil and radon in dwellings to assist in the post-closure assessment of indoor radon related to near-surface radioactive waste disposal at the Low Level Waste Repository in England. The data sets used are (i) estimated 226Ra in the <2 mm fraction of topsoils (eRa226) derived from equivalent uranium (eU) from airborne gamma spectrometry data, (ii) eRa226 derived from measurements of uranium in soil geochemical samples, (iii) soil gas radon and (iv) indoor radon data. For models comparing indoor radon and (i) eRa226 derived from airborne eU data and (ii) soil gas radon data, some of the geological groupings have significant slopes. For these groupings there is reasonable agreement in slope and intercept between the three regression analysis methods (LS, TS and WTLS). Relationships between radon in dwellings and radium in the ground or radon in soil differ depending on the characteristics of the underlying geological units, with more permeable units having steeper slopes and higher indoor radon concentrations for a given radium or soil gas radon concentration in the ground. The regression models comparing indoor radon with soil gas radon have intercepts close to 5 Bq m−3 whilst the intercepts for those comparing indoor radon with eRa226 from airborne eU vary from about 20 Bq m−3 for a moderately permeable geological unit to about 40 Bq m−3 for highly permeable limestone, implying unrealistically high contributions to indoor radon from sources other than the ground. An intercept value of 5 Bq m−3 is assumed as an appropriate mean value for the UK for sources of indoor radon other than radon from the ground, based on examination of UK data. Comparison with published data used to derive an average indoor radon: soil 226Ra ratio shows that whereas the published data are generally clustered with no obvious correlation, the data from this study have substantially different relationships depending largely on the permeability of the underlying geology. Models for the relatively impermeable geological units plot parallel to the average indoor radon: soil 226Ra model but with lower indoor radon: soil 226Ra ratios, whilst the models for the permeable geological units plot parallel to the average indoor radon: soil 226Ra model but with higher than average indoor radon: soil 226Ra ratios

Quantum Cryptography

Quantum cryptography is a new method for secret communications offering the ultimate security assurance of the inviolability of a Law of Nature. In this paper we shall describe the theory of quantum cryptography, its potential relevance and the development of a prototype system at Los Alamos, which utilises the phenomenon of single-photon interference to perform quantum cryptography over an optical fiber communications link.Comment: 36 pages in compressed PostScript format, 10 PostScript figures compressed tar fil

Accurate Galactic 21-cm H I measurements with the NRAO Green Bank Telescope

Aims: We devise a data reduction and calibration system for producing highly-accurate 21-cm H I spectra from the Green Bank Telescope (GBT) of the NRAO. Methods: A theoretical analysis of the all-sky response of the GBT at 21 cm is made, augmented by extensive maps of the far sidelobes. Observations of radio sources and the Moon are made to check the resulting aperture and main beam efficiencies. Results: The all-sky model made for the response of the GBT at 21 cm is used to correct for "stray" 21-cm radiation reaching the receiver through the sidelobes rather than the main beam. This reduces systematic errors in 21-cm measurements by about an order of magnitude, allowing accurate 21-cm H I spectra to be made at about 9' angular resolution with the GBT. At this resolution the procedures discussed here allow for measurement of total integrated Galactic H I line emission, W, with errors of 3 K km s^-1, equivalent to errors in optically thin N_HI of 5 x 10^18 cm^-2.Comment: 49 pages, 25 figures; A&A, in pres