The principles of public transport network planning: a review of the emerging literature with select examples

This paper highlights for urban planners the key strategies and tactics that can be deployed to improve suburban public transport networks. Introduction The governance and management of public transport systems is an essential component of metropolitan planning and urban management. Most metropolitan strategies in Australia and in other jurisdictions presuppose the provision of public transport. Yet there is often a disconnection between transport plans and land-use schemes. Similarly, metropolitan land-use plans that do integrate with transport plans tend to focus on infrastructure rather than service quality and connectivity. A failure to adequately consider the quality of public transport networks in land-use planning analysis has the potential to produce poor planning outcomes in two key ways. First new land-uses may be inadequately served with public transport services, leading to dependence on alternative travel modes, such as cars. Second, the failure to recognise the significance of well-planned local public transport networks may result in the preclusion of some land-use options. This preclusion may relate to the location of land-uses or their design, such as over-provision of carparking. The continuing debate over whether to address suburban cardependence via land-use change or via transport planning is a case in point. And while the arguments in favour of and against land-use change as a means to overcome car dependence are well known in the planning literature. There is a growing if not yet widely appreciated literature that advocates improvements to public transport network planning and coordination as a means of reducing car dependence. The recognition of improved public transport network planning as a means of reducing car dependence is immensely significant because it offers planners an additional or alternative tool for managing urban transport patterns beyond land-use variation or investment in heavy infrastructure. Urban planning practitioners are not yet well served and informed by the broader public transport planning literature on the advantages of public transport network planning. While there is an extensive literature focusing on the economics and engineering of urban public transport systems the planning literature on the practices that contribute to success in public transport network design and operations is relatively poorly documented. There is also very little literature dedicated to public transport network design within Australian cities which are distinguished by highly centralised radial heavy rail networks with bus or tram networks that are well developed in inner urban zones but less so in the outer suburbs. The remainder of this paper has four objectives for transport planning theory and practice. First the paper reviews the literature on public transport network planning principles; next the paper attempts to formulate these principles in practical terms such that they can be applied to line and network design; third the paper considers further dimensions of network planning, including institutional arrangements and transition points in network design. The paper is intended for three audiences. The first is planning scholars who are involved in debates about public transport. The second is strategic policy officials in planning agencies who are involved in the planning and design of public transport networks. The third audience comprises those involved in development processes and who seek insights into the technical components of public transport network planning. Some caveats are appropriate however. The paper is not seeking to justify public transport network planning. The authors consider that the case for dedicated planning is implicit in the assumption that cities should provide good quality public transport to their residents. The wider case in favour of network planning has been successfully advanced elsewhere. Conversely, the paper is not intended as a directly applicable manual of detailed transport planning practice. While it does offer some insights into the practical public transport network planning task such guidance is better provided by Nielsen et al and Vuchic. Instead the paper highlights for urban planners the key strategies and tactics for that can be deployed to improve suburban public transport networks. Understanding these principles should thus assist urban planners – and urban scholars – to better shape and evaluate urban development processes and patterns

Longitudinal stability augmentation of seaplanes in planing

The towing tank experiments conducted at Yokohama National University from November 30 to December 9 in 2005 suggested a new way of suppressing a dangerous coupled motion between heave and pitch called porpoising. The research in this paper was developed on the observations made in the experiments and conducted numerical simulations to further investigate the parametric design space. Two linear-time-invariant models were developed: rigid-body planing craft (conventional float planes or flying boats), and flexibly supported planing craft. The latter could simulate the new method found in the experiments for suppressing porpoising. In this study, the stability of the oscillatory motions was analyzed to see the effect of design variables on the inception of porpoising. The parametric study of flexibly supported float planes in the context of porpoising was a new contribution in the conceptual design of seaplanes

Gorongosa by the sea: First Miocene fossil sites from the Urema Rift, central Mozambique, and their coastal paleoenvironmental and paleoecological contexts

The East African Rift System (EARS) has played a central role in our understanding of human origins and vertebrate evolution in the late Cenozoic of Africa. However, the distribution of fossil sites along the rift is highly biased towards its northern extent, and the types of paleoenvironments are primarily restricted to fluvial and lacustrine settings. Here we report the discovery of the first fossil sites from the Urema Rift at Gorongosa National Park (central Mozambique) at the southern end of the EARS, and reconstruct environmental contexts of the fossils. In situ and surface fossils from the lower member of the Mazamba Formation, estimated to be of Miocene age, comprise mammals, reptiles, fishes, invertebrates, palms, and dicot trees. Fossil and geological evidence indicates a coastal-plain paleoenvironmental mosaic of riverine forest/woodland and estuarine habitats that represent the first coastal biomes identified in the Neogene EARS context. Receiving continental sediment from source terranes west of today's Urema Graben, estuarine sequences accumulated prior to rifting as compound incised-valley fills on a low-gradient coastal plain following transgression. Modern environmental analogues are extremely productive habitats for marine and terrestrial fauna, including primates. Thus, our discoveries raise the possibility that the Miocene coastal landscapes of Gorongosa were ecologically-favorable habitats for primates, providing relatively stable maritime climate and ecosystem conditions, year-round freshwater availability, and food both from terrestrial and marine sources. The emerging fossil record from Gorongosa is beginning to fill an important gap in the paleobiogeography of Africa as no fossil sites of Neogene age have previously been reported from the southernmost part of the EARS. Furthermore, this unique window into past continental-margin ecosystems of central Mozambique may allow us to test key paleobiogeographic hypotheses during critical periods of primate evolution.National Geographic SocietyNational Geographic Society [GEFNE169-16]John Fell Fund, University of Oxford [153/086]Philip Leverhulme Prize [PLP-2016-114]Foundation for Science and Technology (FCT-Portugal)DFGGerman Research Foundation (DFG) [LU 2199/1-1]St. Hugh's College, University of Oxfor

Kalistrontite, its occurrence, structure, genesis, and significance for the evolution of potash deposits in North Yorkshire, U.K.

The rare mineral kalistrontite, K 2 Sr(SO 4 ) 2 , has been discovered in exceptional quantities in exploration boreholes targeting Permian polyhalite [K 2 Ca 2 Mg(SO 4 ) 4 ·2(H 2 O)]-bearing evaporite deposits in North Yorkshire, U.K. The ka - listrontite is associated with anhydrite, polyhalite, halite, magnesite, and traces of celestine in the Fordon (Evaporite) Formation, English Zechstein 2 cycle, at depths of ~1.5 to 1.7 km below surface. It was first encountered here during quantitative X-ray diffraction assays of composited drill-core samples over an identified ~50 m interval in York Potash Ltd.’s boreholes SM6, SM9, and deflections SM9A and 9B. X-ray diffraction including structural refinement, thermal analysis, Raman spectroscopy, petrographic examina - tion, quantitative microanalysis, and Sr isotopic analysis have been employed to fully characterize the kalistrontite and determine its genesis to understand its distribution and significance for the polyhalite deposits. Petrographic examination reveals that the kalistrontite is present in two general forms. First as irregularly shaped, poikilotopic millimeter-scale patches of subhedral, equant to elongate millimeter-scale crystals that enclose fine, rounded, irregular anhedral and rarely euhedral crystals of anhydrite, halite, and magnesite. Second as a vein-fill formed of an interlocking mosaic of elongate sub-millimeter scale, euhedral crystals that are compositionally zoned and again enclose fine rounded anhydrite and halite crystals at vein margins. Kalistrontite displays largely replacive contact relationships with both the earlier and generally simultaneously formed anhydrite and halite but before at least some of the polyhalite. Vein-fill kalistrontite was deposited by mineralizing fluids proceeding along fractures, patchily replacing the pre-existing low-porosity anhydrite and halite. EDX microanalysis of the North Yorkshire kalistrontite indicates a purer composition than previously reported but some (5–12% stoichiometric) substitution of Ca for Sr is identified and directly linked to petrographic textures identified during backscattered scanning electron imaging. Improved resolution XRD data for the kalistrontite is comparable to that previously published, with similar unit-cell dimensions [ a = 5.45826(5) Å, c = 20.8118(2) Å, α = 90°, β = 90°, γ = 120°, V = 536.968(3) Å 3 ] and space group R 3 m (166), despite the limited Ca substitution for Sr. Thermal behavior, published for the first time, shows that kalistrontite is essentially stable from ambient to ~960 °C. Melting occurs from ~960 to 1430 °C with a resulting weight loss of 62.57%, accompanied by the evolution of SO 2 . Minor endothermic features are tentatively ascribed to the boiling of K from surface sites. The first published Raman spectrum for kalistrontite shows a major frequency shift at 968 cm –1 with minor features of decreasing intensity at 458, 617, 1095, 1152, 650, 170, and 127 cm –1 . Consistent 87 Sr/ 86 Sr values for kalistrontite and anhydrite (mean, 0.707014 ± 0.000010, 2 S.E. and 0.707033 ± 0.000020, 2 S.E., respectively) along with very similar values obtained for the polyhalite are indicative of Late Permian seawater in an open environment with very limited evidence of basin constriction or Sr contribution from hydrother - mal or meteoric source(s). When compared to the LOWESS global curve, the 87 Sr/ 86 Sr values suggest a consistent formation date of 255 ± 2 Ma (late Wuchiapingian), the first published date for the EZ2 deposits in North Yorkshire. Diagenetic processes, particularly the late-stage supply of K- and Sr-rich fluid, must have proceeded extensively in the North Yorkshire deposits. However these show only limited spatial development, within the shelf zone on the margins of the main polyhalite deposit. The K-rich nature (26.3 wt% K 2 O) of kalistrontite, compared to other K-bearing evaporite minerals (e.g., kainite 18.9 wt% K 2 O, carnallite 17.0 wt% K 2 O, polyhalite 15.6 wt% K 2 O), has a significant effect on borehole γ-ray response (303 compared to 229, 200, and 185 API units, respectively) and therefore considerable implications for evaporite deposit modeling and the determination of deposit-grade. Understanding the character and distribution of kalistrontite is necessary for modeling the nature, extent, and grade of the world’s richest-known deposit of polyhalite. York Potash Ltd. has recently commenced construction of the $3.0 bn Woodsmith Mine to support large-scale polyhalite production, promising the creation of thousands of jobs and a boost to both local and national economies. First production is scheduled for late 202