bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation Mechanisms of Snow Crystals at Low Temperature
Authors: Sato Noboru , Kikuchi Katsuhiro 
Published: February 2017

To study crystal shapes, and formation and growth mechanisms of snow crystals formed below -20 °C, a new type of diffusion chamber was constructed. Using this chamber, different kinds of “peculiar shaped” crystals previously observed in nature have been produced, together with normal types of snow crystals. Gohei twins, one of the most typical polycrystalline shapes in nature, have been produced artificially. The vapor pressure was at or near water saturation at the time of nucleation. Analysis of photomicrographs and replicas of Gohei twins that were replicated in the polar regions show that the number frequency of the tip angle has a maximum frequency at about 77° and a minor one at about 54°.On the basis of these results, a formation mechanism for some Gohei twins is proposed in this paper.
A one-dimensional model of the evolution of snow-cover characteristics
Authors: Yamazaki Takeshi , Kondo Junsei , Sakuraoka Takashi , Nakamura Toru 
Published: February 2017

A one-dimensional model has been developed to simulate the evolution of snow-cover characteristics using meteorological data. This model takes into account the heat balance at the snow surface and heat conduction in the snow cover as well as liquid water flow and densification. The basic variables of the model are snow temperature, liquid water content, snow density and the solid impurities density. With these four variables, the model can calculate albedo, thermal conductivity, liquid water flux, snow depth, water equivalent and the amount of runoff.
Diurnal variation of profiles of snow temperature, water content and snow density, and meteorological elements were observed at Mount Zao Bodaira, Yamagata Prefecture, Japan. Simulated diurnal variation patterns of each component by the model were in good agreement with the observations. Moreover, the snow-cover characteristics were simulated for three 90-day periods with meteorological data and snow pit observations at Sapporo. It was found that the model was able to simulate long-period variations of albedo, snow depth, snow water equivalent and the snow density profile.
An automatic system for controlling snow on roofs
Authors: Tamura Moriaki 
Published: February 2017

In Honshu Island, Japan, tremendous amounts of snow falls over a vast area facing the Sea of Japan. The depth of deposited snow sometimes exceeds 2 m, even in urban areas. The weight of snow on roofs can damage conventional wooden houses. It is of great importance, therefore, to monitor and control roof snow loads.
A model system has been developed for controlling snow on roofs. A precipitation detector capable of differentiating between solid and liquid precipitation and a water gauge for detecting the meltwater from a roof are combined to estimate the roof snow load. When the calculated load exceeds a critical value, an electric heater on the roof is energized to melt a portion of the snow. The whole system is controlled by a personal computer. The system was tested for about a month in 1990 with satisfactory results.
Kinematic GPS survey of geometry changes on Svalbard glaciers
Authors: Eiken Trond , Hagen Jon Ove , Melvold Kjetil 
Published: February 2017

The difficulty of using traditional direct mass-balance methods on large glaciers and ice caps requires the development of new methods. The objective of this paper is to evaluate whether a precise global positioning system (GPS) survey of geometry changes can be used to detect and monitor mass-balance changes. A joint project between Norway, Poland and Russia has investigated three high-altitude, large ice masses on Spitsbergen (Lomonosovfonna, Amundsenisen and Kongsvegen). The GPS survey was conducted using two methods.

(1)
Static GPS survey of stakes drilled into the ice was used for flow-velocity and emergence-velocity measurements.

(2)
Kinematic GPS survey was used to measure longitudinal profiles of surface elevation between the stakes.

The accuracy of the measurements has proved to be better than 5 cm in horizontal position and 10 cm in height. Comparisons show that the GPS survey is applicable and gives sufficient accuracy to replace traditional methods and is thus especially useful on large glaciers where traditional surveying by electronic distance meter is impossible.
The reaction of mountain glaciers to climatic change under continental conditions
Authors: Kunakhovitch M. G. , Sokalskaya A. M. 
Published: February 2017

Data on the distribution of accumulation with elevation were used to calculate ablation, internal accumulation, annual mass balance and glacier runoff for the Tien Shan glaciers with a total area of about 15 500 km2. The altitudinal profile of normalized ablation is approximated by an exponential curve. Mass-balance components and glacier runoff are calculated for the whole possible range of glacier equilibrium-line positions in the major river and lake basins of the Tien Shan.
For steady state it was found that the equilibrium line rises from 3600 m in western areas to 4400 m in the east, whilst the accumulation area ratio and glacier runoff increase eastward from 63% to 71%, and from 600 to 1200 mm, respectively. Losses of meltwater runoff for internal accumulation average 7% (5–11%).
In abnormally warm years, mass balance may reach –2300 mm w. e. in the west and –855 mm in the east and in the internal Tien Shan (Khan Tengry massif). Glacier runoff volume in those years has been estimated at 40 km3 year–1, which is 2.5 times as large as for the steady state.
Texture-based classification of cloud and ice-cap surface features
Authors: Rees W.G. , Lin I-I 
Published: February 2017

It is well known that the interpretation of high resolution (&lt;100 m) visible and near infrared (e.g. Landsat) imagery of large ice masses is hindered by the uniform reflectivity of snow, ice and cloud surfaces. Such interpretation is at present largely performed manually, but there is a good prospect that it could be automated by the incorporation of image texture. This paper describes preliminary work towards the identification of the most appropriate texture technique, or combination of techniques, and assesses the likely performance of such methods.
Different textures are identified with different types of surface cover, and the use of these differences to classify images is investigated. Specifically, we compare a traditional texture measure, the Grey Level Co-occurrence Matrix (GLCM), with a modification of a relatively new technique, fractional Brownian motion (FBM). These two methods are applied to three Landsat MSS images of the Nordaustlandet ice cap, Svalbard. The classification accuracy, computation time and memory required, advantages and limitations of the two methods are compared. The GLCM technique appears to be able to distinguish three groups of image classes, namely dry snow, wet snow, and melt features, ablation areas or cloud cover. The FBM technique is computationally more efficient, and though it performs in general less well than the GLCM technique it gives better discrimination of cloud cover.
Polythermal modelling of steady states of the Antarctic ice sheet in comparison with the real world
Authors: Hansen I. , Greve R. 
Published: February 2017

An approach to simulate the present Antarctic ice sheet with reaped to its thermomechanical behaviour and the resulting features is made with the three-dimensional polythermal ice-sheet model designed by Greve and Hutter. It treats zones of cold and temperate ice as different materials with their own properties and dynamics. This is important because an underlying layer of temperate ice can influence the ice sheet as a whole, e.g. the cold ice may slide upon the less viscous binary ice water mixture.
Measurements indicate that the geothermal heat flux below the Antarctic ice sheet appears to be remarkably higher than the standard value of 42 m W m−2 that is usually applied for Precambrian shields in ice-sheet modelling. Since the extent of temperate ice at the base is highly dependent on this heat input from the lithosphere, an adequate choice is crucial for realistic simulations. We shall present a series of steady-state results with varied geothermal heat flux and demonstrate that the real ice-sheet topography can be reproduced fairly well with a value in the range 50–60 m W m−2. Thus, the physical parameters of ice (especially the enhancement factor in Glen’s flow law) as used by Greve (1995) for polythermal Greenland ice-sheet simulations can be adopted without any change. The remaining disagreements may he explained by the neglected influence of the ice shelves, the rather coarse horizontal resolution (100 km), the steady-state assumption and possible shortcomings in the parameterization of the surface mass balance.
Simulating the effects of mean annual air-temperature changes on permafrost distribution and glacier size: an example from the Upper Engadin, Swiss Alps
Authors: Hoelzle Martin , Haeberli Wilfried 
Published: February 2017

Models are developed to simulate changes in permafrost distribution and glacier size in mountain areas. The models exclusively consider equilibrium conditions. As a first application, the simplified assumption is used that one single parameter (mean annual air temperature) is changing.
Permafrost distribution patterns are estimated for a test area (Corvatsch-Furtschellas) and for the whole Upper Engadin region (eastern Swiss Alps) using a relation between permafrost occurrence as indicated by BTS (bottom temperature of the winter snow cover) measurements, potential direct solar radiation and mean annual air temperature. Glacier sizes were assessed in the same region with data from the World Glacier Inventory database. The simulations for the glaciers are based on the assumption that an increase or decrease in equilibrium-line altitude (ELA) would lead to a mass-balance change. Model calculations for potential future changes in ELA and mass balance include estimated developments of area, length and volume. Mass changes were also calculated for the time period 1850–1973 on the basis of measured cumulative length change, glacier length and estimated ablation at the glacier terminus.
For the time period since 1850, permafrost became inactive or disappeared in about 15% of the area originally underlain by permafrost in the whole Upper Engadin region, and mean annual glacier mass balance was calculated as −0.26 to −0.46 m w.e.a−1 for the larger glaciers in the same area. The estimated loss in glacier volume since 1850 lies between 55% and 66% of the original value. With an assumed increase in mean annual air temperature of +3°C, the area of supposed permafrost occurrence would possibly be reduced by about 65% with respect to present-day conditions and only three glaciers would continue to partially exist.
The steady-state crystal size of deforming ice
Authors: Jacka T.H. , Jun Li 
Published: February 2017

Previous studies have established that, together with the development of a preferred crystal-orientation fabric in ice undergoing creep deformation to high strains, there also develops a tertiary equilibrium crystal size, i.e. the crystal size, rather than affecting the creep rate, is a result of the deformation to large strains.Equilibrium crystal size is considered here as a “balance” between crystal growth with time as a function of temperature and crystal change as a result of temperature dependent deformation. The temperature effects in these two processes (Arrhenius relation) are similar and consideration of the activation energies for the two processes indicates that it may be appropriate to cancel them, yielding a dependence of equilibrium crystal size on stress alone. The results from laboratory experiments of steady-state crystal size plotted as a function of stress support the above proposition.The possibility of using the relationships between steady-state crystal size and deviatoric stress as a polar ice-mass piezometer is discussed.
Local climate, circulation and surface-energy balance of an Antarctic blue-ice area
Authors: Bintanja R. , van den Broeke M. R. 
Published: February 2017

Results of measurements performed on and around an Antarctic blue-ice field are presented in this paper. The measurements were carried out in a valley of Heimefrontfjella, Dronning Maud Land, during a 2 month field season in the austral summer of 1992–93. A simple model is used to evaluate the surface-energy balance from measured meteorological quantities. The large differences in the surface-energy-balance values between snow and blue ice are mainly caused by differences inalbedo, surface roughness, thermal conductivity and short-wave radiation extinction coefficient. Taking into account uncertainties in the calculations, it appears that the calculated sublimation rates over ice and snow do not differ much.Furthermore, typical circulation patterns are described. The large continental-scale katabatic flow is forced by radiative cooling of the surface (night-time) and the mesoscale horizontal temperature gradient (daytime). The latter penetrates to the surface due to enhanced mixing in an unstable stratified boundary layer. At night, shallow katabatic layers form along local fall lines. On some occasions the large-scale katabatic winds decrease through the presence of a high-pressure system in the weddell Sea and a local circulation can develop inside the valley.
Glacier disequilibrium in the Convoy Range, Transantarctic Mountains, Antarctica
Authors: Chinn T.J. 
Published: February 2017

Field work for a geological map of the Convoy Range included mapping glaciers, moraines and surficial deposits. A range of glaciological indicators, including supraglacial and other moraines and margin morphology, has been used to assess the present equilibrium of the glaciers. Fields of rafted supraglacial moraine have accumulated over long periods of time at specific low-gradient, low-velocity locations. As the glacier regime changes, the shape of the moraine field distorts, signalling a change in flow pattern. By reversing the ice flow vectors directed at the moraine field, the directions from whence the debris came are shown. Unsorting the contortions of supraglacial moraine fields reveals the nature of the changes in glacier regime. Moraine-field configurations all suggest that local glaciers are expanding in response to higher local precipitation, estimated to have occurred between 2000 and 8000 year BP, most likely coincident with the world-wide “climatic optimum” of about 6000 year BP.Ice-cliff morphology, fresh terminal moraines and boulder trains indicate that larger local glaciers are currently receding from a Holocene maximum, while the margin of the large Mackay Ice Sheet outlet glacier shows no evidence of recent recession and is probably close to its Holocene maximum. In contrast, areas of present snow cover are expanding, superimposing a recent positive balance (decades to hundreds of years), which has yet to reverse a general recession of mid- to high-altitude glaciers. Local hollows in some névé areas imply that glacier flow is not in equilibrium with snow accumulation.
Gliding and Man Powered Flight
Authors: Welch Lorne 
Published: February 2017

As at present envisaged the man powered aircraft will more closely resemble the glider than any other type of flying machine. Because of this it was suggested that a paper on the relationship between gliding and man powered flight might be of value.The papers which have been read to the Group have dealt with the aerodynamic, physiological and engineering aspects of the problem and they show that a man powered aircraft capable of flight just clear of the ground is a possibility.Before undertaking the detail design a fourth aspect—pilotage—must be considered. It is in this field that the experience which exists in flying gliders is applicable and should be used.
Power Units for Future Aircraft
Authors: Banks F. R. 
Published: February 2017

This Paper was originally written at the request of L'Association Francaise des Ingenieurs et Techniciens de L'Aeronautique (AFITA) and was presented at a meeting in Paris on 30th April, 1946. The Service Technique of the French Air Force were also interested.The Paper reproduced here represents the entire lecture, except for those parts which were concerned purely with the French picture.
Fuel Systems for Gas Turbine Engines
Authors: Lawrence O. N. 
Published: February 2017

Seven years ago a paper on this same subject was read before the Main Society. This has been used as a basis from which to start.It will be seen that great strides have been made in performance, and the projects in the Design Office and on the drawing boards particularly, would even satisfy parliamentary critics. In Derby, however, where jet lift was conceived, such things are well known. From the fuel system standpoint in general the changes in requirements have been routine, merely much greater fuel demands, greater altitudes and air speeds and hence, a greater range of fuel flow, and it is this which gives the fuel system engineer his greatest worries. Beyond this there is always the need for smaller and lighter units in fancy shapes.
The Strength of Rigid Airships
Authors: Burgess C. P. , Hunsaker J. C. , Truscott S. 
Published: February 2017

The rigid airship in its modern form is a German conception, but the nature of the strength calculations employed by the Germans has been a carefully guarded secret. When the U.S. Navy undertook the construction of rigid airships it was arranged to have one ship designed and built in the United States, the ZR. 1, and one ship designed and built in England, R.38 (ZR.2). Lacking practical information and experience, fundamental theory had to be resorted to in undertaking the design of ZR.i, and all available information had to be analysed,, compared and, so far as possible, tested. After the unfortunate loss of R.38 the calculations for ZR. 1 were reviewed and additional calculations and investigations undertaken.The authors of this paper, under the direction of Rear-Admiral W. A. Moffett, Chief of the Bureau of Aeronautics, U.S. Navy Department, have been charged with the design of ZR.i and have had in the course of duty to make, or cause to be made, such studies and investigations as would assist in analysing and simplifying the problem as much as was possible in advance of full-scale experiments in flight.
Note on the Longitudinal Stability of Aeroplanes with Special Reference to Tail Plane Design
Authors: Laurence Le Page W. 
Published: February 2017

The problems of aeroplane stability in flight have been studied very thoroughly, both practically and in theory. Extensive mathematical investigations have been carried out by such men as Bairstow, Bryan, etc., and it is largely due to this work that the numerous questions arising with regard to the stable flight and equilibrium of the aeroplane are so well understood.Nevertheless, though the work of these investigators is undoubtedly of primary importance, a discussion of the more practical aspects of the subject will be more within the scope of the designer. It is proposed in the present paper to deal with but one form of stability, namely, longitudinal, and to discuss the requirements of practical design together with the methods of complying with these. The question, therefore, resolves itself into an investigation of the main points controlling the size and setting of the tailplane of the aeroplane.
The Reaction of a Stream of Viscous Fluid on a Rotating Cylinder.
Authors: Low A. R. 
Published: February 2017

In “Die Naturwissenschaften,” 6th February, 1925, p. 93, there appears an article by Prandtl entitled “ Magnuseffekt und Windkraftschiff,” giving the following explanation of the phenomena under consideration.In a stream of viscous fluid a non-rotating cylinder builds up an accumulation of retarded fluid with considerable vorticity (Fig. 5). This fluid reaches the neighbourhood of the near dead water point with a loss of kinetic energy and velocity by dissipation. At the somewhat indeterminate boundary of the boundary layer it is in contact with fluid which has lost its kinetic energy and velocity in acquiring an increase of pressure approaching the dead water pressure. The retarded fluid is pushed away from the dead water point by the higher pressure fluid (Figs. 6, 7), and ultimately it breaks up into cylindrical masses which are detached and carried away by the stream (Fig. 8).
Some Materials in Aircraft Construction
Authors: North John D. 
Published: February 2017

There are various considerations which govern the use of materials in engineering construction. The use of many of them is founded on precedent, and in the case of the older branches of engineering the original reason for their use is sometimes obscured.From time to time as new classes of materials are developed they aregradually incorporated, often breaking their way with difficulty through the wall of prejudice with which engineering caution so often surrounds its designs.
Radial Air-Cooled Aero Engines
Authors: Fedden A. H. R. 
Published: February 2017

Although the static air-cooled radial engine is by no means an innovation irr the history of aero-engine development, its career has been somewhat chequered. Some ten years ago several practical comparatively low-powered air-cooled radials were produced and successfully flown, but they were ousted by the rotary engine on the score of power/weight ratio.When in 1917 it was found that the limit of the air-cooled rotary had been reached, a demand arose for an engine of the same characteristics of manoeuvrability, compactness and light weight as this type, but of much higher power, and with a general all-round performance and fuel consumption comparable with the water-cooled engine of that date.
Notes on the Flying Qualities of the Light Aeroplane Compared with Larger Types
Authors: Haig R. A. DE H. 
Published: February 2017

At the request of the Secretary I have attempted to prepare some notes on the flying qualities of the light aeroplane as compared with those of its larger prototype.I am indebted to the Air Ministry for the facilities granted me in preparing these notes, but at the same time it must be understood that in this paper I am expressing entirely my own personal views.
The Technical History of the Aeroplane
Authors: Green F. M. 
Published: February 2017

The history and development of mechanical flight may be confined almost entirely to the present century. In the last century some success had been achieved in gliding flight, model aeroplanes had been made and flown, and at least two man-carrying aeroplanes had actually left the groundj but it was not until the year 1903 that the Wright Bros., having ended a painstaking research in gliding flight, earned for themselves the honour of being the first men to fly.Directly the success of the Wright Bros, became known, or rather when people began to believe that what the Wright Bros, claimed was actually true, the development of flying became rapid in the extreme. To-day one is tempted to wonder why it was that it had taken man so many centuries of civilisation to do what now seems to most of us rather an ordinary thing.
Biobehaviorism and Small Group Research
Authors: Emmert Mark A. 
Published: February 2017

The small group is a major cause in the formation of attitudes, beliefs, and behavior. The group forms the primary reference for the individual in terms of the socialization of norms and values and the establishment of loyalties. This led Golembiewski (1978:28) to write:In this elemental sense, the group is a medium of control. It is a major context in which people develop their concepts of who they are, or to say almost the same thing, of how they relate to others. If for no other reason, this role of the small group implies its centrality in Political Science. For the quality of civic life basically depends upon the kind and quality of behavioral control.