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original way of thinking when he, together with Frank O Gehry, designed the provocative Ginger & Fred building on one Prague's most prestigious embankments.

The more visually appealing architecture of Hvezda 8's buildings is conceptually miles away from the concrete blocks of flats known as panelaks built in the communist years, and buyers could choose from many types of apartments with various layouts.

Since then the market has matured. As of 1999, 18 new condominium projects had been finished, yielding a total of 2103 apartments. They range from an individual building with 12 apartments to a large complex of buildings with 663 apartments. The two largest projects that together represent over 40 percent of the market were completed by IPB Real, a subsidiary of IPB Bank.

However, the market is even more diversified than these 1999 numbers suggest. Over 25 companies are currently building or preparing new projects. Though the number of finished apartments in 2000 will be lower than in 1999, they still rein force an apparent buying pattern.

It seems that Czechs continue to like to live in an area, not necessarily in, but near Prague's centre, and with easy public transportation to the centre.

Though there is a trend towards living in modem buildings that offer a contemporary standard of living, surprisingly, such perks as reception, fitness, and other in-house facilities are not as demanded as much as a pleasant, natural setting, and hills are particularly popular with

Czechs. In short, open space, open view, and easy access to centre are the most important factors involved in choosing a dwelling.

One of the companies that experienced this fact was Gama-Metrostav, with its very successful U Krize complex, in Prague 5, Jinonice. 480 apartments were built here within three and a half years and the last units were sold two weeks before completion.

Purchase decisions are more rational now, as opposed to emotional or impulse based in the past. People attentively ask about terms of construction, the payment schedule, and guarantees, and they prefer to visit the apartment before making any decision, quite unlike the situation in the market's early days.

Given this selective approach, the developer can bet that 20-25 percent of units with the nicest views will be pre sold soon after the beginning of construction.

From the wealth of projects being built, the most talked about residential developments currently under construction in Prague are Cerveny Vrch in Prague 6, Cibulka in Prague 5, and Zeleny Udoli in Prague 4.

Each bears characteristics, locational or otherwise, that make it noteworthy. Cerveny Vrch, by Skanska, is close to the rambling Sarka Valley,

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and is a well prepared concept. Cibulka, by Metrostaz-Intertrade, is also close to green, and is in a silent residential area.

IPB Real's Zelene Udoli is a notably large project also close to greenery, the name itself translating as Green Valley. Byty Podoli represents a something that is soon to be talked about: the project by AT Development is not only close to the centre but benefits from the good feeling of being on the edge of a villa neighbourhood.

A METHOD FOR ESTIMATING IMMEDIATE SETTLEMENT

OF PILES AND PILE GROUPS

KIYOSHI YAMASHITA, MATSUJIRO TOMONO, AND MASAAKI KAKURAI

ABSTRACT

In this study we examine a method based on Mindlin's solution in order to estimate the load-settlement behavior of piles and pile groups for rational design of pile foundations. First, the theoretical aspects of the previous method proposed by Poulos and other investigators are briefly presented. Some modifications are made to the method so as to consider additional factors such as soil non-linearity and multi-layering. Next, in order to evaluate the numerical accuracy, vertical displacements and axial forces of pile groups or single piles embedded in non-homogeneous soil calculated by the previous method and by the modified method are compared with values calculated by more sophisticated methods such as the boundary element method and the finite element method. As a result, we conclude that, from a practical point of view, the modified method based on elasticity is sufficiently accurate in regard to axial force distribution as well as settlement. We also propose tentative input soil constants for immediate settlement using solely the results of SPT. Finally, the values of pile top settlement calculated by the modified method are compared with the results of 26 field vertical load tests on cast-in-place concrete piles. The results show that the calculated values coincide approximately with the measured values, meaning that the proposed modified method of calculation and the proposed input soil constants seem to be adequate for the preliminary estimation of immediate settlement of cast-in-place concrete piles.

INTRODUCTION

When designing pile foundations for various ground conditions, estimating their settlement is important in many cases in addition to examining the bearing capacity. In such cases, it is necessary to use a practical method with relatively high accuracy, and the method should be based upon a model

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that can illustrate clearly the pile-bearing-system characteristics such as load distribution between end resistance and skin friction, and the efficiency of the pile group. Among the many methods developed recently for calculating the settlement of piles, those which provide a means of evaluating the efficiency of pile groups can be classified into the following three categories:

1.methods based on Mindlin's solution of elasticity

2.the finite element method (Ellison et al., 1971; Ottaviani, 1975)

3.the boundary element method (Banerjee, 1976; Banerjee and Davies, 1977) When we wish to consider accurately the conditions of multilayer ground

and the conditions of compatibility of pile-soil interface, we must use one of the methods in categories 2 or 3. However, if we use a finite element method to analyze group piles, we must deal with three-dimensional models. If elastoplastic conditions are included in the analysis, considerable effort is required in order to obtain reasonable results. Therefore, finite element methods are normally utilized only for single piles, small scale group piles or special cases. The boundary element methods have essentially the same problems.

Methods using Mindlin's solution have been employed by several investigators (Poulos, 1968; Poulos and Davis, 1968; Mattes and Poulos, 1969; Butterfield and Banerjee, 1971; Yamagata and Yao, 1977) and this approach is superior from the points of view of the ease of preparing input data and the smaller computation time required. This method can also deal easily with the problem of pile-soil slip. Further, computation methods for some cases of nonhomogeneous soil where the elastic modulus of soil below the pile tip level is relatively high (Poulos and Mattes, 1969) and where the soil elastic modulus increases linearly with depth (Poulos, 1979 a; Poulos, 1979 b) have been proposed. However, the applicability of this method in studies of multi-layered ground has not yet been fully examined, nor has the applicability of the method to non-linear soil behavior.

In this paper, some modifications are made to the method based on Mindlin's solution of elasticity so as to consider soil non-linearity and multilayered ground. The accuracy of this approach is examined by comparing it with more sophisticated methods such as the boundary element method and the finite element method. Finally, pile top settlements calculated from the modified method are compared with the results of 26 field vertical load tests on cast-in-place concrete piles using input soil constants tentatively proposed in the present paper.

6) Машины, агрегаты и процессы нефтяной и газовой промышленности

Heavy-lift crane at work at Saint John refinery

On June 19, 1999, a new 460-tonne vacuum distillation column was lifted into place in Irving Oil Ltd.'s crude unit by the largest lift capacity, mobile land-

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based crane in the world. The 2,000-tonne crane, owned and operated by Van Seumeren Holland BV, is a breakthrough in heavy-lift crane design. It can be taken apart and transported in sections of 20 to 40 ft and fits in 84 railway containers.

The crane is unofficially christened "Beatrix," after the Queen of Holland. On July 4, Beatrix walked on her own tracks for the first time ever. Previously, the crane had been disassembled and moved to its next location, even on the same construction site, where it was reassembled.

Van Seumeren designed a track system for the crane that enabled it be moved without reassembly. As a result, a move that would have taken 10 days was shortened to 1 day. On July 10, after this first move, Beatrix lifted the new 279-tonne crude atmospheric column into place.

Downhole fiber-optic sensor

The Kern River field near Bakersfield, California, was the test site for a prototype downhole fiber optical acoustic sensor for investigating the continuity of oil-bearing layers.

The sandstone layers are separated by impermeable siltstones and shales with limited lateral continuity that can allow steam injected into one layer to break through to another, less-productive layer.

According to Litton Inc., modern surface seismic techniques have been unsuccessful at Kern River because of surface statics, caused in part by a thick interval of unsaturated rock.

The field test recorded several cross-well data sets between two observation wells, 518 ft apart. One well, with 4-in. casing, contained the receiver, consisting of a four-channel array with a hydrophone spacing of 5 ft. The other well, with 7-in. casing, contained the source, which was a singlecomponent axial vibrator with power source. A workstation displayed and processed the data on-site.

Litton indicates the test showed that a clamped downhole source together with a uniform diameter array largely eliminated the common problem with tube waves. It concluded that although Kern River formation seismic-wave attenuation and scatter are high, the source strength and receiver sensitivity provided signal bandwidth and data resolution far superior to what has been achieved with surface seismic techniques.

For more than 50 years, traditional sensors developed for monitoring parameters (temperature, pressure, flow, strain, acoustics, etc.) relied on the same basic technical principle, which is a device that produced an electrical output that varied with the parameter being measured.

Through the years, improvements have primarily come in the way of improved electronic circuitry and packaging techniques (miniaturization,

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digitization, filtering, etc.) to more accurately translate the traditional sensor's voltage output into a usable, high fidelity signal.

Fiber optic sensors, on the other hand, produce minute phase changes in the light traveling through an optical fiber that varies with the parameter being measured. These sensors are completely passive, contain no active electronics, and Litton expects them to be more reliable, smaller in size and weight, much simpler in operation, maintenance-free, and lower in cost.

In a fiber optic sensor system, light travels and returns from the sensor via a fiber optic cable. The sensor consists only of optical fiber coils and a device that splits the light, called an optical coupler (Mach-Zehnder hydrophone interferometer). In Litton's design no other components are required at the sensor location.

Litton says because light travels through optical fiber with very low losses, the distance from the receiver/processor to the sensor can be several hundred kilometers, with no sacrifice in performance. It adds that the fiber optic sensors operate with high fidelity in environments considered impossible for traditional sensor systems.

The Irving Oil refinery

Situated on a 780-acre site, the Irving Oil refinery can handle a variety of crudes and has the ability to produce a diverse range of petroleum products, including high octane gasolines, jet fuel, diesel fuel, home heating oil, propane, kerosine, and asphalt.

The facility has the largest volume throughput and is one of the most energy-efficient refineries in Canada. Benchmarks established by Solomon Associates Inc. rank it as one of the best performing refineries in North America.

The refinery opened on July 20, 1960, with an original capacity of 40,000 barrels a day (b/d). An expansion in 1971 increased capacity to 120,000 b/d. Another expansion in 1974 increased capacity to 250,000 b/d, where it stands today.

In the past decade, Irving Oil has invested more than $250 million on upgrades, improving overall efficiency and environmental controls. These improvements increased octane levels of gasoline, made Irving Oil the producer of gasoline with the lowest sulfur in Atlantic Canada, increased production, and improved environmental performance.

Irving Oil was the first company in Canada to remove lead from its gasoline and the first in Atlantic Canada to offer low-sulfur premium diesel fuel.

Owners of Irving Oil Ltd. aim to increase economic and environmental performance by investing in a $1-billion upgrade. They are adding several units

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to the refinery to enhance production capabilities and improve efficiency. Also, the project will decrease overall sulfur dioxide emissions and increase the reliability of environmental controls. The upgrade consists of the followings:

-Three process units: a crude distillation unit, a residue fluid catalytic cracking unit, and an alkylation unit.

-Five environmental units: a flue-gas scrubber, a sulfuric acid regeneration unit, a sulfur plant tail-gas unit, an amine sulfur-recovery unit, and a sour-water stripping unit.

-The refinery’s interconnecting piping, utilities infrastructure, a cooling tower, firewater and fresh water pumps, and an electrical substation.

Adjustable-gauge stabilizer in motor provides better inclination control

Drilling tools

The industry has a wide range of tools for drilling increasingly complex and expensive wells. Long horizontal sections can be drilled with anything from a simple rotary assembly to the latest generation of rotary steerable systems, depending on the complexity of the well design.

Generally in high-angle wellbore zones, the main objective is to control the wellbore inclination in response to changes in the reservoir geology. In certain reservoirs that exhibit lateral variations in porosity and permeability, however, it may be necessary to maintain a control of wellbore direction. Although this can be done with conventional steerable assemblies, the assemblies may cause problems that result in high-induced doglegs and poor hole cleaning when drilling in a sliding mode.

A drilling assembly for these wells, therefore, is required that maximizes control of inclination in the rotary mode, retains some ability to control azimuth, minimizes induced doglegs, and does not require expensive 3D rotary steerable systems.

Controlling inclination

In directional drilling, drillers generally control wellbore inclination by making changes in the bottomhole assembly or using a steerable motor.

Changes in the bottomhole assembly require time-consuming trips, and steerable motors, which require slide or oriented drilling, substantially reduce rate-of-penetration (ROP), and increase torque and drag.

Sliding also can result in poor hole cleaning and potential sticking problems.

In the late 1980s, the industry developed new stabilizers whose effective blade OD could be changed while the tool was downhole. With these

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adjustable-gauge stabilizers, the driller could change stabilizer OD without having to make time-consuming and costly trips out of the hole.

The gauge adjustments downhole also provided less abrupt inclination changes than those caused by a motor alone. This resulted in smoother wellbores,

Various stabilizers became available. One design used mudflow rate to signal the tool to change its diameter. Buttons in the stabilizer blade moved in or out every time the tool recognized circulation. This simple mechanism was easy to control and resulted in a rugged and reliable tool. A shift in the standpipe pressure base line level indicated whether the buttons were extended or retracted.

Adjustable stabilizers run in rotary drilling assemblies often were placed near the bit or positioned about 15-30 ft from the bit. In these positions, changes in their gauge could effectively control the build or drop tendency of the assembly.

Because they controlled inclination while in the rotary mode, these assemblies became known as 2D rotary systems. This designation indicated that one could not effectively control the wellbore direction azimuth in the rotary mode.

Adjustable stabilizers could also be run with steerable mud-motor systems. Placement of the adjustable stabilizer above the motor made it possible to control inclination with the stabilizer while drilling in the rotary mode. If the wellbore required a change in azimuth, one would have to revert to a sliding mode.

With this assembly, it seemed at first that both inclination and azimuth could be controlled without too many compromises.

2D rotary limitations

Limitations of the 2D system became evident during drilling. The system required the adjustable stabilizer to be above the motor, about 30 ft from the bit. In this position, changes in the stabilizer OD are relatively limited to doglegs of only 0.5-1°/100 ft, depending on tool and hole sizes.

For 6-in. holes, the motor may be too limber so that the effect of stabilizer gauge changes on inclination can be almost zero. This may be fine for situations in which one only requires limited control of inclination; however, in other situations requiring more rapid change in inclination, one may be forced to resort to steerable motor and slide drilling that could cause problems.

The industry now commonly drills horizontal sections with a geological steering or pay-zone steering device that usually consists of a logging-while- drilling (LWD) tool with a resistivity sensor. A resistivity sensor, with its deep investigation depth, can detect a geologic change many feet before the bit

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penetrates that boundary. This ability may allow one to bold the drilling assembly in the reservoir by steering it with a conventional steerable motor and adjustable stabilizer away from either an upper or lower boundary.

In certain reservoirs, however, a resistivity sensor cannot be used for geological steering. In these cases, one must use a gamma ray or formation porosity sensor. Because of their shallower depths of investigation, these tools may only detect the boundary at about the time the bit is already at a boundary. In this case, one has to quickly change the wellbore path to remain within the pay zone.

With a steerable assembly, the driller must revert to slide drilling to change the path, but his first problem may be a loss in the ability to slide because of excessive torque and drag having built up in the wellbore.

If an adjustable stabilizer is above the motor, he might be able to change the gauge and make a slow correction of the path back into the reservoir. This correction, however, may be so slow that possibly hundreds of feet of pay zone are missed before the wellbore enters the pay zone.

Drilling in the sliding mode is slower than rotary drilling so that such a correction run may, depending on the exact circumstances, take more time to drill. In addition, hole cleaning while sliding in the horizontal section may become a problem.

The dogleg introduced by using the motor to control inclination, if repeated, may result in additional torque and drag that could possibly prevent the horizontal section from reaching its planned TD.

The industry, therefore, needed a drilling system that allowed sufficient control of inclination for pay-zone steering purposes while remaining in the rotary mode.

Motor with stabilizer

The main problem of a conventional adjustable stabilizer-steerable motor assembly is that the stabilizer is too far from the bit.

One solution has been the placement of the adjustable stabilizer between the motor.

This has been tried with a certain degree of success. But in this configuration, stresses on both stabilizer and motor have caused reliability problems in both systems.

A more recent solution is the adjustable-gauge motor with an adjustablegauge stabilizer built into the motor just above the bearing housing. In this configuration, the stabilizer is about 10 ft from the bit, and changes in blade diameter have more effect on inclination changes.

In addition, the assembly allows a bend to be set in the motor's adjustable housing.

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Although the maximum bend allowed might be less than in a conventional steerable motor, it will still be sufficient to allow orientated drilling.

Placement of the adjustable stabilizer above the motor's bearing housing also means that the mechanical reliability of both the motor and stabilizer are not compromised.

The adjustable-gauge motor, therefore, is as reliable as a standard motor.

Russian oil refineries facing big problems

Russian oil refineries were built to satisfy the demands of Soviet industry: large volumes of fuel oil, low-quality diesel and low-octane gasoline. They no longer produce what the market requires, an increasingly acute problem as Russian product demand is undergoing a fundamental and permanent transformation.

The refineries' equipment and processes are often outdated and inefficient. Additionally encumbered with disproportionate tax, payroll, social burdens, and often incompetent or corrupt management, Russian refineries find themselves on the very edge of survival. Equally threatened are the regional budgets, labor force, industry, and agriculture that heavily depend on them.

Two factors exacerbate the problem: refineries process too much crude and they produce the wrong products. Since export pipeline capacity limits crude exports to about 40% of production, the rest must be domestically refined.

This excess crude goes to refineries with a severe lack of conversion capacity. Many Russian refineries exhaust their hydrotreating and reforming capacities when the crude unit is at 40% of capacity. Other refineries have limited or no conversion facilities.

Russian refineries inadvertently provide a multibillion dollar subsidy to Western economies because they can't extract light fractions from the crude. They export 25 million tonnes/year (tpy) of low-value fuel oil to the West, where the fractions are extracted and used. Instead of fuel oil, these products could be high-value diesel or gasoline exports.

Lack of secondary processing capacity limits the average gasoline yield to 16% or less. To meet total Russian gasoline demand of 24 tpy, refineries need to process a minimum of 160 million tonnes. The resulting surplus of low-value products will be about 30 million tonnes of fuel oil.

Worse yet, as nearly all the naphtha fraction is required for gasoline production, the Russian petrochemical industry is starved of a primary feedstock.

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7) Технология и машины лесозаготовок и лесного хозяйства

I. MOVING OF PRODUCTS FROM THE FOREST

Those operations in timber harvesting that involve the movement of products in and from the forest are the most costly, because green forest products are bulky and heavy and the application of either animal or mechanical power is necessary. Therefore, much attention is given in harvesting to locating correctly roads, logging railroads, or other transportation routes that need to be constructed and to the choice of equipment for skidding, loading, and hauling forest products. Transportation of products does not influence their quality or volume yield, as do felling and bucking, but it is an important series of operations because of the large proportion of the total harvesting cost that is involved and the need for efficiency to realize the full value of the timber harvest.

Moving the products from the forest include bunching, skidding (yarding), piling or decking, loading and primary transportation.

Bunching. Bunching is the assembly of groups of products for skidding. It is intermediate skidding. Its object is to assemble logs for skidding to the loading point. Bunching is done primarily for more efficient skidding. Bunching is done by tractors or, with small products, by hand; on rough ground it is done by cable methods, generally high-lead.

Bunching of tree products or tree length before skidding is not as widely practiced as formerly when animals were commonly used.

Bunching is seldom done for cable skidding because cable skidding can be used only when there is a relatively large volume per acre over extensive areas. The abundance of logs on the ground makes it unnecessary to bunch in such cases.

Skidding. Skidding is the movement of tree products from the felling area over unimproved terrain to a skidway1, landing, deck rollway2 or banking ground3 for further movement to the point of use.

Skidding is also called yarding. Both terms, however, refer to the movement of single products or bunches of products for comparatively short distances from stump site to point of loading on primary transportation facilities. The distance seldom exceeds 1 mile and is more generally under 1/2 mile. Sometimes, skidding is performed in two stages by two different methods, such as by cable from a swamp or steep or broken ground and then by tractor to loading points. In such cases the first stage is often called skidding and the second yarding. In the Douglas fir region the first is termed "cold decking" and the second "swinging".

Skidding methods have always been limited by the available sources of energy. For many years animals were the only source of mobile power that