Blog Archives

Mines and gold mining on the Iberian peninsula

Posted by on 20/ 11/ 15

Spain and Portugal are lands of mines during the Roman period: gold in the northwest, copper and silver in the southwest, silver in the southeast. Quite a panoply of hydraulic machines are used to evacuate water from deep galleries in the peninsula’s Roman mines: Archimedes screws, Ctesibios pumps, water wheels. Water is also used to wash sediments so that heavy metals, like gold and silver, can be settled out and recovered. This is the classic technique of gold miners working on rivers, a technique that has come down to us from Antiquity. After having visited silver extraction installations in the region of Cartagena (Carthago Nova), Strabo writes:

“[…] as for the silver ore collected, […] it is broken up, and sifted through sieves over water; that what remains is to be again broken, an...

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Roughing-In DWV Pipes

Posted by on 20/ 11/ 15

In new construction, pros typically start the DWV system by connecting to the sewer lead pipe, sup­porting the main drain assembly every 4 ft. and at each point a fitting is added.

Renovation plumbing is a different matter altogether, unless an existing main is so corroded or undersize that you need to tear it out and replace it. Rather, renovation plumbing usually entails tying into an existing stack or drain in the most cost – and time-effective manner. There are three plausible scenarios: (1) cutting into a stack to add a branch drain, (2) building out from the end of the main drain where it meets the base of the soil stack, and (3) cutting into the main drain in mid-run and adding fittings for incoming branch drains.

This discussion assumes that the existing pipes are cast iron and th...

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Dams of the Iberian peninsula

Posted by on 20/ 11/ 15

Spain is one of the oldest Roman provinces – and it is the native province of Trajan and Hadrian. At the end of the Punic wars in 202 BC, Spain is taken by the Carthaginians, who found Cartagena (Carthago Nova). The south becomes rapidly romanized, but the pacification of the northwest is not fully achieved until 19 AD. Toward the end of the 1st century AD the conjunction of the emperor’s protection, along with generalized eco­nomic development in the western provinces and the relatively recent Roman compe­tence in dam technology lead them to build increasing numbers of dams in the area. Today the remains of some 80 structures are known, either dams or weirs, between 1 and 19 m high and of equally variable lengths up to 700 m.[265] Most of these structures serve

Dams of the Iberian peninsula

Figure 6...

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LONGITUDINAL FAT SPOTS OF BINDER

Posted by on 20/ 11/ 15

Longitudinal fat spots are the most frequently seen defects when using SMA. Such spots may be defined as areas with an excess of binder or mastic that are shaped longitudinally and are parallel to the path of the paver.

There are two types of longitudinal fat spots—binder fat spots and mastic fat spots—which differ only in the content of the fat spot’s components.

Longitudinal fat spots (Figure 11.1) contain, firstly, some amount of binder appearing on the surface of a course. They are easily recognizable simply by scratching the fat spot with the metal stem of a thermometer. A thin binder layer

image109

FIGURE 11.1 Longitudinal fat spots of binder. (Photo courtesy of Bartosz Wojczakowski.)

is visible on the surface of the SMA course, with regular SMA underneath...

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Water Influence on Mechanical Behaviour of Pavements: Constitutive Modelling

Posted by on 20/ 11/ 15

Lyesse Laloui[22], Robert Charlier, Cyrille Chazallon, SigurOur Erlingsson, Pierre Hornych, Primoz Pavsic and Mate Srsen

Abstract This chapter deals with the effects of water on the mechanical behaviour of pavements. The analysis is based on constitutive considerations. Constitutive models devoted to both routine and advanced pavement analysis and design are introduced and both the resilient behaviour as well as the long term elasto-plastic approaches are presented. As soon as the approach considers the material as a two phase (solid matrix and a fluid), the introduction of the effective stress concept is required. In the last section an analysis is made on the extension of the constitutive models to the characterisation of partially saturated materials.

Keywords Constitutive models ■ resi...

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CRASHWORTHY CONCERNS OF ROADSIDE FEATURES

Posted by on 20/ 11/ 15

The need for traffic signs, roadway illumination, utility service, and postal delivery results in roadside features frequently placed within the roadway right-of-way. (Also see Chap. 6, Safety Systems.) The presence and location of these obstacles varies by roadway type and location. Rural freeways, for example, can be designed where traffic signs are the only obstacles that are added to the roadside. Signs, light pole standards, utility poles, and mailboxes are all frequently encountered on rural collectors. These obstacles, when present, perform a necessary function, but are also potential fixed objects for an errant vehicle...

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Concerns on Use of Supplemental Advance Warning Devices

Posted by on 20/ 11/ 15

A large number of supplemental advance warning devices have been used by roadway agencies to inform motorists of unusual geometric, operational, or traffic control fea­tures. The use of a device by an agency does not imply that it is a viable or desirable device to use for identified deficiencies. The following concerns should be considered prior to the installation of any device not specified in MUTCD:

• Many warning devices are attempts at political, inexpensive, and/or quick solutions to totally inappropriate roadway conditions. The proper countermeasure for many of these conditions is to correct the fault rather than installing an additional motorist warning...

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Other univariate distributions and computer programs

Posted by on 20/ 11/ 15

The algorithms described in the preceding subsections are for some probability distributions commonly used in hydrosystems engineering and analysis. One might encounter other types of probability distributions in an analysis that are not described herein. There are several books that have been written for gen­erating univariate random numbers (Rubinstein, 1981; Dagpunar, 1988; Gould and Tobochnik, 1988; Law and Kelton, 1991). To facilitate the implementa­tion of Monte Carlo simulation, computer subroutines in different languages are available (Press et al., 1989, 1992, 2002; IMSL, 1980)...

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SOFFIT AND SIDING DETAILS

Posted by on 20/ 11/ 15

GABLE WALL

Soffit (unvented) Barge rafter Roof shingles

Metal drip edge

2-in. gap Baffle Double above baffle J top plate for ventilation

STEP 7 Finish the Soffits

Подпись: . wy-.'» - : .v' vv ШШЩШ Подпись:Подпись: NICE 30B! To avoid hammering the vinyl, a volunteer uses a metal pin to drive soffit nails their final distance.SOFFIT AND SIDING DETAILSVinyl soffit material has small holes to allow air to enter freely. Before attaching this mate­rial along eave walls, make sure that all the baffles between rafters are in place to keep insulation out of the eaves and allow airflow into the attic. On this house, we cut the vinyl soffit sections into short lengths that overlap each other and ran them perpendicular to the siding. Insert the ends of each soffit panel into vinyl J-channel trim nailed to the wall and nail the other end to the bottom edge of the gutter board (see the illustration on p. 169).

Gable-end soffit details

Soffit work is also required to finish off the unde...

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Installing the top piece of eave-wall siding

Posted by on 20/ 11/ 15

The last piece of siding at the top of an eave wall can be fastened in different ways. If the eaves will be left open, use strips of undersill trim and cut and fasten the final panel in the same way as the one under the window. If the eaves will be closed with soffit material (as was done on this house), the uppermost sid­
ing panel can simply be nailed in place above the level of the soffit. The J-channel trim for the soffit, and then the soffit itself, will cover the top siding panel.

Siding gable-end walls

Begin by nailing 2×2 blocking between the lookouts and along the barge rafter, as shown in the illustration on the facing page. This allows J-channel to be nailed up the rake, where it can receive the angled ends of the siding panels. Some builders prefer to hold the J-channel Zi in...

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