Blog Archives

Hierarchy

Posted by on 19/ 11/ 15

Good home design entails a lot of categorizing. The categories we use are determined by function. In organizing a home, everything that is used to prepare food would, for example, most likely go into the "kitchen” category. If something in the kitchen category functions primarily to wash dishes, it would probably be placed into the subcategory of "kitchen sink area.” The categories proposed by our predecessors usually serve as pretty good tools for organizing a home. Ideas like "kitchen,” "bathroom,” and "bedroom” stick around because they generally work. But these ideas cannot be allowed to dictate the ultimate form of a dwelling; that is for necessity alone to decide.

Sacred Geometry

Organizing the tops of windows and doors along a horizontal axis and deliberately spacing porc...

read more

Finishes

Posted by on 19/ 11/ 15

Introduction

Finishes include all surface materials and treatments in the home. They are what is seen on a daily basis and, along with furnishings, constitute the personal signature of the owner. Finishes are the predominant source of odors in a new home. They can introduce a multi­tude of toxic volatile organic compounds into the air and will continue to volatilize, or out – gas, for years after the home is completed. However, when chosen carefully, finishes can enhance health and well-being as well as add to the aesthetic value of the home.

Until recently, nonpolluting finishing products were considered specialty items. Fortunately, healthier products are now regu­larly appearing on the market...

read more

Sign Supports

Posted by on 19/ 11/ 15

Roadway signs include overhead signs, large roadside signs (area over 50 ft2 or 5 m2), and small roadside signs.

Overhead signs include sign bridges and cantilevered signs. Their supports are generally too large to adapt to a breakaway design. When possible, install overhead signs on existing bridges or other structures. Otherwise, supports within the clear zone should be shielded with a traffic barrier.

Large roadside signs typically have two or more supports, each of which is of the break­away type. Figures 6.9 and 6.10 show the loading conditions and the breakaway features.

Sign Supports

Note the hinge joint with fuse plate just below the sign and the breakaway base (shear

plate). The supports must resist ice and wind loads and also meet the following criteria:

• The hinge must be at least 7 ...

read more

Repairable Systems

Posted by on 19/ 11/ 15

For repairable hydrosystems, such as pipe networks, pump stations, and storm runoff drainage structures, failed components within the system can be re­paired or replaced so that the system can be put back into service. The time required to have the failed system repaired is uncertain, and consequently, the total time required to restore the system from its failure state to an operational state is a random variable.

Repairable Systems

Repairable Systems

20

 

20

 

15

 

Repairable Systems

TABLE 5.2 Reliability and Maintainability of Water Distribution Subsystems by Generic Group

Subsystem

MTBF* (x 106 hours)

MTTR* (hours)

Pumps

Centrifugal, open impeller

0.021660

7.825

Axial flow, propeller

0.074191

16.780

Power transmission

Concentric reducer

0.122640

2.000

P...

read more

Effect of age on reliability

Posted by on 19/ 11/ 15

In general, the reliability of a system or a component is strongly dependent on its age. In other words, the probability that a system can be operational to perform its intended function satisfactorily is conditioned by its age. This conditional reliability can be expressed mathematically as

Подпись: Ps(M 11)

P(TTF > t, TTF > t + M)
P(TTF > t)

P(TTF > t + M) Ps(t + M) P (TTF > t) = ps(t)

in which t is the age of the system up to the point that the system has not failed, and ps(M 11) is the reliability over a new mission period M, having successfully operated over a period of (0, t ]. In terms of failure rate, ps(M 11) can be written as

t-t+M

I h(r) dr

 

Ps(M | t) = exp

 

(5.13)

 

Effect of age on reliability

Figure 5...

read more

FRAMING THE WALLS

Posted by on 19/ 11/ 15

Once the plates are marked up and detailed, you can begin to assemble the walls. When I first started framing walls, carpenters used to toenail a stud in each corner, string the top plate across from stud to stud, and then work off a ladder to nail in the remaining studs. Each wall took a long time to build because we had to nail in one stud, move the ladder, and nail in another. And the fact that we were working on ladders made the work unnecessarily dangerous. It wasn’t long before we learned to frame walls flat on the floor, then raise them into position.

If you’ve done a good job marking the plates, framing walls should be easy. Simply follow the marks, nailing in studs where needed. But first, clean the floor. There’s no need to have extra wood or tools around that might trip you up.

read more

The aqueducts of Lyon

Posted by on 19/ 11/ 15

Lucius Munatius Plancus founds Lugdunum (Lyons) in 43 BC on the Fourviere hill, 130 m above the waters of the Saone and Rhone rivers. Thirty years later, Augustus makes Lyon the capital of Gaul. It is often the case that such cities are initially established on high ground for strategic reasons, and consequently not well supplied with water. Then the cities rise in importance to become regional capitals, necessitating significant efforts to provide adequate water supply. This was the case of Pergamon as we described in Chapter 5.

At Lugdunum, it was necessary to cross a valley some hundred meters deep to reach the Fourviere hill, only its western facade being accessible...

read more

INSTALLING A GFCI RECEPTACLE

Posted by on 19/ 11/ 15

Important: Read earlier sections about installing standard receptacles before installing a GFCI receptacle. As already mentioned, the NEC requires GFCI protection in the following loca­tions: all bathroom receptacles; all kitchen counter receptacles; kitchen receptacles within 4 ft. of a sink; all outdoor receptacles; accessible basement or garage receptacles; and receptacles near pools, hot tubs, and the like.

О Shut off power to the outlet and test with a voltage tester to be sure it’s off. Carefully read the instructions that come with your GFCI. Devices vary, and your warranty—and your safety — depends on your installing the device correctly. GFCI receptacles are amperage rated (15 amp and 20 amp) and should match the cable wire size and be correctly sized for the circuit load.

G...

read more

Fixtures, and Switches

Posted by on 19/ 11/ 15

О Before working around any electrical device, disconnect the power to it and test with a voltage tester to make sure the power is off.

WIRING RECEPTACLES

Before beginning this section, read the previous sections on grouping and splicing wire. The fol­lowing discussion assumes that each wire group (hot, neutral, ground) in the box is spliced together and has a pigtail that attaches to a receptacle terminal. Connecting wires and devices in this manner ensures that there will be continuous current to outlets downstream, even if a receptacle upstream malfunctions or is tem­porarily removed.

Method one: Using pigtails. First attach the grounding pigtail to the green grounding screw on the receptacle. If the grounding pigtail is insu­lated, strip ‘A in...

read more

SIGN AND LUMINAIRE SUPPORTS AND SIMILAR FEATURES

Posted by on 19/ 11/ 15

Approximately 15 percent of all fixed-object fatalities involve sign and luminaire supports or utility poles. The options available to the highway engineer to improve on this record
are similar to those presented earlier: remove or redesign, relocate, use a breakaway device, shield, or delineate. Although it is desirable to have an unobstructed roadside, it is not always possible to relocate appurtenances such as signing and lighting supports, because they must remain near the roadway to fulfill their intended purpose. Thus, emphasis is given to the use of breakaway hardware—selection of the most appropriate device and installing it to ensure acceptable performance. (See Chap. 7...

read more