Cold frames

All young plants grown under cover must be acclimatized gradually to the cooler and less humid conditions outside. This is known as "hardening off." The best place to do this is in a cold frame, but you can also cover plants with a cloche or fleece and remove it gradually over a few days. 

In cool climates, zucchini, marrows, pumpkins, sguashes, and cucumbers can crop outdoors if raised in warmth and transplanted into warm soil, after the last frost. In warmer regions they can be sown direct outside. Melons need warm conditions and may have to be grown in a cool greenhouse or cold frame if you live in a region with a short growing season. 

For very early bloom, sow pansy seeds in August and overwinter plants in a cold frame. Otherwise, sow- seeds indoors in winter. Make... 

In the North, parsley may be seeded as soon as the ground can be worked in the spring. Earliness and surer results may be obtained by starting the plants indoors and transplanting them to the open ground. Plants should be started about midsummer for the fall crop and for the crop grown during the winter in cold frames. 

You can even grow a crop of salad leaves in the winter by starting tbem off indoors in modules and hardening tbem off before planting out into tbe window box. In frosty weather, the crop will need to be protected witb a cloche or cold frame. Good choices to try are winter purslane, mizuna, salad rocket, and corn salad. 

You can buy sweet peas as young plants from nurseries and farmers markets but, if you have time, you can grow your own from seed. Make sure that you choose one of the richly scented varieties—some sweet peas are bred for the shape and size of their flowers—and either sow the seeds under cover in a cold frame or greenhouse in late winter, or outdoors at the foot of the teepee poles in early- and mid-spring. 

Throughout the winter the beds can be protected by a layer of straw, cardboard or new chips topped with plastic. This is particularly important for harsh climates. Other possibilities include making the bed inside a cold frame or plastic greenhouse. Certain regions of the country like the Northwest are better suited to natural culture than others. In this respect it is desirable to use a local strain adapted to local conditions. In climates unsuitcd To ouTdoorculTivation, the wood chips can be filled Into trays and brought Inside. 

FIG. 11-49 Plate-and frame heat exchanger. Hot fluid flows down between alternate plates, and cold fluid flows up between alternate plates. Theimal Division, Alfa-Laval, Inc.)... 

FRAME KNOCKS 1. Loose crosshead pin, pin caps or crosshead shoes. 2. Loose/worn main, crankpin or crosshead bearings. 3. Low oil pressure. 4. Cold oil. 5. Incorrect oil. 6. Knock is actually from cylinder end. 

Care must be taken regarding the method of supporting ceiling panels. Large portal framed steel holdings may provide a cheap outer shell but do have a considerable amount of roof movement. Panels hung from this type of structure can be subjected to movement which cannot be tolerated in cold store construction. A tied portal, however, can be acceptable [38]. The outer shell may also be required to bear the weight of the evaporators and, in the case of stores for carcase meats, the rails and the product itself. 

Automatic stacker cranes were first used in a cold store in the USA in 1962 and there are now many installations throughout the world. The store height can be increased considerably, to 16-20 m, or even higher if the rack frame is used to support the roof of the cold store. The operation of such a store can be by using a crane with the operator inside the store, driving the crane from a heated, insulated cab, or can be fully automatically operated by a computer. One crane can service some 4000 pallet positions at the rate of 50 pallets per hour. 

Any of various types of heat transfer equipment, whereby relatively cold water flowing over a surface will, by conduction and convection means, transfer heat away from a process. The most common types of heat exchangers are plate and frame and shell and tube designs. A boiler is also a type of heat exchanger. 

Consider a planar premixed flame front, such as that sketched in Figure 5.1.1. For the moment, we will be interested only in long length scales and we will treat the flame as an infinitely thin interface that transforms cold reactive gas, at temperature and density T p, into hot burnt gas at temperature and density T, A.-The flame front propagates at speed Sl into the xmbumt gas. We place ourselves in the reference frame of the front, so cold gas enters the front at speed = Su and because of thermal expansion, the hot gases leave the front at velocity 14 = Sl(Po/a)- The density ratio, Po/Pb, is roughly equal to the... 

Cold flow studies have several advantages. Operation at ambient temperature allows construction of the experimental units with transparent plastic material that provides full visibility of the unit during operation. In addition, the experimental unit is much easier to instrument because of operating conditions less severe than those of a hot model. The cold model can also be constructed at a lower cost in a shorter time and requires less manpower to operate. Larger experimental units, closer to commercial size, can thus be constructed at a reasonable cost and within an affordable time frame. If the simulation criteria are known, the results of cold flow model studies can then be combined with the kinetic models and the intrinsic rate equations generated from the bench-scale hot models to construct a realistic mathematical model for scale-up. 

Enhanced pre-engineered metal buildings are comprised of steel Frames with cold-formed steel panels supported on cold-formed steel girts and purlins as illustrated in Figure 4.1. The steel frame is designed to resist all vertical and lateral loads. Design improvements to enhance blast resistance can be achieved by ... 

The enhancement of these types of buildings is achieved by using closer spacing for the building frames and girts and combining sections of the standard AISI cold formed shapes to achieve symmetry. 

Thermal insulation made from expanded polystyrene or other foams, thermoplastic window frames, etc. help to reduce heat loss. This is very important in cold countries because domestic heating can represent almost one quarter of the total energy consumption. Consequently ... 

---