(TLE 40)Clothing and Grooming

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(TLE 11)Foods 2: Baking

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(TLE 10)Foods 1: Food Selection, Prepartion and Cooking

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(TLE 51)Handicraft

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(TLE 12)Food 3: Food Processing

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(TLE 20)Agricultural Arts

Bokashi compost

Inside a recently started Bokashi bin. The aerated base is just visible through the food scraps and Bokashi bran.

Bokashi is a method of intensive composting. It can use an aerobic or anaerobic inoculation to produce the compost. Once a starter culture is made, it can be used to extend the culture indefinitely, like yogurt culture. Since the popular introduction of effective microorganisms (EM), Bokashi is commonly made with only molasses, water, EM, and wheat bran.

In home composting applications, kitchen waste is placed into a container which can be sealed with an air tight lid. These scraps are then inoculated with a Bokashi EM mix. This usually takes the form of a carrier, such as rice hulls, wheat bran or saw dust, that has been inoculated with composting micro-organisms. The EM are natural lactic acid bacteria, yeast, and phototrophic bacteria that act as a microbe community within the kitchen scraps, fermenting and accelerating breakdown of the organic matter. The user would place alternating layers of food scraps and Bokashi mix until the container is full.

Organic fertilizers are naturally-occurring fertilizers (e.g. peat moss or green manure), or naturally occurring mineral deposits (e.g. saltpeter).

Naturally occurring organic fertilizers include manure, slurry, worm castings, peat, seaweed, humic acid, brassin and guano. Sewage sludge use in organic agricultural operations in the U.S. has been extremely limited and rare due to USDA prohibition of the practice (due to toxic metal accumulation, among other factors).

Processed organic fertilizers include compost, bloodmeal, bone meal, humic acid, amino acids, brassin and seaweed extracts. Other examples are natural enzyme digested proteins, fish meal, and feather meal. Decomposing crop residue from prior years is another source of fertility.

Advantages

Although the density of nutrients in organic material is comparatively modest, they have many advantages. The majority of nitrogen supplying organic fertilizers contain insoluble nitrogen and act as a slow-release fertilizer. By their nature, organic fertilizers increase physical and biological nutrient storage mechanisms in soils, mitigating risks of over-fertilization. Organic fertilizer nutrient content, solubility, and nutrient release rates are typically much lower than mineral (inorganic) fertilizers. A University of North Carolina study found that potential mineralizable nitrogen (PMN) in the soil was 182–285% higher in organic mulched systems, than in the synthetics control.

They re-emphasize the role of humus and other organic components of soil, which are believed to play several important roles:

  • Mobilizing existing soil nutrients, so that good growth is achieved with lower nutrient densities while wasting less
  • Releasing nutrients at a slower, more consistent rate, helping to avoid a boom-and-bust pattern
  • Helping to retain soil moisture, reducing the stress due to temporary moisture stress[citation needed]
  • Improving the soil structure[citation needed]
  • Helping to prevent topsoil erosion (responsible for desertfication and the Dust bowl[citation needed]

Organic fertilizers also have the advantage of avoiding certain problems associated with the regular heavy use of artificial fertilizers:

  • The necessity of reapplying artificial fertilizers regularly (and perhaps in increasing quantities) to maintain fertility[citation needed]
  • Extensive runoff of soluble nitrogen and phosphorus,[citation needed] leading to eutrophication of bodies of water (which causes fish kills)
  • Costs are lower for if fertilizer is locally available[citation needed]

According to the PPI institute website, it is widely thought[by whom?] that organic fertilizer is better than inorganic fertilizer. However, balanced responsible use of either or both can be just as good for the soil[citation needed].

Disadvantages

Organic fertilizers have the following disadvantages:

  • As a dilute source of nutrients when compared to inorganic fertilizers, transporting large amount of fertilizer will incur higher costs. Especially with slurry and manure
  • The composition of organic fertilizers tends to be more complex and variable than a standardized inorganic product.[citation needed]
  • Improperly-processed organic fertilizers may contain pathogens from plant or animal matter that are harmful to humans or plants. However, proper composting should remove them.
  • Increased Labor costs from composting. Some of the cost is offset by reduced cash purchase.

Rice hulls (or rice husks) are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material, or fuel.

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(TLE )Basic Electricity

Electric circuits

A basic electric circuit. The voltage source V on the left drives a current I around the circuit, delivering electrical energy into the resistor R. From the resistor, the current returns to the source, completing the circuit. An electric circuit is an interconnection of electric components such that electric charge is made to flow along a closed path (a circuit), usually to perform some useful task. The components in an electric circuit can take many forms, which can include elements such as resistors, capacitors, switches, transformers and electronics.


Circuits

Electric power, like mechanical power, is represented by the letter P in electrical equations. The term wattage is used colloquially to mean "electric power in watts."


Direct current

In direct current resistive circuits, electrical power is calculated using Joule's law:

where P is the electric power, V the potential difference, and I the electric current.
In the case of resistive (Ohmic, or linear) loads, Joule's law can be combined with Ohm's law (I = V/R) to produce alternative expressions for the dissipated power:
where R is the electrical resistance.

Alternating current

In alternating current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow. The portion of power flow that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as real power (also referred to as active power). That portion of power flow due to stored energy, that returns to the source in each cycle, is known as reactive power.


SERIES CIRCUITS

A series circuit is the simplest circuit. The conductors, control and protection devices, loads, and power source are connected with only one path to ground for current flow. The resistance of each device can be different. The same amount of current will flow through each. The voltage across each will be different. If the path is broken, no current flows and no part of the circuit works. Christmas tree lights are a good example; when one light goes out the entire string stops working.

A Series Circuit has only one path to ground, so electrons must go through each component to get back to ground. All loads are placed in series.
Therefore:
1. An open in the circuit will disable the entire circuit.
2. The voltage divides (shared) between the loads.
3. The current flow is the same throughout the circuit.
4. The resistance of each load can be different.

PARALLEL CIRCUIT

A parallel circuit has more than one path for current flow. The same voltage is applied across each branch. If the load resistance in each branch is the same, the current in each branch will be the same. If the load resistance in each branch is different, the current in each branch will be different. If one branch is broken, current will continue flowing to the other branches.

A Parallel Circuit has multiple paths or branches to ground. Therefore:
1. In the event of an open in the circuit in one of the branches, current will continue to flow through the remaining.
2. Each branch receives source voltage.
3. Current flow through each branch can be different.
4. The resistance of each branch can be different.

SERIES PARALLEL CIRCUIT

A series-parallel circuit has some components in series and others in parallel. The power source and control or protection devices are usually in series; the loads are usually in parallel. The same current flows in the series portion, different currents in the parallel portion. The same voltage is applied to parallel devices, different voltages to series devices. If the series portion is broken, current stops flowing in the entire circuit. If a parallel branch is broken, current continues flowing in the series portion and the remaining branches.

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