eChapters

Japanese plum (Prunus salicina) is usually eaten as fresh while as European plum (Prunus domestica) required to process before consumption. Plum ranks next to peach as for as its economic importance is concerned. It is a delicious juicy fruit, prized both for its exquisite fresh fruit flavor and in processing industry. Due to its typical chilling requirement it is grown in cooler region. Two types of plum i.e. Japanese plum and its hybrids and European plum are grown in India.

There are number of eating type kiwi fruits in world but Actinidia deliciosa Chev, is most common. It was the recently introduced fruit in India. It was origin of China the oval fruits have flavor of gooseberry. It is egg sized, fuzzy, brown skinned green fleshed kiwifruit. Fruit is a berry, where as Actinidia chinenses a yellow fleshed fruits.

Ber (Ziziphus mauritiana L) ancient fruit of India grown in arid regions, ‘king of arid zone fruits’, thrive well in marginal areas. During severe hot, it shed off its leaves completely and thus conserves moisture by getting rid of transpiration mechanism. Flowering and fruiting mainly take place on secondary and tertiary branches.

Papaya (Carica papaya) is a important delicious fruits of herbaceous in nature,. It is most precocious fruit crops cultivated as pure as well as intercropped with mango, guava, peach, and coconut. Papaya starts bearing in 8-10 months after planting.

Bael (Angle marmelos) is an important arid fruits belongs to family Rutaceae and consists 2-3 species of which only one is in cultivation. It is important indigenous fruits of India, drought hardy tree, flowering and fruiting coincides with the onset of monsoon and fruits mature before commencement of summer. The tree shed off entire leaves during hot summer and fruits are exposed to direct sunlight, which favors ripening of fruits.

1.1 Introduction

Like animals, plants are living beings and so require water and air for their survival. In addition, they need water for preparation of food by the process of photosynthesis. Majority of this water requirement of the crops is met from different forms of precipitation. However, when the water requirement is not fully met from precipitation, then growth of the crops is affected. This results in reduction of yield of the crops. The reduction in yield depends on the amount of scarcity of water requirement of the crops. It also depends on the stage of crop growth and also depends on the types of the crops. Generally all the crops are sensitive to water stress during reproductive stage. Water requirement of crops depend on many factors. It depends on the type of crops, irrigation schedules practiced, soil texture, position of groundwater table below effective root zone of the crop and management practice followed in crop cultivation. The pulses, oilseeds, vegetables etc. which are also otherwise termed as dry land crops need less water compared to rice which is a water loving crops and perennial crops like sugarcane, banana etc.

Water requirement of crops is partly met by the upward flux of groundwater. The capillary rise of shallow water table in the form of upward flux helps in meeting the water requirement of crops to some extent. The upward flux depends on the type of the soil, effective root zone depth of the crop, depth of water table below effective root zone depth of the crop and potential gradient of soil moisture suction. If the soil is heavy like clay, effective root zone depth of the crop is more (deep rooted crop) and position of ground water table is near to ground level (shallow water table), then the upward flux is more.

2.1 Introduction

Rain and snow are the two chief sources of water of the earth. In-situ conservation of rainwater helps the plants to meet some of their consumptive uses directly. Not all the amount of rainwater that falls at a point is conserved by the soil reservoir to support the plant growth. Some part of it flows over the soil surface as surface runoff and some seeps down as infiltration and finally adds to the under ground reservoir. Therefore, rain or snow, which is not used directly by the plants, becomes a potential source of either surface or ground water for irrigation. In areas with extreme low temperature, snow contributes major source of water supply wherever, in humid and sub humid regions, rain is the principal source. Precipitation, rain or snow, is the first stage of the continual cycle of water in its round from atmosphere to the earth and return by evaporation from water bodies, snow surfaces and land surfaces. The continual cycle of distribution of water is governed by the process called as hydrologic cycle. Thus, precipitation or atmospheric water is the first form of water above the earth’s surface, the second form being the surface water on earth and the third form is the subsurface water or underground water. The study of occurrence, distribution and circulation of precipitation through the unending hydrologic cycle forms the basic part of study of hydrology. As mentioned above, the part of precipitation that is not used by the plants in-situ flows over the soil surface as runoff and contributes to either surface or ground water supply.

3.1 Introduction

Water used for irrigation can be stored mainly in three sources i.e. soil reservoir, surface reservoir or groundwater reservoir. Accordingly the storage system can be defined as soil reservoir storage system, surface reservoir storage system or groundwater storage system. Each of these storage systems has its own merit and demerit. Some of the storage systems though economical but are not helpful to store the irrigation water for longer periods. On the other hand, some other storage systems are very costly, but the irrigation water can be stored there for a longer period. However, before adopting a particular storage system, economics of the system need to be calculated. The cost of installation of the system and the water stored in the storage system and its use as supplemental irrigation to the crops to increase the production in terms of monetary benefit need to be assessed and then the economics of the system should be computed. The storage system that gives maximum benefit-cost ratio and net present value should be adopted for storage of irrigation water. The different types of storage systems are discussed below.

4.1 Introduction

Discharge is also called as rate of flow. Discharge is defined as the volume of water flowing through a cross section in a unit time. It can be expressed as cubic metre per second (cumec), cubic feet per second (cusec), litre per sec (lps) etc. One cumec is equivalent to 35.5 cusecs or 1000 lps. The measurement of discharge is very important in everyday life starting from deciding the amount of irrigation to be supplied to a crop at a particular growth stage, or amount of water supply for domestic and industrial uses, for flood control and power generation etc. It plays a vital role in water resources planning. If a stage-discharge (also called as gauge-discharge) relationship for a particular gauging site is developed, then daily measurement of discharge in the gauging site is not required. Discharge can be estimated from the developed relationship of discharge versus stage if the measurement of stage is known.

5.1 Introduction

A reservoir that collects and harvests in-situ rainfall as well as runoff from the catchment area can be used for many purposes: the most important of which is the supply of water to crops as supplemental irrigation. The water of the reservoir can be used for domestic and industrial uses. It is also a good source for recreational use. Total water demand of the reservoir including irrigation to different crops in different seasons, domestic and other non agricultural uses are to be assessed. While estimating the crop water requirement and irrigation requirement, various crops to be grown in the service area of the reservoir, their water requirements, crop duration, extent of coverage and water management practices followed are to be taken into consideration. Multiplying the irrigation requirement with crop coverage area, volumetric irrigation water requirement of crop can be found out. Summation of irrigation requirement of all crops grown in service area of the reservoir gives total irrigation demand of the reservoir.

Small farm reservoirs are normally used for irrigation to crops as well as to meet the live stock water demand. Normally the large live stocks like horse, cattle require 20 thousand litres of water per head per year whereas the small live stocks like sheep, goat, pigs require 2 thousand litres of water per head per year. Adding the irrigation demand to the livestock demand, total water requirement of the reservoir is calculated. In addition to this, water used for industrial, domestic and other sectoral purposes are to be added to irrigation and livestock demand to estimate the total water demand of the reservoir.

6.1 Soil

The term ‘soil ’is defined in various ways depending on the general professional field in which it is used. However to an agriculturist, soil is the substance existing on the earth surface, which grows and develops plant life. For an engineer, soil is the unaggregated deposits of mineral and organic particles covering major part on the earth crust. It includes widely different materials like boulders, sand, gravel, clays and silts. Soil is produced by the weathering of solid rocks. The formation of soil is due to geologic cycle continuously taking place on surface of the earth. The geologic cycle comprises weathering or denudation, transportation, deposition and upheaval, again followed by the above mentioned processes. Weathering may be natural or artificial. In natural weathering, physical processes like temperature changes, flow of water, ice, wind and rain play the role. In artificial weathering animals especially human beings interference causes soil erosion and formation.

7.1 Introduction

For maximization of yield of crops, it is essential to provide irrigation to crops. When either the natural sources like rainfall, dew, snowfall and other forms of precipitation or when the capillary rise of groundwater is not sufficient to meet the crop water demand, then there is need to supply irrigation. This irrigation water is a precious resource and need to be used cautiously. There are three important things need to be understood for optimum utilization of irrigation water with basic purpose to maximize the yield and returns. These three things are:

(i) When to irrigate?

(ii) How much to irrigate? and

(iii) How to irrigate?

In fact these three things form the core concept of irrigation scheduling.

8.1 Introduction

After knowing when to irrigate and how much to irrigate, next important thing is how to irrigate the crop field. Methods of irrigation play a very crucial role in deciding how to irrigate the crop fields since all the crops do not require same methods of irrigation. Depending on the sources of water available for irrigation, type of crop to be irrigated, quantity and quality of water to be applied and other economic considerations, methods of irrigation will vary. Irrigation water may be applied to the crops by flooding it on the field surfaces as surface irrigation, by applying it beneath the soil surface as subirrigation, by spraying it under pressure as sprinkler or overhead irrigation or by applying it in drops around the root zone of the crop as trickle irrigation. The commonly used methods of irrigation are described in schematic diagram as follows:

9.1 Introduction

In order to increase the production and productivity of crops, provision of irrigation system is highly essential. A project that makes use of weir or a barrage for providing irrigation to fields is called as direct irrigation system. On the other hand, a storage irrigation system makes use of storage reservoir by construction of dams. In order to provide irrigation by both the schemes, it is necessary to have a network of canal systems. A canal is an artificial channel, generally trapezoidal in shape constructed on the ground to carry water to the fields. The canal systems that provide water to the fields include main canals, branch canals, distributaries, minors and watercourses. It is imperative to design the canal systems properly for a certain realistic value of peak discharge that must pass through them so as to provide sufficient irrigation to the command areas. The flow irrigation that provides irrigation water to the fields may be of two types i.e. Inundation irrigation and Perennial irrigation.

10.1 Introduction

Irrigation is an age old practice. It has been practiced for thousands of years. It is chiefly used to irrigate rice in wetter areas; especially in Asian countries and dry land crops including vegetables and fruits in dry land areas having low rainfall in all most all countries. Devices for irrigation water lifting range from age old indigenous water lifts to highly efficient pump. Unlike canal irrigation where water is fed to the fields through gravity system, water from the surface and sub-surface sources is lifted either mechanically by pump or manually by any indigenous lifting devices. Irrigation by lifting water from a lower level to a higher level is called as lift irrigation. Several types of indigenous water lifting devices are in vogue in India since ancient times. These are animal or/and manually operated ones, the animal operated ones being more efficient than the manually operated ones. The earliest water lifts were simple man-powered devices, many of which are still being used with modifications in different forms. With gradual improvement, principles of simple machines, like the liver, pulley, screw etc. were employed in smooth lifting of water from surface and sub-surface sources. The selection of a suitable water lifting device for a particular situation depends on the following factors:

(i) Characteristics of source of water and the lifting device

(ii) Amount of water to be lifted

(iii) Depth of water table

(iv) Type and amount of power available and

(v) Economic status of the farmers.

11.1 Introduction

The entire amount of water that is diverted at the canal head regulator does not reach at the field for use of irrigation. Major amount of it is lost on way during its movement in the canal systems. During the passage of water from main canal to outlet at the head of the water course, water may be lost either by evaporation from the surface or by seepage through the peripheries of the channel. These losses are sometimes very high, and may go up to 50 % of the total water diverted into the main canal. Evaporation losses are low and may go to a maximum of about 7 percent.of total losses. The major loss of water in the conveyance system is the seepage loss. Seepage loss depends on the channel geometry and evaporation loss is proportional to the area of free surface. In determining the designed channel capacity, a provision of these water losses must be made. The provision for the water lost in the watercourses and in the field however, already made in the outlet discharge factor, and hence no extra provision is made on that account. However, excluding the above two losses, there is operational loss which when added to the evaporation and seepage losses, the total losses goes up the maximum 50 percent level. The operational loss includes spillage, over-toping, leakage through rodent holes, dead storage, initial infiltration and evapotranspiration from the vegetation along the watercourse. Evaporation and seepage losses of the canals are discussed below.

12.1 Introduction

Rainfall is the major source of water that contributes lion’s share for irrigation to crops. Before it reaches the earth, it is to a great extent pure in nature. By the time it falls on the ground surface, it comes in contact with various types of gases and suspended materials of the atmosphere and also after it flows as runoff on the surface it gets dissolved with many types of salts, impurities etc. that render the water to be impure. Many a time the industrial waste, agricultural wastes, pesticides, fungicides, chemical fertilizers etc. get mixed with water and make it unsuitable for irrigation use. Water being a universal solvent, it dissolves all most all organic impurities, salts etc. which makes it objectionable for both domestic and agricultural uses.

Irrigated agriculture is dependent on an adequate water supply of usable quality. In the past, water quality concerns were neglected because good quality water supplies were plentiful and readily available. This situation is now changing in many areas. Especially, in the arid and semi-arid zones, water quality is fast deteriorating which is posing threat to irrigated agriculture.

Conceptually, water quality refers to the characteristics of a water supply that will influence its suitability for a specific use. On the other hand, it refers to the situation of how well the quality meets the needs of the user. There are three quality indicators. They are physical, chemical and biological indicators. Even a personal preference such as taste is a simple evaluation of acceptability. For example, if two drinking waters of equally good quality are available, people may express a preference for one supply rather than the other; the better tasting water becomes the preferred supply. In irrigated agriculture, emphasis is placed on the chemical and physical indicators of the water and rarely the biological indicator is considered important.

13.1 Introduction

In agricultural lands, when the pores of the soil within the root zone of the crop get saturated with the subsoil water due to infiltration of high rainfall, excess irrigation or heavy seepage loss in the unlined canal systems, the air circulation within the soil pores get totally stopped. This phenomenon is called as waterlogging. In canal commands where there is continuous flow of water in the canals and canals are mostly unlined, there is heavy loss of seepage which raises the ground water table. This raising water table sometimes comes up to the ground surface which impedes surface drainage. By capillary action, under ground water rises to the crop root zone and submerges the roots of the crops for most of the time. This situation is called as waterlogging which creates salinisation and alkalinisation problems affecting the plant growth.

The height to which soil water rises above the water table by capillary action is called as capillary fringe. Generally, the height of the capillary fringe varies from 1 to 1.5 m. When the water table comes to 1.5 m below the surface of the soil, the land is said to be waterlogged. At times, due to poor drainage conditions, surface water cannot be freely drained out. The stagnate water in these low lying areas also causes waterlogging which enhances the weed growth consequently affecting the crop yield.

14.1 Introduction

Groundwater is an important source of water for irrigation. It is the most abundant fresh water resource of the earth. Underground water reservoirs contain large stock of fresh water resources. Total quantity of groundwater within 800 m distance below the ground surface is more than 30 times the total water in all fresh water lakes, more than 60 times the total water in soil and other unsaturated rock materials, more than 300 times the water vapour in the atmosphere and 3000 times the average volume of all rivers and rivulets in the world (Lenka, 2001). But the distribution of groundwater is not uniform. At some places, it lies below a few metres whereas at other places, it is a thousand metres or more below the ground surface. In some places, there is abundant groundwater potential whereas at other places there is meager potential.

Groundwater is the water reaching the groundwater reservoir from the infiltrated water of precipitation which constitutes an important component of the hydrologic cycle. It is only the part of the subterranean water that occurs in the saturated pores of the containing rock materials underlain by water held in a zone of aeration. It should not be confused that all the water present in soil below the ground surface is groundwater.

15.1 Introduction

The laws governing the flow of water in wells are referred to as the hydraulics of wells. Just like surface water flows from a higher elevation to a lower elevation by gravity, groundwater also flows from a region of higher water table to a region of lower water table. This difference of water table measured by any two piezometers divided by the longitudinal distance between them is called as hydraulic gradient. Hydraulic gradient plays a dominant role in deciding the flow of groundwater. This hydraulic gradient together with the hydraulic conductivity of the aquifer material forms the main law of well hydraulics called as Darcy’s law. An understanding of Darcy’s law together with some other laws as discussed subsequently in this chapter is essential in order to know the discharge of a well in a particular formation. Darcy’s law is valid for studying groundwater flow in alluvial formations. However, it is not valid for aquifers having hard rock areas.

16.1 Introduction

Producing more crops, livestock, fish and forest products per unit of water use is an essence of water productivity and is highly essential for both food and environmental security. A variety of options exist for improving the productivity of water in agriculture through breeding, better management practices and supporting policies and institutions. It is imperative to identify a range of means to enhance water productivity in agriculture, assess their potential and the consequences of their adoption. The production systems to be considered can vary from purely rainfed to irrigated, and from dry zones to semi-humid monsoonal areas.

The productivity of water used in agriculture has almost doubled during 1961 to 2001, It is mainly due to increases in crop yields. Irrigated rice yields doubled and rain-fed wheat yields rose by 160% in that period, with little variation in water consumption per kilo of output. Globally, FAO estimates that water needs for food per capita halved from about 6 m³/day to less than 3 m³/day during 1961 to 2001 which is a significant saving and an equally significant gain for other water users.

According to an estimate, a 1% increase in water productivity in food production enables to save about 24 lit/day of water per head of population, while a 10% increase would equal current domestic water consumption. Importance of saving water in agriculture can be realised from the above observation.

Abnormal combustion: Combustion that does not proceed in the normal way, in which knock, pre-ignition, run-on or surface ignition occurs. Refer knock.

Abrasion: It is the surface discontinuity brought to any solid by the process of removal of surface material through friction of another solid, liquid or gas or combined thereof.

Absolute or specific humidity: It is the mass of water vapour present in a unit mass of dry air. It is also called as humidity ratio.

Absolute instrument: It is an instrument, which measures a quantity (such as pressure, temperature etc.) in absolute units by means of simple physical measurements on the instrument.

Absolute pressure: It is the actual pressure at a given position and it is measured relative to absolute vacuum (i.e., absolute zero pressure). Absolute pressure = pressure shown on the pressure gauge + atmospheric pressure. At sea level, atmospheric pressure is 14.7 psi (1.033kg/cm²).

Babbitt: 1. A tin base alloy containing 88% tin, 8% antimony and 4% copper. 2. In machinery, to line, bush, fill or face with Babbitt metal, e.g. to babbit a bearing.

Back furrow: A raised ridge left at the centre of the strip of land when ploughing is started from centre to side. See Fig. 1B.

Backfire: The accidental explosion of an overly rich mixture in the exhaust manifold of a spark-ignition engine. Backfire conditions can also develop if the premature ignition occurs near the fuel intake valve and the resultant flame travels back into the induction system.

Backlash: The clearance or play between two parts, such as meshed gears.

Cable conveyor: A power conveyor in which a trolley runs on a flexible, torque transmitting cable that has helical threads.

Cable: 1. A general term applied to rope or chain used for engineering purposes. 2. The standard wire with insulating cover used for conducting electrical current.

Cage harrow: A rolling harrow with horizontal shafts each fitted with star shaped tines joined by rods forming the lines of cylinder.

Dah: A metal with handle used for cutting trees and cleaning jungle growth. See Fig.1D.

Dead axle (tractor trolley): An axle beam, which does not drive the road wheels. Usually refers to a rear axle which does not have any rotating parts within it, but on which the rear wheels are mounted with antifriction bearing.

Dead centre: 1. The centre, which is fitted into the tailstock of a lathe and does not rotate with the work. 2. The extreme top or bottom position of the crankshaft throw at which the piston is not moving in either direction.

Dead furrow: An open trench left in between two adjacent strips of land after finishing the ploughing operation. See Fig.1B

Dead weight: The weight of a vehicle or carrier itself as distinguished from carried or live load.

Ear plug: A device made of a pliable substance, which fits into the ear opening; used to protect an ear from excessive noise or from water.

Ear protector: A device, such as a plug or ear muff, used to protect the human ear from loud noise that may be injurious to hearing, such as that of jet engines.

Earned value: The budgeted cost of the work performed for a given project.

Earth moving: Tillage action and transport operations utilized to loosen, load, carry and unload the soil.

Earthmover: A machine used to excavate, transport, or push earth.

Fabrication: The act of building or putting together. Forming into a whole by uniting or assembling of parts.

Face lathe: A short-bed, deep gap lathe designed for the machining of large, flat surfaces.

Face milling: Milling flat surfaces perpendicular to the rotational axis of the cutting tool.

Faceplate or face chuck: A circular plate for attachment to the spindle in the headstock of a lathe. Work may be clamped or bolted to it. The slots engage the tail of the lathe dog.

Factor of safety: The number, which results by dividing the ultimate strength of a material by the actual stress on a sectional area.

Factor of stress intensity: The ratio of the maximum stress to which a structural member can be subjected to the maximum stress of safety.

Gadget: A slang word applied to any small, handy appliances or devices.

Gagging tape: A metal measuring tape used to determine the depth of liquid in a tank.

Gal.: The unit of acceleration in the centimeter-gram-second system, equal to 1 centimeter per second square; commonly used in geodetic measurement. Formerly known as Galileo, symbolized as Gal.

Galling: A characteristic of metals, which causes them to seize when, brought into intimate contact with each other. A material, which is subjected to galling, is one, which will seize or ‘freeze’ when brought into close contact with like material under pressure and no lubricant.

Gallows plough: An animal-drawn plough, the end of the beam rests freely on a bolster fixed to two front wheels, which is drawn through the front wheel assembly.

Galvanic corrosion: The accelerated corrosion of one metal when it is connected with a more noble metal, e.g. if steel and copper are connected together in seawater, the steel will suffer accelerated corrosion and the copper will be protected.

Half round file: A file, which is flat on one side and curved on the other. The amount of convexity never equals a semicircle.

Half section: In mechanical drawing, a sectional view that terminates at the centreline, showing an external view on one side of the centerline and on the other side an interior view.

Hammer: An instrument or tool used for striking blows in metalworking, driving nails, etc. Hammers are of various kinds, each bearing a name according to the purpose it has to serve.

Hammer mill: 1. A type of impact mill or crusher in which materials are reduced in size by hammers revolving rapidly in a vertical plane within a steel casing. Also known as beater mill. 2. A grinding machine, which pulverizes feed and other products by several rows of thin, hammers revolving at high speed.

I beam: A steel beam shaped like the letter I, used in structural work.

I. H.P. (Indicated Horse Power): ‘Pure’ horse power as measured in the combustion chamber before friction and other loses are subtracted.

IC Engine (ICE): Internal Combustion Engine.

Ideal compression-compression refrigeration cycle: completely vaporizes the refrigerant before it is compressed and expands the refrigerant with a throttling device, such as an expansion valve or capillary tube. The compression-compression refrigeration cycle is the most widely used cycle for refrigerators, air-conditioning systems, and heat pumps. It consists of four processes:l- 2 Isentropic compression in a compressor; 2-3 Constant- pressure heat rejection in a condenser; 3-4 Throttling in an expansion device; 4-1 Constant-pressure heat absorption in an evaporator

Ideal cycle: is an actual cycle stripped of all the internal irreversibilities and complexities. The ideal cycle resembles the actual cycle closely but is made up totally of internally reversible processes.

Ideal gas: Is a gas that obeys the ideal-gas equation of state.

Jack, electric: A form of metallic spring contact, connection being made by inserting a plug, which is attached to a cord. Commonly used on telephone switchboards and radios.

Jack, hydraulic: Device for raising weight or exerting pressure by pumping oil or other liquid under a piston or ram.

Jack: A mechanical device used for lifting heavy loads through short distances with a minimum expenditure of manual power.

Jacket: An outer casing, as around a boiler or tank, to preserve heat or cold, or around a motor cylinder, permitting a flow of water to prevent overheating.

Jacking up: The raising up of masses of machinery and heavy structures by means of jacks.

Jackscrew: Small screw jacks for leveling work in jigs.

Kelvin scale: The thermodynamic temperature scale in the SI and is named after Lord Kelvin (1824-1907). The temperature unit on this scale is the Kelvin, which is designated by K (not °K; the degree symbol was officially dropped from Kelvin in 1967). The lowest temperature on the Kelvin scale is 0 K.

Kelvin unit: magnitude was established at the International Conference on Weights and Measures in 1954. The triple point of water (the state at which all three phases of water exist in equilibrium) was assigned the value 273.16°K (0.01 °C). The magnitude of a Kelvin is defined as 1/273.16 of the temperature interval between absolute zero and the triple-point temperature of water. The magnitudes of temperature units on the Kelvin and Celsius scales are identical (1 K, 1°C). The temperatures on these two scales differ by a constant 273.16.

Labeled: Equipment or materials to which has been attached a label, symbol or other identifying mark of an organization acceptable to the “authority having jurisdiction” and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.

Laboratory: A place where scientific tests, experiments, analysis, etc., are carried on.

Ladder: An aid to climbing. Usually made of two parallel uprights connected by regularly spaced rungs.

Ladle: Receptacle used for taking the molten metal from the cupola, in transporting it, and in pouring it into the molds. Ladles are of various shapes and sizes with capacities from 25 pounds to 100 tons.

M

Mach number: Named after the Austrian physicist Ernst Mach (1838-1916), is the ratio of the actual velocity of the fluid (or an object in still air) to the velocity of sound in the same fluid at the same state.

Machine: 1. A combination of rigid or resistant bodies having definite motions and capable of performing useful work. 2. A device for transforming or transferring energy.

Machine drawing: A mechanical drawing of a machine or machine parts provided with notes and dimensions for workshop information.

Machine drilling: The d rillin g of work under a power-driven machine.

Machine molding: The use of special machines in the preparation of molds for the production of castings.

Machine rating: The amount of power a machine can deliver without overheating.

Machineable: Material capable of being finished by tools or cutters in or on a machine tool.

Machinery: A group of machines; also, the working parts of an engine or machine.

Machining: Performing various cutting or grinding operations on a piece of work.

Natural gas: Produced from gas wells or oil wells rich in natural gas. It is composed mainly of methane, but it also contains small amounts of ethane, propane, hydrogen, helium, carbon dioxide, nitrogen, hydrogen sulphate, and water vapour. It is stored either in the gas phase at pressures of 150 to 250 atm as CNG (compressed natural gas) or in the liquid phase at 162° C as LNG (liquefied natural gas).

Natural-draft cooling tower: Uses the naturally occurring density gradients between the inside air-water vapour mixture and the outside air which create an airflow from the bottom to the top of a wet cooling tower.

Needle valve: A valve in which the flow of liquid or gas is regulated by the adjustment of a pin or needlepoint, which sets in a cone-shaped depression having a small hole at the bottom.

Negative: One of the two terminals in an electrical circuit, presumably the one through which the current returns to the source.

Negative camber: The condition existing when two tyres are closer together at the top than at the bottom.

Oak: A hard, durable, and very strong wood used for many purposes like furniture, flooring, decoration etc.

Octane number: It is the percetage of iso-octane (C₈H₁₈) in the mixture of iso-octane and normal heptane (C₇H₁₆), when it produces the same knocking effect as the fuel under test. It is used to indicate the octane rating of a gasoline, describes the anti-knock properties of a fuel when used in an internal combustion engine. Knock is a secondary detonation that occurs after fuel ignition due to heat buildup in some other part of the combustion chamber. When the local temperature exceeds the auto ignition temperature, knock occurs.

Octane rating: A measure of the antiknock properties or engine knock resistance of a gasoline. The higher the octane rating, the more resistant the gasoline is to abnormal combustion.

Octane requirement: The fuel octane number needed for efficient operation (without knocking or spark retardation) of an internal combustion engine.

Odorization: A process of adding a distinctive odor to natural gas so that its presence can be easily detected.

Packing: 1. The material, which is enclosed in a stuffing box for the purpose of preventing leakage around a piston rod. 2. The act or process of inserting packing material. 3. Blocking up.

Paddy dehusker: An equipment to remove husk from paddy grain. It is also known as paddy Sheller.

Paddy separator: A machine, which is used for the separation of brown rice from the paddy brown rice mixture.

Paddy thresher, pedal operated: Equipment used for threshing of paddy crop, consisting of mainly a balanced cylinder with series of threshing teeth fixed on slats and worked by a pedal and gear drive mechanism.

Quadrangle: A square or quadrangular space surrounded by buildings, as on college grounds.

Quadrant: 1. The quarter of a circle, an arc of 90°. 2. An instrument for measuring altitudes.

Quadrilateral: A plane figure with four sides and four angles.

Quarter turn belt: The arrangement of a belt to drive two shafts, which are at right angle.

Quarter turn drive: A belt drive connecting pulleys whose axes are at right angles.

Quartering machine: A machine that bores parallel holes simultaneously in such a way that the centre lines of adjacent holes are at 90 deg. apart (axes of the holes are perpendicular to the plane on which an angular measurement are taken.)

R

Rabbet: A rectangular groove or cut made in the edge of a board, so that another similar cut may fit into it to form a rabbet joint.

Rack and pinion: A gear arrangement consisting of a toothed bar that meshes with a pinion. These are used to transform circular motion in to rectilinear motion and vice versa.

Rack and pinion steering: A steering system in which the rotation of pinion gear at the end of the steering column moves a toothed bar (the rack) left or right to transmit steering movements.

Radial arm: The movable cantilever, which supports the drilling saddle in a radial drilling machine.

Radial bearing: Bearing made with cylindrical or with barrel shaped rollers. The direction of action of the load transmitted to the axis of shaft.

Radial drill: l.A drilling machine in which the drill spindle can be moved along a horizontal arm, which itself can be rotated about a vertical pillar. 2. A heavy drilling machine, so constructed that the position of the drill can be adjusted to the work without moving the latter.

Radial engine: An engine, which has stationary cylinders, arranged radially around a common crankshaft.

SAE: Society of Automotive Engineers; used to indicate a grade or weight of oil measured according to the SAE.

Safe load: The load that a piece can support without exceeding the working unit stress.

Safety device: An installation designed to protect the operator or other persons. E.g., shields, grass-catching equipment, deflectors, covers for chains, belts, drive shafts, etc.

Safety factor: The degree of surplus strength over and above normal requirements, which serves as insurance against failure.

Safety hitch: A hitch incorporating a device to avoid breakage when an implement works against an abnormal resistance.

Safety valve: 1. An automatic valve, which opens and relieves the pressure when it reaches a predetermined value, thereby protecting the system and operator. 2. A safety device for allowing steam or water to escape from a boiler when the pressure may become dangerous. Usually adjusted to permit not more than 5 pounds of pressure above maximum allowable working pressure of the boiler.

T bolt: A bolt shaped like the letter “T, the head being a transverse piece, which fits into the recessed under cut T slots, as on a table of a milling machine or planning machine.

T head engine: A cross section of an engine block resembles the letter T. Valves are arranged on both sides of the engine; requiring two camshafts and two camshafts drive gears. An expensive type of construction.

Tachometer: An instrument for measuring the speeds of shafts in revolutions per minute.

Tail pulley: A pulley at the tail of the belt conveyor opposite the normal discharge end; may be drive pulley or an idler pulley.

Tail screw: The screw, which operates the spindle of the tailstock on a lathe.

Taillight: A signal light, required by law to be carried on the rear of every automobile, and lighted when the car is driven at night.

Tailstock: The movable head of a lathe as distinguished from the headstock, which is fixed.

Take up: A tensioning device in a belt conveyor system for taking up slack of loose parts.

U clamp: A clamp shaped like the letter ‘U’ used for clamping down work on planer beds.

Ultimate strength: The highest unit stress that can be sustained, this occurring just at or just before rupture in stress strain diagram.

Ultrasonic drilling: A vibration drilling method in which ultrasonic vibrations are generated by the compression and extension of a core of electrostatic or magneto static material in a rapidly alternating electric or magnetic field.

Ultrasonic machining: The removal of material by abrasive bombardment and crushing in which a flat-ended tool of soft alloy steel is made to vibrate at a frequency of about 20,000 Hz and an amplitude of 0.001-0.003 inch (0.0254-0.0762 millimeter) while a fine abrasive of silicon carbide, aluminum oxide, or boron carbide is carried by a liquid between tool and work.

Uniform: Implies no change with location over a specified region.

V belt: An endless power transmission belt with a trapezoidal cross section, which runs in a pulley with a V-shaped groove. The top surface of the belt approximately flush with to top of pulley. V belt transmits higher torque at less width and tension than a flat belt.

V blocks: Metal blocks cut ‘V’ shaped on one side to permit holding cylindrical work while machining or testing.

V type engine: An engine with cylinder blocks arranged in a ‘V’ shape. One crankshaft serves both banks of cylinders.

Vacuum: Negative gauge pressure, or a pressure less than atmospheric pressure. Vacuum can be measured in psi, but is usually measured in inches or millimeters of mercury (Hg); a reading of 30 in. Hg (762 mm Hg) would indicate a perfect vacuum.

Walking machine: A machine designed to carry its operator over various types of terrain; the operator sits on a platform carried on four mechanical legs, and movement of his arms control the front leg of the machine while movement of his legs control the rear legs of the machine.

Wane: Wane is a defect in a timber or plank.

Washer: A small, flat, perforated disk, used to secure the tightness of a joint, screw, etc.

Washer cutter: A device having a fixed center and either one or two adjustable cutting points for cutting washers from leather, rubber, etc.

Waste heat: Energy, that must be dissipated to the atmosphere from a process such as the heat transferred from condensing steam in the condenser of a steam power plant.

Waste spark system: An ignition system, that energizes the spark each time the piston is at top dead center whether or not the piston is on the compression stroke or on its exhaust stroke. For hydrogen engines, the waste sparks are a source of pre-ignition.

Water (H₂O): 1. A colorless, transparent, odorless, tasteless liquid byproduct of the combining of hydrogen and oxygen, 2. The liquid form of steam and ice. Fresh water at atmospheric pressure is used as a standard for describing the relative density of liquids, the standard for liquid capacity, and the standard for fluid flow. 3. The melting and boiling points of water are the basis for the Celsius temperature system. 4. Water is the only substance that expands on freezing as well as by heating, and has a maximum density at 4°C.

X engine: An in line engine with the cylinder block so arranged around the crankshaft that they resemble the letter X when the engine is viewed from the end.

Aromatic plants synthesise and preserve a variety of biochemical products, many of which are extractable and useful as chemical feed stocks or as raw materials for various scientific investigations. Many secondary metabolites of plants are commercially important and find use in a number of perfumery, flavouring and pharmaceutical compounds. The characteristic property of the plant is due to a variety of complex chemical compounds and hence aromatic plants are generally referred to as ‘natural bio-chemical factories’ or ‘chemical goldmines’.  Not all these natural chemicals can be synthesised in laboratory. Aromatic plants possess odorous volatile substances, which occur as essential oil, green exudate, balsam and oleoresin in one or more parts, namely, root, wood, stem, foliage, flower and fruit.  The term essential oil is concomitant to fragrance or perfumes because these fragrances are oily in nature and they represent the essence or active constituents of plants. They are called volatile or ethereal oils as they evaporate when exposed to air at ordinary temperatures.

Though more than 1500 species contain volatile aromatic principles, only around 50 species serve as commercial source of essential oil and aroma-chemicals. Among these, aromatic crops under large-scale cultivation hardly exceeds two dozens. Important aromatic plants of world are classified according to economic part used, growth habit, habitat, crop duration and propagation method besides usual botanical classification.

Essential, volatile or ethereal oils are mixtures composed of volatile liquid and solid compounds which vary widely in regard to their composition and boiling points. Plants owe their fragrance to presence of traces of essential oils in different parts. Numerous fragrance materials are present in roots, stems, barks, leaves, flowers, fruits and heartwoods.     
Several processes like distillation, enfleurage, maceration, expression, solvent extraction and fluid extraction are available for extraction of aroma principles. Application of these processes, either singly or in combination depends upon nature of material and essential oil or absolute intended to be recovered.

Essential oils are products of secondary metabolism and are secreted by specialized cells located in specified parts of most plants. By virtue of certain characteristic properties, they have wide spread use in perfumery, flavouring and medicine. Essential oils are variable mixtures of terpenoids. Since these oils are produced by plants, composition varies with species and variety of plant besides geography, climate and cultivation practices. Since, chemical components are highly reactive, physical and chemical environment to which oil is subjected to during the processes of its extraction, processing and storage have a great influence on final composition. Entire chain of activities from cultivation, extraction, processing, storage to packing has to be perfectly standardized and regulated to assure end product consistency. Being a valuable item of trade, this is important from the point of view of delivering desired activity as well as safety to consumer.

“The way to health is the way to have an aromatic bath and a scented massage everyday”                        Hippocrates

Aromatherapy is the art and science of using fragrant volatile plant oils and herbs including essential oils, for psychological and physical well-being of man by promoting natural healing and health. It is an emerging art of healing through essential oil, which has got therapeutic effect on body, mind and soul.  Essential oils give calmness, emotional and hormonal balance, stress relief and rejuvenation. Medicinal and spiritual properties of scented herbs were noted by ancient Egyptians and Babylonians. Embalming of body of Egyptian Pharaohs was a practice to purify body for afterlife, whereas Egyptian priests used oils and incense as healers. Books were written in ancient Arabia indicating uses and benefits of certain aromas. Perfumed mortar was used by Babylonians to build temples and mosques, for premises cleaning and cleansing aromas. Ancient Greek believed sweet smells were of divine origin and they used to take aromatic bath to drench them in purity. Aromatic bath and scented massage were ways to health for Romans.