eBook Chapters

INTRODUCTION
Hydraulics is the study of liquids and their behavior, specifically focusing on the use of pressurized fluid to generate power in engineering systems. Hydraulic systems operate by applying pressure to a small amount of fluid, which in turn generates significant power. The development of hydraulic technology has enabled major advancements, such as lifting heavy loads and rotating large shafts with minimal effort through mechanical linkages.
Compared to mechanical and electrical systems, hydraulic power systems offer greater flexibility and produce more power relative to their size. They also provide quick and precise responses to control inputs. As a result, hydraulic systems are widely used in modern applications such as aircraft, automobiles, heavy industrial machinery, and various machine tools. This article will focus on the hydraulic systems used in tractors.
HYDROSTATIC TRANSMISSION
Hydrostatic transmissions rely entirely on hydraulics, using the power of oil to transmit energy. The system consists of two main components: a variable displacement pump and a hydraulic motor. The pump’s displacement is controlled by a movable swash plate, which adjusts the piston stroke. Essentially, the system operates as a variable-displacement hydraulic pump driving a fixed-displacement hydraulic motor.
The key benefits of hydrostatic transmissions include the ability to infinitely vary ground speed and rapidly change directions. They are also known for their reliability, with self-protecting features that prevent operator abuse.
Additionally, foot pedal-controlled systems have a built-in safety feature that allows for a controlled stop simply by lifting the foot from the pedal. However, hydrostatic transmissions have some drawbacks, including high cost, sensitivity to contamination, and slight power loss at the PTO shaft. Additionally, when

Hydraulic turbines is a device which transforms the hydraulic energy or potential energy existing with the working medium to mechanical energy. The working medium is normally water which run the hydraulic turbine. The hydraulic energy is available with water by virtue of its height or altitude. The water which flow through the mountains is stored by constructing a dam or reservoir.

In drip irrigation water is distributed throughout the field from a system of pressurized pipelines. The pressure must be sufficient to overcome the frictional losses and elevation differences. The system also deserves discharge from all the emitters and the emitters must dissipate the pressure difference between the inlet to emitters and atmospheric pressure.

The flow through the drip pipes may be laminar or turbulent or a combination of both. The laminar flow is characterized by the layers of cylindrical tubes of which the maximum velocity is at the center about double of the average velocity. The turbulent flows having pulsatory cross current velocities and maximum velocity is about only 1.25 time of the average velocity. Turbulent f lows loss more energy than laminar flow due to development of the cross current velocity.

Reynolds Number

The criterion for distinguishing the flow from laminar to turbulent was developed by Osborne Reynolds (1842-1900) and was named as Reynolds number; Re . The Reynolds number in circular pipes flowing full is expressed as

11.1. Hydraulic system

It is a mechanism in a tractor to raise, hold or lower the mounted or semi-mounted equipment by hydraulic means. All the present day tractors are equipped with a hydraulic control system for operating three point hitches. Some of the tractors are fitted with a hydraulic brake system and a few others are fitted with a hydraulic steering system. Tipping trailers, front mounted loaders or dozers are examples of multi use of hydraulics.

11.2. Principle

The working principle of a hydraulic system is based on Pascal’s law (Fig 11.1.) This law states that the pressure applied to an enclosed fluid is transmitted equally in all directions. A small force acting on a small area can produce higher force on a surface of larger area.

14.1 Introduction

Hydro-electric power is electricity produced by the movement of fresh water from rivers and lakes. Gravity causes water to flow downwards and this downward motion of water contains kinetic energy, that can be converted into mechanical energy, and then from mechanical energy into electrical energy in hydro-electric power stations. (“Hydro” comes from the Greek word hydra, meaning water). At a good site hydro-electricity can generate very cost-effective electricity.

Hydro-climatology is defined as the investigation of the impact of climate upon the waters of the earth. This topic includes hydrometeorology, the water processes of evaporation (surface and near surface), rainfall-runoff, and groundwater studies (Langbein, 1967; Wendland, 1998). Hydroclimatology provides a systematic foundation to assess how the climate system causes spatiotemporal changes in the hydrologic cycle with respect to global or local aspects. Variations in the relationship between the hydrologic cycle and the climate system underlie droughts, floods, and future impacts of global warming on available water resources. Both land and satellite based data and computer programming and modelling contribute to our knowledge of the spatiotemporal changes of physical processes shared by the hydrologic cycle and the climate system (Shelton, 2009).

Abstract

The Mesozoic sediments contribute around 54% of the oil and 44% of the gas reserves of the world (Bois et al. 1982). Indian Mesozoic basins occupy an area of about 400 x 103 sq. km and are characterized as frontier basins under category II - IV. These basins are mostly overlain by the Deccan Traps of Late Cretaceous age and are least explored. Deccan Syneclise is one of the largest Mesozoic basins in India, covering an area of ~ 273 x 103 sq. km. Geophysical studies have inferred hidden sub-trappean Mesozoic sediments with thickness up to 2.5 km. It is considered that requisite heat generation due to Deccan Trap volcanism soon after the Cretaceous sedimentation may have acted as a catalyst in hydrocarbon generation. Surface geochemical prospecting surveys along with carbon isotopic studies have been used to assess hydrocarbon generation potential of this part of the basin. The area adjoining Nandurbar beneath Narmada-Tapti region of Deccan Syneclise was selected for geochemical studies where geophysical studies have shown considerable sediment thickness. Surface geochemical studies indicate the generation of light gaseous hydrocarbons, C1 and SC2+ in the range of 3 to 1187 ppb and 1 to 1449 ppb, respectively. The carbon isotopic signatures of selected soil gas samples dC13 CH4 in the range of - 24 to -39.4‰ PDB) suggest thermogenic origin

Abstract

A total of 30 groundwater samples were collected in four different seasons (Pre Monsoon, South West Monsoon, North East Monsoon and Post Monsoon) from the coastal aquifers of Kalpakkam region of Tamilnadu. The samples were collected covering the seasonal and lithological variations to infer the influence of natural geochemical processes and anthropogenic sources on the groundwater chemistry. The collected samples were analysed for the parameters like EC, pH and Major ions. The saturation index of silicates and carbonates shows that state of saturation to over saturation, but the sulphate minerals is dominantly under saturated. In the inverse modeling three models are obtained using PHREEQC and the error percentage is noted as 7.45%.

Abstract

In Gadilam river basin, groundwater is found in both hard rock and sedimentary terrain and is the most important source of rural/urban drinking water supply. Gadilam river basin has gained its importance due to the presence of Neyveli Lignite open cast mine (NLC), group of industrial estate (SIPCOT), extensive depressurization of Cuddalore aquifer and boreholes of New Veeranam Scheme (NVS) in the downstream of the basin. A total of 178 water samples were collected in four different seasons at various lithologies. The collected samples were analyzed for various physico-chemical parameters using standard procedures. Geochemical indicators of groundwater were used to identify the chemical processes that control hydrogeochemsitry. Interpretation of hydrogeochemical data suggests that leaching of ions followed by weathering and anthropogenic impact controls the chemistry of the groundwater. Isotopic study reveals that recharge from meteoric source in sedimentary terrain and rock water interaction with significant evaporation prevails in hard rock region. This thorough understanding helps us to make judicial usage and to maintain the quality of this commodity.

Abstract

Quality of water is affected by natural and man induced contamination to groundwater system. Area chosen for study has gained its own importance due to the location of two lignite mines and a Thermal power plant in operation. Extensive large scale pumping of water is done for lignite mining. The mine drainage and drainage from thermal power plant along with agricultural return flow from lignite charged waters increases the severity of problem. In order to achieve a panacea for the above-mentioned situation, the study has incorporated and integrated in all related factors to get a meaningful interpretation for groundwater quality and quantity management in and around Neyveli area. The frequent failure of monsoon has added to the existing problem of over exploitation. To attain a panacea for water chemistry groundwater samples were collected for four different seasons. Higher EC and TDS values are observed in Southeast and Southwest part of the study area. In Southwest monsoon and Summer seasons HCO₃Cl dominates the anions, with few representations for SO₄. In Northeast monsoon and Post monsoon season Na + K – Ca + Mg is the dominant. Thermodynamic, studies reveal that groundwater of the region are stable with Kaolinite stability field in all the silicate systems. Bicarbonates derived from silicate mineral weathering are noted in the NW, Northern and in the mining region. These regions are located in the NW and NE part of the study area. Comparison of water quality to standards shows that the water can be used for drinking and for irrigation purposes except in few locations.

ABSTRACT

Mecheri Panchayat union lies in the northwestern part of Salem district and adjascent to Dharmapuri district of Tamil Nadu. It lies between the latitudes 11°43’ -12° and longitudes 77° 48’ -78° 03’ of Toposheet No. 58 E/13 of scale 1:50,000 published by survey of India in 1973. Mecheri Panchayat union covers a total area of about 177.6 Sq.Km with a population nearly 1 lakh, live in 150 hamlets. Groundwater is the only replenshable nature resources available to man. The use of groundwater has been growing steadily over the years for domestic, agricultural and industrial purposes. Hydrogeochemical study is a dynamic process undergoing constant change in space and time. In unconfined aquifers, the change likely to be quite rapid and cyclic in nature with respect to the mode of recharge and discharge and related to the nature of host aquifer. In this study an attempt has been made for understanding the chemical quality of groundwater in theunconfined aquifer of Mecheri union. Groundwater samples have been collected from 10 representative dug wells lying in the Mecheri union during December 2004 and analysed by the standard procedures of water analyses. It is essential in determining its usefulness for domestic, industrial and agricultural purposes. Presentation of Geochemical data in the form of graphical charts such as Collin’s bar, Stiff’s polygon diagram, Pie diagram, Piper tri linear diagram, USSL classification and thematical maps were prepared for recognizing various hydrogeochemical types in the Mecheri union. Deleterious effects of fluoride on the human beings are well known. Fluoride are known to be beneficial, when present in concentration ranging from 0.5 ppm to 1.2 ppm. But when it exceeds the limit 1.2 ppm it is found to cause fluorosis. Dental, skeletal and non-skeletal fluorosis may be caused depending upon the concentration of fluorides in drinking water. The main source of drinking water for the majority of people of Mecheri union is groundwater obtained through dug and bore wells. The analysis of groundwater samples showing high (> 1.5 ppm) fluorite content observed in the following villages, viz Mallikundam, Kuttapatti Aranganur, Banapuram, Sathappadi, Mecheri town, Virudasampatti and Amaram.

ABSTRACT

The sources of fluoride in groundwater are minerals like fluorite, apatite, mica, amphiboles,cryolite and fluor.spar. The undue concentration of fluoride greater than 1 mg/l has befallen a major toxicological and geoenvironmental issue in India. Excess of fluoride in groundwater causes skeletal and dental fluorisis. The study area forms part of Salem district with records of endemic fluorisis. To decipher process and chemistry of fluoride, a total of 46 groundwater samples were collected from major litho units of the study area (Peninsular gneiss and Charnockite) and analyzed for fluoride using standard procedures for two seasons viz. pre and post monsoon. In pre-monsoon, maximum and minimum fluoride in Peninsular gneiss and charnockite were ranging from 2.85 to 0.4 mg/l and 4.02 to 0.37 mg/l respectively. The coresspnding figures in post monsoon ranges from 2.84 to 0.32 mg/l and 1.91to 0.37 mg/l respectively. Higher concentration was noted in charnockite folowed by peninsular gneiss in pre monsoon and the effect of dilution was well noted in post monsoon season. Statistical analysis undercovers the relationship of fluoride minerals with other ions. Modeling results represent the leaching of fluoride minerals and their variation along with seasons.

Introduction

Water is among the most precious gifts of nature to mankind. Most of the ancient towns of the world grew on the banks of the river, and some of the ancient civilizations are known by the names of rivers. Rivers have always been important sources of drinking water and the means of sustaining human, animal and plant life. Whenever one is dealing with water resources development and utilization, it has to be kept in mind that not only quantity of water but also quality of water is very important. The well being and development of our society is dependent on the availability of water. An increase in groundwater development and utilization for industries and urban water supply has created improper disposal of liquid waste. Defective well constructions, sewage and waste disposal in man made lakes with in the city, open quarries with water and failure to seal the abandoned wells in city area have provided possible openings for downward movement of polluted water into subsurface formations without undergoing the process of natural filtration.

INTRODUCTION

Remote Sensing is an indigenous tool for the Environmental Impact Assessment study. It plays vital role in preparing various thematic maps for understanding the changes that have taken place in an area before and after the establishment activities. In this study we have utilized the capability of the remote sensing techniques in understanding the mining environment. Our study area is in and around the Dalmiapuram Cement Industry in the central part of Tamil Nadu state and it covers part of Trichy and Perambalur districts. It falls between 11₀ 02’ 42’’and 1₀ 03’ 08’’E and 79₀ 09’ 39’’and 79₀ 10’ 30’’N.Dalmiapuram Cement Industry is located in the Kovandakurichi village of Pullambadi block, Trichy district. The mines for cement manufacturing are Perianagalur (PNR), Periathirukonam (PTK), Kallakudi (KLK), Kovandakurichi (KVK) and A&K Mines.

The litho units are Limestone beds containing various proportions of bioclastic and siliciclastic materials. They show wackstone to rudstone fabric and have clasts of re-deposited bound stones. Deposition in a periodically restricted shallow marine setting was indicated by lithological and faunal information. Lower contact is an unconformity surface associated with marine flooding and the upper contact is non-depositional and erosional with overlying biostormal member.

Common groundwater investigations include necessary considerations of the system’s influx sources, flow regime, discharge points and geomorphological characteristics of the area. Often, hydrogeomorphological mapping of an area is required as to determine these characteristics. The primary data can be acquired from the survey of India toposheet map and the satellite images. The secondary data set includes the satellite imageries, the preparation of digital elevation model (DEM) and digitized precipitation maps.

The first step in the procedure of hydrogeomorphological mapping is to calculate the watershed/basin area, which serves as a mask to define the area of interest. The watershed/basin calculation relies on the digital elevation data and assumes that topographic aspect (dip direction of the cell surface) completely controls the extent to which surface flow emanating from each point in the study area can reach the low point in the valley. The calculation of the potential annual recharge of the aquifer combines techniques described above with data for recharge areas, DEM aspect, and precipitation. First, the catchment area of the recharge zones must be calculated in a process similar to the watershed analysis, returning the area associated with the catchment coded as “1”. A simple multiplication overlay with the precipitation data and the catchment areas yields a result giving the amount of precipitation for each catchment cell. Before using the precipitation data, we converted it to meters so as to keep units consistent. The precipitation amounts within the catchment area (i.e. each cell value) are to be summed, yielding the amount of water available for influx into the groundwater system. Finally precipitation per year data can be acquired.

Identifying surface areas of groundwater discharge is based on the observation that such areas provide a relatively constant source of moisture, which is readily exploited by vegetation in semi-arid region. Thus areas with year-round green vegetation are assumed to be indicators of discharge. The relative amount of vegetation in a scene can be estimated by calculating a vegetation index (Reddy et al, 1989 and Tucker 1979).

The world is head98ing towards a water crisis. Africa and West Asia are likely to be worst affected by water scarcity, but with increasing population, water may fall short even in the other parts of the world. According to the recent UN report, the supply of clean and fresh water is depleting at such an alarming rate in some regions, that within 30 years, about two third of population will suffer moderate to severe water stress.

In hydrogeomorphological context of social environment the water is an essential natural resource for sustaining life. The available water resources are under tremendous pressure due to increased demands. The time is not far when water, which is the free gift of nature, will become a scare commodity. Therefore, conservation and preservation of water resources are urgently required to be done at priority basis. Water management has always been practiced in our communities since ancient times. But such practices have faded away during the past few decades mainly due to lack awareness. Hydrogeologists feel that the water harvesting practices must be urgently implemented to overcome the problem of water crises. In India the Ministry of water Resources is endeavouring to make rainwater harvesting a part of every day life in villages and cities as a people’s movement. Hydrogeomorphological aspect of social environment include (a) Social - Cultural -Administrative Consideration (b) Education and Training in Hydrogeology for Professionals and Technicians (c) Education for Farmers and Women (d) Education for Masses. These are described as below:

The beginning of the 20^th century was heralded by methodological revolution in geomorphological studies brought in by Davis (1899). His classical model of geographical cycle defined by him ‘ as a period of time during which and uplifted landmass undergoes its transformation by the process of land sculpture ending into a low featureless plain (peneplain)’ dominated the geomorphological investigations all over the world throughout 1^st half of the 20^th century.

The statistical techniques by Horton (1932 and 1945) brought quantitative revolution in the field of geomorphology when he presented quantitative analysis of morphometric characteristics of fluvially originated drainage basin. Post 1950 geomorphology has undergone vast change in the methods and approaches to the study of landforms, conceptual framework, paradigm and thrust areas of study. The most outstanding contribution to the advancement of geomorphological knowledge in this period is the adoption of quantitative approach based on deductive scientific method to the study of landforms and processes at short spatial and temporal scales (Strahler, 1956 and Schumm, 1956).

Several attempts have been made in the world in past to classify large territories and landforms into morpho-units. Valuable contributions pertaining to landform analysis have been summarized below: Joerg (1914) subdivided North America into natural regions, Fenneman (1914) established physiographic boundaries and gave physiographic divisions of the United States, whereas Anderson (1941) gave physiographic divisions of Columbia plateau. Howard and Spock (1940) and Weaver (1965) presented the excellent ways of classification of the landforms while Wood and Snell (1960) applied the quantitative systems for the classification of the landforms. However, Linton (1951) and Hammond (1954 and 1965) gave techniques for mapping delineating small scale and large-scale landforms.

6.1 Introduction

When rainfall strikes a ground surface, some losses like initial and infiltration will occur. After these losses are fulfilled, runoff will begin. The runoff will ultimately reach a stream. The main routes through which runoff flows are (i) overland flow, (ii) interflow and (iii) groundwater flow. Overland flow which is also called as surface flow flows over the land mass and reaches a stream. Overland flow soon reaches a stream and if it occurs in sufficient quantity, it forms an important element in the formation of flood peaks. In small and moderate storms, there may have predominant initial and infiltration losses resulting minimum amount of surface runoff and this is especially true in case of permeable soils. If the soil is impermeable, then there may have reasonable runoff. However, surface runoff is an important factor in streamflow only for heavy or high intensity rainfall.

Water is a social requirement. Society now become aware about it’s dependence upon water and hence realized the importance of water in sustaining not only the development but also life. Water: too little, too much, too dirty; is general scenario in the world. But with increase in population water become limiting resource and is becoming scarcer and scarcer day by day. As water become scarcer commodity, the users (stakeholders) become more conscious regarding their share in water and ultimately this situation may lead to water conflicts. Earlier water related problems were generally tackled by hydro-engineers, but now in present climate changed scenario these problems go beyond the hydraulics and hydrology. Now a days politicians, ecologists, Non Government Organizations (NGOs), the media and the stakeholders etc are playing a crucial role in decision making in respect to water management issues. Now water projects are designed in reference to social context (Social context means cultural, economic, political, sociological, legal and other such aspects). When social factors are taken into consideration while tackling the water problems, it could not possible to satisfy all involved. Thus it is required to agree upon a compromise solution acceptable to all. Over recent few decades, information and communication technology (ICT) flourishes with great advances. It provides the ways to search for compromise solutions. In this chapter information, hydroinformatics, evolution of hydroinformatics and role of internet in hydroinformatics are discussed.

In this era of computer, mathematical models become integral part of hydrologic studies due to advancement in soft technology. But question always arises as ‘Why should modeling?’ It was well expressed by Rosenblueth and Wiener (1945) as

No substantial part of the universe is so simple that it can be grasped and controlled without abstraction. Abstraction consists in replacing the parts of the universe under consideration by a model of similar but simpler structure. Models, formal or intellectual on the one hand, or material on the other are thus a central necessity of scientific procedure.

Hydrological cycle involves four major steps, Viz., Evaporation, Transpiration, Condensation and Precipitation. Though the cycle has neither a beginning nor an end, the concept of cycle begins with the water of oceans, since it occur nearly ¾ of the Earth’s surface. Radiation from the Sun, evaporates water as water vapour from the oceans into the atmosphere. The water vapour rises and collects to form clouds. Under certain condition, the cloud moisture condenses and falls back to the Earth as rain, snow, hail etc. Precipitation reaching the Earth surface may be intercepted by vegetation or enter into the soil, may flow as run-off or may evaporate.

Evaporation may be from the surface of the ground or from free water surface. Transpiration may be from plants.

Condensation: The physical process by which a vapour becomes a liquid or solid – opposite of evaporation.

Water is the most important natural resource that governs and exercises control on living organisms on earth besides supporting all human activities. The demand for water is almost increasing at exponential rate due to increase in population and industrialization. All sectors of agriculture including crop production, horticulture, animal husbandry, poultry and fi sheries primarily depend upon water. Water scarcity can cause all kinds of miseries. The water exists in all 3 different forms on earth. It exists as snow or ice in glaciers and ice caps, liquid water in rivers, lakes, streams, tanks, ponds and as groundwater storage. The water exists in all three different forms in the atmosphere. The clouds may contain fi ne ice particles, tiny water droplets and as well as water vapour. The air in atmosphere also contains water vapour. It is estimated that 97% of water is salt water and remaining 3% of water is pure and fresh water. Approximately two-thirds of the fresh water is trapped in glaciers and ice caps. Most of the fresh water (30%) exists as groundwater. About 0.7% of fresh water exists as soil water and 0.3% a fresh water accounts for surface water resources and water present in the atmosphere as water vapour, water drops and ice particles. The circulation of water between oceans, earth and atmosphere forms hydrologic cycle.
2.1. Hydrological Cycle
The hydrological cycle explains the continuous recirculation and transport of water between the atmosphere, oceans and earth. It is a very complex system that has many sub cycles associated with it. For example, the water from earth surface, oceans and water bodies get evaporated due to heat energy received from the sun in the form of incident solar radiation (Fig.2.1).

Water is fundamental to life, supporting ecosystems, driving economies, and sustaining human well-being. However, the availability of this essential resource is increasingly threatened by hydrological drought, a complex phenomenon characterized by prolonged deficits in surface and subsurface water supplies. Unlike meteorological drought, which is defined by precipitation shortages, hydrological drought manifests as reduced stream flow, diminished lake and reservoir levels, and depleted groundwater, impacting water availability long after the rains have ceased. This chapter looks into the critical aspects of hydrological drought management, exploring the multifaceted nature of this challenge and outlining strategies to mitigate its devastating consequences. We will navigate the intricate web of factors that contribute to hydrological drought, from climatic drivers to the profound influence of human activities. Understanding these causes is paramount to developing effective management approaches.

Groundwater exists at many places beneath the surface of the earth. It is normally hidden from view but, on occasion, can be seen flowing from springs and wells or seeping into tunnels. Certain properties of the various geologic materials control the ability of groundwater to enter into, move through, be stored in, or be extracted from the ground. Therefore, an understanding of geology is necessary in order to gain an understanding of groundwater found within a particular area of investigation. A basic part of the study of the geology of an area includes the preparation of a map showing surfacial exposures of each rock type. Interpretation of the map facilitates the study of the underground configuration, characteristics, and physical properties of these materials. This, in turn, enables the evaluation of groundwater storage, movement, and yield, as well as the identification of areas of ground water quality problems, recharge, and extraction.

The fundamental unit of a geologic study is the geologic formation. A formation has been defined as any assemblage of rocks, which have some character in common, whether of origin, age, or composition. In this sense, the term “rock” is defined as any naturally occurring part of the earth’s crust, made up of aggregate of minerals and includes hard, dense granite, lava ash, clay, sand, and even loose-uncohesive soil.

Q. 1 The Lysimeter is used to determine
(A) Sun shine hours   (B) Wind velocity
(C) Flow velocity        (D) Evapotranspiration

Technical Term                        Definition

Hydrology                               Hydrology is the science of water derived from Greek wordî hydro + logosî i.e., water + sciences and hance defined as the science which deals with occurrence, distribution and circulation of atmospheric water through unending Hydrologic cycle.

A disaster is sudden event that causes significant damage to the people, environment and the economy. Disasters are serious disruptions to the functioning of a community that exceed its capacity to cope up using its own resources. The disasters that result either due to excess water or severe water deficit are floods and droughts.
12.1. Floods
The flood is an overflowing of water onto land that is normally dry. Floods may occur due to
• Heavy rainfall
• Ocean waves
• Snow melting
The economic losses due to floods will be very high and nearly 68 per cent of the economic losses are attributed to floods only. During the year 2018, India suffered a loss of nearly 90,000 crores due to floods alone. There are several causes for occurrence of floods in India. The major causes are
• Severe cyclonic storms in coastal areas which produce continuous heavy rainfall for 3 to 4 days in succession
• Encroachment of flood plains with residential structures
• Inadequate strength of river banks when there is high flows of water in the rivers
• Unplanned growth of urban areas
• Silting of water storage structures due to increased soil erosion thereby decreasing the storage capacity of reservoirs
• Simultaneous flooding of rivers and tributaries due to excessive water flows

Etiology

Group 1 adenovirus. First reported in Pakistan in 1987, where it caused a devastating effect on broiler industry. It has spread to all continents.

5.1 Introduction

Hydroponics is a method of growing plants in a nutrient solution rather than in soil. Terrestrial plants may be grown with only their roots exposed to the nutritious liquid.

Traditionally, the soil supports the crop’s roots by helping them remain upright and ensuring the delivery of water and essential nutrients. In hydroponics farming, crops are supported by an inert medium such as perlite, gravel, or other substrates. Therefore, the nutrients are supplied by using various practices that bring mineral nutrient solutions to the crops. In the present situation there excessive use of chemical fertilizers, affecting fertility of soil is badly affected. The fertility of the soil is falling that affects the plants growth but in hydroponics, the plant remains unaffected. Plants grow faster than in soil. Produce better quality of plants and higher yields. It use less water. It is possible to use hydroponics on outdoor crops, but most of the hydroponics production is in greenhouse. Hydroponic farming system has the potential to reduce the problem associated with traditional crop production. Therefore, it could serve to be a turning point in feeding the global population. The greenhouse and its environment control system are the same whether plants are grown conventionally or with hydroponics. The difference comes from the support system and the method of supplying water and nutrients.

The hydroponic farming has been successfully demonstrated by the commercial growers for fast-growing crops such as tomatoes, cucumbers, spinaches, lettuce, radishes, strawberries, bens, spring onions, coriander, and ornamentals. Indeed, hydroponics technology enables a more precise control of micro climatic conditions. In this technique, the vigorous development of a root system is taking place, which enable the uptake of essential nutrients from nutrient solution for better crop yield. The initial investment in hydroponics farming is high and required constant energy input. Owing to this, hydroponics farming is recommended for growing high value crops in developed countries such as the United States, Canada, Europe and Japan.

Introduction

The Greek terms hydro, which means water and ponos, which means labor are the roots of the word hydroponics, which literally means water work. Maharana and Koul (2011) defined hydroponics as a technique of growing plants in soil less conditions with their roots immersed in a nutrient solution. According to Savaas (2017), hydroponics can be briefly defined as the cultivation of plants without soil. So, it is clear that in hydroponics, plants are grown without soil, and they get nutrients from nutrient solutions added to water.

Introduction

Instead of using soil, the unique technique of hydroponics grows plants in a nutrient-rich water solution. Using a tightly controlled environment, gardeners may optimise factors including sunlight, pH balance, and nutrient levels to maximise plant development in this agricultural approach. Hydroponics allows plants to grow more quickly and produce more by delivering nutrients straight to their roots. Water efficiency, less soil-borne disease risk, and the capacity to grow crops in non-arable or urban areas are just a few of the benefits of this technology. More and more people are turning to hydroponics as a means to grow their own food in a more regulated and efficient manner, all while reducing their impact on the environment.

Hydroponics is a subset of hydroculture and is a method of growing plants using mineralnutrient solutions, in water, without soil. Terrestrial plants may be grown withtheir roots in the mineralnutrient solution only or in an inert medium, suchas perlite, gravel,mineral wool, expanded claypebbles or coconut husk

The techniques on hydroponics are widely used in plant sciences to elucidate several problemson nutrition. Primarily, this has been not only used to evaluate deficiency symptoms of an essential element but also used to assess waters stress effects in crop plants. There has been a considerable controversy whether such responses paralled with field responses. Though these techniques have their limitations, it is certain that it has its relevance in identifying certain genotypes relatively tolerant to some stresses such as water, O₂ and nutrition. Without entering to such debatable issue, it can be said thatwherenecessity demands, such techniques would proveuseful in demonstration purposes and evaluation of macronutrient deficiencies in tomato and maize. Thegrowing of plants in nutrient solution is called as water culture or hydroponics. These experiments in nutrient solutions are carried out to study the mineral nutrient relation of plants. By elements required for plant growth, specific deficiency symptoms can be produced in water culture experiments. Thesuccess of these experiments of producing deficiency symptoms depends upon the use of homogenous biological material and purity of culture solution in respect of different plant nutrients. Hydroponics is a subset of soilless culture. Many types of soilless culture do not use the mineral nutrient solutions required for hydroponics.

Plants that are not traditionally grown in a climate would be possible to grow usinga controlled environment systemlike hydroponics. NASA has also looked to utilize hydroponics in the space program. Ray Wheeler, plant physiologist at Kennedy Space Center’s Space Life Science Lab, believes thathydroponics will create advances within space travel. He terms this as a bioregenerative life support system.

Every research in agriculture aims at developing a promising new technology or refines an age old technology that can help addressing the improvement in crop yield. This is a worldwide scenario to meet up with the food needs of the growing population and reducing agricultural land resources. Many traditions in the world are associated with vast knowledge of cultivating the food crops, vegetables, fruits etc using selected methods that are modified based on the needs, climatic conditions and the resources available in the place of settlements. Soil based agriculture is the most popular method of growing plants since soil is considered as the main source of nutrients and water required for the healthy growth of crops. Generally it includes 3 major steps, ploughing, sowing and harvesting.

Introduction
A sustainable and effective replacement for conventional soil-based farming, hydroponics technology signifies a paradigm shift in agricultural techniques. Instead of using soil to develop their plants, hydroponic systems submerge their roots in a nutrient-rich water solution or provide it to them on a constant basis. This technique allows for maximum nutrient uptake and faster development by giving plants all the vital elements they require for growth. Hydroponics has many different and extensive uses in horticulture. Leafy greens like lettuce, spinach, and kale as well as vine crops like tomatoes, cucumbers, and peppers are among the many crops that are grown there.
Furthermore, strawberries, herbs, and even decorative plants like flowers grow beautifully in hydroponic systems. One of the key advantages of hydroponics is its ability to maximize resource efficiency. By delivering nutrients directly to the plants’ roots, hydroponic systems minimize nutrient wastage and water consumption compared to traditional soil-based agriculture. Because of this, hydroponics is especially appropriate for areas with limited arable land or water resources. Hydroponics’ adaptability to climate and location is yet another important benefit. No matter the outside weather, hydroponic systems can be installed indoors, in greenhouses, or even in urban settings to allow for yearround growing. This enables farmers to raise crop yields, lengthen growing seasons, and maintain steady levels of quality and output all year round.

Agriculture nowadays is facing a complex problem. It’s the rate at which we are turning arable land into non-arable. To solve this problem, we cannot simply stop farming and wait for the Earth to return to its natural state. Hence, alternative farming methods have become increasingly popular in recent years. Hydroponics is one of these options that can help produce crops without soil and other resources needed for crops to grow.

2.1 Definitions

Hydroponics is the term for growing plants without soil and in a water-based solution, the roots may be physically supported by an inert medium such as perlite, gravel, or other substrates. While it can be used to grow all kinds of crops, hydroponics is particularly effective for growing leafy vegetables, herbs and salad greens that have high water requirements, as well as for growing plants that have very shallow root systems. 

Hydroponics is a technique of growing plants using mineral nutrient solutions with or without the use of an inert medium such as gravel, soil, vermiculite, rock wool, peat moss, saw dust, coir dust and coconut fibre-provide mechanical support. The term Hydroponics was derived from the Greek words ‘hydro’ means water and ‘ponos’ means labour and means water work. The word hydroponics was coined by Professor William Gericke in the early 1930s; describe the growing of plants with their roots suspended in water containing mineral nutrients. Researchers at Purdue University developed the nutriculture system in 1940. During 1960s and 70s, commercial hydroponics farms were developed in Arizona, Abu Dhabi, Belgium, California, Denmark, German, Holland, Iran, Italy, Japan, Russian Federation and other countries.

Safe, wholesome and nutritious food is vital for sustenance, good health, food and nutritional security and augmentation of sustainable development of an individual. Also, safe food helps in the growth of the national economy and enhances the trade and tourism sector. Foods that are unsafe containing various kinds of microorganisms can cause chronic diseases or illnesses varying from diarrhea to cancer.

Indicator bacteria are types of bacteria that are used to provide an indication of poor hygiene, inadequate processing and or post - process contamination in seafood, water, feed, ice, equipments, workers, etc. Absence of indicator bacteria in seafood and aquaculture products provides a degree of quality assurance that the fishery products are hygienically good and have employed proper processing methods whereas their presence clearly indicates either severe problem or failure occurred during the processing, under-processing or post-process contamination. The indicator bacteria in fish and fishery products are mainly from enterobacteriaceae and coliforms group of bacteria. Traditionally, indicator micro-organisms have been used to suggest the presence of pathogens (Berg, 1978) and it includes the general microbial Process indicators, Faecal indicators, and Index and Model indicator organisms. The Process indicator is a group of organisms that indicates the efficacy of a processing and tested by Total Plate count (TPC)/ Total heterophilic count or total coliforms (MPN method). Fecal indicator is a group of organisms that indicates the presence of fecal contamination and could be tested for fecal coliforms, thermotolerant coliforms (MPN method) and E.coli (EMB and IMViC test). Index and model organisms are a group of organisms that indicates the presence of pathogens such as E.coli are an index for Salmonella and coliphages as model of human enteric viruses. The pathogenic indicator bacteria viz., Coliforms, Fecal coliforms, E.coli, Klebsiella, Enterobacter, Citrobacter, Fecal Streptococci, Sulphite reducing clostridia, Clostridium perfringens, Bifidobacteria, Bacteriophages, coliphages and Bacteroides fragilis etc., are associated with food poisoning. In addition, pathogenic viruses, protozoa and parasites are also present in fecal matter. Fecal contamination is mainly from sewage of human source, livestock, poultry manure, pets and wildlife. Infection caused by these pathogens mainly depend on the level of microbial load.

Poultry hatchery is a place where the hatching egg is transformed into a one day old chick, during 21 days. The environment of a poultry hatchery is very susceptible to contamination by microorganisms which can adversely affect hatchability of the eggs and can result in embryonic deaths. E. coli, Staphylococcus species, Streptococcus species, Aspergillus fumigates and Pseudomonas species are mainly isolated from hatchery and it adversely affects chick quality and cause embryonic deaths. Poor standards of hatchery hygiene may lead ultimately to an explosion of pathogenic organisms resulting in severe economic loss.

Dairy equipment and utensils with which milk and milk products come into contact are the main sources of contamination in the products. By the use of effective equipment cleaning and sterilization methods on routine basis, milk of high bacteriological quality can be consistently produced. In composite milk plant, a variety of equipment and utensils are used. The use of stainless steel for the fabrication of dairy utensils and equipment provide highly polished and hard smooth surface that can be cleaned readily, apart from showing resistance to corrosive action of detergents and bactericidal solutions. Utmost care is taken to avoid dents and scratches, which could be the possible focal points of subsequent contamination. To overcome all these problems aluminium and stainless steel vessels and equipment present an ideal situation.

Abstracts

To ensure safe food and adequate sanitation programs, the equipment used for processing of food products must be designed, fabricated, constructed, and installed according to sound hygienic design principles. This ensures the equipment can be adequately cleaned and sanitized, and that surfaces are resistant to daily exposure to corrosive food products and cleaning/sanitizing chemicals. This chapter focuses primarily on fundamental principles of hygienic design, which protect the product from microbial, chemical, and foreign-body contamination. This is followed by a discussion of general aspects of hygienic construction and design of food equipments, the selection of materials of construction and specification of surface finishes, fabrication, installation and cleaning and sanitization. Quality of raw materials or foods ingredients, proper processing, packaging and storage of finished products decides the quality of the food products. Planning for plant and equipment layout, its design, services (water, air, refrigeration, steam), waste disposal etc. are some of the critical factors, which contributes to quality. In addition, the food processing equipment must comply with strict standards and regulations, which are necessary for securing the quality and safety of the food products to the consumers.

Fresh fish serves as a protein-rich food for people of all income groups. Dry fish is in greater demand when the availability of fresh fish in the market is low. Dry fish have a higher concentration of protein (in terms of weight) as compared to wet fish and are an inexpensive source of animal protein. Moreover, dry fish production provides employment opportunities to fishermen, fish farmers, rural youth, and women and also helps them to generate extra income. In addition, it also provides food and nutritional security to the rural, underprivileged population. Though dry fish enterprises have a significant role in improving the livelihood as well as the nutritional security of society, not much attention has been paid to the production and marketing of dry fish products.

The Concept of ‘Clean Milk’ Production

Although milk is nature’s most ideal and perfect single food both for the newborn and the mature human beings, the possibility of it being a source of biological and chemical hazards cannot be excluded. In view of the immense dietary importance of milk, the need for production of safe, clean and wholesome milk is emphasized. The term ‘clean milk’ does not mean milk in which all visible dirt is absent or milk from which it has been removed; rather it does denote raw milk from healthy animals, that has been produced and handled under hygienic conditions; that contains only small number of harmless bacteria and that possesses a good keeping quality without being treated by heat. In other words, the unhygienic production of milk may lead to inferior keeping quality as a result of rapid microbial multiplication under favourable storage conditions apart from serving as a potential health hazard. These microorganisms cause the milk to sour quickly, putrefy and develop undesirable flavours, colour defects, ropiness and bitterness. On the other hand, the pathogenic microorganisms, which may gain entry through various sources, may cause many diseases to the consumers.

The ruminoreticulum, part of the ruminant digestive system, plays a pivotal role in food processing, fermentation and nutrient absorption in animals such as cattle, buffaloes, sheep, goats, and deer. This compartmentalized stomach, comprising the rumen and reticulum, is critical for fermentative digestion, enabling ruminants to utilize fibrous plant materials. While its normal function is essential for health and productivity, hyperactivity of the ruminoreticulum can significantly impact an animal’s well-being, physiology, and economic value in agricultural contexts.
Structure and function of the ruminoreticulum
The ruminoreticulum is a fermentation chamber harbouring billions of microorganisms, including bacteria, protozoa, and fungi. It is designed to break down complex carbohydrates, such as cellulose and hemicellulose, into volatile fatty acids (VFAs), which provide a significant portion of a ruminant’s energy. The coordinated motility of the rumen and reticulum ensures proper mixing of ingested feed with saliva and microbes, enhancing fermentation efficiency.
Rhythmic contractions of the ruminoreticulum known as primary and secondary cycles, aid in mixing, stratification of digesta, and eructation of fermentation gases. When these contractions increase in frequency or intensity beyond physiological norms, it constitutes hyperactivity of the ruminoreticulum.

The immune system has been designed to provide protection to the body from various diseases. But the same system which is aimed to provide protection may sometimes become harmful to the body and may even life-threatening. There are situations when immune response against harmless and inert antigens is exaggerated and actually causes diseases. Such a condition is called hypersensitivity or commonly as allergy. Though the term ‘hypersensitivity’ indicates an increased response but the immune response is not always heightened, instead it may be an inappropriate response to an antigen.

The basic purpose of the immune system is to provide defense to the body from various types of infections. But, sometimes, the system which is aimed to provide protection become damaging or even life-threatening. There are situations when immune response against harmless and inert antigens is exaggerated and cause diseases.

Definition

Hypersensitivity is an altered reaction to a specific antigen that results in pathologic reactions upon the exposure of a sensitized host to that of specific antigen.

Explanation

Hypersensitivity reactions are inappropriate or misdirected responses to a specific antigen that result in harmful reactions upon exposure of a sensitized host to that specific antigen.

Affected animals require a sensitization phase in which the animal must have had either a previous exposure or a prolonged exposure to the antigen so that it can develop an immune response to the inciting antigen.

The harmful effects resulting from hypersensitivity reactions occur in the effector phase and are most commonly manifested through inflammation or cell lysis.

ABSTRACT

This paper reviews the various application of hyperspectral remote sensing data carried out by the scientists of India emphasizing its advantages.

1. INTRODUCTION

The most significant recent breakthrough in remote sensing has been the development of hyperspectral sensors. The ‘Hyper’ in hyperspectral means ‘too many’ and refers to the large number of measured wavelength bands. Hyperspectral images are spectrally over determined, which means that they provide ample spectral information to identify and distinguish spectrally unique materials. Hyperspectral imagery provides the potential for more accurate and detailed information, extraction than is possible with any other type of conventional remotely sensed data.

Imaging spectroscopy (Goetz et al., 1985) in hyperspectral imaging is concerned with the measurement, analysis, and interpretation of spectra acquired from a given scene (or specific object) at a short, medium or long distance by an airborne or satellite sensor. The concept of imaging spectroscopy originated in the 1980's, when A. F. H. Goetz and his colleagues at NASA's Jet Propulsion Laboratory began a revolution in remote sensing by developing new instruments such as the Airborne Imaging Spectrometer (AIS), then called AVIRIS, for Airborne Visible Infra-Red Imaging Spectrometer (Green et al., 1998). This system is now able to cover the wavelength region from 0.4 to 2.5 μm using more than two hundred spectral channels, at nominal spectral resolution of 10 nm. The special characteristics of hyperspectral datasets pose different processing problems, which must be necessarily tackled under specific mathematical formalisms, such as classification and segmentation (Jia et al., 1999, Green, R 1998) and spectral mixture analysis (Adams et al., 1986; Smith et al., 1990a, b).