Determination of the concentration of ammonia that could have lethal effect on fish pond

Joel Ogbonna F. and Amajuoy Chinomso A.

A local fish farmer experienced high mortality rate of fishes from his fish pond located in a city of Port Harcourt, Nigeria. In order to ascertain the cause of the death of these fishes, some selected physicochemical and microbiological parameters were used to determine the concentration which resulted in lethal effect on the fishes. Test results indicated that among the parameters determined, the concentration of ammonia in both the storage tank and aquarium exceeded the maximum limit of 0.2mg/l for aquatic life. The ammonia concentrations from test results ranged from 0.25mg/l to 0.50mg/l. The sample with 0.50mg/l also indicated the highest level of total coliform of 3.52 x 10³(cfu/100ml) as against the sample with 0.25mg/l with Total Coliform of 0.0 (cfu/100ml). Moreover, higher values of pH (7.45), TDS (104mg/l), Electrical conductivity (208µScm^-1), Chloride (75.76mg/l), Nitrate (2.00mg/l), Calcium (0.94mg/l) respectively were seen in the sample with the highest level of ammonia (0.5mg/l). The death of the fishes was more evident with the sample having 0.5mg/l, followed by the sample with 0.35mg/l of ammonia.  Test result therefore confirms that ammonia concentration of above 0.20mg/l in fish ponds has a tendency to harm the fishes.

Effect of non-standard curing methods on the compressive strength of laterized concrete

Felix F. Udoeyo, Robert Brooks, Christopher Utam, Philip Udo-Inyang and Eno C. Ukpong

Thirty concrete mixes of differing water-binder ratio containing 0, 10, 20, 30, 40 and 50 % laterite as a partial replacement for sand were used to prepare laterized concrete specimens for the study of the effect of nonstandard curing methods on the strength of specimen. The effectiveness of a curing method was measured quantitatively as the ratio of the compressive strength of specimen cured using the non-standard method to those cursed using the standard water-curing method specified in the BS1881: Part 3:1970 (control). The results of the investigation show that with continuous wetting of the nonstandard curing media by sprinkling with water, the strength of the concrete obtained could be comparable to those cured using the control method. Of the four nonstandard curing methods considered in the study it was observed that the strength of sand- and sawdust-cured specimen were in some instances the same as or higher than those of the standard cured specimens at early age (7days). Although at later age (28 days) there were significant differences between the strength of specimens cured using the nonstandard methods and those of corresponding laterite content and water-binder ratio cured using the control method as established by t-test, the designed strength of 20 MPa was attained by all specimens cured using the nonstandard methods, which is indicative that these nonstandard methods could be used as alternative to the standard water curing, especially in situations where much water may not be available for curing specimens.

Active control of the flow behind a backward facing step by a periodic perturbation

Zouhaier Mehrez, Mourad Bouterra, Afif El Cafsi, Ali Belghith and Patrick Le Quere

In this paper the active control of the turbulent separated and reattaching flow over a backward facing step is studied numerically by the Large Eddy Simulation (LES) method. The objective of the control consists to modify the separation phenomenon of the fluid in the edge of the step by application a periodic perturbation. The perturbation is realized by zero-net alternative suction and blowing of the fluid in the step edge into a separated shear layer. The found results showed the reduction of the reattachment length and enhancement of the shedding vortical frequency by the applied periodic perturbation. Also, the existence of an optimum frequency, Stp = 0.25, in term of promotion of reattachment and the increase of shedding vortical frequency. At this perturbation frequency an important modification of the dynamic of the flow is observed. The modifications observed at the optimum frequency are noticeable as the perturbation amplitude increases.

Average and instantaneous fuel consumption of Iranian conventional tractor with moldboard plow in tillage

H. Fathollahzadeh, H. Mobli, A. Rajabipour, S. Minaee, A. Jafari and S.M.H. Tabatabaie

John Deere 3140 tractors work powerful and useful in Iran farmlands now. In this study two flow meter sensors were used for measuring tractor fuel consumption and the measurement system was installed on diesel engine of a 72.3KW John Deer 3140. A three-share moldboard plow was used for studying the effect of plow depth variations on tractor fuel consumption. Results showed that the tractor with the moldboard plow attached and operating at depths of 0.15, 0.25 and 0.35 m consumes 27.446, 30.096 and 34.06 liters of fuel per hectare, respectively. Increasing plow depth from 0.15 to 0.25 and 0.15 to 0.35 m increases fuel consumption by 9.66 and 24.1%, respectively. The average fuel consumption is 30 L/ha in the common plow depth of 0.2 to 0.25 m which is close to results reported from other parts of the world. Instantaneous fuel consumption during operation of moldboard plow at three depths shows increase of instantaneous fuel consumption when working depth increases. In the farm experiments, only working depth of plow was changed but variations in time-consumption diagram showed that there were other factors affecting draft and thereby fuel consumption during operation.

Fuzzy transportation problem with additional restrictions

Debashis Dutta and A. Satyanarayana Murthy

Abstract:

This paper deals with the transportation problem with additional impurity restrictions where costs are not deterministic numbers but imprecise ones. Here, the elements of the cost matrix are subnormal fuzzy intervals with strictly increasing linear membership functions. By the Max-Min criterion suggested by Bellman and Zadeh, the fuzzy transportation problem can be treated as a mixed integer nonlinear programming problem. We show that this problem can be simplified into a linear fractional programming problem. This fractional programming problem is solved by the method given by Kanti Swarup.

Investigations and study on the effect of AR glass polymer fibres in self-compacting self-curing concrete

S. U. Kannan, Selvamony C., M. S. Ravikumar and S. Basil Gnanappa

Abstract:

This experimental study is exposing the relationship between permeability and compression strength of AR Glass fiber-reinforced concrete. In addition, it inspects the influence of AR Glass fiber reinforcement on concrete permeability. The AR Glass fibers decrease permeability of specimens with increased volume of fibres. Here an attempt is made to study the permeability of super plasticised concrete with different types of fibres. The fibres are added at the percentages varying from 0.2% to 1.0% by weight of cement at intervals of 0.20%. To maintain a good workability, superplasticiser is added at the dosages of 0.8% by weight of cement. The dosage is arrived considering the workability and strength on simultaneous reduction of cement and water content ranging from 5% to 20% of the reference concrete. The experiment was conducted in a six cell permeability cell at the pressure of 10 kg/cm² for 100 hours. Water permeability test is conducted as per IS: 3085-1987 and it is found that on addition of fibres, the co-efficient of permeability of concrete is reduced considerably.

Selecting proper connection points for y-capacitor to reduce EMI in SMPS

Milind M. Jha, Kunj Behari Naik and Shyama P. Das

Y-capacitors are used to reduce EMI in SMPS. This is a capacitor connected between primary and secondary of the SMPS transformer to bypass EMI currents and thus preventing them to reach mains port. Proper connections points for this capacitor are discussed and experimental results are analyzed to verify their effectiveness.

Emission and performance characteristics of Karanja biodiesel and its blends in a C.I. engine and its economics

Nagarhalli M. V., Nandedkar V. M.  and Mohite K. C.

Abstract:

In the present investigation experimental work has been carried out to analyze the emission and performance characteristics of a single cylinder 3.67 kW, compression ignition engine fuelled with mineral diesel and diesel-biodiesel blends at an injection pressure of 200 bar. The performance parameters evaluated were break thermal efficiency, break specific energy consumption (BSEC) and the emissions measured were carbon monoxide (CO), carbon dioxide (CO₂), hydrocarbon (HC), and oxides of nitrogen (NOx). The results of experimental investigation with biodiesel blends were compared with that of baseline diesel. The results indicate that the CO emissions were slightly higher, HC emissions decreased from 12.8% for B20 and 2.85% for B40, NOx emissions decreased up to 39% for B20 and 28% for B40. The efficiency decreased slightly for blends in comparison with diesel. The BSEC was slightly more for B20 and B40. From the investigation it can be concluded that biodiesel can be used as an alternative to diesel in a compression ignition engine without any engine modifications.

Effects on major power quality issues due to incoming induction generators in power system

K. S. Sandhu and Sudhir Sharma

Abstract:

This paper presents a laboratory study on the effects of integration of induction generators on grid power quality parameters such as voltage, frequency power factor, harmonics and reactive power. Study is carried out with different switching sequence of grid connected induction generators. The analysis is done with two squirrel cage induction generators and one wound rotor induction generator coupled to DC shunt motors. Experimental results as obtained with different switching sequence are found to be very interesting and useful for final recommendations.

Improving the environmental cooling for air-coolers by using the indirect- cooling method

Farhan A. Khmamas

Abstract:

Air-coolers are widely used as a cheap and convenient method for cooling; however, noise, humidity, smoking, and difficulty in controlling the interior temperature are its major disadvantages. In this research, we suggest using the indirect evaporative cooling method instead of the direct method. In this method the air-cooler is modified to operate as a cooling tower to produce cooling water by the evaporation process; this represents the outdoor unit. The cooled water is pumped to the indoor unit which consists of a fan coil unit. Many experiments were carried out to calculate the evaporation cooling effectiveness (ECE) in case of the direct and indirect cooling (forced or natural). The results for the two cases were compared. It is concluded that the ECE reduces by 15% for forced evaporation case, and by 22% for the natural case, as compared with the direct case and (with in 30/5/2008 and 16/6/2008).

Quintic B-splines Galerkin method for fifth order boundary value problems

K. N. S. Kasi Wiswanadham and P. Murali Krishna

Abstract:

A finite element method involving Galerkin method with quintic B-splines as basis functions has been developed to solve fifth order special case boundary value problems. The basis functions are redefined into a new set of basis functions which vanish on the boundary where the Dirichlet types of boundary conditions are prescribed. The method is tested for solving both linear and non-linear boundary value problems and is compared with the methods available in literature.

Cuette flow of two immiscible fluids between two permeable beds

T. V. A. P. Sastry, M. Venkata Krishna, S. Sreenadh and M. V. Ramanamurthy

Abstract:

Couette flow of two viscous, incompressible, immiscible fluids in a channel bounded by permeable beds is investigated. The lower bed is of finite thickness with high permeability and the upper bed is of infinite thickness with low permeability. The flow in the lower permeable bed is described by Brinkman equation whereas the flow in the upper permeable bed is described by Darcy’s law. The flow between the two beds is governed by Navier-Stokes equations. The velocity field and the mass flow rate are obtained. It is observed that the velocity is in increasing trend with the increment in the Reynolds number.