70 research outputs found
Thermodynamic Analysis of a Gas Turbine Power Plant Modelled with an Evaporative Cooler
Performance of a gas turbine is mainly depends on the inlet air temperature. The power output of a
gas turbine depends on the flow of mass through it. Inlet air cooling increases the power output by
taking advantage of the gas turbine’s feature of higher mass flow rate when the compressor inlet
temperature decreases. This is precisely the reason why on hot days, when air is less dense, power
output falls off. A rise of 1°C temperature of inlet air decreases the power output by 1%. In this paper
the performance enhancement of gas turbine power plants by cooling the compressor intake air with
an evaporative cooler is studied. This study investigated the effect of inlet air cooling system on the
performance of an existing gas turbine power plant in Nigeria. The results show that for each 5oC
decrease of inlet air temperature, net output power increases around 5-10% and the first and second
law efficiencies increase around 2-5%. It is shown that the amount of this increase is higher when the
pressure ratio is high and turbine inlet temperature is low. The results of this study shows that
retrofitting of the existing gas turbine plant with inlet air cooling system gives a better system
performance and may prove to be an attractive investment opportunity to the Nigeria government and
stakeholders of the plant
Occupational mobility in engineering profession (craftman and artisan) in Oyo State, Nigeria.
This paper evaluate occupational mobility in engineering professional in Oyo State of Nigeria with the goal
assessing causes and readiness of the professionals to return to the profession when the hindering factors
are removed as well as sufficiency of the survey instrument in addressing the research problems. The
study was conducted using a well structured questionnaire administered in 20 local government of Oyo
State, Nigeria representing the sample space of 0.424. The Cronbach’s alpha of the reliability test of 0.453
was returned for the scale mean statistics of 11516.83 and variance of 0.0000007 showing that the survey
instrument was sufficient and could be relied upon. The result of the socio economic analysis showed that
80% of the respondents were married while (15%) were single and the rest (5%) were divorced. The age
distribution of the respondents ranged between greater than 50 years groups (12%) and 30 -39 years
group (39%).The result of the analysis of job characteristics of the respondents showed that the longer the
year of graduation, the lesser the number of graduates still in the business. The cross table analysis of the
socio-economic indices with the job status of the respondents showed that marital status and level of
education does not have significant effects on the job status of the respondents (whether still practicing or
not) because 1.454 and 5.223 returned for both marital status and level of education are not significant
(P<0.05). Also, the contingency table analysis of the effects of the skill acquisition methods showed that
more of the respondents who acquired their skill via Technical School (70%) are willing to go back to the
professions. However, for those who acquired their skill through Learning/artisanship, less than average
(32%) of the respondents are ready to return to the profession. Lastly, the establishment of the regression
model for the relationship between the proportion of the people wishing to go back to the profession and
year of practicing the profession provide a necessary impetus for addressing the Job mobility problem
faced by the profession
Turbidity and Urine Turbidity: A Mini Review
Turbidity, the measurement for impurity and the opposite phenomenon of
clarity, is described as the reduced transparency of a liquid caused by the
existence of undissolved matter in the form of suspended particles. The
permissible volume of light through the liquid, or light that is not dispersed or
absorbed but emitted through the liquid and propagated toward the observer,
provides a foundation for the analysis of various subject matters, such as
liquid mass concentration and impurity identification. The turbidity of urine is
increased by the presence of cellular debris, cast, and, in some cases, crystal
and other debris in the urine. Blood (both red and white blood cells),
hemoglobin, cholesterol, albumin, leukocyte esterase, nitrites, ketones,
bilirubin, and urobilinogen are all substances that are not expected to be
found in urine, the presence of which can increase urine turbidity. Owing to
the principle of turbidimetry, it is not the detection of turbidity that is the
cause of the turbid state of urine but the presence of suspended particles and
a rough estimate of the number of suspended particles in urine. This research
exposes the different methods of obtaining the turbidity of a liquid sample
and the working principles of turbidimetry and nephelometry
Smart Toilets and Toilet Gadgets in Sustainable Smart Cities: An Overview of Personal Health Monitoring
Healthcare as a service in most developed countries has advanced more than
just electronic medical records (EMR), automated hospital experience, hospital
information systems, and the like of it. Healthcare services have attained the
height of remote surgery, computer-aided surgery, and remote patient
monitoring and care due to the advancements in information and
communication technology coupled with the advancement in artificial
intelligence (AI) ability on the Internet of things. The use of smart gadgets in
the toilet capable of collecting data relevant to healthcare makes the gadget a
personal health monitoring device, which is a medical care supplement to
traditional health monitoring. This provides an effective, non-invasive, nondestructive,
low-cost, accuracy, and timesaving method of conducting health
monitoring on the user in real time
Modification to Metal Matrix Composites Nomenclature
Naming Metal matrix composite (MMC) is very crucial to both the developer and
the end users. It is an indication of what the developer put together which goes a
long way in assisting the end user in selecting from myriad of available MMCs.
The existing nomenclature put forward by Aluminium Association identified the
matrix, reinforcement, percentage composition and the form of reinforcement but
left out the particle size of the reinforcement. The particle sizes have been found
to have significant effect on the properties of MMC and should be included in the
adopted naming system. This paper revised the existing standard from
‘Matrix/reinforcement/volume%form
Performance Evaluation of a Centrifugal Pump with different Impeller Materials
Many factors affect the performance characteristics of a pump. One of
these is the impeller material. This paper is on the effect of impeller material on the
operating characteristics of a centrifugal pump. The impeller materials used were
cast iron, bronze and zinc. Cost, pumping efficiency, pressure head and power
consumption are the factors that were taken into consideration. The results from the
test, showed that the impeller made of zinc material was found to be more efficient
(48.24%) and required the most power (3.38bhp). The zinc impeller was the least
expensive to manufacture and pumped better head. The zinc impeller however failed
at (very) high pump speed due to the fact that its strength could not match up with
the pump speed. The cast iron impeller on the other hand, required the least power
(0.86bhp) to run but pumped the least head (6.25m) and was more efficient (46.35%)
than the bronze impeller; this was majorly due to cavitation and friction losses. The
bronze impeller pump was the least efficient (38.79%), the most expensive to
manufacture but pumped more head (8.50m) than the cast iron impeller and required
more power (2.32bhp) than the cast iron impeller
SOME PHYSICAL PROPERTIES OF SELECTED VEGETABLE
Physical attributes of biomaterial are needed as parameter in computer simulation of
deformation of Agricultural and Food material under compressive loading using Discrete
Element method. In this study, two vegetable namely chilli pepper (Capsicum frutescens)
and bell pepper (Capsicum annum) were selected and some physical properties (mass,
major diameter, intermediate diameter, minor diameter, and volume) at 10.88% w.b and
9.79% w.b moisture content were determined using standard methods. The results of the
study show that the frequency distributions of each of the size of the two pepper varieties
follow a normal distribution curve. The average geometric mean diameter and sphericity
of bell pepper are 43.94mm and 64.23%while that of chilli pepper are 25.55mm and 86%
respectively The mean mass, volume, true density and bulk density for bell pepper were
29.91g, 27.75cm3, 1.117gcm-3 and 0.52gcm-3 while that of chilli pepper were 8.4g,
8.23cm3, 0.90gcm-3 and 0.41 gcm-3 respectively. These data are useful in the design and
development of handling and processing machine
DESIGN AND PERFORMANCE ANALYSIS OF A MODEL PICO SIZE PELTON WHEEL TURBINE
A hydropower generation is an ancient but evergreen energy source that utilises mechanical energy of water strolling down from an elevated head to drive an electric generator thus producing electricity. Small Hydropower (SMH) turbines are rotated by a relatively low-pressure head and usually generates low energy output usually referred to as mini, micro or Pico energy range. Pelton Turbines are generally found to be amongst the most suitable for a low flow power generation. This study focuses on the design of a model Pico size Pelton Wheel modified to use the velocity of water harvested from rooftops during rainfall for the purpose of supplementing energy supply. By the design, the rainwater from the building rooflines are collected and passed through the downspouts into an elevated tank and then the height of the bottom of the tank gives the required head (pressure) to spin the microturbine and then generates a Pico level energy. The Pico size hydropower system directly connected to a small, variable speed, an electric generator which is capable of supplying the power needed for some minimal but very essential functions like charging handsets, mini gadgets and low energy lighting purposes. Specific design calculations, as well as analysis of the model Pico size energy system, was performed to ascertain the feasibility of the design meeting some specified energy needs, thus reducing energy poverty
Anticorrosion Effect of Silicon Nitride and Zirconium Diboride Composite on Ni–P– Zn Electroless Deposition on Mild Steel
Electroless nicked-based deposition on mild steel surface from a nickel–zinc
phosphate bath with NiSO4·6H2O, ZnSO4·7H2O, and NaH2PO2·H2O salt in the
presence of silicon nitrides and zirconium diboride as additives at a constant
time was studied. The structural evolution of electroless deposited mild steel
surface was characterized for crystal change formation using a scanning
electron microscope (SEM) and elemental quantification done using energydispersive
spectroscopy (EDS). The electrochemical corrosion analysis of the
deposited mild steel with and without composite additives was analyzed using
linear polarization resistance and open circuit potential in both H2SO4 and
NaCl solution. From the results, significant presence and the effect of wt% of
additives were noticeable on the electroless mild steel surface. Ni–P–Zn in the
presence of 10ZrBr2 and 10Si3N4 actively provide an induced weight gain of
0.0974 g and 0.0973 g, respectively. A correspondent, 0.034 g/m2 coating per
unit area of zirconium diboride additives, was obtained against 0.030 g/m2 for
silicon nitrides. The structural evolution shows proper homogeneous crystal
formation and stable packed additive concentrated at the lattices with EDS showing the presence of induced peak. From the corrosion assessment result,
electroless deposited mild steel with Ni–P–Zn–10ZrBr2 and Ni–P–Zn–
10Si3N4 with optimum particle concentration shows better corrosion resistance
performance with a corrosion rate of 0.5048 mm/year, and 5.1347 mm/year, as
against the unadditive deposition with 11.393 mm/year in NaCl solution
Modelling some ergonomic parameters with machine parameter using hand powered maize sheller
The economic situation in most developing countries have left farmers and processors operating at the small scale, hence the use of automated and electric power driven equipment is limited to the few large scale processors. The effect of the ergonomic parameters namely; weight, age, height and arm length in relation to the resulting efficiencies; shelling efficiency, cleaning efficiency, mechanical damage and percentage sieve loss of a hand powered Maize Sheller incorporating a blower were studied using a non linear regression analysis. The study was with a view to developing a model for the performance of the hand powered maize sheller. The power transmission increases the speed of the blower for high cleaning efficiency. Preliminary studies were carried out to determine the ergonomic data of operator, and moisture content and grain/chaff. The results on studies with maize with 12% dry basis moisture content and grain/chaff ratio of 3.04:1 show that weight has the most significant effect (p<0.05). The mean of the shelling efficiency, cleaning efficiency, sieve loss and mechanical damage of the machine are 94.3, 96.4, 2.3 and 5.23% respectively and the coefficient of determination for the regression equations relating the ergonomic parameters to machine efficiency and parameters ranges from 0.29 to 0.86 with quadratic regression obtained. Equations were derived to relate the variables and an approximate solution was obtained from a particular example, which validates the theoretical prediction with known results
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