Semilogarithmic Research Articles

Methods used to evaluate the peroxyl (ROO·) radical scavenging capacities of four common antioxidants

Different methods that are used to measure peroxyl radical (ROO·) scavenging capacity were used in model systems containing four common antioxidant compounds: ascorbic acid, cysteine, gallic acid and Trolox, a water-soluble vitamin E analogue. Five tests were performed, with differences in the method of peroxyl radical generation (lipoxygenase, azo-compound thermal degradation and spontaneous oxidation from a natural source of fatty acids) and in the addition of probes such as linoleic acid, crocin, fluorescein and electron paramagnetic resonance (EPR) by spin-trapping with α-phenyl-N-tert-butyl-nitrone. Significant differences were found in antioxidant reactivity, evaluated by dose–effect semi-logarithmic plots and EC50 values, and a possible explanation for these differences was explored. In assays in which ROO· was generated by the azo-compound or spontaneous oxidation, gallic acid was the most powerful antioxidant. When lipoxygenase was used to produce ROO·, ascorbic acid had the highest scavenging index, while cysteine and gallic acid had low levels of activity. Another difference was identified regarding the molecular probe: ascorbic acid and Trolox were the least reactive in the EPR system and azo-bis system with fluorescein, while in assays with crocin, these compounds had intermediate activities. Ascorbic acid and Trolox were the best antioxidants in an enzymatic-linoleic acid system, with a reciprocal ratio of 6:1, while adding crocin to the same system changed the reciprocal ratio to 2:1. A literature examination indicated that out of the antioxidant compounds tested, cysteine has the highest bond dissociation enthalpy, and this compound showed, as expected, low scavenging activity in three of the five tests in this study.

Acceleration factor for ageing measurement of dye solar cells

Three different temperatures are used to stress Dye-sensitized Solar Cells (DSCs) under 1 Sun irradiation in order to accelerate their ageing process. A linear degradation law for the efficiency data has been supposed, deduced from the experimental efficiency vs. time curves. Based on the Arrhenius model for first order kinetics, an acceleration factor has been extracted, depending on the device stress temperature. From the semi-logarithmic plot of the acceleration factor as a function of 1/T we could also calculate an activation energy of about 1eV for the degrading process to be activated.

Nucleophilic Reactivities of Hydrazines and Amines: The Futile Search for the α-Effect in Hydrazine Reactivities

The kinetics of the reactions of amines, hydrazines, hydrazides, and hydroxylamines with benzhydrylium ions and quinone methides were studied in acetonitrile and water by UV-vis spectroscopy, using conventional spectrometers and stopped-flow and laser-flash techniques. From the second-order rate constants k(2) of these reactions, the nucleophilicity parameters N and s(N) were determined according to the linear free energy relationship log k(2) = s(N)(N + E). While methyl groups increase the reactivities of the α-position of hydrazines, they decrease the reactivities of the β-position. Despite the 10(2) times lower reactivities of amines and hydrazines in water than in acetonitrile, the relative reactivities of differently substituted amines and hydrazines are almost identical in the two solvents. In both solvents hydrazine has a reactivity similar to that of methylamine. This observation implies that replacement of one hydrogen in ammonia by Me increases the nucleophilicity more than introduction of an amino group, if one takes into account that hydrazine has two reactive centers. Plots of log k(2) versus the corresponding equilibrium constants (log K) or Brønsted basicities (pK(aH)) do not show enhanced nucleophilicities (α-effect) for either hydrazines or hydroxylamine relative to alkylamines.

A quantitative approach to nucleophilic organocatalysis

The key steps in most organocatalytic cyclizations are the reactions of electrophiles with nucleophiles. Their rates can be calculated by the linear free-energy relationship log k(20 °C) = sN(E + N), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by the solvent-dependent nucleophilicity (N) and sensitivity (sN) parameters.Electrophilicity parameters in the range –10 < E < –5 were determined for iminium ions derived from cinnamaldehyde and common organocatalysts, such as pyrrolidines and imidazolidinones, by studying the rates of their reactions with reference nucleophiles. Iminium activated reactions of α,β-unsaturated aldehydes can, therefore, be expected to proceed with nucleophiles of 2 < N < 14, because such nucleophiles are strong enough to react with iminium ions but weak enough not to react with their precursor aldehydes. With the N parameters of enamines derived from phenylacetaldehyde and MacMillan’s imidazolidinones one can rationalize why only strong electrophiles, such as stabilized carbenium ions (–8 < E < –2) or hexachlorocyclohexadienone (E = –6.75), are suitable electrophiles for enamine activated reactions with imidazolidinones. Several mechanistic controversies concerning iminium and enamine activated reactions could thus be settled by studying the reactivities of independently synthesized intermediates.Kinetic investigations of the reactions of N-heterocyclic carbenes (NHCs) with benzhydrylium ions showed that they have similar nucleophilicities to common organocatalysts (e.g., PPh3, DMAP, DABCO) but are much stronger (100–200 kJ mol–1) Lewis bases. While structurally analogous imidazolylidenes and imidazolidinylidenes have comparable nucleophilicities and Lewis basicities, the corresponding deoxy Breslow intermediates differ dramatically in reactivity. The thousand-fold higher nucleophilicity of 2-benzylidene-imidazoline relative to 2-benzylidene-imidazolidine is explained by the gain of aromaticity during electrophilic additions to the imidazoline derivatives. O-Methylated Breslow intermediates are a hundred-fold less nucleophilic than deoxy Breslow intermediates.

Building a Link between Retirement Planning in the Civil Service and Entrepreneurship Development in Nigeria

Retiree involvement in entrepreneurship is known to address their wellbeing challenges hence the interest to ascertain the determinants and level of their contribution among retirees of the Civil Service of Akwa Ibom State of Nigeria. Data were obtained through the use of structured Questionnaire which was administered during the annual verifi cation exercise of retirees. Multi regression analysis using four functional forms of linear, double log, semi log and exponential; Pearson Product Moment Correlation, chi square and T-test methods were used to test the hypotheses. The basis for the selection of the bestfit model and lead equation was the one with relatively highest R value, lowest number of significant, lower error of estimation and appropriateness of a prior signs. Double log provided the best option. The result showed that all the independent variables were signifi cant at 0.05 level of probability. These relative effects suggest that these factors if given adequate corresponding attention would lead to a healthy and increased post retirement involvement in entrepreneurship. It is recommended that measures be taken to invigorate pre-retirement training, hitherto ignored as an essential and integral part of the retirement planning process of the Civil Service of the State. Key words: Retirement planning; Civil service; Entrepreneurship development; Nigeria

Karst aquifer draining during dry periods

2 Abstract: We analyzed hydrographs of five karst springs in southern Italy during the recession period using ten continuous years of daily discharge measurements and provided conclusions on the aquifer behavior under dry periods and droughts. A straight line was fitted to a semilogarithmic plot (log-discharge versus time), and the recession coefficient (the slope of the line generated from the equation) was calculated for each spring and for each year considered. A deviation from the straight line produced by a simple exponential decay of discharge through time provides information on the actual emptying rate of the aquifer compared to a simple exponential decline. If the recession coefficient decreases or increases, the aquifer is empting more slowly or more quickly than expected, respectively. Water level of a monitored well inside the karst catchment was also assessed and provided information on the water distribution into aquifers. The results describe the hydraulic behavior of karst aquifers during their emptying and provide information for better management of karst springs.

Trend of settlement in primary and secondary consolidations

The trend/rate of settlement of any load on clay can be measured at any time without knowing the past history of load increment. It can be a source of some useful information like quick evaluation of consolidation characteristics, time-compression data of the present, past and future, type and stage of consolidation, drainage conditions, time of load increment, etc. Basic mathematical/graphical properties of vertical, radial, 3D and secondary consolidations are studied from this angle. Two types of 3D consolidations are discussed. First is the combined vertical and radial consolidation with vertical drains. Second is the general 3D consolidation in Cartesian co-ordinates where drainage occurs through all the six phases of a parallelopipe-shaped sample. But the settlement in both cases is allowed in the vertical direction only. It is shown that primary compression after 60% consolidation, with whatever simple or complicated drainage conditions, essentially gives a straight line on a linear plot of settlement versus rate of settlement while secondary consolidation is a straight line on semi-log plot of settlement versus rate of settlement.

Free Energy Relationships for Reactions of Substituted Benzhydrylium Ions: From Enthalpy over Entropy to Diffusion Control

Second-order rate constants k(2) for the reactions of various donor- and acceptor-substituted benzhydrylium ions Ar(2)CH(+) with π-nucleophiles in CH(2)Cl(2) were determined by laser flash irradiation of benzhydryl triarylphosphonium salts Ar(2)CH-PAr(3)(+)X(-) in the presence of a large excess of the nucleophiles. This method allowed us to investigate fast reactions up to the diffusional limit including reactions of highly reactive benzhydrylium ions with m-fluoro and p-(trifluoromethyl) substituents. The rate constants determined in this work and relevant literature data were jointly subjected to a correlation analysis to derive the electrophilicity parameters E for acceptor-substituted benzhydrylium ions, as defined by the linear free energy relationship log k(2)(20 °C) = s(N)(N + E). The new correlation analysis also leads to the N and s(N) parameters of 18 π-nucleophiles, which have only vaguely been characterized previously. The correlations of log k(2) versus E are linear well beyond the range where the activation enthalpies ΔH(++) of the reactions are extrapolated to reach the value of ΔH(++) = 0, showing that the change from enthalpy control to entropy control does not cause a bend in the linear free energy relationship, a novel manifestation of the compensation effect. A flattening of the correlation lines only occurs for k(2) > 10(8) M(-1) s(-1) when the diffusion limit is approached.

Dose Dependence of Strength After Low-Temperature Irradiation in Metallic Materials

This study intends to review and characterize the low-temperature (<473 K [200 °C]) irradiation-hardening behaviors in metallic materials and to propose new interpretations on the dose dependence of strength, particularly in the prehardening and saturation regimes. The analysis of results of yield stress-dose curves indicate that four dose-dependence regimes exist: the prehardening, main hardening, saturation, and embrittlement regimes. The semilog plots of yield stress vs dose data revealed that the prehardening regime displaying zero hardening or softening was common at least for the alloys with low-dose data available. It was observed that the dose range of the prehardening regime increased with the strength of material, which indicates that slower initiation in irradiation hardening is expected when strength is higher. For the majority of the metallic materials analyzed, it was reconfirmed that the exponent of the power-law hardening function was evaluated to be about 0.5 in the main hardening regime and about 0.1 in the saturation regime. In these positive hardening regimes, the low strength pure metals such as Fe, Ta, Cu, and Zr displayed lower hardening exponents. The minimum dose to the saturation of irradiation hardening was in the range of 0.003 to 0.08 dpa, depending on the category of materials. It was also reaffirmed that there exists a strong relationship between the saturation in irradiation hardening and the occurrence of plastic instability at yield.

C max and t max verification using Fibonacci sequence and absorption rate

The aim of this study was to verify the values of maximal observed concentration (C max,obs) and the time, at which maximum concentration is observed (t max,obs) using the analysis of the absorption rate constant (k ab). It focused on the changes in concentration over time (C-T) for drugs, for which several peaks of concentration occur. In addition, the attempt was made to use Fibonacci sequence to facilitate the visual analysis of the dynamics in changes of concentration on C-T graphs. The analyses were conducted with the use of three hypothetical data groups (groups I, II and III), which had distinct C-T profiles, and with the in vivo data form healthy subjects (n=10) taking part in a bioequivalence study, who was given a single oral dose of topiramate (100mg). The comparison of hypothetical and real in vivo data demonstrated that for the C-T curves, in which there are several peaks of concentration C max,obs and t max,obs values can easily be miscalculated when the increase in concentration is not properly related to the appropriate absorption phase (63.2, 87.50, 96.88%). It was also demonstrated that the data transformation with the use of Fibonacci sequence exposes slight differences in the observed concentration values in a semi-logarithmic scale. The results of this study show that in case of C-T curves with several peaks of concentration, the verification of C max and t max data obtained taking into account different absorption phases enables more precise evaluation of these parameters.

DNA sensor based on vapour polymerised pedot films functionalised with gold nanoparticles

Poly-3,4-ethylenedioxythiophene, PEDOT, films have been deposited on gold electrodes using polymerization from the vapor-phase in which the surface is first covered with a Fe (III) tosylate oxidant and then exposed to 3,4-ethylenedioxythiophene, EDOT, vapor. Gold nanoparticles were then electrodeposited to give a nanocomposite material, PEDOT-AuNP. Thiolated capture strand DNA, that is complementary to the sequence associated with the pathogen S. aureus that causes mammary gland inflammation, was then immobilized onto the gold nanoparticles and the underlying gold electrode. The target oligo was then hybridized to the capture strand DNA. A probe strand, labeled with horse radish peroxidase, was then hybridized to the target. The concentration of the target was determined by measuring the current required to reduce hydroquinone oxidized during the regeneration of the HRP label. Semi-log plots of the pathogen DNA concentration vs. faradaic current are linear from 150pM to 1μM and pM concentrations can be detected without the need for molecular, e.g., PCR or NASBA, amplification.

SU-E-J-155: Evaluate a Stepped TE Segmented EPI Sequence for 3D Dose Monitoring Using Gel Dosimetry.

Gel based MR relaxometry provides accurate 3D dosimetric mapping. The routinely used multi spin echo (MSE) sequence has limitations. Our aim was to evaluate a stepped TE segmented EPI sequence for 3D dose monitoring at 1.5T and 3T. The polymer gel (BANG KIT, MGS Research) was prepared under normoxic conditions and stored in glass vials. Calibration was performed under dose range of 3-18 Gy with irradiation using the True Beam. Segmented Echo Planar Imaging Sequence was evaluated for T2 relaxometry at 1.5T and 3T (GE medical systems). The parameters of the stepped TE segmented Echo Planar Imaging Sequence were kept identical at both 1.5 and 3T: TE=15.6,27,39,51,63,75,87,99 ms; TR= 4000ms; FOV=22*22;Slice thk/gap: 3/3; # Shots=14; Scan time=8 min. The MSE sequence parameters were set close to the EPI sequence on both scanners (scan time: 18 mins). The EPI image quality at 1.5 T was comparable to MSE sequence; at 3T ghosting artifacts could be seen in EPI images. The log linear plot of signal intensities of the segmented EPI sequence for irradiation in the range 0-20 Gy is shown at 1.5 and 3T (fig 1 & 2). The T2 values agreed with that of corresponding MSE sequences at both 1.5 and 3Tand the fit was much better using the segmented EPI sequence than the MSE sequences. The dose calibration factor,a, was similar for all the sequences (fig. 3- 3T a: MSE=0.93, EPI=0.99; fig.4- 1.5T a: MSE=0.79, EPI=0.95) Conclusions: The EPI image quality at 1.5T was comparable to MSE. The dose calibration factor evaluated with the EPI sequences was comparable at 1.5T and 3T and close to the MSE sequence. Acquisition time of EPI is less than half of MSE sequence with more flexibility in choice of TEs .The study establishes EPI as a novel sequence for dose mapping.

SU-E-J-50: Measurement of the HVL Value for the 120keV Photon Beam of the X-Ray Volume Imager (XVI) Using Ionization Chamber, Gafchromic Film XRQA2 and Diode.

The value of Half Value Layer (HVL) is essential in quantifying the ability of an x-ray beam to penetrate the material being studied. This paper examines the use of three different types of detectors for measuring HVL of the 120keV photon beam of the X-ray Volume Imager (XVI) cone beam CT system mounted on the Elekta Synergy (Crawley, UK) Linac: ionization chamber, Gafchromic film and diode. The effects of collimator diameters are presented and the chamber tip and chamber horizontalmethods are compared to investigate the source of variations in the measurement of HVL. The measurements are done in free airboth using an ionization chamber calibrated for absolute dosimetry [University of Wisconsin Accredited Dosimetry Laboratory] and the Gafchromic film dosimeters [XR-QA2 (International Specialty Products, Wayne, NJ)]. The beam is collimated to the size of the detector to measure the exposed dose. The different thicknesses of the aluminum attenuators are added to beam to measure individual doses every time and repeated until the dose fell to below 50% of the initial unattenuated value. Dose measurements with a semiconductor diode detector [Barracuda MPD (RTI Electronics AB, NJ)] is also carried out. We plotted all results on a semi-log graph to find HVL value. When the measurements are made using ionization chamber with different collimator diameters we obtained 1.6% difference in HVL values. Measurements with chamber tip and horizontal methods agree with each other to within approximately 1.6% percentage difference. The percentage difference of the HVL values measured using the diode and ionization chamber is about 6.4% and that of using Gafchromic film and ionization chamber is about 8% percent. Gafchromic films and diodes can be used to measure HVL value of 120 keV photon beams. Recommendations for consistency in HVL measurements are provided.

Ideal organic homojunction diode obtained using controlled alignment of localized density of states across doped/undoped interface

We show that for organic semiconductors, it is sufficient to have a doped/undoped homojunction to obtain a near ideal diode with exponential dependence of current density (J) on voltage (V), though the physics is very different from the ideal Shockley equations for conventional p–n junction. Unlike Shockley diodes, the slope of the semi-log plot in this regime is independent of temperature, and is related to the broadening parameters of Gaussian density of states (DOS). We show that physics of transport in the regime is controlled by alignment through local DOS and tunneling across the interface. The mechanism sets in beyond a newly identified threshold voltage (Vth) which decreases linearly with temperature and corresponds to offset in energy of localized DOS at the interface at which overlap begins to occur. The temperature dependence of all other significant features is shown to be consistent with localized Gaussian density of states model of disordered solids.

Electrical Conductivity Modeling of Polypropylene Composites Filled with Carbon Black and Acetylene Black

Composites of polypropylene filled with carbon black or acetylene black at different concentrations were prepared by melt mixing followed by compression molding. The influences of filler type and filler concentration on the composites conductivity were studied. It was found that the percolation threshold is located at a lower concentration in composites filled with the acetylene black, than that of the composites filled with carbon black. The model of Mamunya gives a fairly good agreement in the evaluation of the conductivity of polymeric composites loaded with carbon black or acetylene black, beyond the percolation threshold. The Boltzman equation was adopted to develop a model that represents more faithfully all results obtained. The expressions of the electrical conductivity, calculated with the model developed, are in good agreement with experimental results for the entire concentration range studied in linear or semilogarithmic scale.

Estimating the volume of tephra deposits: A new simple strategy

Research Article| May 01, 2012 Estimating the volume of tephra deposits: A new simple strategy C. Bonadonna; C. Bonadonna 1University of Geneva, 13 rue des Maraîchers, 1205 Geneva, Switzerland Search for other works by this author on: GSW Google Scholar A. Costa A. Costa 2University of Reading, P.O. Box 217, Reading, Berkshire RG6 6AH, UK3Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328, 80125 Naples, Italy Search for other works by this author on: GSW Google Scholar Author and Article Information C. Bonadonna 1University of Geneva, 13 rue des Maraîchers, 1205 Geneva, Switzerland A. Costa 2University of Reading, P.O. Box 217, Reading, Berkshire RG6 6AH, UK3Istituto Nazionale di Geofisica e Vulcanologia, Via Diocleziano 328, 80125 Naples, Italy Publisher: Geological Society of America Received: 23 Aug 2011 Revision Received: 30 Nov 2011 Accepted: 06 Dec 2011 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2012 Geological Society of America Geology (2012) 40 (5): 415–418. https://doi.org/10.1130/G32769.1 Article history Received: 23 Aug 2011 Revision Received: 30 Nov 2011 Accepted: 06 Dec 2011 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation C. Bonadonna, A. Costa; Estimating the volume of tephra deposits: A new simple strategy. Geology 2012;; 40 (5): 415–418. doi: https://doi.org/10.1130/G32769.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Volume determination of tephra deposits is necessary for the assessment of the dynamics and hazards of explosive volcanoes. Several methods have been proposed during the past 40 years that include the analysis of crystal concentration of large pumices, integrations of various thinning relationships, and the inversion of field observations using analytical and computational models. Regardless of their strong dependence on tephra-deposit exposure and distribution of isomass/isopach contours, empirical integrations of deposit thinning trends still represent the most widely adopted strategy due to their practical and fast application. The most recent methods involve the best fitting of thinning data using various exponential segments or a power-law curve on semilog plots of thickness (or mass/area) versus square root of isopach area. The exponential method is mainly sensitive to the number and the choice of straight segments, whereas the power-law method can better reproduce the natural thinning of tephra deposits but is strongly sensitive to the proximal or distal extreme of integration. We analyze a large data set of tephra deposits and propose a new empirical method for the determination of tephra-deposit volumes that is based on the integration of the Weibull function. The new method shows a better agreement with observed data, reconciling the debate on the use of the exponential versus power-law method. In fact, the Weibull best fitting only depends on three free parameters, can well reproduce the gradual thinning of tephra deposits, and does not depend on the choice of arbitrary segments or of arbitrary extremes of integration. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Experimental studies of flame stability limits of biogas flame

Flame stability of premixed biogas flame for Reference Test Burner (RTB) was investigated. In this study, six kinds of test gases were used to simulate biogas in which CO2 volume fraction varied from 30% to 45%. A series of experiments were conducted on two RTBs with different port diameters and at different outlet unburned mixture temperatures. It was found that the lifting and yellow tipping limits show similar trends regardless of the biogas components, port diameters and mixture temperatures. A “float off” phenomenon could be observed at low gas flow rate and low primary air ratio. Low mixture temperature, small ports and high CO2 concentration in biogas can lead to the unstable condition of “float off”. The lifting limits are enhanced with an increase of port diameter or mixture temperature and with a decrease of CO2 concentration. The yellow tipping limits are extended with an increase of CO2 concentration and with a decrease of mixture temperature or port diameter. In addition, the lifting limit curve becomes a straight line when semi-logarithmic graph paper is applied. The intercept increases with a decrease of the CO2 concentration in biogas and with an increase of port diameter or gas temperature.

Comment on ‘‘Determination of soil–water characteristic curve variables” by Qian Zhai and Harianto Rahardjo [Comput. Geotech. 42 (2012) 37–43

The determination of soil–water characteristic curve variables, proposed by [1] provides more flexibility compared to conventional methods such as [4]. However, if the method “A” described by the authors is used, the air-entry and residual suctions would be difficult to compute, because the parameters m and n depend directly on the residual suction and vice versa, which leads to more unknowns than equations. It should be noted that the parameters of the original formula of [2] composed of the correction factor, are calculated in semi-log plot by using the neperian logarithm and not with the decimal logarithm.

Electrophilicities of Bissulfonyl Ethylenes

Kinetics of the reactions of bissulfonyl ethylenes with various carbanions, a sulfur ylide, and siloxyalkenes have been investigated photometrically at 20 °C. The second-order rate constants have been combined with the known nucleophile- specific parameters N and s(N) for the nucleophiles to calculate the empirical electrophilicity parameters E of bissulfonyl ethylenes according to the linear free energy relationship log k(20 °C)=s(N)(N+E). Structure-reactivity relationships are discussed, and it is shown that the electrophilicity parameters E derived in this work can be employed to define the synthetic potential of bissulfonyl ethylenes as Michael acceptors.

Econometric evaluation of rice profitability determinants in Kogi State, Nigeria

The study was designed to determine the level of profitability of rice and factors influencing rice profitability in Kogi State, Nigeria. Primary data was randomly collected from 120 rice farmers with the aid of a set of structured questionnaire and interview schedule. The data were analyzed using descriptive statistics and regression analyses models applying four functional forms. The lead equation, semi-log model, was chosen using appropriate theoretical and econometric criteria after diagnostic tests including tests for heteroscedasticity and multicollinearity. Results indicated that rice farming in the state was profitable, with an average farm posting a profit of at least US$788.30 (N122, 974.40K) annually. Rice profitability in the area was largely influenced by farmers’ socio-economic attributes as well as production factors including farmers’ age, farming experience and years of formal education recorded by the farmers. The resource inputs that significantly influenced rice profitability in the area of study was volume of farm credit accessed, value of fertilizer applied and water/irrigation expenses. Consequently it was recommended that policies that will make farm credit available at affordable rates to the farmers, promotion of rice as a means of livelihood, enhanced access of farmers to educational facilities and removal of subsidy/government interference in fertilizer which increases the market price of fertilizer in the country be put in place in Nigeria. Government should however invest more in irrigation facilities to reduce the cost of fertilizer production in the study area. Key words: Rice profitability, econometric evaluation, costs and returns, profitability determinants, Kogi State, Nigeria.