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Browsing Chemical & Petroleum Engineering-Scholarly Publications by Author "Akinola, A. A."
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- ItemOpen AccessAutomation of a Dust Sampling Train.(Journal of Modelling, Design and Management of Engineering Systems,, 2007) Akinola, A. A.; Muir, D. M.The accuracy of measuring the concentration of particulate matter in flue gas streams by a dust sampling train can be significantly improved or minimized by automating the sampling process using a microprocessor based system. Two situations are presented here, in which a dust sampling train is interfaced via appropriate transducers with a microprocessor and additional circuit boards. The results obtained from this work show that the flue gas sampling process can be automated using a microprocessor-based control system and a sampling train. Using the sampling train developed by the British Coal Utilization Research Association (BCURA) with both the internal and external flow-meter arrangements, the maximum error in iso-kinetic sampling velocity throughout the sampling period did not exceeding 5%.
- ItemOpen AccessComputational Accuracy in Calculating In-Duct Iso-Kinetic Sampling Rates in A Sampling Train Using a Microprocessor(Journal of Engineering Research, 2011-09) Akinola, A. A.The microprocessor is the heart of many automated devices in use at the present time. These microprocessors are used mainly in devices where repeated and rapid rates of calculations are required. To achieve' rapid rates of calculation, the microprocessor is programmed directly in machine or assembly language. This paper presents the results of work done in programming a microprocessor in the Assembly programming language to calculate iso-kinetic sampling rates in a dust sampling train. The accuracies of the calculation are examined by comparing the results of the calculations with those obtained when using a mainframe computer. The results show that the accuracy of the calculations is within -4.5 %and +2.5%
- ItemOpen AccessComputer Aided Design of Circular Clarifiers,(Journal of the Nigerian Society of Chemical Engineers, 2013) Odediran, E. T.; Ayo, D. B.; Akinola, A. A.An algorithm was developed for the design of primary circular clarifier for Wastewater treatment. Three computer programs were developed using Microsoft Excel, FoxPro and MATLAB respectively, all based on the algorithm. Computational Results from the three programs were not significantly different from those carried out manually. The algorithm was validated by feeding operational data (influent and effluent conditions) from the Primary clarification unit of the City of Springfield Wastewater Treatment Plant (WWTP), Ohio, USA into the three computer programs. The results of calculations from the computer programs using data from the Springfield WWTP were not significantly different from the design data of the WWTP.
- ItemOpen AccessCyber-Security Evaluation for a Hypothetical Nuclear Power Plant using the Attack Tree Method(Journal of Physical Security, 2015) Akinola, A. A.; Kuye, A. O.; Ayodeji, AThe widespread introduction of digital network systems in nuclear power plants has increased such infrastructures vulnerability to cyber-attacks. The attack tree approach to evaluate and analyze cyber-attacks quantitatively, in a nuclear power plants’ network system is presented in this work. Information on a hypothetical nuclear power plants’ network system was used to build attack trees that show different attack paths that external adversaries can use to compromise the network system. To assert the ease or difficulty of compromising each attack tree, numerical values are assigned to the leaf nodes of each attack tree. The return on attack for each intermediate node and the root node are then calculated. This calculation is done by randomly varying the vulnerability values of the leaf nodes within the designated range. On observing high return of attack values with the two attack trees developed, countermeasures were then implemented. Modified network systems were constructed and the return on attack recalculated. The return on attack (ROA) values for the nodes were observed to decrease, after implementing the countermeasures on the network security systems.
- ItemOpen AccessDehydration and Rehydration Characterization of Yam (Dioscorea Rotundata) Tuber Slices Using a Refractance WindowTM Dryer,(Zimbabwe Journal of Science & Technology, 2017) Akinola, A. A.; Shittu, A. S.; Ezeorah, S. N.The effect of slice thickness on the dehydration and rehydration characteristics of yam was studied in a Refractance Window TM (RW) type dryer constructed from a laboratory water bath. Yam slices 1.5, 3.0 and 4.5 mm thick were dried in a laboratory scale RW dryer where the water in the bath was maintained at temperature of 80 °C. The initial moisture content of the yam samples was 69% on a wet basis (wb). The drying process was carried out until the final moisture content of the product was below 10% (wb). The experimental data indicate that the drying time decreases rapidly as the yam slices decrease; the 1.5 mm, 3.0 mm and 4.5 mm thick yam slices, dried to below 10% within 40 minutes, 80 minutes and 120 minutes respectively. The experimental data indicated that the drying kinetics for the yam slices fitted the Haghi and Ghanadzadeh thin-layer drying model with a regression coefficient exceeding 99.9 % for the 1.5, 3.0 and 4.5 mm thick slices. The rehydration ratio increased to a steady value of about 1.91 when soaked in water for about 180 minutes.
- ItemOpen AccessDehydration Characterization of Carrot (Daucus Carota) Slices Dried Using the Refractance Window™ Drying Technique(Zimbabwe Journal of Science & Technology, 2016) Akinola, A. A.; Malomo, T. O.; Ezeorah, S. N.The drying characteristics of yellow carrots (Daucus Carota) were studied using a laboratory scale batch Refractance Window™ (RW) dryer. This study was performed to facilitate the understanding of the design on a continuously operating RW dryer, by studying the drying characteristics of a batch RW drying process. A dryer was constructed by modifying a laboratory water bath. The bath is covered with a transparent Polyethylene terephthalate (PET) plastic film that has a drying area of 10 cm by 10 cm. 3 mm thick slices of carrots were dried on the Refractance WindowTMdryer, and the variation of the moisture content of the slices was measured during the drying process. The water temperature beneath the plastic film was maintained at 60 oC. From the experimental data the drying curves, the drying rate curves and the Krischer curves were plotted. The thin layer mathematical drying model that describes the drying kinetics of the drying data was determined. The bulk density of the powdered carrots and the variation of the rehydration ratio of the carrot slices with time was determined. The effective moisture diffusivity of the carrots is also estimated. Observations indicate that the carrot slices dried to below 10% moisture content on a dry basis in about 200 minutes. Regression analysis suggests that the Haghi and Ghanadzadeh model best describes the drying behaviour for the 3 mm thick slices with a coefficient of determination (R2) value of 0.999 for the 17 models studied. The Rehydration Ratio of the carrot samples varied from 2.457 to 4.126 with rehydration times of 10 to 60 minutes. An average bulk density value of the carrot powder samples was 0.8625 grams/ml. The effective moisture diffusivity of the 3 mm thick carrot slices was determined to be 7.29513×10-8 m2/s.
- ItemOpen AccessDehydration Kinetics of Cassava, Yam and Potato Slices Using a Refractance WindowTM Dryer(FUOYE Journal of Engineering and Technology, 2018) Akinola, A. A.; Ezeorah, S. N.This study aims to investigate the drying characteristics of cassava, yam, and potato slices using a laboratory scale batch Refractance Window™ (RW) dryer. The experimental dryer was constructed by modifying a laboratory water bath. The bath was covered with a transparent Polyethylene terephthalate (PET) plastic film held in-place with angled edges. The cassava, yam, and potato slices were dried on the Refractance WindowTM dryer, and the variation of the moisture content of the slices during the drying process was measured. The water temperature beneath the plastic film was maintained at 60°C. The dehydration data were fitted to thin-layer drying models. Regression analysis suggested that the Haghi and Ghanadzadeh model best describes the dehydration behaviour for the 3 mm thick slices for the cassava, yam, and potato tubers. The coefficient of determination (R2) values of 0.999, 0.998, and 0.998 for the cassava, yam, and potato slices respectively were reported in all the models studied. The drying curves, the drying rate curves, and the Krischer curves, from the experimental drying data, was plotted. Observations indicate that the cassava, yams, and potatoes slices dried to below 0.11 g water/gsolid moisture content in about 150 min. This study was performed to facilitate the understanding of the design, modelling, and operations of a continuously operating RW dryer.
- ItemOpen AccessEffective Moisture Diffusivity and Activation Energy Estimation of Cucumber Fruit Slices Using a Refractance WindowTM Dryer(Journal of The Association of Professional Engineers of Trinidad and Tobago, 2018) Akinola, A. A.This paper presents an estimation of the effective moisture diffusivities and the activation energy of cucumber fruit slices by studying the effect of temperature on the drying kinetics. A laboratory scale Refractance WindowTM dryer was used to obtain dehydration data for cucumber fruit slices. Experiments carried out on 3 mm thick cucumber fruit slices with water temperatures in the dryer at 65 oC (338K), 75 oC (348K) and 85 oC (358K) were performed. The experimental drying data were fitted to 8 thin layer drying models to select the most appropriate drying model. The Haghi and Ghanadzadeh model was determined to be the most suitable for the process conditions studied. Fick’s second law was used to calculate the effective moisture diffusivity. The moisture diffusion coefficient varied between 1.94 x 10-9 m2s-1 and 2.54 x 10-9 m2s-1 for the process conditions studied. The activation energy was estimated using the Arrhenius equation and for the given temperature range. The corresponding activation energy was calculated to be 13.55kJ/mol. A knowledge of the effective moisture diffusivities and activation energy of the cucumber fruit slices, when determined using the Refractance WindowTM drying technique will aid in understanding the design, analysis, and optimisation of such equipment for the drying of food.
- ItemOpen AccessEstimation of the Thermal Diffusivity of Beans Using a Simple Apparatus(FUOYE Journal of Engineering and Technology, 2019) Akinola, A. A.; Adeniji, O. B.A simple apparatus for the determination of the thermal diffusivity of black-eyed beans samples, using the transient heat conduction method is presented. This apparatus is a stainless steel cylindrical tube, containing the sample, placed into a constant temperature water bath. The variation of the temperature at the center of the tube with time is recorded. The thermal diffusivities were determined from the temperature-time relationship data of the sample, and the dimensions of the equipment. The estimated thermal diffusivity values of the samples varied between 4.70 x 10-8 to 6.94 x 10-8 and 5.26 x 10-8 to 7.68 x 10-8 when the temperature in the water bath was 50oC and 60oC, respectively. Also, the thermal diffusivity was higher when the water bath temperature was 60oC rather than 50oC for the sample range of particle sizes studied. As black-eyed beans are a staple food in many parts of West African, they are grown, harvested, and stored. The thermal diffusivity information is useful in determining the behaviour of this Argo-product when stored.
- ItemOpen AccessEvaluation of the Dehydration Characteristics of Ginger (Zingiber Officinale) Root Slices Using Refractance Window Drying Technology(FUOYE Journal of Engineering and Technology, 2018) Akinola, A. A.; Azeta, O; Ezeorah, S. N.This study investigates the drying characteristics of ginger (zingiber officinale) root slices using the Refractance Window™ drying technology. A laboratory-scale dryer was constructed by modifying a water bath. 3 mm thick ginger root slices were dried on the transparent Mylar PET plastic film that covered the bath, and the variation of the moisture content of the slices with time was determined as the drying progressed. A water temperature of 60 oC was maintained beneath the plastic film. Various drying kinetic data curves are plotted from the drying data and the thin layer model that best fits the drying data was determined. Observations indicated that the ginger root slices dried to a moisture content of 0.1g H2O/g solid on a dry basis in about 210 minutes. The regression analysis results showed that the Haghi and Ghanadzadeh thin layer model best describes the drying data for 3 mm sized slices with the coefficient of determination ( ) value of 0.9985. An effective moisture diffusivity of 8.99 x 10-8 m2/s was observed for the ginger root slices.
- ItemOpen AccessEvaluation of the Drying Kinetics of Cassava (Manihot Esculenta) Slices Using a Refractance WindowTM Dryer(Journal of Engineering Research, 2017) Akinola, A. A.; Ezeorah, S. N.The dehydration kinetics of cassava slices dried using a Refractance WindowTM, a novel contact surface drying technique, is presented in this study. The dryer was constructed by modifying a laboratory water bath. Cassava slices of 3 mm thick were dried on the Refractance WindowTM, and the moisture content of the slices was measured as the drying progressed. A water temperature between 75 – 80 oC was maintained beneath the plastic film. Drying curves were obtained from the drying data, and the thin layer model that best fit the drying data was determined. The bulk density and rehydration ratio of the dried cassava were determined. The cassava slices were observed to dry to about 5 % moisture content after 210 minutes. The regression analysis results showed that the Haghi and Ghanadzadeh thin layer model best described the drying data for 3 mm thick sized cassava slices. The Mean Bias Error (MBE), the Coefficient of Determination (R2), the Root Mean Square Error (RMSE) and the Chi-square (χ2) values were -8.83x10-6, 9984.34x10-4, 4.20x10-4 and 4.41x10-4 respectively. The Rehydration Ratio increased to a steady value of 3.17 in about 180 minutes.
- ItemOpen AccessKinetics of the Dehydration of Cucumber Slices with a Refractance Window™ Dryer(The Journal of the Association of Professional Engineers of Trinidad and Tobago, (JAPETT), 2018) Akinola, A. A.; Adegoke, O. E.; Ezeorah, S. N.Cucumber (Cucumis sativus) slices, 3 mm thick, were dried in a laboratory scale batch Refractance WindowTM dryer. To construct the dryer, a laboratory water bath was modified by covering the bath with a transparent polyethylene terephthalate (PET) plastic film. A water temperature of 60oC was maintained beneath the plastic film. The variation of the moisture content of the cucumber slices was measured during the drying process. Using the experimental data, the drying curve, the drying rate curve, and the Krischer curve, were plotted. The thin-layer mathematical drying model that best describes the drying kinetics of the drying data was determined. The variation of the rehydration ratio of the cucumber slices with rehydration time was determined. The effective moisture diffusivity of the 3 mm thick cucumber slices was also determined. Observations indicate that the cucumber slices dried to a moisture content of less than 10% (dry basis) in about 120 minutes. The regression analysis results showed that from the 17 models studied, the Haghi and Ghanadzadeh thin-layer drying model best describes the drying behaviour of the 3 mm thick slices with a coefficient of determination (R2) value of 0.9994. The rehydration ratio of the cucumber samples varied from 3.47 to 5.25 with rehydration times of 10 to 300 minutes respectively. The moisture content after 300 minutes of rehydration was about 1150% dry basis (92% wet basis). The effective moisture diffusivity of the 3 mm thick cucumber slices was determined to be 7.30×10-10 m2/s. The implications of the work are that the Refractance WindowTM (RW) drying technique will dry cucumber slices at a faster rate than the traditional methods and the drying data obtained can be used in the design of an industrial scale RW dryer.
- ItemOpen AccessModelling of Thin-Layer Refractance WindowTM Drying Kinetics of Okra (Abelmoschus esculentus) Fruit Slices at Different, Temperatures,(Journal of Engineering and Computer Science, (JECS),, 2018) Akinola, A. A.; Adehoun, S. O.; Ezeorah, S. N.This paper presents the effect of temperature on the drying kinetics of the okra fruit slices using a Refractance WindowTM dryer. Okra fruit slices, 3 mm thick were dried at three temperatures. The slices were dehydrated at separate times at temperatures of 75oC, 85oC, and 95oC. Themoisture content of the slices was determined periodically during the drying process. The experimental data obtained were fitted tothin-layerdrying models commonly used in the dehydration kinetics of fruit and vegetables. Observations indicated that the slices dried to a moisture content below 0.11 g-water/g-solid (dry basis) in about 90 - 110 minutes for the process conditions studied. For the nine models considered, the regression results suggested that the Haghi and Ghanadzadeh thin-layer model best describes the drying kinetics for the 3 mm thick slices for the temperatures 75oC, 85oC, and 95oC; the coefficient of determination (R2) values were 0.9992, 9973, 9993 for the respectively. The benefit of the work done here will aid in understanding the design, analysis, and optimization of the Refractance WindowTM equipment in the drying of food
- ItemOpen AccessModelling the Rehydration Characteristics of White Yam(West Indian Journal of Engineering, 2019) Akinola, A. A.Presented in this paper is a proposed model describing the variation in the rehydration ratio with rehydration time for yam slices. The ‘new’ model describes the relationship between the moisture content of yam slices with time when rehydrated. The changes in mass and moisture content data with rehydration time, during the rehydration process, were recorded. Rehydration was carried out at 27 oC, 40 oC, 60 oC, and 80oC for 3.0 mm thick dehydrated yam slices. Regression analysis established that the variation in rehydration ratio vs rehydration time data, better fitted a two-term exponential equation rather than a quadratic equation. Also, regression analysis done on variation in rehydration ratio vs rehydration time data of cube sweet potatoes found it literature, further validated that the rehydration ratio vs rehydration time data better fitted a two-term exponential equation rather than a quadratic equation. For the recorded moisture content versus rehydration time data, a better fit was obtained for the new model rather than the Weibull, Peleg, and Exponential models. This study is essential for a better understanding of the rehydration characteristics of yam slices during the rehydration process. Information about rehydration characteristics of the yam slices presented in this work will also be valuable to optimise and characterise the soaking conditions, design yam-processing equipment and predict water absorption as a function of time and temperature. The rehydration process clearly indicates that rehydration occurs very rapidly in the first few minutes of the rehydration process, and this process is faster as the rehydration temperature increases.
- ItemOpen AccessMoisture Diffusivity and Activation Energy Estimation of White Yam (Dioscorea rotundata) Slices Using Drying Data from a Refractance WindowTM Dryer(FUOYE Journal of Engineering and Technology, 2019) Akinola, A. A.; Ezeorah, S. N.The objective of this study was to estimate the moisture diffusivity of different sizes of white yam slices at different temperatures using a Refractance WindowTM dryer. To achieve this objective, dehydration of 1.5, 3.0 and 4.5 mm thick yam slices was performed with water temperatures of 65, 75, 85 and 95 oC in the flume of a Refractance WindowTM dryer. Variation of moisture content with dehydration time data were obtained during the dehydration operations. The activation energies of dehydration for different sizes of yam slices were estimated for the temperatures considered. For the process conditions studied, the effective moisture diffusivities varied from 5.35 x 10-08 to 1.45 x 10-07 m2/s. The effective moisture diffusivity, Deff, at a specified temperature was observed to increase with increasing yam slice size. The effective moisture diffusivity, Deff, at a specified yam slice size is observed to increase with increasing dehydrating temperature. The activation energy, Ea, for the yam slices, ranged from 23.21 to 28.30 (kJ/mol) and it was observed to increase with increasing thickness of the yam slices. The activation energy values estimated were within the range observed for other equipment. This study is important in that, the moisture diffusivities and activation energy parameters estimated will be useful in the design, modelling, and optimization of such dryers.
- ItemOpen AccessA Proposal for the Management of Plastic Packaging Waste(Journal of Environmental Science, Toxicology and Food Technology, 2014) Akinola, A. A.; Adeyemi, I. A.; Adeyinka, F. M.An Environmental Impact Assessment study was performed using the Life Cycle Assessment (LCA) technique for a range of plastic packaging waste disposal technologies, to determine which waste management strategy has the potential to provide significant environmental benefits over existing waste management strategies. Comparisons were made between the various technologies; a number of scenarios are considered to build up supply chains for the disposal process. The Life Cycles of Plastic packaging waste disposed via the Landfill, Incineration and Integrated Plastic Waste Management (IPWM) methods were compared and their environmental burdens calculated using the Eco-indicator 99 method. The Single Score and Damage Assessment revealed that IPWM offers the most significant environmental benefits. Characterization plots of the effect on Climate change , Ozone layer depletion ,Eco-toxicity , Respiratory organic and inorganic gases, Carcinogens , Radiation, Acidification/ Eutrophication, Land use and Minerals also confirmed that environmental benefits were most significant with IPWM.
- ItemOpen AccessQuantitative Evaluation of Cyber-Attacks on a Hypothetical School Computer Network(Journal of Information Security, 2019-07) Akinola, A. A.This paper presents the attack tree modeling technique of quantifying cyber-attacks on a hypothetical school network system. Attack trees are constructed by decomposing the path in the network system where attacks are plausible. Considered for the network system are two possible network attack paths. One network path represents an attack through the Internet, and the other represents an attack through the Wireless Access Points (WAPs) in the school network. The probabilities of success of the events, that is, 1) the attack payoff, and 2) the commitment of the attacker to infiltrate the network are estimated for the leaf nodes. These are used to calculate the Returns on Attacks (ROAs) at the Root Nodes. For Phase I, the “As Is” network, the ROA values for both attack paths, are higher than 7 (8.00 and 9.35 respectively), which are high values and unacceptable operationally. In Phase II, countermeasures are implemented, and the two attack trees reevaluated. The probabilities of success of the events, the attack payoff and the commitment of the attacker are then re-estimated. Also, the Returns on Attacks (ROAs) for the Root Nodes are re-assessed after executing the countermeasures. For one attack tree, the ROA value of the Root Node was reduced to 4.83 from 8.0, while, for the other attack tree, the ROA value of the Root Node changed to 3.30 from 9.35. ROA values of 4.83 and 3.30 are acceptable as they fall within the medium value range. The efficacy of this method whereby, attack trees are deployed to mitigate computer network risks, as well as using it to assess the vulnerability of computer networks is quantitatively substantiated.
- ItemOpen AccessRefractance Window™ Drying of Red Onions (Allium Cepa)(Journal of the Nigerian Society of Chemical Engineers, 2014) Akinola, A. A.; Lawal, S. O.; Osiberu, A. S.A Refractance Window dryer was fabricated and used to study the drying characteristics of red onions (Allium Cepa). The data for the drying of the 1mm, 2mm and 3mm sized shreds of red onions were obtained experimentally and the drying curves and mathematical model that best fit the drying data were determined. The quality of the dried red onion powder was determined and compared with dried onion powder obtained from the local supermarket. The results obtained, established that size affects the drying time of the onion samples. The 1mm sized shreds dried fastest reducing from a moisture content of 7.19kg water per kg dry solids to less than 0.2kg water per kg dry solids within 40 minutes of drying. The time of drying increased with size. Of the 13 Thin-layer drying curve models studied, the regression results showed that the Haghi and Ghanadzadeh model best describes the drying curve of the 1mm, 2mm and 3mm sized shreds with the highest coefficient of determination (R2) values of 0.99196, 0.98570 and 0.99523 respectively. The dried onion powder had a Bulk density of 0.4501 grams/ml while those of the market onion powder were 0.4616 grams/ml.
- ItemOpen AccessSome Physico-Chemical and Adsorptive Reclamation Strategies of Used Automobile Engine Lubricating Oil(Journal of Engineering Research., 2017) Owolabi, R. U.; Akinola, A. A.; Oyelana, O. A; Amosa, M. K.This study aims to reclaim the base oil component of used lubricating oils for reuse. The base oil reclamation strategies were carried out in a three-stage process namely, physical, chemical and adsorptive processes. The physical processes adopted include sedimentation and natural settling by gravity, magnetization, and filtration for the removal of metallic and non-metallic related particles.The chemical process included acidification with H2SO4, alkalinization with NaOH, solvent extraction and hydro-treatment. The adsorption process used a combination of bentonite powder and silica gel / activated carbon adsorbent in specific proportions.Comparison of lubricating properties of all the samples indicated that sample 6, which passed through the adsorption process in addition gave the best conditions for the base oil reclamation process.Of all the lubricating properties investigated, only the flash point was not significantly reclaimed in comparison with others. The infra-red spectroscopy of the samples was also performed and indicated that peak infra-red spectroscopy values occurred at approximately equal wave numbers of 1457.76, 2852.28 and 2921.01cm-1.
- ItemOpen AccessTemperature Dependence of the Effective Moisture Diffusivity of Yam (Dioscorea rotundata) Slices Dried Using a Refractance WindowTM Dryer(The Journal of the Association of Professional Engineers of Trinidad and Tobago, (JAPETT), 2018) Akinola, A. A.; Ayo, D. B.; Ezeorah, S. N.The study presents the dependence of the effective moisture diffusivity of yam slices on temperature. A laboratory-scale Refractance WindowTM dryer was used in the investigation. Moisture content measurements of 4.5 mm thick yam slices, dehydrated at water temperatures of 65oC, 75oC, 85oC, and 95oC in the dryer were determined. The experimental drying data obtained was used to estimate the moisture diffusivities, and the activation energy for the process conditions considered. The effective moisture diffusivities estimated using Fick’s second law for 4.5 mm thick yam slices, varied between 1.94 x10-09 m2s-1 and 2.54 x10-09 m2s-1 for the temperatures studied. The activation energy estimated using the Arrhenius type equation was 29.64 kJ/mol for the given temperature range. The effective moisture diffusivities values are slightly higher than those reported in the literature because the investigations were performed at higher temperatures than those found in the literature. Higher moisture diffusivities imply that there is higher moisture movement through the interstices of the slices, which in turn indicates a higher rate of drying. However, the activation energy is within those reported in the literature. Knowledge of these parameters will aid in the design, modelling, and operation of a Refractance WindowTM dryer.