Unit Gain Research Articles

AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistors with ZnO gate layer and (NH4)2Sx surface treatment

The AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) with ZnO gate insulator deposited using a vapor cooling condensation system were fabricated. The AlGaN surface treatment using (NH4)2Sx was performed to improve the quality of the interface between the ZnO layer and AlGaN layer. The (NH4)2Sx-treated MOS-HEMTs exhibited a higher saturation drain-source current of 0.74 A/mm, a maximum extrinsic transconductance of 200 mS/mm, an unit gain cutoff frequency of 9.1 GHz, a maximum frequency of oscillation of 17.1 GHz, and the Hooge’s coefficient of 8.28×10−6. The improved performances of the (NH4)2Sx-treated MOS-HEMTs were attributed to the reduction in surface states.

PREDICTING THERMAL RESPONSE OF CONDUCTIVE FOODS DURING START‐UP OF PROCESS EQUIPMENT USING TRANSFER FUNCTIONS

ABSTRACT Transfer function approach to predict thermal histories of conductive foodstuffs when surroundings present different forcing functions during start‐up of processes is reported. Food is assimilated to a delayed first‐order system with unit gain and characterized by two parameters, the dead time (L) and the time constant (τ). The comparison of experimental data with the proposed models for cooking as well as for retorting processes presented very satisfactory results when the equipment evolved as first‐order, second‐order and bounded integrating systems.PRACTICAL APPLICATIONSTransfer functions appear as relevant mathematical tools because they are relatively simple models that need only dynamics input–output data to represent more complex systems related to food process engineering, generally nonlinear ones. Besides, their potential application allows the performance of optimal process control in real‐time modality. In particular, this paper deals with the problem of processes start‐up, which represents a transient operation to be overcome, and also with the ability of the transfer function methodology to estimate both food and equipment temperature evolution during different food operations when changes in the surrounding temperature take place.

Forward Adaptation of Novel Semilogarithmic Quantizer and Lossless Coder for Speech Signals Compression

In this paper new semilogarithmic quantizer for Laplacian distribution is presented. It is simpler than classic A-law semilogarithmic quantizer since it has unit gain around zero. Also, it gives for 2.97 dB higher signal-to-quantization noise-ratio (SQNR) for referent variance in relation to A-law, and therefore it is more suitable for adaptation. Forward adaptation of this quantizer is done on frame-by-frame basis. In this way G.712 standard is satisfied with 7 bits/sample, which is not possible with classic A-law. Inside each frame subframes are formed and lossless encoder is applied on subframes. In that way, double adaptation is done: adaptation on variance within frames and adaptation on amplitude within subframes. Joined design of quantizer and lossless encoder is done, which gives better performances. As a result, standard G.712 is satisfied with only 6.43 bits/sample. Experimental results, obtained by applying this model on speech signal, are presented. It is shown that experimental and theoretical results are matched very well (difference is less than 1.5%). Models presented in this paper can be applied for speech signal and any other signal with Laplacian distribution.

Optimization of Rayleigh-Limited WDM-PONs With Reflective ONU by MUX Positioning and Optimal ONU Gain

In this work, the influence of the distribution element position and the reflective optical network unit (ONU) gain in wavelength-division-multiplexing passive optical networks are reported. After the theoretical and experimental analysis, it is determined that the best crosstalk-to-signal ratio is achieved if the multiplexer is placed either in the ONU or optical light termination vicinity, and the ONU gain has a new optimum value depending on the position. Also, it is demonstrated that Rayleigh backscattering is generally irrelevant in downstream transmission.

Measurement of crude protein requirement of cockerel finishers by two empirical methods

Two empirical methods, namely the orthodox or traditional and diet dilution technique, were used to measure the responses of 96 14-week-old Black Olympian cockerel finishers to graded dietary crude protein (CP) levels of 16, 18, 20 and 22 per cent on airdry basis in a 6-week trial. The diets were isocaloric (ca 2600 kcal kg-1 metabolisable energy). Both methods indicated that weight gains, feed conversion ratio, and protein efficiency ratio were optimized by diets containing 18 per cent CP level at minimal cost of feedper unit gain. The results, thus, confirm that both methods are equally good in predicting the CP requirements of finishing cockerels.

Evaluation of Reduced Fish Meal Diets for Second Year Growout of the Largemouth Bass, Micropterus salmoides

Abstract Development of efficient cost‐effective diets is a critical component in the refinement of production technologies for the largemouth bass, Micropterus salmoides (LMB). One of the first steps in reducing feed costs can be to decrease the amount of fish meal in the diet. The objective of this study was to evaluate reduced levels of fish meal, and a least‐cost formulation diet, for second year growout of LMB under practical pond conditions. Twelve 0.04‐ha ponds were stocked with juvenile LMB (210.1±3.3 g) at a stocking density of 8650 fish/ha (350 fish/pond). Each pond was randomly assigned one of the four dietary treatments with three replicate ponds per treatment. The three experimental diets contained varying levels of fish meal. Diets FM‐45, FM‐24, and FM‐8 contained 45, 23.5, and 8% fish meal, respectively. In diets FM‐24 and FM‐8, fish meal was replaced by varying levels of poultry by‐product meal, soybean meal, and blood meal. The fourth diet was a commercial salmonid diet widely used as a LMB growout feed (Nelson and Sons, Inc., SilvercupTM, Steelhead, Murray, UT, USA). This diet served as a commercial control (CC) and contained 46% crude protein. The experimental diets were formulated to be isonitrogenous and isocaloric with the CC diet and were fed once daily to apparent satiation for 180 d. At harvest, there were no significant differences between treatments (P > 0.05) in terms of survival, which averaged 95% overall. Mean weights of fish fed the three experimental diets FM‐45, FM‐24 and FM‐8 were not significantly different (P > 0.05) and averaged 518, 546, and 529 g, respectively, but were all significantly greater (P≤ 0.05) than those fed the CC (488 g). Feed conversion ratio (FCR) of fish fed the FM‐45 and FM‐8 diets (1.43 and 1.46, respectively) was significantly greater (P≤ 0.05) than those fed the FM‐24 diet (1.34). The FCR of fish fed the CC diet (1.39) was not significantly different (P > 0.05) from fish fed other diets. Feed cost per unit of weight gain ($US/kg) was significantly lower (P≤ 0.05) in fish fed the FM‐24 and FM‐8 diets ($0.73 and $0.72/kg, respectively) than in fish fed other diets. Feed cost per unit gain of fish fed the FM‐45 diet ($0.83/kg) was significantly lower (P≤ 0.05) than those fed the CC diet ($1.04/kg). There were no significant differences (P > 0.05) in dress‐out percentages or proximate composition among fish fed the four diets. This study indicates that fish meal levels in feeds used for the second year growout of LMB can be reduced to≥8% of the formulation without reducing survival or growth and without negatively impacting body composition.

Dynamic Analysis of a Si/SiGe-Based Impact Ionization Avalanche Transit Time Photodiode With an Ultrahigh Gain-Bandwidth Product

We investigate the dynamic performance of a Si/SiGe-based impact ionization avalanche transit time photodiode (PD) fabricated on a standard Si substrate that operates at the 830-nm wavelength. The bandwidth-enhancement effect under negative-photoconductance (NPC) operation can greatly relax the internal transit time as well as the tradeoff between the gain and bandwidth performance that characterizes the traditional avalanche PD. Our modeling and measurement results show that the extracted internal resonant frequency increases significantly with the reverse leakage current. By choosing the proper bias voltage in the NPC region, we can simultaneously achieve a wide 3-dB bandwidth (30 GHz), ultrahigh gain-bandwidth product (690 GHz) with a 53.2% external efficiency at unit gain, and clear eye opening at 10 Gb/s.

A CMOS 90 nm 55 mW 3.4-to-9.2 GHz 12 Band Frequency Synthesizer for MB-OFDM UWB

A frequency synthesizer for ultra-wideband (UWB) multiband orthogonal frequency division multiplexing (MB-OFDM) applications is designed in TSMC 90 nm CMOS technology. It is based on two wideband PLLs (8 MHz open loop unit gain frequency) capable of settling in less than 300 ns with a 66 MHz external reference. The PLL tuning range (6.6-9.2 GHz) is extended down to 3.4 GHz by a dedicated circuit able to divide the output frequency by 1, 1.5 and 2 with a power consumption of less than 3 mW. Measured data fit the UWB MB-OFDM specifications with an integrated phase noise of 2.8RMS o at maximum output frequency and an aggregate spurious tone power of less than -27 dBc. The joint power consumption is 55 mW and the synthesizer core area occupies less than 0.5 mm2 .

A totally implantable hearing system – Design and function characterization in 3D computational model and temporal bones

Implantable middle ear hearing devices are emerging as an effective technology for patients with mild to moderately severe sensorineural hearing loss. Several devices with electromagnetic or piezoelectric transducers have been investigated or developed in the US and Europe since 1990. This paper reports a totally implantable hearing system (TIHS) currently under investigation in Oklahoma. The TIHS consists of implant transducer (magnet), implantable coil and microphone, DSP-audio signal processor, rechargeable battery, and remote control unit. The design of TIHS is based on a 3D finite element model of the human ear and the analysis of electromagnetic coupling of the transducer. Function of the TIHS is characterized over the auditory frequency range in three aspects: (1) mass loading effect on residual hearing with a passive implant, (2) efficiency of electromagnetic coupling between the implanted coil and magnet, and (3) functional gain of whole unit in response to acoustic input across the human skin. This paper focuses on mass loading effect and the efficiency of electromagnetic coupling of TIHS determined from the FE model of the human ear and the cadaver ears or temporal bones. Some preliminary data of whole unit function are also presented in the paper.

A 10-bit 50-MS/s sample-and-hold circuit with low distortion sampling switches

A fully-differential switched-capacitor sample-and-hold (S/H) circuit used in a 10-bit 50-MS/s pipeline analog-to-digital converter (ADC) was designed and fabricated using a 0.35-μm CMOS process. Capacitor flip-around architecture was used in the S/H circuit to lower the power consumption. In addition, a gain-boosted operational transconductance amplifier (OTA) was designed with a DC gain of 94 dB and a unit gain bandwidth of 460 MHz at a phase margin of 63 degree, which matches the S/H circuit. A novel double-side bootstrapped switch was used, improving the precision of the whole circuit. The measured results have shown that the S/H circuit reaches a spurious free dynamic range (SFDR) of 67 dB and a signal-to-noise ratio (SNR) of 62.1 dB for a 2.5 MHz input signal with 50 MS/s sampling rate. The 0.12 mm2 S/H circuit operates from a 3.3 V supply and consumes 13.6 mW.

Infancy Weight Gain Predicts Childhood Body Fat and Age at Menarche in Girls

Rapid postnatal weight gain has been associated with subsequent increased childhood adiposity. However, the contribution of rapid weight gain during specific infancy periods is not clear. We aimed to determine which periods of infancy weight gain are related to childhood adiposity and also to age at menarche in UK girls. A total of 2715 girls from a prospective UK birth cohort study participated in the study. Routinely measured weights and lengths at ages 2, 9, and 19 months were extracted from the local child health computer database. Body composition was assessed by dual-energy x-ray absorptiometry at age 10 yr, and age at menarche was assessed by questionnaire (categorized into three groups: <12.0, 12.0-13.0, and >13.0 yr). Faster early infancy weight gain between 0 and 2 months and also 2 to 9 months were associated with increased body fat mass relative to lean mass at age 10 yr and also with earlier age at menarche. Each +1 unit gain in weight sd score between 0 and 9 months was associated with an odds ratio (95% confidence interval) = 1.48 (1.27-1.60) for overweight (body mass index > 85th centile) at 10 yr, and 1.34 (1.21-1.49) for menarche at less than 12 yr. In contrast, subsequent weight gain between 9 and 19 months was not associated with later adiposity or age at menarche. In developed settings, rapid weight gain during the first 9 months of life is a risk factor for both increased childhood adiposity and early menarche in girls.

Feed consumption, growth performance and carcass evaluation of Korean Holstein bulls fed either conventional or organic diets

Feed consumption, bodyweight gain and carcass evaluation of Holstein bulls fed either conventional (CON) or organic (ORG) diets were compared. Animals were randomly assigned to either CON (n = 15) or ORG (n = 15) treatments when 6 months old. Inclusion rates of the ingredients were similar in CON and ORG diets formulated for growing (6–12 months of age) and fattening (13–18 months of age) periods. Ingredients of organic origin were used to formulate ORG growing and fattening diets. The bulls on the CON diet were vaccinated, de-wormed and treated conventionally (with antibiotics) against any sign of illness. No dietary or implant growth promotant was used. The bulls on the ORG diet were vaccinated although they were not de-wormed or treated against illness using conventional methods. Instead they were allowed to recover naturally from illness for 3 days. However, if the illness persisted beyond 3 days, they were treated using conventional methods. Consumption of concentrate and rice straw during growing, fattening and overall periods (6–18 months of age) was the same in bulls fed the CON or ORG diets. Bodyweight gain, total dry matter (concentrate and straw) intake and feed to gain ratio during growing and fattening were not affected by the treatments. Daily feed cost and feed cost for unit gain were greater in bulls fed the ORG diet than those fed the CON diet. Weight of cold carcass and different carcass cuts of the bulls were not affected by the treatment. According to the Korean beef grading system, the carcasses from bulls fed either CON or ORG diets were graded similarly but were of lower quality. The Korean beef quality grade is primarily determined by marbling score. The bulls in this study were slaughtered earlier (at 18 months of age) than the conventional slaughtering age of beef cattle (~30 months) in Korea to produce highly marbled beef. It is concluded that the bulls fed ORG diets performed equally, and produced carcasses of similar quality, to those fed CON diets. However, feed costs for a unit bodyweight gain were significantly greater in the ORG diet compared with the CON diet.

Fine mapping quantitative trait loci for feed intake and feed efficiency in beef cattle1

Feed intake and feed efficiency are economically important traits in beef cattle because feed is the greatest variable cost in production. Feed efficiency can be measured as feed conversion ratio (FCR, intake per unit gain) or residual feed intake (RFI, measured as DMI corrected for BW and growth rate, and sometimes a measure of body composition, usually carcass fatness, RFI(bf)). The goal of this study was to fine map QTL for these traits in beef cattle using 2,194 markers on 24 autosomes. The animals used were from 20 half-sib families originating from Angus, Charolais, and University of Alberta Hybrid bulls. A mixed model with random sire and fixed QTL effect nested within sire was used to test each location (cM) along the chromosomes. Threshold levels were determined at the chromosome and genome levels using 20,000 permutations. In total, 4 QTL exceeded the genome-wise threshold of P < 0.001, 3 exceeded at P < 0.01, 17 at P < 0.05, and 30 achieved significance at the chromosome-wise threshold level (at least P < 0.05). No QTL were detected on BTA 8, 16, and 27 above the 5% chromosome-wise significance threshold for any of the traits. Nineteen chromosomes contained RFI QTL significant at the chromosome-wise level. The RFI(bf) QTL results were generally similar to those of RFI, the positions being similar, but occasionally differing in the level of significance. Compared with RFI, fewer QTL were detected for both FCR and DMI, 12 and 4 QTL, respectively, at the genome-wise thresholds. Some chromosomes contained FCR QTL, but not RFI QTL, but all DMI QTL were on chromosomes where RFI QTL were detected. The most significant QTL for RFI was located on BTA 3 at 82 cM (P = 7.60 x 10(-5)), for FCR on BTA 24 at 59 cM (P = 0.0002), and for DMI on BTA 7 at 54 cM (P = 1.38 x 10(-5)). The RFI QTL that showed the most consistent results with previous RFI QTL mapping studies were on BTA 1, 7, 18, and 19. The identification of these QTL provides a starting point to identify genes affecting feed intake and efficiency for use in marker-assisted selection and management.

Influence of particle size and xylanase supplementation on the performance, energy utilisation, digestive tract parameters and digesta viscosity of broiler starters

1. The aim of the present experiment was to examine the influence of particle size and xylanase supplementation on the performance, energy utilisation, and gross morphological and histological parameters of the digestive tract of broiler starters fed wheat-based diets. The experimental design was a 2 × 2 factorial arrangement of treatments evaluating two wheat particle sizes (medium and coarse) and two levels of xylanase supplementation (without or with 1000 xylanase units/kg diet). The two particle sizes were achieved by grinding the whole wheat in a hammer mill to pass through 3 and 7 mm screens, respectively. Broiler starter diets, based on wheat and soybean meal, were formulated and each diet was fed ad libitum to 6 pens of 8 male broilers each from d 1 to 21 post-hatch. 2. Wheat particle size had no effect on the performance of broilers. Xylanase supplementation had no effect on weight gain and feed intake. However, a significant particle size × xylanase interaction was observed for feed per unit gain with xylanase lowering feed per gain only in the coarse particle size diet. Xylanase supplementation improved the nitrogen-corrected apparent metabolisable energy at both particle sizes. 3. Xylanase supplementation decreased the relative weight and relative length of all gut components. Villus height and crypt depth and total extent of the mucosal layer were unaffected by both wheat particle size and xylanase supplementation. 4. The apparent viscosity of intestinal digesta, determined over the physiological range of shear rates, was not influenced by xylanase addition or particle size. 5. The findings of this study suggest that the effectiveness of exogenous xylanase in broiler diets is influenced by wheat particle size.

Linearly Constrained Adaptive Array Processing with Alternate Mainbeam Nulling

This paper concerns with signal cancellation problem in a linearly constrained adaptive array processor in coherent environment. Alternate mainbeam nulling approach was proposed to prevent the signal cancellation phenomenon. The linearly constrained LMS algorithm with a unit gain constraint and that with a null constraint in the direction of the desired signal is alternately implemented to reduce the signal interaction between the desired signal and the interferences, which is the main cause of the signal cancellation. It is shown that the proposed method performs better than a conventional method.

Genomewide selection in oil palm: increasing selection gain per unit time and cost with small populations

Oil palm (Elaeis guineensis Jacq.) requires 19 years per cycle of phenotypic selection. The use of molecular markers may reduce the generation interval and the cost of oil-palm breeding. Our objectives were to compare, by simulation, the response to phenotypic selection, marker-assisted recurrent selection (MARS), and genomewide selection with small population sizes in oil palm, and assess the efficiency of each method in terms of years and cost per unit gain. Markers significantly associated with the trait were used to calculate the marker scores in MARS, whereas all markers were used (without significance tests) to calculate the marker scores in genomewide selection. Responses to phenotypic selection and genomewide selection were consistently greater than the response to MARS. With population sizes of N = 50 or 70, responses to genomewide selection were 4-25% larger than the corresponding responses to phenotypic selection, depending on the heritability and number of quantitative trait loci. Cost per unit gain was 26-57% lower with genomewide selection than with phenotypic selection when markers cost US $1.50 per data point, and 35-65% lower when markers cost $0.15 per data point. With population sizes of N = 50 or 70, time per unit gain was 11-23 years with genomewide selection and 14-25 years with phenotypic selection. We conclude that for a realistic yet relatively small population size of N = 50 in oil palm, genomewide selection is superior to MARS and phenotypic selection in terms of gain per unit cost and time. Our results should be generally applicable to other tree species that are characterized by long generation intervals, high costs of maintaining breeding plantations, and small population sizes in selection programs.

Nutritional value of animal feed grade wheat as replacement for maize in lamb feeding for mutton production

AbstractThe utilization of abundantly available animal feed grade wheat (AFW) as a replacement for conventional and costly cereal supplement in lamb feeding to lower the cost of mutton production was explored. Thirty‐five growing lambs divided into five equal groups and were fed diets containing 0, 118, 235, 353 or 470 g kg−1 AFW replacing equal quantity of maize. The diets were fed in the form of composite feed mixture, which had a roughage (Prosopis cineraria leaves) to concentrate ratio of 25:75. Dry matter intake (DMI) was not different in these groups, ranging from 35 to 42 g kg−1 body weight, while AFW inclusion linearly (P &lt; 0.05) reduced DMI. The digestibility coefficients of dry matter (DM), organic matter (OM), crude protein (CP) and cellulose were not affected by AFW addition, whereas neutral detergent fibre and acid detergent fibre digestibility coefficients were reduced (P &lt; 0.05). The digestible CP content (142.7–162.7 g kg−1 diet) increased (P &lt; 0.01) linearly with increased AFW inclusion levels. However, AFW additions did not affect metabolizable energy (ME) value of diet (10.2–10.5 MJ kg−1 diet DM). Digestible CP intake was similar but digestible DM and OM intake tended to decrease (P &lt; 0.05) linearly when expressed in terms of g kg−1 W0.75. ME intake (MJ d−1) was not different among the diets but showed linear (P = 0.041) reducing trends with increasing AFW levels in diet. The efficiency of ME and N utilization for unit gain was also not affected by AFW incorporation. N retained as g d−1, percentage of intake and percentage of absorbed ranged from 15.4 to 19.5 g, 49.7% to 60.3% and 62.6% to 74.6%, respectively. Intake and utilization of dietary N was not affected but urinary N excretion reduced (P &lt; 0.05) linearly by AFW. Daily microbial N (MN) flow estimated by urinary purine derivative excretion was significantly (P &lt; 0.01) higher for lambs fed a diet with AFW 235 g kg−1 (3.05 g MN) and 353 g kg−1 (2.51 g MN) compared to without AFW diet (1.31 g MN). MN when expressed as g kg−1digestible organic matter intake (DOMI) and microbial protein g kg−1 digestible organic matter apparently fermented in rumen (DOMR) followed a similar trend. During the growth trial, lambs fed diets containing AFW (353 g kg−1), which replaced 75% maize had higher total gain (14 kg, P &lt; 0.05) and average daily gain (ADG 154 g, P &lt; 0.05). However, feed efficiency (feed consumed kg−1 live weight gain) was not different. Rumen pH and microbial enzyme activities studied 4 h post feeding revealed that AFW did not affect rumen pH, which ranged from 5.95 to 6.30. Similarly, carboxymethyl cellulase and β‐xylosidase enzyme activities were not different among treatments, but AFW inclusion linearly (P = 003) increased carboxymethyl cellulase enzyme activities. The α‐amylase enzyme activity differed significantly (P &lt; 0.05) and was highest (22.6 IU) in groups where AFW replaced maize completely. It was concluded that, in lambs reared under intensive system for mutton production on high concentrate diets, conventional and costly energy supplements like maize can be replaced up to 75% with a low‐cost animal feed grade wheat to economize on cost of production. However, more studies are required to confirm these inclusion levels for greater economic returns. Copyright © 2007 Society of Chemical Industry

Automatic robust adaptive beamforming via ridge regression

In this paper we derive a class of new parameter free robust adaptive beamformers using the generalized sidelobe canceler reparameterization of the unit gain constrained minimum variance problem. In this parameterization the minimum variance beamformer is obtained as the solution of a linear least squares (LS) problem. In the case of an inaccurate steering vector and/or few data snapshots this marginally overdetermined system gives an ill fit causing signal cancellation in the standard minimum variance (LS) solution. By regularizing the LS problem using ridge regression techniques we get a whole class of robust adaptive beamformers, none of which requires the choice of a user parameter, as opposed to many existing methods. In this context we also propose a parameter free empirical Bayes-based ridge regression technique which, to the best of our knowledge, is novel. The performance of our approach is illustrated by numerical simulations and compared to other robust adaptive beamformers.

Superconducting cavity control based on system model identification

A digital control system for the superconducting cavities for a linear accelerator is presented. The low level radio frequency system for the FLASH project in DESY is introduced. A field programmable gate array-based controller managed by MATLAB was developed to investigate the novel firmware implementation. An algebraic complex domain model is proposed for the system analysis. The calibration procedure of a signal path is considered for multi-channel control. For a given model structure, the input–output relation of the real plant with unknown parameters is applied. The over-determined matrix equation is created covering a long enough measurement range with the solution according to the least squares method. A base function approximation by a cubic B-spline set is applied to estimate the time-varying cavity detuning during the pulse. Control tables, feed-forward and set point, are determined for the required cavity performance, according to the recognized process. The feedback loop is tuned by fitting complex gain of the corrector unit according to the determined gain table. An adaptive control algorithm is applied for feed-forward and feedback modes. Experimental results including field measurement are presented for a cavity representative operation.

Effect of dimensions on the cooling rate of whole potatoes applying transfer functions

The evolution of temperature in the geometrical centre of potatoes during cooling was analysed using a transfer function approach. The response to a sudden change in the surrounding temperature was approximated assuming that the sample behaved as a delayed first-order system with unit gain. This model involves two parameters, the time constant and the dead time. These parameters depend on the product dimensions. Samples were assumed to have ellipsoidal shape. Expressions to estimate the time constant and the dead time from the three axes of the ellipsoid are presented. The temperature response in the geometrical centre subjected to changes in the surrounding temperature can be predicted using the model parameters. Good approximations between predicted and experimental values were obtained.