Brahm P. Verma

Fuzzy Logic for Biological and Agricultural Systems

Fuzzy logic is a powerful concept for handling non-linear, time-varying, adaptive systems. It permits the use of linguistic values of variables and imprecise relationships for modeling system behavior. The paper presents an overview of fuzzy logic modeling techniques, its applications to biological and agricultural systems and an example showing the steps of constructing a fuzzy logic model.

MODELING BLUEBERRY FIRMNESS AND MASS LOSS DURING COOLING DELAYS AND STORAGE

Blueberry mass and firmness losses were measured to determine the effect of cooling delays at selected temperatures in postharvest environments. Models were developed from the slopes of firmness and mass values plotted against time for four temperatures (4°C, 21°C, 27°C, and 32°C) and 95% relative humidity. The models were validated by holding other sets of blueberries at three temperatures (21°C, 27°C, and 32°C) and at 95% relative humidity for cooling delays of 0, 2, 4, 8, 12 and 24 h before storage at 4°C and 95% RH up to 96 h. The models developed were suitable for evaluating the benefit of lowering temperature during cooling delays of selected durations or the benefit of reducing cooling delays at specified temperatures. The impact of cooling delays was less than expected when compared with losses caused by low-temperature storage for only four days. Additional studies are needed to model the effect of various relative humidity levels and to learn the extent of variation in the rate constants for different cultivars and different crops.

APPARENT MODULUS OF ELASTICITY FROM FIRMTECH 2 FIRMNESS MEASUREMENTS OF BLUEBERRIES

The firmness of blueberries and other small fruits can be measured rapidly with a FirmTech 2 Fruit Firmness Tester. The output of the instrument is the slope of a chord joining selected minimum and maximum forces on a force/deformation curve. The overall objective of this study was to improve the firmness measurements obtained with the Firm Tech 2. In this study, both simulations and tests with rubber balls showed that firmness measurements of a single ball increased as minimum or maximum force was increased. If repeatable results are to be obtained from the FirmTech instrument, standard values for the force settings must be established. Equations from ASABE Standard S368.4 were adapted for calculating the apparent modulus of elasticity (Ea) for both parallel plate and single plate compression using FirmTech 2 output. Ea values for a simulated force/deformation curve with deformation taken to the 3/2 power were the same when calculated using the ASABE equations and when calculated using the equations developed, regardless of which combination of minimum and maximum force was selected. When rubber balls with three diameters were compressed with a universal testing machine, the Ea values calculated from the ASABE equations were similar to those calculated using the equations developed in this study. The firmness of blueberries was measured using both the FirmTech 2 and the universal testing machine. The Ea values were calculated using the equations developed in this article and compared to values calculated from the universal testing machine curves using the ASABE equations. Results indicated the loading applied by the FirmTech 2 support plate was somewhere between a parallel plate and a single plate compression test. Additional research could show benefits from using the equations developed in this study for calculating Ea from loading curves obtained using universal testing machines.

Radiographic Detection of Soil-Incorporated Granular Pesticides and Impacts of Application Methods on Wireworm Management

ABSTRACT Atechnique was developed for detecting the locations of chlorpyrifos (Lorsban 15G) and fonofos (Dyfonate lOG) granules after incorporation into soil. The technique involved treatment of the insecticide granules with iodine and a thin coating of lead dust. The granules were detected in soil samples with X-ray computed tomography (CAT scanning). Two field experiments were conducted to compare wireworm management in sweet potatoes and distributions of chlorpyrifos and fonofos granules after six different pesticide incorporation procedures. Analyses of variance indicated marked differences between incorporation procedures for dispersions of granules, locations of granules, and numbers of granules detected. Wireworm control with fonofos was effective for all incorporation procedures. For chlorpyrifos, the best wireworm control was with two incorporation procedures which dispersed the chemical to all soil in contact with the growing sweet potatoes.

Lubricated and Non-Lubricated Cone Penetrometer Performance Comparison in Six Soils

ABSTRACT LUBRICATED cone penetrometers were compared with non-lubricated cone penetrometers in the laboratory using six soils with textures ranging from sands to loams. Effects of varying cone angles were studied at three compaction levels and up to four moisture levels. Additionally, cone size effects were evaluated in three soils at three compaction levels and two soil moisture levels. The Cone Index (CI) vs penetration depth was determined for both lubricated and non-lubricated penetrometers for each cone angle and cone size. A concept of stress relaxation was developed and evaluated. Lubricating the cone had a substantial effect on the rate of change of CI with depth. The level of stress relaxation also appeared to be related to the rate of CI change. Results identify several new directions for future research.

A Decentralized System for Nursery Potting Operations

ABSTRACT Anew concept of decentralized potting plants in con-tainers and placing them on field beds was developed. A five-container wide epxerimental machine was designed, constructed and tested to evaluate some aspects of the system performance.

Shattering Pecan Shells with High-Speed Projectiles

ABSTRACT Anew concept for shelling pecans and other nuts is presented. A low-mass, free-traveling projectile impacts the shell at high velocity to shatter the shell without damaging the kernel. Theoretical considerations suggested the amount of kinetic energy needed to fracture the shell should be achieved with a minimum amount of momentum. An experimental cracker/sheller was developed to test the new concept. Pressurized air was used to accelerate an unconstrained projectile along the inside of a tube until it impacted a nut held against the opposite end. Tests with pecans verified that a fairly consistent kinetic energy was required regardless of projectile mass. Impacts from projectiles with low momentum produced the best cracking/shelling. A 7 g projectile with a velocity of 22 m/s consistently produced undamaged pecan kernels while shattering the shells sufficiently to make additional shelling unnecessary..

Palletized Container Handling for Nurseries

ABSTRACT Apalletized system of handling and transporting con-tainers in nurseries was developed and tested. Im-provements in labor output were 38 percent for potting and loading, 137 percent for loading in the field and 232 percent for loading trucks for shipping.

Modeling Blueberry Firmness and Mass Loss During Cooling Delays and Storage

Blueberry mass and firmness losses in postharvest environments were measured to determine the effect of cooling delays at selected temperatures. Models were developed from the slopes of mass and firmness values plotted against time for four temperatures (4, 21, 27 and 32 °C). The models were evaluated by holding other sets of blueberries at three temperatures (21, 27 and 32 °C) and at high relative humidity (95 %) for cooling delays of 0, 2, 4, 8, 12 and 24 hours before storage at 4 °C for 24 or 96 hours. Good correlations among predicted versus observed data showed that it was possible to model the mass and firmness losses of blueberries at different temperatures and cooling delays. The impact of cooling delays was less than expected when compared with losses caused by low temperature storage for only four days.

A Machine for Removing Thatch from Turf

ABSTRACT MECHANICAL removal of thatch from turf is a common practice. Presently, a separate operation is re-quired for picking the thatch loosened by mechanical devices. The principle of the machine reported in this paper per-mits simultaneous loosening and dis-charging of the loosened thatch to a catching unit.