Martin H. Graham

Relationship of electric power quality to milk production of dairy herds — Field study with literature review ☆

Public Utility Commissions (PUC) in several states adopted 0.5 volt rms (root mean squared) or 1.0 milliampere as the actionable limit for utilities to respond to complaints of uncontrolled voltage. This study clearly shows that the actionable level should be reduced to 10 mV p-p (peak-to-peak), which is 140 times less than the current standard. Dairy farmer complaints that animal behavior and milk production were affected by electrical shocks below adopted standards were investigated on 12 farms in Wisconsin, Michigan, and Minnesota. Milk production per cow was determined from daily tank-weight pickup and number of cows milked. Number of transient events, transients, voltage p-p, waveform phase angle degree, sags, and sag-Vrms were measured from event recorders plugged into milk house wall outlets. Data from 1705 cows and 939 data points were analyzed by multiherd least-squares multiple regression and SAS-ANOVA statistical programs. In five herds for 517 days, milk/cow/day decreased -0.0281 kg/transient event as transient events increased from 0 to 122/day (P<0.02). Negative effects on milk/cow/day from event recorder measurements were significant for eight independent electrical variables. Step-potential voltage and frequency of earth currents were measured by oscilloscope from metal plates grouted into the floor of milking stalls. Milk decreased as number of 3rd, 5th, 7th, 21st, 28th, and 42nd harmonics and the sum of triplen harmonics (3rd, 9th, 15th, 21st, 27th, 33rd, and 39th) increased/day (P<0.003). Event recorder transient events were positively correlated with oscilloscope average V p-p event readings. Steps/min counted from videotapes of a dancing cow with no contact to metal in the barnyard were correlated with non-sinusoidal 8.1 to 14.6 mV p-p impulses recorded by oscilloscope for 5 min from EKG patches on legs. PUC standards and use of 500-Ohm resistors in test circuits underestimate effects of non-sinusoidal, higher frequency voltage/current common on rural power lines.

Relationship of Electric Power Quality to Milk Production of Dairy Herds

Public Utility Commissions (PUC) in several states adopted 0.5 volt or 1.0 milliampere as the actionable limit for utilities to respond to complaints of uncontrolled voltage. Dairy farmer complaints that animal behavior and milk production were affected by electrical shocks below adopted standards were investigated on 12 farms in Wisconsin, Michigan, and Minnesota. Milk production per cow was determined from daily tank-weight pickup and number of cows milked. Number of transient events, transients, voltage (peak-to-peak), waveform phase angle degree, sags, and sag-Vrms were measured from event recorders plugged into milk house wall outlets. Data from 1705 cows and 939 data points were analyzed by multiherd least-squares multiple regression and SAS-ANOVA statistical programs. In five herds for 517 days, milk/cow/day decreased -0.0281 kg/transient event as transient events increased from 0 to 122/day (P<0.02). Negative effects on milk/cow/day from event recorder measurements were significant for eight independent electrical variables. Step-potential voltage and frequency of earth currents were measured by oscilloscope from metal plates grouted into the floor of milking stalls. Milk decreased as number of 3rd, 5th, 7th, 21st, 28th, and 42nd harmonics and the sum of triplen harmonics (3rd, 9th, 15th, 21st, 27th, 33rd, and 39th) increased/day (P<0.003). Event recorder transient events were positively correlated with oscilloscope average Vp event readings, with number of measures over 90 Hz, and number of 4th, 7th, 10th, and 42nd harmonics per day. Steps/min counted from videotapes of a dancing cow with no contact to metal in the barnyard were correlated with non-sinusoidal 8.1 to 14.6 mVp impulses recorded by oscilloscope for 5 min from EKG patches on legs. PUC standards and use of 500-Ohm resistors in test circuits underestimate effects of non-sinusoidal, higher frequency voltage/current common on rural power lines.

Latent Components in the Electrocardiogram

A new decomposition technique useful for representing a set of observed electrocardiograms is presented. This decomposition is different from past techniques in the constraints placed on the component waveforms in that they must be positive and start, stop, and overlap in a prescribed manner. The number of component waveforms is dependent on the maximum error tolerated in the reconstruction of the observed waveforms from the component representation.

Processing and Stereophonic Presentation of Physiological Signals

Since the inception of electroencephalography (EEG), several devices have been built that make brain waves audible; they are known as electroencephalophones (EEP). None has so far taken advantage of the human binaural hearing capability. The system described here presents an effective stereophonic display of four channels of EEG, each from one quadrant of the skull. The signals from the two front quadrants are represented by a single tone whose pitch varies about a center frequency of 1250 Hz and which appears to move laterally in auditory space. The signals from the two occipital quadrants are similarly represented about center frequency of 700 Hz, so that they are readily distinguished from frontal activity. All channels are played through a single pair of headphones. The left headphone represents the combined activity of the two left-hand quadrants; the right headphone, of the two right-hand quadrants. The scheme may be used to supplement conventional graphic EEG records; under special conditions (e. g., routine monitoring, sleep research, training,) it may replace them altogether. Moreover, it may be adapted to vector electrocardiography (EKG) and even to the presentation of signals other than physiological, for instance in seismography.

Time optimal control of a linear hyperbolic system

The time optimal control of transmission lines with amplitude constraints on the control is considered as a typical problem involving systems governed by hyperbolic partial differential equations. Using a Laplace transformation formulation to yield a time ‘optimal’ solution, it is shown how this sub-optimal control which is bang-bang develops into an optimal control which is not always at its limiting values—demonstrating the effect which the nature of the differential equation has on the form of the optimal control. A simple physical interpretation of the results is given.

Error Correction in Batch-Fabricated Memories

Error correcting codes can be used in memories to produce perfect storage modules from components with some defects. The calculations indicate that the additional complexity of using these codes may be very profitable in increasing the yields of integrated circuit memory arrays.