Cost Effectiveness of Bio-Gas Systems for Dairy Farms

Considerable attention has recently been focused on the development of farm management practices that utilize the total resource potential of animal wastes. In addition to the fertilizer value of manure, energy in the form of bio-gas can be generated from manure wastes by an anaerobic digestion process. The purpose of this economic analysis was to evaluate the feasibility of producing energy from the anaerobic digestion of dairy-cow manure. Anaerobic digestion systems were rationally designed for several farm management practices on Vermont dairy farms. These designs were sized to accommodate dairy herds of 20, 50, 100, and 200 cows for both free- and tie-stall arrangements. The realistic evaluation of the potential of any energy source must include a cost effectiveness analysis. This 1974 economic analysis, with selected 1977 cost updatings, included considerations of both the total annual financial investment and the unit cost of net energy production. Minimum unit costs of net energy production for 1977 prices are approximately $0.19 per kwh for the 20-cow operation, but these values decrease with increasing herd size to$0.05 per kwh for the 200-cow dairy farm. At the present time, the generation of bio-gas from the anaerobic digestion of dairy farm manures becomes economically feasible as an alternate source of energy for dairy farms in excess of 200 cows

System Performance Projections for TPV Energy Conversion

TPV technology has advanced rapidly in the last five years, with diode conversion efficiency approaching >30%, and filter efficiency of {approx}80%. These achievements have enabled repeatable testing of 20% efficient small systems, demonstrating the potential of TPV energy conversion. Near term technology gains support a 25% efficient technology demonstration in the two year timeframe. However, testing of full size systems, which includes efficiency degradation mechanisms, such as: nonuniform diode illumination, diode and filter variability, temperature non-uniformities, conduction/convection losses, and lifetime reliability processes needs to be performed. A preliminary analysis of these differential effects has been completed, and indicates a near term integrated system efficiency of {approx}15% is possible using current technology, with long term growth to 18-20%. This report addresses the system performance issues

The photochemistry of N-p-toluenesulfonyl peptides: the peptide bond as an electron donor

The scope of photobiological processes that involve absorbers within a protein matrix may be limited by the vulnerability of the peptide group to attack by highly reactive redox centers consequent upon electronic excitation. We have explored the nature of this vulnerability by undertaking comprehensive product analyses of aqueous photolysates of 12 N-p-toluene-sulfonyl peptides with systematically selected structures. The results indicate that degradation includes a major pathway that is initiated by intramolecular electron transfer in which the peptide bond serves as electron donor, and the data support the likelihood of a relay process in dipeptide derivatives

Intramedullary and Extramedullary Cervical Neurenteric Cyst Requiring Fixation and Fusion

BACKGROUND: Spinal neurenteric cysts are rare in the literature, described by sporadic case reports and small case series. In the vast majority of cases, these lesions are intradural extramedullary. We report the novel case of a cervical neurenteric cyst that was simultaneously intramedullary and extramedullary. CASE DESCRIPTION: A 47-year-old man underwent C2 through C7 laminectomies for microsurgical resection of a large cystic intradural mass, with C1 through T1 instrumentation and fusion. Gross total resection was obtained. Fusion was necessary after removal of the posterior elements because the vertebrae were thinned extensively and remodeled around the tumor, a treatment paradigm that has not been described adequately for neurenteric cysts previously. CONCLUSIONS: A novel case of cervical intramedullary and extramedullary neurenteric cyst is presented with clinical, radiographic, and histologic details. Given the potential for bony remodeling around these developmental tumors, the possibility exists for instability after certain neurenteric cysts are resected. Thus, the present case adds fixation and fusion to the potential treatment paradigm for select spinal neurenteric cysts

Automated Detection and Location of Indications in Eddy Current Signals

A computer implemented information extraction process that locates and identifies eddy current signal features in digital point-ordered signals, said signals representing data from inspection of test materials, by enhancing the signal features relative to signal noise, detecting features of the signals, verifying the location of the signal features that can be known in advance, and outputting information about the identity and location of all detected signal features

Cervical 1-2 Posterior Instrumented Fusion Utilizing Computer-Assisted Navigation With Harvest of Rib Strut Autograft: 2-Dimensional Operative Video

Nonunion of a type II odontoid fracture after the placement of an anterior odontoid screw can occur despite careful patient selection. Countervailing factors to successful fusion include the vascular watershed zone between the odontoid process and body of C2 as well as the relatively low surface area available for fusion. Patient-specific factors include osteoporosis, advanced age, and poor fracture fragment apposition. Cervical 1-2 posterior instrumented fusion is indicated for symptomatic nonunion. The technique leverages the larger posterolateral surface area for fusion and does not rely on bony growth in a watershed zone. Although loss of up to half of cervical rotation is expected after C1-2 arthrodesis, this may be better tolerated in the elderly, who may have lower physical demands than younger patients. In this video, we discuss the case of a 75-yr-old woman presenting with intractable mechanical cervicalgia 7 mo after sustaining a type II odontoid fracture and undergoing anterior odontoid screw placement at an outside institution. Cervical radiography and computed tomography exhibited haloing around the screw and nonunion across the fracture. We demonstrate C1-2 posterior instrumented fusion with Goel-Harms technique (C1 lateral mass and C2 pedicle screws), utilizing computer-assisted navigation, and modified Sonntag technique with rib strut autograft. Posterior C1-2-instrumented fusion with rib strut autograft is an essential technique in the spine surgeon\u27s armamentarium for the management of C1-2 instability, which can be a sequela of type II dens fracture. Detailed video demonstration has not been published to date. Appropriate patient consent was obtained