Applicability of thermoplastic composites for space structures

The discussion defines a thermoplastic resin and compares the structural and environmental properties and the fabrication and repairability of the thermoplastic composite with a typical epoxy composite. Low labor costs exhibited by the thermoplastic composites make them a priority consideration for use in space structure

Development of liquid oxygen compatible adhesive system, part 2 Final report, Jul. 1968 - Dec. 1968

Development of liquid oxygen compatible adhesive syste

Coal fires: an environmental disaster

The mission of the Coal Fire Gang (CFG) is to spread awareness about the global issue of uncontrolled coal fires, and to highlight them as a low-hanging fruit of immediate emissions reduction. This report summarizes CFG’s research for the WERC competition, for which this topic was chosen as an open task. Beyond raising awareness, CFG modeled, developed and built an experimentation apparatus meant to prove the validity of a relatively cheap extinguishing method which was also novel to the regions in which it could be employed. The apparatus, which simulated an underground coal fire, was used to test a sand and water extinguishing method. CFG’s results on the experimental research side suggest that the sand and water approach to extinguishing coal fires, though requiring attention and labor for long periods of time (up to a few years depending on how long the coal fire has been burning prior to extinguishing activities), is very cost effective. Exact economics of a particular coal fire would have to be determined on a case-by-case basis, depending on the size and age of the fire, but those costs include only sand, water, labor, and heavy equipment to transport the sand around. The proposed extinguishing technique involves capping all exhaust vents of a fire with sand, and then saturating the sand with water. The steam created by the water on contact with the heated ground and coal then expands and flows through the cavity, flowing out of what were originally combustion air influent vents. This flow reversal could significantly reduce the oxygen intake while also removing heat. Over time, as more vents are discovered or created, they can be capped in the same manner. On the economics side, CFG proved that even at conservative estimates of the cost to extinguish fires and the cost of alternative CO2 sequestering methods, extinguishing coal fires is the for immediate global emission reduction. CFG proposes that coal fires around the world are prioritized ahead of new and expensive technology for emission reduction, and that at the very least the emissions from coal fires are drawn into some regulating system so that they can be tracked and better managed

Development of a fluidic mixing nozzle for 3D bioprinting

3D bioprinting is a relatively new and very promising field that uses conventional 3D printing techniques and adapts them to print biological materials that are suited for use with cells. These bioprinters can be used to print cells encapsulated within biological ink (bio-ink) to create and customize complex three-dimensional tissues and organs. Our work has focused on developing a new bioprinter nozzle that addresses critical gaps with present-day bioprinters, namely, the lack of standardized, physiologically-relevant biomaterials, and their one nozzle per composition printing capacity. These shortcomings preclude printing a range of cellular and biomaterial compositions (including gradients of cells and matrix components) within a single tissue construct. Type I collagen oligomers, a new soluble collagen subdomain that falls between molecular and fibrillar size scales, are ideally suited for tissue fabrication. This collagen formulation, which is produced according to an ASTM voluntary consensus standard, i) exhibits rapid suprafibrillar self-assembly yielding highly interconnected collagen-fibril matrices resembling those found in the body\u27s tissues, ii) supports cell encapsulation, and iii) allows customized, multi-scale design across the broadest range of tissue architectures and physical properties. These properties, along with its superior physiologic relevance, support the use of this biomaterial in the development of a bioprinting nozzle that is able to address the key gaps in the field of 3D bioprinting. After researching microfluidic mixing devices and current bioprinters, early iterations of a 3D bioprinting nozzle were designed and machined to mix three fundamental reagents required to form a broad array of collagen-fibril matrix compositions, namely oligomeric type I collagen (oligomer), oligomer diluent (diluent), and self-assembly reagent (S.A.R). The nozzle was designed to mix specified proportions of these solutions using a combination of hydrodynamic focusing and twisted channel mixing mechanisms before depositing the selfassembling collagen. Three syringe pumps were used to continuously drive varying flow rates of the three reagents to the nozzle, which allowed for the creation of a broad array of cell and matrix compositions, including fibril-density gradients. To validate nozzle performance, three experiments were conducted to define dispensing volume accuracy and precision, mixing quality, and functional performance of dispensed materials, including cells and matrix. In summary, the integration of standardized self-assembling collagens with this innovative fluidic mixer effectively minimizes the number of printing reservoirs, employs a single dispensing nozzle, and most importantly supports on demand fabrication of various tissue compositions. This advanced 3D bioprinting technology, together with our mechanistic-based tissue engineering design principles, is expected to support customized design and fabrication of complex and scalable tissues for both research and medical applications

The Effect of Early Skin-to-Skin Contact on Breastfeeding Duration and Exclusivity: a Mixed Methods Study

Background: Breastfeeding is beneficial to the health of both mother and infant and fosters optimal growth for the baby in the first two years of life. Evidence based guidelines followed by the Baby Friendly Hospital Initiative (BFHI) includes Ten Steps. Step Four recommends placing the newborn skin-to-skin on the mother\u27s chest to foster the initiation of breastfeeding in the first hour after birth.;Objectives: The first and second objective determined if skin-to-skin contact (SSC) between mother and infant in the healthy postpartum breastfeeding mother affected duration and exclusivity rates at 6 weeks, 3 months and 6 months. The third objective described mothers\u27 lived experience with breastfeeding and bonding following SSC per policy.;Design: A retrospective, cohort, mixed methods design was used in a small rural hospital in West Virginia (WV). The sample included 55 women who met the inclusion criteria of healthy mothers whose babies were vaginally delivered January 2012--September 2016. The intervention cohort received SSC per the Baby Friendly Step 4 policy. The comparison group did not receive SSC.;Methods: Duration rates, exclusive breastfeeding (EBF) rates, and mothers\u27 lived experience following SSC were collected via phone interview and transcription.;Results: Comparing the SSC to the comparison cohort, breastfeeding duration rates were: 82.4% vs. 61.6% at 6 weeks (p. = 0.170); 73.5% vs. 52.4% at 3 months (p. = 0.190); 44.1% versus 42.9% at 6 months (p. = 0.170). EBF rates were: 73.5% vs. 51.7% at 6 weeks (p= 0.336); 64.7% vs. 52.4% at 3 months (p = 0.533); 20.6% vs.23.8% at 6 months (p. = 1.00). In most time intervals the SSC cohort rates were higher than the comparative cohort rates, yet none of the rates reached significance. Mothers identified that SSC had a positive effect on their breastfeeding and bonding experience in the first months of their babies\u27 lives

The Economic Benefits of Portable Instrumentation on the Criminal Justice System: A Comprehensive Return-on-Investment Analysis

Prosecuting crime is an expensive endeavor. This thesis compiles data from a variety of sources to show that, in 2015, the average cost of prosecuting a seized-drug case in the United States was about {dollar}26,000. Of that amount, crime laboratories only cost about {dollar}275 per seized-drug case, or less than ~1% of the total cost of prosecuting a drug case. We show that the criminal justice system could save millions of dollars per year by strategically investing in portable chemical instrumentation and conducting seized-drug confirmatory analyses at the scene of the crime, or at booking, instead of in the laboratory. Such investments would require that on-site analyses meet the same strict standards for drug identifications as conventional laboratory protocols and that drug identification reports be completed before booking.;By implementing confirmatory portable instrumentation to analyze seized-drug samples in the field, the initial cost of investment can be justified by the benefits and cost savings in the court system. For example, one major economic benefit of on-site testing is the reduction of pretrial costs---like jail time---for suspects awaiting trial. Our calculations show that marginal savings between {dollar}1.5M and {dollar}20M within the first year and between {dollar}8M and {dollar}90M by the fifth year of implementation are possible for each set of portable instruments purchased. The economic analysis includes expenses such as the capital equipment costs, supplies, service contracts, full-time equivalent employees and their benefits and travel. The estimated cost of deployment is ~{dollar}327,000 in the first year and an additional cost of ~{dollar}214,000 a year thereafter. On-site analyses are expected to save an average of 150 jail days per case, which, at an average cost of {dollar}129 per day, would save approximately {dollar}10K per case. In addition to the economic benefits, some additional benefits for pre-booking drug tests include reduced recidivism rates, better prosecutorial accuracy, increased public faith, and decreased compensation costs for the wrongly convicted. For all these reasons, portable instrumentation can greatly benefit the entire criminal justice system

Development of polyphenylquinoxaline graphite composites

The potential of polyphenylquinoxaline (PPQ)/graphite composites to serve as structural material at 316 C (600 F)has been demonstrated using a block copolymer, BlCo(13), PPQ derivative. Initially, thirteen polyphenylquinoxalines were evaluated. From this work, four candidate polymers were selected for preliminary evaluation as matrices for HMS graphite fiber reinforced composites. The preliminary composite evaluation enabled selection of one of the four polymers for advanced composite preparation and testing. Using an experimentally established cure schedule for each of the four polymers, preliminary laminates of 50% resin volume content, prepared without postcure, were tested for flexure strength and modulus, interlaminar shear strength (short beam), and tensile strength and modulus at ambient temperature. A block copolymer (Bl Co 13) derived from one mole p-bis (phenylglyoxalyl) benzene, one fourth mole 3,3'-diaminobenzidine and three-fourths mole 3,3', 4,4'-tetraminobenzophenone was selected for extensive study. Tensile, flexural, and interlaminar shear values were obtained after aging and testing postcured BlCo(13) laminates at 316 C (600 F). The potential of PPQ/graphite laminates to serve as short term structural materials at temperatures up to 371 C (700 F) was demonstrated through weight loss experiments