The effects of fiber and constructional variables on the properties of hydroentangled nonwovens important to their performance when used as batting components in firefighter turnout systems are investigated. Para-aramid, meta-aramid and oxidized PAN constructions are characterized on the basis of thermal insulation, flexibility and durability performance. The contribution of batting properties to the thermal protective performance provided by multilayer turnout systems is examined for selected turnout lay ups. Optimized thermal liner systems are suggested based on layered constructions including the properties of the face cloth components.

Despite the latest polymer materials and surgical suturing techniques, the knot will always be the weakest point of the tied suture loop. In theory, the knot must be as small as possible to prevent an excessive amount of tissue reaction and a delay in healing. There have been reports suggesting that topical cyanoacrylate adhesives could have a reinforcing effect on a surgeonâs knot. Such an outcome could lead to the elimination of knot slippage and the unsatisfactory performance of some surgical knots. The main purpose of this study was to determine if cyanoacrylate adhesive could have a significant reinforcing effect on typical suture types and sizes when tied as a surgeonâs knot. The second aim was to evaluate if the cyanoacrylate adhesive could replace an additional throw in the surgeonâs knot so as to achieve an equivalent mechanical performance. The topical cyanoacrylate adhesive LiquiBand® was combined with six different suture materials (TicronTM, SurgidacTM, Ethilon*, Nurolon*, BiosynTM and PDS*II) in four different sizes (USP 5-0, USP 3-0, USP 0 and USP 1). The surgeonâs knot (2=1) with and without one (2=1=1) and two additional throws (2=1=1=1) were tied in a reproducible way and mechanically tested. Six dependent variables were used to evaluate the performance of each knot with and without adhesive. The performance criteria were: the force at loop failure, the maximum loop-holding force, the loop holding capacity, the knot efficiency, the knot elongation efficiency and the loop distraction. From the results and from scanning electron microscopic observations of the reinforced knots, the cyanoacrylate adhesive was found to significantly improve the knot performance. The improvement was superior with braided sutures and with absorbable polymer sutures. The reinforcement was more significant with thicker suture sizes and with the plain surgeonâs knot. Finally, it was found that, according to the six performance criteria, the cyanoacrylate adhesive could not replace an additional throw in the surgeonâs knot.

Flame retardant chemicals were used as topical finishes on cotton and cotton blended fabric. Comparison of flame resistance and durability of non-bromine/non-antimony flame retardants were explored based on flame resistance testing and physical testing results. Three 100% cotton fabrics and 3 cotton blended fabrics were used. Twenty one different commercially available flame retardants were used as topical finishes on all fabric types. Fabrics were treated and tested at 0, 5, 10 and 25 washes. Final results show that two of the phosphorus flame retardants were durable to 25 washes. Physical testing results show that there were undesirable side effects from the two durable topical treatments. The two phosphorus based flame retardants outperformed the bromine/antimony flame retardants and the non-treated samples in flame resistance.

The purpose of this research was to develop a model to reduce errors in transactional processes within companies. The model created utilized three error proofing concepts: the FMEA, TRIZ Solution Directions, and the Error Proofing Healthcare (EPH) model. The research involved analyzing 250 FMEAâs that were previously conducted in a large transactional corporation and obtaining feedback from associates. The model that was created consisted of three phases. Phase one identifies the potential failures that could occur within a process while phase two uses TRIZ solution directions to create multiple innovative solutions and phase three uses a method called Solution Priority Number (SPN) to rank and evaluate the solutions generated. The SPN consists of the return on investment (ROI) and the ease of implementation of each solution. Excel worksheets were created to support the Error Proofing Transaction (EPT) model. A case study was performed within a large transactional corporation. A team completed the existing FMEA and then completed the new EPT model. When comparing the existing FMEA and the EPT model it was found that the EPT model reduced the team meeting time by 50% and produced more failure modes, more effects, more causes, more high risk failure modes, as well as a more enhanced set of solutions.

The purpose of this research was to develop a composite flooring system to be used in the equine surgical unit in the College of Veterinary Medicine at North Carolina State University. This material was developed due to an extensive need for a new flooring system that would accurately meet the needs of the customers and stakeholders involved. Research included the origin of Design for Six Sigma (DFSS), tools that differentiated it from previous design processes, past/present flooring solutions, structure/dynamics of a horse, horse tendencies, and composite theories. By implementing the five step procedure of DFSS, Define, Measure, Analyze, Design, and Verify, a sound product was able to be realized. Certain DFSS tools were implemented such as Voice of the Customer Analysis, Reverse Engineering, Brainstorming, Design of Experiment, Pugh Concept Analysis, Computer Aided Design, and Finite Element Modeling. The end solution was a composite flooring system that meets the needs of not only the primary market but many secondary markets as well.

In the United States alone, people consume and discard over 500 billion pounds of wastes annually. Wastes discarded in landfills create threats to land, air, and water, but also represent lost resources. Recycling has the ability to divert wastes from landfills and recover precious raw materials. However, recycling activities are only as efficient as the reverse logistics and supply chains that support them. These areas are relatively new, but successful implementations have real benefits for companies in terms of profits and environmental goodwill. Many companies are creating closed loop supply chains where forward and reverse activities are interlinked in cyclical processes. Ideally, a virgin input enters the system only once and is recycled forever. The problem with most current closed loop supply chains is that they are product-specific. When a closed-loop supply chain is designed, the product must be designed so that it can easily be recycled back into the supply chain. The problem is that the product must contain a minimum number of dissimilar components. For textile products, this presents a real challenge because of fiber blends and finishes that make component separation difficult. These problems create the need to design textile recycling systems. This research focuses on the logistical systems necessary to recycle textile materials. Methodologies for estimating post-consumer carpet (PCC) returns and trailer loading capacities are first discussed, followed by location allocation models that determine the geographical placement of recycling sites of an existing carpet collection network. The location allocation model utilizes zip code populations to allocate percentages of the PCC returns to the collection sites. The population for each site is determined by summing the five-digit zip code populations within a specified collection radius. The collection site weight is then calculated as the percentage of the total population for the collection network. A proposed national network model, based on three-digit zip codes, has also been developed. This model includes economies of scale for recycling processing costs. Increasing annual returns have been modeled to study the effects of changing network morphologies on the location and allocation of recycling sites. A PCC reverse supply chain cost model is also presented to study the cost relationships of the activities that comprise the recycling network. Transportation costs from the location allocation models were utilized in the model, as well as cost data from industry. It was found that processing costs are the main drivers in a nylon 6 recycling network, while a nylon 6,6 network is sensitive to cost changes in any reverse activity. Quantified results show that either recycling technologies must become more efficient or virgin nylon prices must increase for recycled nylon to be competitive with virgin polymers.

The mechanical properties and morphology of multi-wall carbon nanotube (MWNT)/polypropylene (PP) nanocomposites were studied as a function of nanotube orientation and concentration. Through melt mixing followed by melt drawing, using a twin screw mini-extruder with a specially designed winding apparatus, the dispersion and orientation of multi-wall carbon nanotubes was optimized in polypropylene. Tensile tests showed a 32% increase in toughness for a 0.25 wt % MWNT in PP (over pure PP). Moreover, modulus increased by 138% with 0.25 wt % MWNTs. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) all demonstrated qualitative nanotube orientation. Wide angle X-ray diffraction was used to calculate the Herman?s Orientation Factor for the composites as function of nanotube loading and orientation. No significant changes in PP crystal orientation were found indicating that the alignment of the nanotubes did not significantly affect the orientation of the PP crystals. In addition, differential scanning caloriometry (DSC) qualitatively revealed little change in overall crystallinity. In conclusion this work has shown that melt mixing coupled with melt drawing has yielded MWNT/PP composites with a unique combination of strength and toughness suitable for advanced fiber applications, such as smart fibers and high performance fabrics.

The price of cotton is dictated by quality and the most significant factor of contributing to the fiber quality is the length distribution of the fibers contained within the population. Therefore it is of importance to accurately and repeatably measure the length of fibers within a population so that it is graded properly. Current methods are inadequate and thus prior work focused on designing a machine to directly measure individual cotton fibers using digital imaging. The current work begins with the evaluation of the effectiveness of the digital imaging machine. The machine was evaluated and sources of error identified. Modifications were implemented in an attempt to improve the error. After multiple modifications with little success an entirely new design was conceptualized. The new design aimed to eliminate all major sources of error with the existing machine while not creating new sources of error. The new design is discussed and the results are compared to those obtained by the original imaging machine. The new machine was better able to accurately measure the length of cut length fibers. The variation between fibers within a sample and entire samples of cut length fiber was significantly decreased when compared to the variation of the previous system.

The purpose of this study was to investigate the properties of air-textured aramid yarn (ATAY), in a single yarn composite (SYC), in a 3D woven fabric preform, and in a 3D preform composite. Yarn tensile tests demonstrated textured yarn was 70-77% lower in tensile strength, 82-85% lower in tensile modulus, and 60-190% higher in breaking strain than those of the control yarn. The results of SYC testing illustrated that the control yarn composite had only a 5% higher tensile strength, a 27% higher modulus, and 11% lower energy to break than the textured single yarn composite. Fabric tensile tests demonstrated a low initial modulus and a much larger secondary modulus for all 3D woven preforms. The ATAY fabric had a similar initial modulus and a much lower secondary modulus in the weft direction compared to the control fabric. The ATAY fabric had a significantly higher yield shear stress and strain, primary and secondary shear moduli, energy to yield point, and total energy absorbed to 4° than those of the control. With the same fiber volume fraction, the ATAY composite had a slightly lower tensile strength and modulus, but a 120% higher shear modulus, than the regular aramid yarn (RAY) composite. Unlike the RAY composite brittle failure behavior, the ATAY composite failed in a ductile manner with multiple diverting cracks propagating during failure. The ATAY composite had a much higher yield point in the 45° direction tensile test, a much higher softening point in the warp direction tensile test, and increased the interlaminar shear strength of a laminated composite by 37% as compared with the control.

Nanofibers were produced using relatively new electrospinning technique. Single layer nanofibers were fabricated using nylon-6. Several parameters such as polymer molecular weight, concentration, surface tension, applied electric voltage, distance between tip to grounded electrode and feed rate were investigated to optimize fiber consistency and diameter. Scanning electron microscopy was employed to study fiber morphology and diameter. Understanding the effects of various parameters mentioned above, electrospinning strategy was further utilized to produce nanofibers with novel core-sheath structure using chitosan, a biopolymer and polyethylene oxide (PEO). Chitosan is very difficult to electrospin, to alleviate this problem PEO was used as sheath to support chitosan core. For this purpose, rheology of polymer solutions was evaluated for successful fabrication of core-sheath nanofibers. Only 3 wt % chitosan was found to produce coaxial structure with 4 wt % PEO, due to their proximity in rheological behavior. Coaxial morphology of nanofibers was verified by transmission electron microscopy having 250 nm and 100 nm as sheath and core diameters respectively. Fourier transform infrared spectroscopy was employed to investigate the effect of de-ionized water treatment of core-sheath mats where in PEO layer was removed off in order to get pure chitosan nanofibers. Coaxial nanofibers with one component were also fabricated using pure PEO as core and PEO doped with Multi-walled carbon nanotubes as sheath material. Results showed that as carbon nanotubes were subjected to relatively smaller volumes, predominantly on the surface culminated in appreciable increase in conductivity as well as mechanical properties. Coaxial nanofibers produced from electrospinning are of particular interest in tissue engineering and wound healing scaffolds.