This thesis is based on the investigative studies performed on fiberglass crossarm, which will be used in the distribution line structures as an additional insulation component. Lightning impulse voltage tests were conducted on the fiberglass crossarm alone to determine its critical flashover (CFO) voltage, and also the critical flashover voltage of 15 kV polymer suspension insulator plus the fiberglass crossarm. The Added CFO voltage of the fiberglass crossarm to the insulator was determined with polymer suspension insulator as the primary insulation component and the fiberglass crossarm as the secondary insulation component. Added CFO voltage was evaluated for 1 ft through 5 ft length of the fiberglass crossarm for positive and negative polarities, under dry and wet condition. The thesis also presents a comparison of the obtained results made with the previous results of the wood crossarm and polymer crossarm with the polymer suspension insulator.

Glycine-arginine-alpha-ketoisocaproic acid calcium (GAKIC) is an amino acid combination postulated to improve dynamic performance of skeletal muscle during acute, anaerobic exercise in healthy individuals. Purpose: The purpose of this study was to determine the ergogenic effects of GAKIC ingestion on resistance training performance in both trained male and female participants. Methods: Utilizing a double-blinded, crossover design, male participants completed a lower body leg press resistance exercise protocol and female participants completed a lower body leg extension resistance exercise protocol once using 10.2 g GAKIC and the other with a placebo. Results: A significant increase in TLV after GAKIC supplementation was observed in both male and female participants performing a lower body resistance exercise. No significant differences were found in lower body 1RM, HR, BLa, and Glucose between conditions in both groups. Conclusion: We concluded with the specific exercise protocols that were implemented, GAKIC increased TLV in the lower body exercises.

The objective of this study is to identify differences in fully softened shear strength testing based on sample preparation technique and water source. Two sample preparation techniques were used, the blenderizing technique outlined in EM 1110-2-1906 and the hand disaggregation technique outlined in ASTM D 4318-10. The samples used for this study were clay shale samples from the Dallas, Texas area. The two water sources are groundwater and deionized water. Shear strength testing was conducted using a direct shear box. The clay shale Atterberg limits, shear strength, mineralogy, and water chemistry were analyzed to determine the effect on variations in the results.

The paper considers statistical inference for R = P(X < Y) in the case when both X and Y have generalized gamma distributions. The maximum likelihood estimators for R are developed in the case when either all three parameters of the generalized gamma distributions are unknown or when the shape parameters are known. In addition, objective Bayes estimators based on non informative priors are constructed when the shape parameters are known. Finally, the uniform minimum variance unbiased estimators (UMVUE) are derived in the case when only the scale parameters are unknown.

No description available.

When fastener holes are made in structural beams, the Canadian Steel Design Code CAN/CSA-S16.01 -Clause 14.1 (CSA, 2003) states that no deduction in flexural strength is needed for holes up to 15% of the gross flange area. This clause was established many years ago, however, over the years the mechanical characteristics of structural steel have changed. This research study focused on the effects of flange holes on the flexural behavior of steel I-beams made of ASTM A992 steel. This study was conducted primarily based on an experimental investigation involving 25 beam specimens. Holes of various diameters, ranging from 0% to 48% of the gross flange area were laid by drilling holes (a) in the midspan of the tension flange and (b) in the midspan of both the tension and compression flanges. Additionally, beams having holes with fasteners (snug tight) were performed. Based on the test results, this study recommended a design approach, which is analogous to an axial tension member provision as per the current CAN/CSA-S16.01 (CSA, 2003) standard. Accordingly, the effects of holes on the flexural strength can be ignored if the gross-section plastic moment is greater than a modified net-section fracture moment hence, beam members shall be designed to carry the gross-section plastic moment. Otherwise, the beam members shall be designed to carry the modified net-section fracture moment. The comparison of the recommended procedure with the 15% exemption rule as per current steel standard S16.01 (CSA, 2003) demonstrated that the current code provision is unnecessarily conservative for steel grades such as A992 steel. On the other hand, the current provision may be more conservative for high strength steels such as HSLA 80 steel, ASTM A913 Grade 60 and HPS-485W having a minimum yield-to-ultimate strength ration value of more than 0.85. The analytical portion of the research study involved the application of nonlinear finite element method to verify and comprehend the experimental results. The analytical study was conducted using ADINA FE program. The test beams were modeled using 4-node shell element that includes both geometric and material nonlinearities. The material model utilized in the FE analysis was developed based on the experimental-numerical simulation of standard tensile coupons. / Thesis / Doctor of Philosophy (PhD)

Early plastic shrinkage cracking of concrete is an important factor affecting the durability of modern concrete structures. Early cracking (within 24 hours after pouring) may become a problem for any concrete structure. It will promote the entry of harmful materials, destroy the beauty of concrete members, and reduce their durability and performance. In addition, due to long-term shrinkage and/or load, these cracks may gradually expand in the service life of components. Scientific research and engineering technicians often have to face the difficulties caused by early plastic shrinkage cracking of concrete. From the aspects of shrinkage mechanism, measurement method, prediction model and strength development, this paper reviews the scientific and technological status of plastic shrinkage and strength development of early-age concrete, and based on this, summarizes the important conclusions in existing research and establishes the relevant concrete strength prediction model.:1 Introduction 2. Shrinkage in concrete 2.1 Classification and mechanism of concrete shrinkage 2.2 Main factors causing concrete shrinkage 2.3 Concluding remarks 3. Plastic shrinkage in early age concrete 3.1 Method for determining the time of initial and final setting 3.2 Mechanism of plastic shrinkage 3.3 Evaporation 3.4 Capillary pressure 3.5 Main factors affecting plastic shrinkage cracking 3.6 Concluding remarks 4. Different methods for determining the resistance to plastic shrinkage cracking 4.1 Rectangular mould test setup 4.2 ASTM C 1579 4.3 Ring test method (NT BUILD 433) 4.4 Capillary pressure test 5. Development of early age strength of concrete 5.1 Mechanical properties 5.1.1 Compressive strength 5.1.2 Tensile strength 5.1.3 Early-age shrinkage of concrete 5.2 Test and prediction model evaluation 6. Test and quantitative model 6.1 pullout tests on early-age concrete 6.1.1 Tests principle 6.1.2 test result 6.2 Compilation of existing pullout capacity prediction models 6.2.1 Strength and pullout force model based on 𝒉𝒆𝒇 6.2.2 Strength and pullout force model based on 𝒉𝒆𝒇 and ∅𝒉 6.2.3 Tensile strength and pullout force model 6.3 Application of existing prediction model in early age concrete 7. Conclusions 8. Literature

Indiana University-Purdue University Indianapolis (IUPUI) / Clinical evidence suggests that the use of liners in posterior composite restorations may increase the frequency of restoration fractures. Materials that have been used as liner materials for resin composite (RC) restoration include conventional glass ionomers, resin-modified glass ionomers (RMGI), and flowable composites. The aim of this study was to compare the flexural strength of a monolayer of resin composite with that of a bilayer of resin composite and liner. Four types of RC beams were tested: a monolayer control that is an un-lined RC (Tetric EvoCeram, Ivoclar Vivadent) and three “bilayer” specimens that consisted of this same RC lined with one of three liners. The three liners used included two RMGI cements (Vitrebond LC liner; 3M ESPE and, GC Fuji Lining LC; GC America) and a flowable resin composite (Tetric EvoFlow, Ivoclar Vivadent). Each group was tested after water storage for 24 h and 30 d. Altogether, eight, 12-specimen groups were fabricated and tested. Methods: A 25 x 2 x 2 mm mold was completely filled with the RC to form the control beams. To form the bilayer beams, this mold was filled with 0.5 mm of the liner and then with 1.5 mm of the RC. Specimens were stored in 37oC distilled for either 24 h or 30 d. Immediately prior to testing, the 30-day groups were also thermocycled 2500 times, between water baths at 7 oC and 48oC with a 30-s dwell time and a 10-s transit time. Flexural strength was determined using a three-point–bending device. A twoway analysis of variance (ANOVA) with interactions was used to investigate how liner group (or no liner) and storage time affected strength. Results: The interaction between liner type and storage time was significant (p = 0.0128). The un-lined RC (the monolayer beam) was significantly stronger after 24 h than after 30 d in water (p = 0.0098). Water storage between 24 h and 30 d did not change the flexural strength of any of the bilayer (lined) beams (p > 0.05). After storage for 24 h and also for storage for 30 d, both un-lined RC and RC lined with the flowable RC exhibited significantly higher flexural strength (p = 0.0001) than the bilayer beams lined with either RMGI liners.

Indiana University-Purdue University Indianapolis (IUPUI) / Cementing of indirect restorations with resin cements generally requires the pre-treatment of dentin with an adhesive. When dual-cured or chemical-cured resin cements are used with these single-step adhesives, incompatibility issues exist. This has resulted in manufacturers making chemical changes in their products. Kerr Dental markets a new resin cement, Nexus Third generation (NX3), which utilizes a proprietary redox system different from the second generation of composite luting agent (NX2). The aim of this study was to evaluate microtensile bond strength and mode of failure of NX3 and NX2 with two different adhesive systems (total-etch and self-etch) after 1 week and after 3 months of storage. Methods: Sixty-four non-carious teeth were sectioned to expose the dentin using a low-speed saw. Dentin surfaces were ground with 320-grit SiC paper. The adhesives Optibond Solo Plus (SOL), and Optibond All In One (AIO) were applied, and resin cements (NX2, NX3) were used to lute 4-mm composite discs to the treated dentin surfaces. Microtensile bond strength was determined at 1 week (IM) and after 3 months (3MON) of storage using a universal testing machine (MTS). All specimens were examined under the stereomicroscope to determine the mode of failure. Random specimens from each failure group were examined using scanning electron microscopy. Statistical Analysis: Comparisons between the treatment combinations for differences in microtensile bond strength were performed using Weibull-distribution survival analysis. Comparisons between the treatment combinations for differences in the failure mode were performed using Fisher’s Exact tests. The group NX3 SOL IM (30.5 MPa) had significantly higher bond strength than NX3 SOL 3MON (13.4 MPa); NX3 AIO IM (11.3MPa); NX3 AIO 3MON (8.2 MPa; NX2 AIO 3MON (5.8 MPa); NX2 SOL IM (6.3 MPa), and NX2 SOL 3MON (3.2 MPa). The group NX2 AIO IM (19.3 MPa) was not significantly different from NX3 SOL IM. The group NX2 SOL 3MON and group NX2 SOL IM had a significantly higher percentage of teeth with mixed failure than all of the other groups. None of the other groups had significantly different failure mode. The group NX3 SOL IM had 90-percent beam survival beyond 17 MPa, and NX2 AIO IM had 50 percent of beams surviving beyond 17 MPa, a better performance. For all the other groups, more than 50 percent of beams failed below 17 MPa. Results show high evidence of degradation for all groups considered in this investigation. The use of these types of cement adhesive combinations in clinical situations should be used with this understanding.

Traditionally it was thought that the unidirectional strength in the fiber direction of fiber dominated composites was not influenced by the matrix material. As long as the fiber was not affected then the strength would remain. However this thesis will challange that belief. The unidirectional strength in the fiber direction of fiber dominated composites is influenced by the matrix material. The object of this study was to examine the quasi-static tensile strength of unidirectional polymer composites, and then use current analytic models to predict the experimental results. The different matrix materials were polyphenylene Sulfide (PPS), vinyl ester with two different fiber-matrix interface materials, and polyether ether ketone (PEEK). / Master of Science