Many secondary schools in Utah have adopted the Project Lead the Way (PLTW) pre-engineering program. Little research has been conducted in Utah to show how successful these programs are or what factors are perceived to contribute to that success. This research is about defining PLTW program success and identifying factors perceived to improve success. This was accomplished by interviewing career and technical education directors in Utah who have the PLTW program in their districts. Questionnaires were also developed to question PLTW teachers, school administrators, and counselors with PLTW in their schools about factors that might contribute to PLTW program success. A successful PLTW program in Utah was found to be a program that was perceived to meet the goals of implementation, had the ability to attract adequate student enrollment, and was perceived to promote scholarly student achievement. It was found that successful PLTW programs (a) utilize dynamic teachers taking advantage of teacher professional development, (b) capitalize on student interest in the subject and differentiate learning models and environments, (c) utilize a collaborative effort between schools, industry, and community, (d) advertise class offerings and program benefits so students can make wise class choices during registration, and (e) make sure resources and facilities are available for all the curriculum requirements.

Previous studies have shown that the molecule MR1, a cGMP analogue, may be a suitable drug for neurodegenerative eye diseases. These diseases cause the eyesight to greatly deteriorate which in turn can result in the patient becoming blind. In this thesis, several salt forms of MR1 were synthesized and characterized to generate the drugs physicochemical properties, such as solubility and solid-state behavior. This in order to determine the drugs pre-formulation data. Synthesis of MR1 Na+ and MR1 Free form were performed in order generate material for solubility studies and solid state characterizations. Solid-state characterization was done in terms of X-ray, Microscopy, Hot Stage Controller, DSC, TGA and DVS. All salt forms, expect for the Free form, indicated crystallinity through X-ray analyses. However, none of the salt forms showed any clear melting point after being evaluated by DSC. TGA analysis of MR1 Na+ salt form indicated a huge weight decrease. A total amount of 15 % of the sample decreased over a very short time range in just a few seconds. The result is very extraordinary and should be controlled and analyzed once again. Results regarding amorphicity of MR1 Free form did not completely comply with results from DVS and X-ray. Further analyses should therefore be performed with extra material to obtain a more consistent result. Moreover, the solubility of the salt forms was determined and it was observed that MR1 Na+ indicated to be most soluble in all the tested buffers, as compared to MR1 TEAH+ and MR1 Free form. The pre-formulation data from this thesis are of importance for the work on understanding how the drug MR1 behaves. The work carried out in this thesis will continue (beyond the scope of this bachelor thesis) and the results herein will be used for further studies of neurodegenerative eye diseases. / Studier har visat att molekylen MR1, en cGMP analog, kan vara ett lämpligt läkemedel för neurodegenerativa ögonsjukdomar. Dessa sjukdomar leder till att synen kraftigt försämras vilket kan leda till att patienten förlorar sin synförmåga. I detta examensarbete har olika saltformer av MR1 syntetiserats för att frambringa molekylens preformuleringsdata. Denna preformuleringsdata kommer sedan användas för framtida studier inom forskningsområdet. Olika saltformer av MR1 har syntetiserats och karakteriserats med avseende på molekylens fysikalkemiska egenskaper såsom löslighet och karakterisering av dess fasta tillstånd. Syntetisering av MR1 Na+ och MR1 fri form har utförts för att få fram prover till löslighetsstudier och karakterisering av dess fasta tillstånd. Karakteriseringen av saltformernas fasta tillstånd utfördes genom tillämpning av röntgenmetoder, Mikroskopi, Hot Stage Controller, DSC, TGA och DVS. Alla saltformer förutom den fria formen visade sig ha kristallina inslag. Ingen av salterna visade någon tydlig smältpunkt efter att ha analyserats i DSC instrumentet. TGA analysen visade 15 % viktminskning för MR1 Na+ saltet, vilket är ett relativt ovanligt resultat och bör kontrolleras och repeteras ännu en gång. När MR1 fri form analyserades i DVS och röntgen instrumentet för att detektera hur amorft saltet är överstämde resultaten inte med varandra. Analysen bör därmed kontrolleras och repeteras. Löslighetsstudierna visade att MR1 Na+ har högst löslighet i jämförelse med MR1 TEAH+ och MR1 fri form när salterna analyserats i olika buffertar.

The objectives of this study were to determine the effects of deboning time (pre- and post-rigor), processing steps (grinding - GB; salting - SB; batter formulation - BB), and storage time on the microbiological, technological, sensory, and willingness-to-pay attributes of beef sausage. Using the chuck primals from 5 24-month-old Holstein steers, beef was deboned within 2 h post-mortem (pre-rigor) or 72 h (post-rigor) and processed to sausages using beef bratwurst spice mix, water/ice slurry, corn syrup, erythorbate, nitrite, salt, and 0.25% w/w sodium tripolyphosphate and a typical cooking cycle ending at 74 ¡ãC. Samples were collected during grinding, salting, batter formulation, and storage of cooked sausages. Beef deboning time did not influence bacterial counts (P ¡Ý 0.138). However, salting of raw ground beef resulted in a 0.4-log reduction in both aerobic plate count and Salmonella (P ¡Ü 0.001). Lactic acid bacteria increased from 0.5 log on d 0 to 3.8 log on d 120 of vacuum storage (P ¡Ü 0.019). The pH was greater in pre-rigor GB and SB than in post-rigor GB and SB (P < 0.001). However, deboning time had no effect on metmyoglobin reducing activity, cooking loss, and color of raw beef mixtures. Protein solubility of pre-rigor SB (124.3 mg/kg) tended to be greater than that of post-rigor SB (113.9 mg/kg; P = 0.071). TBARS were greater in BB but decreased during vacuum storage of cooked sausage (P ¡Ü 0.018). With the exception of chewiness and saltiness being 52.9 N-mm and 0.3 points greater in post-rigor sausage (P = 0.040 and 0.054, respectively), instrumental texture profile analysis and descriptive sensory analysis detected no difference between pre- and post-rigor sausages (P ¡Ý 0.153). Consumers preferred the aroma, flavor, and overall acceptability of pre-rigor sausage when compared to post-rigor sausage (P = 0.008, 0.029, and 0.011, respectively). Average predicted demand was 0.7 lb greater for pre-rigor than post-rigor sausage at any price point from $1/lb to $10/lb (P ¡Ü 0.001).

The purpose of this study was to describe the perceptions of women diagnosed with gynecologic cancers or pre-cancers regarding participation in an online support group. The study contributed to the literature regarding online support for women with gynecologic cancers and pre-cancers. The data were analyzed using the descriptive univariate analysis method of frequency distribution presented in percentages. Out of a population of 472 members of an online support group for women with gynecologic cancers and pre-cancers, 379 (80%) participated in the study. A survey instrument consisting of 6 parts was used in this study. Part I and Part IV of the instrument were designed to collect data regarding the benefits (personal enrichments) of participating in an online support group. Part II and Part III were designed to collect data regarding the advantages of a support group being online, while Part V collected data regarding online support, illness, information, awareness, and sense of self. Part VI collected demographic information and personal information. The research questions posed in the study were developed to examine benefits, advantages, and information about participating in an online support group. The results from this study indicated that there are many benefits (personal enrichments) of online support for the women with gynecologic cancers and pre-cancers who joined these groups, as well as many advantages for them of a support group being online. The results also suggested that although these members were demographically different and were experiencing a variety of gynecologic cancers and pre-cancers, they were very cohesive in their wants and needs from online support. The results indicated that the experiences, both physical and emotional, of the women in these groups were more similar than different. Conclusions and recommendations based on the findings in this study indicated that online support is a positive addition to the lives of the women dealing with cancers and pre-cancers and that more in-depth studies should be conducted and the information disseminated to cancer patients.

Cattle are naturally colonized by enterohemorrhagic Escherichia coli within the gastrointestinal tract. The most notorious of the enterohemorrhagic E. coli is E. coli O157:H7, which can cause serious illness to humans if ingested. To ensure that the United States has a safe food supply, research is ongoing in pre-harvest food safety and pathogen intervention strategies. While advances in pre-harvest intervention strategies are encouraging, no method has proven to completely eliminate and/or control O157:H7. A key limitation to successful pathogen intervention strategies is the inability to track and monitor pathogens in a real-time fashion. Through the use of bioluminescent plasmids harboring the luxCDABE cassette, pathogen tracking could be a viable solution. Bioluminescent plasmids are capable of facilitating the tracking, pathogenesis and physical locations of pathogens, thus enabling researchers to have a better understanding of the pathogenic process.

Predictive maintenance is extremely important to fleet owners. On-duty automobile engine failures add cost of extra towing, gas and labor expenses which can add up to millions of dollars every year. Early knowledge of upcoming failures helps reduce these expenses. Thus, companies invest considerably in fault detection and diagnosis (FDD) systems to reduce unnecessary costs. Artificial Intelligence (AI) is getting increasingly used in the data driven signal based FDD industry because it requires less labor and equipment. It also results in higher productivity since it can operate continuously. This research offers Artificial Intelligence based solutions to detect and diagnose the degradation of three Internal Combustion Engine (ICE) parts which may cause on-duty failures: lead-acid accessory battery, spark plugs, and Exhaust Gas Recirculation (EGR) valve. Since the goal behind most FDD systems is cost reduction, it is important to reduce the cost of the FDD test. Therefore, all the FDD solutions proposed in this research are based on three types of built-in sensors: battery voltage sensor, knock sensors and speed sensor. Furthermore, the engine database, the Machine Learning (ML) and Deep Learning (DL) models, and the virtual operating machines were all stored and operated in the cloud. In this research, eight Machine Learning (ML) and Deep Learning (DL) models are proposed to detect degradations in three vehicle parts mentioned above. Additionally, novel advanced pre-processing approaches were designed to enhance the performance of the models. All the developed models showed excellent detection accuracies while classifying engine data obtained under artificially and physically induced fault conditions. Since some variant data samples could not be detected due to experimental flaws, defective sensors and changes in temperature and humidity, novel pre-processing methods were proposed for Long Short-Term Memory Networks (LSTM-RNN) and Convolutional Neural Networks (CNN) which solved the data variability problem and outperformed the previous ML/DL models. / Thesis / Doctor of Philosophy (PhD) / Predictive maintenance is extremely important to fleet owners. On-duty automobile engine failures add cost of extra towing, gas and labor expenses which can add up to millions of dollars every year. Early knowledge of upcoming failures helps reduce these expenses. Thus, companies invest considerably in fault detection and diagnosis (FDD) systems to reduce unnecessary costs. Artificial Intelligence (AI) is getting increasingly used in the data driven signal based FDD industry because it requires less labor and equipment. It also results in higher productivity since it can operate continuously. This research offers Artificial Intelligence based solutions to detect and diagnose the degradation of three Internal Combustion Engine (ICE) parts which may cause on-duty failures: lead-acid accessory battery, spark plugs, and Exhaust Gas Recirculation (EGR) valve. Since the goal behind most FDD systems is cost reduction, it is important to reduce the cost of the FDD test. Therefore, all the FDD solutions proposed in this research are based on three types of built-in sensors: battery voltage sensor, knock sensors and speed sensor. Furthermore, the engine database, the Machine Learning (ML) and Deep Learning (DL) models, and the virtual operating machines were all stored and operated in the cloud. In this research, eight Machine Learning (ML) and Deep Learning (DL) models are proposed to detect degradations in three vehicle parts mentioned above. Additionally, novel advanced pre-processing approaches were designed to enhance the performance of the models. All the developed models showed excellent detection accuracies while classifying engine data obtained under artificially and physically induced fault conditions. Since some variant data samples could not be detected due to experimental flaws, defective sensors and changes in temperature and humidity, novel pre-processing methods were proposed for Long Short-Term Memory Networks (LSTM-RNN) and Convolutional Neural Networks (CNN) which solved the data variability problem and outperformed the previous ML/DL models.

This study has been made for three purposes: 1) to find out what difficulties experienced and inexperienced teachers recognize in their teaching; 2)to find out what factors have influenced these difficulties; and 3)to find out, if possible, which difficulties could be eliminated with further pre-service training.

<p>In Chapter 2, an experiment has been developed to investigate the passive pre-chamber jet ignition process in gasoline engine configurations and low-load operating conditions. The apparatus adopted a modified 4-cylinder 2.0L gasoline engine to enable single-cylinder operation. To reduce the complexity, the piston position was fixed at a predefined position relative to the top dead center (TDC) to simulate thermodynamic conditions at ignition and injection timings. High-speed Infrared (IR) imaging was applied to visualize the jet penetration and ignition process inside the main cylinder and to investigate the cyclic spatial variability. Two passive pre-chambers with different total nozzle areas and numbers of nozzles were used. In addition, the pre-chamber volume and pressure at ignition timing were varied to examine their effect on jet ignition performance. Misfire behavior was observed in the main chamber of all test cases, and the results suggested that the main cause is a high Residual Mass Fraction (RMF) in the pre-chamber affecting the subsequent cycle. A larger total nozzle area, smaller volume, higher pressure, and fuel-lean operation tended to mitigate the misfire behavior. For a test case with a spark pressure of 6 bar, a reduced cyclic variability in terms of coefficient of variation peak cylinder pressure (COVPmax) from 10.03% to 7.38% and combustion phasing variation from 81 crank angle degree (CAD) to 12 CAD were observed with increasing pre-chamber volume-to-area (V/A) ratio from 59.37 m to 103.11 m, but slightly higher misfire frequency was observed, from 46.67% to 50.00%, suggesting an accurate combination of pre-chamber design parameters is needed to improve overall performance at low-load operation.</p> <p>In Chapter 3, it examines the influence of passive pre-chamber nozzle diameter and dilution level on jet formation and engine performance. Utilizing a modified constant-volume gasoline direct injection engine with an optically-accessible piston, we tested three passive pre-chambers with nozzle diameters of 1.2, 1.4, and 1.6 mm, while nitrogen dilution varied from 0 to 20%. With the help of high-speed imaging, we captured pre-chamber jet formations and subsequent flame propagation within the main chamber. Our novel findings reveal that asymmetric temporal and spatial jet formation patterns arising from pre-chambers significantly impact engine performance. The larger nozzle diameter pre-chambers exhibited the least variation in jet formation due to their improved scavenging and main mixture filling processes, but had the slowest jet velocity and lowest jet penetration depth. At no dilution condition, the 1.2 mm-PC demonstrated superior performance attributed to higher pressure build-up in the pre-chamber, resulting in accelerated jet velocity and increased jet penetration depth. However, at high dilution condition, the 1.6 mm-PC performed better, highlighting the importance of scavenging and symmetry jet formation. This study emphasizes the importance of carefully selecting the pre-chamber nozzle diameter, based on the engine's operating conditions, to achieve an optimal and balanced configuration that can improve both jet formation and jet characteristics, as well as scavenging.</p> <p>In Chapter 4, it investigates the influence of passive pre-chamber nozzle diameter on jet ignition and subsequent main chamber combustion under varying load conditions and dilution levels using a constant-volume optical gasoline direct injection engine. The results reveal that as the load decreases, both fuel availability and flow conditions deteriorate, leading to delayed and inferior jet characteristics that affect main chamber ignition and combustion processes. In high and medium load conditions without dilution, the smallest nozzle diameter pre-chamber (1.2mm-PC) shows improved jet ignition and main combustion due to earlier jet ejection, enhanced penetration, and intensified jet. This is facilitated by the smaller nozzle diameter enabling faster and higher pre-chamber pressurization. Conversely, under low load conditions, the largest nozzle diameter pre-chamber (1.6mm-PC) performs better, likely due to improved scavenging and reduced residual levels, resulting in less compromised pre-chamber combustion and subsequent jet characteristics. The nozzle diameter also has a significant impact on cycle-to-cycle variations, with smaller diameters enhancing jet ignition performance but increasing variability. The effect of external residuals (dilution) on jet ignition performance varies depending on the nozzle diameter, with the 1.6mm-PC exhibiting less degradation and demonstrating earlier jet ejection and CA50 timing compared to smaller nozzle diameter pre-chambers at higher dilution conditions. The improved scavenging and relatively lower residual levels in the larger nozzle diameter pre-chamber contribute to its increased resistance to dilution and potential extension of dilution tolerance.</p> <p>In Chapter 5, it presents an analysis of the effects of pre-chamber nozzle orientation on dilution tolerance in a constant-volume optical engine. Using a combination of experimental and numerical methodologies, we provide novel insights into how variations in nozzle number, orientation, and size influence combustion performance under different dilution conditions. The findings reveal that an increase in the number of nozzles, for a fixed A/V ratio, tends to enhance ignition performance and stability across a range of dilution scenarios, primarily due to an increase in ignition points and a larger ignition surface area. Meanwhile, swirling pre-chambers, despite their potential to boost initial combustion performance at no dilution condition, may limit dilution tolerance due to the complexity of their internal flow dynamics and increased heat loss through nozzle surfaces. Furthermore, pre-chambers combining swirling and straight nozzle orientations fail to synergize the benefits of each type, and instead, exacerbate challenges such as heat loss, flame quenching, and unfavorable flow dynamics. These findings emphasize the complexity and nuanced trade-offs involved in optimizing pre-chamber design for improved dilution tolerance and suggest potential directions for future research in this area.</p> <p>In Chapter 6, it investigates the behavior of pre-chamber knock in comparison to traditional spark ignition engine knock, using a modified constant-volume gasoline engine with an optically-accessible piston. The aim is to provide a deeper understanding of pre-chamber knock combustion and its potential for mitigating knock. Five passive pre-chambers with different nozzle diameters, volumes, and nozzle numbers were tested, and nitrogen dilution was varied from 0 to 10%. The stochastic nature of knock behavior necessitates the use of statistical methods, leading to the proposal of a high-frequency band-pass filter (37-43 kHz) as an alternative pre-chamber knock metric. Pre-chamber knock combustion was found to exhibit fewer strong knock cycles compared to SI engines, indicating its potential for mitigating knock intensity. High-speed images revealed pre-chamber knock primarily occurs near the liner, where end-gas knock is typically exhibited. The study identified that increasing pre-chamber nozzle diameter resulted in a larger dispersion of knock cycles and more severe knock intensity, likely due to shorter jet penetration depth requiring more time for end-gas consumption. Strategies for mitigating knock in pre-chamber combustion systems include reducing the pre-chamber volume for a fixed A/V ratio and increasing dilution level. The results of this study offer valuable insights for developing effective knock mitigation approaches in pre-chamber combustion systems, contributing to the advancement of more efficient and reliable engines.</p> <p>In Chapter 7, a numerical investigation of different premixed gaseous injection strategies was performed to understand their impact on the scavenging and mixture formation of an air-fuel premixed pre-chamber with high exhaust gas recirculation (EGR) operations. EGR dilution is effective for reducing coolant heat loss, pumping work at throttled conditions, and mitigates knock at high-load conditions, thus increasing engine efficiency. To further extend the EGR limit of an air-fuel premixed pre-chamber engine, the effects of different injection strategies (including timing, duration, pressure, pre-chamber volume, and hardware) on the EGR level, trap efficiency, and parasitic loss were determined. Regardless of injection duration and upstream pressure, injecting too early not only increased the amount of the injected premixed gas leaking into the main chamber but also was inefficient in reducing the EGR level in the pre-chamber. To reduce the EGR level in the pre-chamber to a level where successful ignition and combustion of the pre-chamber mixture is possible, the injection timing should be delayed to be close to the ignition timing. A premixed air-fuel injection is thus proposed to reduce the time required for air-fuel mixing in the pre-chamber. With a delayed end of injection (EOI), both leakage amount and EGR level were reduced compared to the cases with earlier injection timings. The results show that an injection with 15 bar upstream pressure, 20 CA duration, EOI of −20 CAD aTDC (ignition timing), and with guided injection hardware for the base pre-chamber volume resulted in about 0.17% air compression parasitic loss, over a 94% trap efficiency, at the same time maintaining the mean EGR level in the pre-chamber below 20%, ensuring good pre-chamber combustion. With a 50% increase in pre-chamber volume from the base case, the parasitic loss increased by 65% (from 0.17% to 0.28% loss), indicating a problem with a larger pre-chamber with a separate air valve and injector.</p>

There is an urgent call for action to address the energy efficiency, climate, and local air quality concerns associated with transport because of CO2, particulates, nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbons (HC) emissions. This has driven the international policy agenda towards reducing greenhouse gas (GHG) with a major emphasis on CO2 emission. Fossil fuel combustion is considered a main contributor to the emission of CO2. The transport sector with a particular emphasis on ground transport is considered the fastest growing sector among all emission sources. To meet climate change goals, governments around the world may need to implement strict regulations on the transport sector. Governments around the world have indeed set stricter emissions standards for vehicles as a way to reduce greenhouse gas emissions from the transport sector. These standards can be achieved through various methods, such as requiring more efficient engines, alternative fuels, or the adoption of electric vehicles. On the other hand, in recent years, a lot of effort was put into promotion of electric vehicles as zero emissions vehicles. This statement should be reconsidered, since the greenhouse impact of electrical vehicles is not negligible. Conversely, in some cases, an electrical vehicle can have an even higher emission impact than modern vehicles with sophisticated internal combustion engines. In fact, the pollutant emissions discharged at the tailpipe outlet will be so low as to be hardly measurable, and their practical impact on air quality will be negligible. In terms of particulate matter emission for example, the impact of tire and brake wearing is already much higher than that due to the ICE (tire wear produces around 50 mg/km of particulates), reaching values around 10 times the emission from the engine (5 mg/km). This implies that today’s conventional ICE-powered-car is equivalent to fully electric and hybrid cars with regard to particulate emissions, when tire and brake and other contributions (e.g. road dust) are accounted for. All the data indicate that ICEs will never cease to exist and the majority of cars will be powered by ICEs in the future. These factors sparked my work on the simulation of ICEs. The first project was mainly focused on high-pressure isobaric combustion, which is a promising concept that has the potential to introduce high efficiency. This work started with the development and validation of the computational models for full cycle combustion engine simulations to capture the flow and combustion characteristics and their interactions with the intake and exhaust flows through the valves and ports. The computational models were extensively validated against the optical engine experiment data, to ensure the fidelity needed for predictive simulations. Upon identifying the numerical models, a comparative study of isobaric and conventional diesel combustion was conducted. The results revealed the superiority of the isobaric combustion mode compared to the conventional diesel combustion especially at high load conditions. On the other hand, the isobaric combustion led to high soot levels compared to the conventional diesel combustion due to the undesirable spray-to-spray interactions resulting from a single central injector with multiple consecutive injections which introduced a fuel-rich zones. For the same injection technique, a study of the effect of injection pressure and the number of holes were numerically investigated as means to reduce the soot levels. To further decrease the soot emissions, multiple injector configurations were used and the results showed more than 50% drop in the soot levels and an increase in the indicated thermal efficiency due to the lower heat transfer losses. The successful injection strategies for low-emission isobaric combustion mode have further motivated research about fuel flexibility. The potential of using fuels from different sources with varying reactivity was explored by utilizing the high pressure combustion. Various primary reference fuels (PRFs) were employed at the same middle engine load, varying from PRF0 up to PRF100. Different injection methods from a single to four injections were studied. The results demonstrated that various PRFs showed significant discrepancies when using a single injection method, owing to the different fuel auto-ignition capability. On the other hand, excellent fuel flexibility was achieved by employing a small pilot injection, under this condition various fuels led to similar engine combustion performance and emissions. Exhaust gas recirculation (EGR) was used as a way to reduce NOx emissions where 50% EGR was employed. To reduce soot emissions, various volume fractions of three shorter-chain alcohols (methanol, ethanol, and n-butanol) were blended with the baseline fuel (n-heptane). The methanol-blended fuels yielded the lowest soot emissions, but the worst fuel economy was obtained due to the highest heat transfer losses. By increasing the nozzle number and introducing an adequate amount of isochoric combustion, the fuel economy for pure methanol combustion was effectively promoted. The second project was focused on ultra-lean hydrogen combustion using CONVERGE CFD as computational framework. The problem of numerically detecting engine knock and the methods to mitigate such a problem were addressed. Different combustion modes such as port fuel injection spark ignition (PFI SI), homogenous charge compression ignition (HCCI), and pre-chamber (PC) were investigated. The effects of the chemical mechanisms in terms of ignition delay time and laminar flame speed were studied. Starting with the simple combustion mode using PFI SI, high engine knock tendency was observed. The effects of compression ratio, air-fuel-ratio, and spark time were examined as means to reduce engine knock. Upon mitigating the engine knock issue, a comparative study of the PFI spark ignition and the PC modes was conducted. The results revealed that the current used design of the PC introduced high turbulence levels, which resulted in high heat transfer losses to the engine piston. In general , all of these studies (isobaric and hydrogen combustion) were aimed to increase the overall engine efficiency and reduce the emissions.

No description available.