Line narrowing of AgGaSe2 optical parametric oscillator by injection seeding

Solid-state lasers are developed for atmospheric applications. Optical parametric oscillators (OPO) are being investigated as sources of tunable radiation in the 2.5-12 micron range where development of conventional lasers is subject to numerous difficulties. Parametric oscillation is a nonlinear optical technique for converting laser output to longer wavelengths. Incident photons, typically from a pulsed pump laser, are converted into two photons of longer wavelength, while satisfying energy conservation. The particular split of energy is determined by momentum conservation; the wavelength of interest is usually selected by angle orientation of the nonlinear material with respect to the direction of propagation of the pump beam. An OPO based on AgGaSe2 was considered

Proctolin and an Endogenous Proctolin-Like Peptide Enhance the Contractility of the Limulus Heart

Synthetic proctolin increases the force but not the rate of heart contractions of Limulus in a time- and dose-dependent manner. The threshold of this effect is 3 × 10−10M and the ED50 is approximately 10−8M. At concentrations up to 10−7 M, proctolin has no effect on the rhythmic electrical activity of the isolated cardiac ganglion, and it does not change the simple and compound postsynaptic potentials recorded at the cardiac neuromuscular junction. Proctolin acts directly on the cardiac muscle fibres. Electrically stimulated myocardia show a proctolin-induced increase in contraction amplitude with the same concentration dependence as the intact heart. A compound with an apparent molecular weight of 700–800 occurs in the Limulus nervous system, particularly in the cardiac ganglion. This compound resembles proctolin in being heat-stable, resistant to trypsin and chymotrypsin cleavage, and losing activity in a time-dependent manner in response to treatment with leucine aminopeptidase or pronase. This peptide induces spontaneous contractions and a contracture of the cockroach hindgut in a manner similar to proctolin. Moreover, the Limulus inotropic peptide, like proctolin, increases the force of contraction of the Limulus heart without affecting beat frequency. It is concluded that an endogenous, proctolin-like peptide is an inotropic modulator of the Limulus heart, acting directly on the muscle fibres and not affecting cardiac ganglion activity

Factors affecting teachers\u27 level of classroom Internet use and teachers\u27 self -efficacy regarding classroom Internet use

This study examined the factors that affect teacher classroom Internet use and teacher self-efficacy with using the Internet. With regards to classroom Internet use, the factors examined were grade taught, years of teaching experience, type of school technical support, Internet-related professional development training, number of Internet-accessible computers in the classroom, student socioeconomic status, and teacher Internet self-efficacy. For teacher Internet self-efficacy, the factors examined were years of teaching experience, type of school technical support, and Internet-related professional development training. This study surveyed 419 public school teachers, across grades K-12, using stepwise multiple regression to analyze the factors and their relationships with classroom Internet use and teacher Internet self-efficacy.;The results from the 419 survey respondents indicate that grade taught, number of Internet-accessible classroom computers, school socioeconomic status, and teacher Internet self-efficacy were all significant predictors of classroom Internet use. In-service training and multiple-day workshops were also found to be significant predictors of classroom Internet use, but the variable college credit courses was not. Further, the factors of years of teaching experience and type of technical support were not significant predictors. The data for teacher Internet self-efficacy indicated that years of teaching experience was a negative predictor of self-efficacy, while all three types of professional development were a positive predictor. Technical support was not a predictor of teacher Internet self-efficacy

Virtual SATCOM, Long Range Broadband Digital Communications

The current naval strategy is based on a distributed force, networked together with high-speed communications that enable operations as an intelligent, fast maneuvering force. Satellites, the existing network connector, are weak and vulnerable to attack. HF is an alternative, but it does not have the information throughput to meet the distributed warfighting need. The US Navy does not have a solution to reduce dependency on space-based communication systems while providing the warfighter with the required information speed. Virtual SATCOM is a solution that can match satellite communications (SATCOM) data speed without the vulnerable satellite. It is wireless communication on a High Frequency (HF) channel at SATCOM speed. We have developed an innovative design using high power and gain, ground-based relay systems. We transmit extremely wide-wideband HF channels from ground stations using large directional antennas. Our system starts with a highly directional antenna with a narrow beam that enables increased bandwidth without interfering with other spectrum users. The beam focus and power provide a high SNR across a wideband channel with data rates of 10 Mbps; 1000 times increase in HF data speed. Our modeling of the ionosphere shows that the ionosphere has more than adequate bandwidth to communicate at 3000 km and high speeds while avoiding detection. We designed a flexible structure adjustable to the dynamic ionosphere. Our design provides a high-speed communications path without the geo-location vulnerability of legacy HF methods. Our invention will benefit mobile users using steerable beam forming apertures with wide bandwidth signals. This dissertation will focus on three areas: an examination of the ionosphere’s ability to support the channel, design of a phased array antenna that can produce the narrow beam, and design of signal processing that can accommodate the wideband HF frequency range. Virtual SATCOM is exciting research that can reduce cost and increase access to long-range, high data rate wireless communications

Technology Professional Development: Long-Term Effects on Teacher Self-Efficacy

The West Virginia K-12 RuralNet Project was an NSF funded program to train inservice teachers on integrating the Internet into science and mathematics curriculum. The program involved training inservice teachers through an intensive summer workshop and supplemental online courses. This study examines the effects of the project on the long-term self-efficacy of inservice teachers and their use of the Internet in the classroom. The specific research questions addressed are: Do professional development programs affect the long-term self-efficacy of inservice teachers? Did the addition of online courses and follow-up to the program affect self-efficacy levels? Finally, do certain external factors, specifically years of teaching experience, college technology courses, professional development, or participation in other similar professional development programs play a role in teacher self-efficacy? The findings indicate that: (a) Teachers improved level of self-efficacy after the summer workshops remained high even years after their involvement in the program, (b) that combining an intense summer workshop with additional online courses shows a significant difference in some aspects of self-efficacy over just having a professional development workshop, and (c) certain external factors do affect teacher self-efficacy over the long-term

X-ray fluorescence spectroscopic analysis of coal ash

Several coal ashes and prepared mixtures were analyzed by x-ray fluorescence spectroscopy. Various techniques were studied to determine the most reliable procedure for quantitatively estimating, from fluorescent peak intensities, the concentrations of seven major oxides typically present in the ash. These ashes were analyzed with only minimal sample preparation. In order to determine the self-consistency of the procedure, several mixtures of known composition were prepared containing the major elements present in an ash. Because of inter-element absorption and enhancement effects, several computational techniques were used to calculate composition from spectrum peak intensities. The method that yielded the most accurate estimates of the mixtures was an empirical form devised by Criss and Burkes. Comparison of the estimated coal ash compositions by this procedure did not agree with results obtained by atomic absorption analysis. However, it is believed that this is not because of the x-ray fluorescence procedure applied; inconsistent ash sampling and preparation and improper standards are the probable causes

Measurement of waste in concrete construction using lean construction methodologies

This dissertation develops and analyses the quantification of all wastes present in particular construction process. This has been conducted from a lean construction perspective where waste has been defined as any non-value adding process or activity. The specific processes chosen were concrete paving, hand-pouring concrete and the installation of formwork. The types of wastes present in the construction industry have been researched and a comprehensive list collated. A number of waste classifications have been evaluated to organise these wastes into manageable groups. These classifications were also selected on their usability and the potential techniques of measurement. A suitable format for waste reporting has been established and trialled in a construction environment. This has been evaluated by Professional Engineers in management positions within the construction industry. Due to the individual nature of construction projects there are significant inefficiencies in comparison to similar industries such as manufacturing. Of these wastes concrete construction has been deemed the largest contributor to wastage. This leads us to the question of how do we measure not only the materials wasted but the other types of waste in processes. This needs to be answered as efficiencies cannot be improved without the knowledge of where and how they are occurring. This project has been conducted utilising; theoretical research, practical on-site observations and by seeking industry feedback on the conclusions drawn from these investigations. The theoretical research took the form of a literature review on lean construction methodologies and types of ‘waste’. This focused on waste management and classification and how this has been applied to construction projects around the world. Practical on site observations were used to develop activity mapping and waste sampling which were used in the case studies for waste classification and quantification. From this a suitable format for waste reporting has been established and trialled in a construction environment. Industry feedback was sought in the form of structured interviews and an accompanying questionnaire. These interviews were conducted with four Engineering Managers working on a variety of large construction projects. From this evaluation improvements can be made to this structure and a future direction for this research has been determined. This research can be used as a base for lean construction waste reporting within the Australian construction industry. It has shown this it is both practical and useful to implement this reporting process on site. The dissertation has also identified the need for a cost/benefit analysis into waste reporting on construction sites to determine the efficiency of the process itself