Acoustic properties of microperforated panels and their optimizatión by simulated annealing

This thesis investigates the acoustic properties of microperforated panels as an alternative to passive noise control. The first chapters are devoted to the review of analytical models to obtain the acoustic impedance and absorption coefficient of perforated panels. The use of panels perforated with circular holes or with slits is discussed. The theoretical models are presented and some modifications are proposed to improve the modeling of the physical phenomena occurring at the perforations of the panels. The absorption band is widened through the use of multiple layer microperforated panels and/or the combination of a millimetric panel with a porous layer that can be a fibrous material or a nylon mesh. A commercial micrometric mesh downstream a millimetric panel is proposed as a very efficient and low cost solution for controlling noise in reduced spaces. The simulated annealing algorithm is used in order to optimize the panel construction to provide a maximum of absorption in a determined wide band frequency range. Experiments are carried out at normal sound incidence and plane waves. One example is shown for a double layer microperforated panel subjected to grazing flow. A good agreement is achieved between the theory and the experiments. RESUMEN En esta tesis se investigan las propiedades acústicas de paneles micro perforados como una alternativa al control pasivo del ruido. Los primeros capítulos están dedicados a la revisión de los modelos de análisis para obtener la impedancia acústica y el coeficiente de absorción de los paneles perforados. El uso de paneles perforados con agujeros circulares o con ranuras es discutido. Se presentan diferentes modelos y se proponen algunas modificaciones para mejorar la modelización de los fenómenos físicos que ocurren en las perforaciones. La banda de absorción se ensancha a través del uso de capas múltiples de paneles micro perforados y/o la combinación de un panel de perforaciones milimétricas combinado con una capa porosa que puede ser un material fibroso o una malla de nylon. Se propone el uso de una malla micrométrica detrás de un panel milimétrico como una solución económica y eficiente para el control del ruido en espacios reducidos. El algoritmo de recocido simulado se utiliza con el fin de optimizar la construcción de paneles micro perforados para proporcionar un máximo de absorción en una banda determinada frecuencias. Los experimentos se llevan a cabo en la incidencia normal de sonido y ondas planas. Se muestra un ejemplo de panel micro perforado de doble capa sometido a flujo rasante. Se consigue un buen acuerdo entre la teoría y los experimentos

Study of the adhesion of explosive residues to the finger and transfer to clothing and luggage

It is important to understand the extent of transfer of explosive particles to different surfaces in order to better evaluate potential cross-contamination by explosives in crowded security controls such as those at airports. This work investigated the transfer of nine explosive residues (ANFO, dynamite, black powder, TNT, HMTD, PETN, NH4NO3, KNO3, NaClO3) through fingerprints from one surface to another. First, the extent of adhesion of explosive residues from different surfaces to the bare finger, nitrile and latex gloves was studied. Then, the transfer of explosive residues from one surface to another through fingerprints was investigated. Cotton fabric (hereinafter referred to as cotton) as clothing material and polycarbonate plastic (hereinafter referred to as polycarbonate) as luggage material were chosen for the experiments. These surfaces containing explosive particles were imaged using a reflex camera before and after the particles were transferred. Afterwards the images were processed in MATLAB where pixels corresponding to explosive residues were quantified. Results demonstrated that transfer of explosive residues frequently occurred with certain differences among materials. Generally, the amount of explosive particles adhered to the finger decreased in the following order: skin>latex>nitrile, while the transfer of particles from the finger to another surface was the opposite. The adhesion of explosive residues from polycarbonate to the finger was found to be better compared to cotton, while the amount of particles transferred to cotton was higher

Simple multispectral imaging approach for determining the transfer of explosive residues in consecutive fingerprints

This novel investigation focused on studying the transfer of explosive residues (TNT, HMTD, PETN, ANFO, dynamite, black powder, NH4NO3, KNO3, NaClO3) in ten consecutive fingerprints to two different surfaces &- cotton fabric and polycarbonate plastic &- by using multispectral imaging (MSI). Imaging was performed employing a reflex camera in a purpose-built photo studio. Images were processed in MATLAB to select the most discriminating frame &- the one that provided the sharpest contrast between the explosive and the material in the red-green-blue (RGB) visible region. The amount of explosive residues transferred in each fingerprint was determined as the number of pixels containing explosive particles. First, the pattern of PETN transfer by ten different persons in successive fingerprints was studied. No significant differences in the pattern of transfer of PETN between subjects were observed, which was also confirmed by multivariate analysis of variance (MANOVA). Then, the transfer of traces of the nine above explosives in ten consecutive fingerprints to cotton fabric and polycarbonate plastic was investigated. The obtained results demonstrated that the amount of explosive residues deposited on successive fingerprints tended to undergo a power or exponential decrease, with the exception of inorganic salts (NH4NO3, KNO3, NaClO3) and ANFO (consists of 90% NH4NO3)

Cuantificación del servicio ambiental de almacenamiento de CO2 en biomasa aérea de las especies de flora en la Zona de Conservación y Recuperación de Ecosistemas (ZoCRE), Humedal del Alto Mayo, sector Santa Elena - Rioja 2018

Humedales Santa Elena, es considerado como los humedales más altos del país, estas áreas se caracterizan por ser bosques pantanosos e inundables que contienen remanentes de la biodiversidad local. El estudio comprende la cuantificación del servicio ambiental de almacenamiento de CO2 de biomasa aérea de las especies de flora en la Zona de Conservación y Recuperación de Ecosistemas (ZoCRE), humedal del Alto Mayo, desarrollado en el sector Santa Elena en el distrito de Pósic, provincia de Rioja, región San Martín. Al identificar la problemática que se desato en el mundo por el incremento del CO2, me motivo para desarrollar el presente proyecto cuyo planteamiento del problema se sintetiza en la siguiente interrogante: ¿Cuál es el potencial de almacenamiento de CO2 como servicio ambiental en la biomasa aérea de las especies de flora en la ZoCRE? Como objetivo se planteó cuantificar el servicio ambiental de almacenamiento de CO2 en biomasa aérea de las especies de flora en la ZoCRE. En la presente investigación se utilizó el diseño metodológico descriptivo simple; se identificó el área de estudio y se establecieron 2 parcelas de 50 x 100m, luego se levantó la información de las cinco especies de plantas, se calculó la biomasa aérea de las especies por parcela y área de estudio (1 ha), y se estimó el almacenamiento de CO2. Los instrumentos como: las fichas de identificación de especie, registro forestal e inventario forestal han conllevado a los resultados donde muestran que la biomasa aérea arbórea calculada fue de 325.99 Mg/ ha para los dos tipos de ecosistema, humedal semidenso y denso, la captura de carbono fue de 163.00 Mg/ ha para las dos parcelas de muestreo, el almacenamiento de CO2 en ambas parcelas se obtuvo 598.193 Mg/ha y el pago por servicio ambiental de almacenamiento de CO2 que se obtuvo de todas las especies evaluadas en las dos parcelas estudiadas tuvo un total de $3529.34.Santa Elena Wetlands, is considered as the highest wetlands in the country, these areas are characterized by swampy and flooded forests that contain remnants of local biodiversity. The study includes the quantification of the environmental service of CO2 storage of aerial biomass of the species of flora in the Zone of Conservation and Recovery of Ecosystems (ZoCRE), wetland of the Alto Mayo, developed in the sector Santa Elena in the district of Pósic, province of Rioja, San Martín region. By identifying the problem that was unleashed in the world by the increase of CO2 has motivated to develop the following project whose approach to the problem is summarized in the following question: What is the storage potential of CO2 as an environmental service in aerial biomass? of the flora species in the ZoCRE? The objective was to quantify the environmental service of storage of CO2 in aerial biomass of the flora species in the ZoCRE. In the following investigation, the simple descriptive methodological design was used; the study area was identified and two plots of 50 x 100m were established, then the information of the five plant species was collected, the aerial biomass of the species was calculated by plot and study area (1 ha), and it was estimated the storage of CO2. The instruments such as: the species identification, forest registration and forest inventory have led to the results showing that the calculated tree aerial biomass was 325.99 Mg / ha for the two types of ecosystem, semi-dense and dense wetland, the capture of carbon was 163.00 Mg / ha for the two sampling plots, the CO2 storage in both plots was obtained 598.193 Mg / ha and the payment for environmental CO2 storage service that was obtained from all the species evaluated in the two plots studied He had a total of$ 3529.34.TesisAp

Preservice Teachers: Investigations in Early Fieldwork and Mathematics Efficacy Beliefs

In this quasi-experimental study, 127 preservice teachers from two community colleges enrolled in a mathematics for teachers two-course sequence. Control and experimental groups were used to investigate the effect that fieldwork had on efficacy beliefs. The Mathematics for Teaching Efficacy Beliefs Instrument (MATHEMATICS TEACHING EFFICACY BELIEFS INSTRUMENT) was used to gather data. Fieldwork was determined not to be a significant factor of personal mathematics efficacy or outcome expectancy. Personal mathematics teaching efficacy did significantly increase for both experimental and control groups; however, mathematics teaching outcome expectancy significantly increased only for the experimental group. Results also showed that length of term was a significant factor of teaching efficacy. Suggestions for further research are also included

Implementation of 4T score documentation on PF4 testing in patients with Suspected heparin induced thrombocytopenia (HIT)

Purpose: Heparin-induced thrombocytopenia (HIT) is a severe complication of heparin therapy. Diagnosis requires clinical evaluation and laboratory testing. The 4T score is a pretest clinical scoring system used to assess the probability of HIT. A non-profit community hospital implemented mandatory 4T score documentation prior to ordering PF4 tests for suspected HIT patients, following a pharmacy-driven approach to optimize the prescribing of argatroban. The purpose of this performance improvement project is to evaluate the implementation of 4T score documentation on PF4 testing and argatroban utilization. Methods: In a retrospective, multi-site chart review study conducted, electronic records of patients were reviewed to assess the effects of 4T score documentation on PF4 testing orders. The study included adult patients who were admitted to one of the five practice sites between January 2020 and November 2022 and had a suspicion HIT with a PF4 test ordered. The primary outcomes assessed the number of PF4, and SRA tests ordered and the percentage of positive results for HIT annually. Secondary outcomes included the number of SRA orders and results, reporting of heparin allergy in patients with negative SRA results, time taken for SRA results, and the utilization of argatroban. Data collected from each patient\u27s medical record included baseline demographics, SRA results, documentation of heparin allergy, initial anticoagulant prescribed, platelet trend, ordering provider, and argatroban utilization. The analysis involved using χ2 test and Fisher\u27s exact test for the primary outcomes. Results: A total of 42 patients with a positive PF4 test were included in the analysis Mandatory 4T score documentation significantly reduced PF4 orders by 68% over two years (p Conclusion: Implementation of mandatory 4T score documentation significantly reduced PF4 orders and improved HIT diagnostic testing. Challenges remain in heparin allergy reporting and appropriate discontinuation of argatroban. The results of this project have demonstrated that standardized documentation is essential for optimizing HIT diagnosis and management protocols. Future efforts will focus on improving heparin allergy reporting practices and providing clear recommendations for discontinuing alternative anticoagulant therapy through a multi-disciplinary approach

Being Honors Worthy: Lessons in Supporting Transfer Students

In the ever-growing discussion of how to build and support honors programs that reflect the diverse communities our institutions serve, the recruitment of transfer students has only recently been identified as a key avenue to enacting more equitable programs. Reflecting on four years of recruiting, enrolling, and graduating transfer students in the University Honors Program at the University of California, Davis, we push the conversation beyond how to welcome transfer students in honors to how to meaningfully support them. We present the initial findings of our ongoing self-assessment to stimulate discussion about the unique challenges and opportunities transfer students experience in honors as well as how administrators and practitioners can rethink how our program structures and processes help our transfer students achieve success or hinder them from doing so. Drawing on descriptive statistics and focus groups, we found that, while transfer students in honors outperformed non-honors transfer students with similar backgrounds in terms of GPA and engagement with undergraduate research, many still struggled with not feeling, as one student described, “honors worthy.” Our preliminary findings suggest that concerns over belonging in honors can be mitigated by a cohort model that provides a sense of community, by a restructuring of the GPA requirements to cushion “transfer shock,” and, critically, by mentorship from administrators and faculty. Given the pool of diverse potential honors students currently in the community college pipeline and the recognition within NCHC that diverse cohorts best prepare students to engage meaningfully with the world around them, now is the time to increase the admissions of transfer students into honors programs. Lessons from early adopters such as UC Davis can help initial programming meet students’ needs and cultivate their talents

Being Honors Worthy: Lessons in Supporting Transfer Students

In the ever-growing discussion of how to build and support honors programs that reflect the diverse communities our institutions serve, the recruitment of transfer students has only recently been identified as a key avenue to enacting more equitable programs. Reflecting on four years of recruiting, enrolling, and graduating transfer students in the University Honors Program at the University of California, Davis, we push the conversation beyond how to welcome transfer students in honors to how to meaningfully support them. We present the initial findings of our ongoing self-assessment to stimulate discussion about the unique challenges and opportunities transfer students experience in honors as well as how administrators and practitioners can rethink how our program structures and processes help our transfer students achieve success or hinder them from doing so. Drawing on descriptive statistics and focus groups, we found that, while transfer students in honors outperformed non-honors transfer students with similar backgrounds in terms of GPA and engagement with undergraduate research, many still struggled with not feeling, as one student described, “honors worthy.” Our preliminary findings suggest that concerns over belonging in honors can be mitigated by a cohort model that provides a sense of community, by a restructuring of the GPA requirements to cushion “transfer shock,” and, critically, by mentorship from administrators and faculty. Given the pool of diverse potential honors students currently in the community college pipeline and the recognition within NCHC that diverse cohorts best prepare students to engage meaningfully with the world around them, now is the time to increase the admissions of transfer students into honors programs. Lessons from early adopters such as UC Davis can help initial programming meet students’ needs and cultivate their talents

Síndrome de Burnout del personal de enfermería en los hospitales públicos de la provincia de Imbabura - 2021

Determinar el nivel del Síndrome de Burnout del personal de enfermería de los Hospitales Públicos de la provincia de Imbabura.El Síndrome de Burnout es una patología que se manifiesta frecuentemente en los trabajadores de salud y se caracteriza por agotamiento físico y mental, debido a la actual pandemia de COVID-19 la presencia de este síndrome ha aumentado. El objetivo fue determinar el nivel del Síndrome de Burnout del personal de enfermería de los Hospitales Públicos de la provincia de Imbabura. Estudio con enfoque cuantitativo no experimental, descriptivo, campo y de corte transversal, se utilizó un muestreo no probabilístico conformado por los profesionales de enfermería que laboran en Emergencia, Medicina Interna, Unidad de Cuidados Intensivos y Aislamiento respiratorio de los Hospitales de Imbabura. Entre los resultados predominaron los profesionales de sexo femenino, estado civil casado y la mayoría pertenecían al grupo de adultos jóvenes. Se determinó que el 23% de los profesionales presentan un nivel alto de Síndrome de Burnout y la mayor parte presenta un nivel medio, con tendencia de padecer este síndrome. Además, se encontró que la condición de los factores laborales en el personal de enfermería se encuentra en un rango adecuado en un 73%. Se concluyó que la dimensión de Despersonalización es la que más influye en la aparición de este síndrome, lo que indica que existen actitudes negativas y distanciamiento de los profesionales hacia los usuarios, por lo tanto, se recomienda tomar medidas preventivas para procurar el bienestar del trabajador y asegurar la calidad de atención.Licenciatur