134 results on '"D. Vick"'
Search Results
2. Secrets from a Prison Cell: A Convict's Eyewitness Accounts of the Dehumanizing Drama of Life Behind Bars
- Author
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Tony D. Vick, Michael T. McRay
- Published
- 2018
3. NanoMi: an open source electron microscope component integration
- Author
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M Malac, D Homeniuk, M Kamal, J Kim, M Salomons, M Hayashida, J A Marin-Calzada, D Vick, D Price, and RF Egerton
- Subjects
Instrumentation - Abstract
We are developing a public-license electron-microscope column referred to as NanoMi, whose electron optics is suspended inside a vacuum envelope based on ConFlat hardware, see Fig. 1. The design of individual components has been reported earlier. We are now developing software control, column alignment procedures and integration of the components. A significant part of the work has been done by undergraduate students in our laboratory. Parts of the software and modeling are available for download from GitHub and from Open Science Foundation sites and are released under a GPL v3 license. An initial version of the blueprints is now shared on case-by-case basis.
- Published
- 2023
4. Postfundoplication submucosal prolapse syndrome
- Author
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Shou-Jiang Tang, Kenneth D. Vick, and Shengyu Zhang
- Subjects
GE, gastroesophageal ,medicine.medical_specialty ,business.industry ,Gastroenterology ,medicine ,PFSPS, postfundoplication submucosal prolapse syndrome ,Radiology, Nuclear Medicine and imaging ,Video Case Report ,business ,Surgery - Published
- 2021
- Full Text
- View/download PDF
5. Gemcitabine as chemotherapy of head and neck cancer in Fanconi anemia patients
- Author
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Anne M. van Harten, Ronak Shah, D. Vicky de Boer, Marijke Buijze, Maaike Kreft, Ji-Ying Song, Lisa M. Zürcher, Heinz Jacobs, and Ruud H. Brakenhoff
- Subjects
Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Fanconi anemia (FA) is a rare hereditary disease resulting from an inactivating mutation in the FA/BRCA pathway, critical for the effective repair of DNA interstrand crosslinks (ICLs). The disease is characterized by congenital abnormalities, progressing bone marrow failure, and an increased risk of developing malignancies early in life, in particular head and neck squamous cell carcinoma (HNSCC). While ICL-inducing cisplatin combined with radiotherapy is a mainstay of HNSCC treatment, cisplatin is contra-indicated for FA-HNSCC patients. This dilemma necessitates the identification of novel treatment modalities tolerated by FA-HNSCC patients. To identify druggable targets, an siRNA-based genetic screen was previously performed in HNSCC-derived cell lines from FA and non-FA tumor origin. Here, we report that the Ribonucleotide Reductase (RNR) complex, consisting of the RRM1 and RRM2 subunits, was identified as a therapeutic target for both, FA and non-FA HNSCC. While non-FA HNSCC cells responded differentially to RNR depletion, FA-HNSCC cells were consistently found hypersensitive. This insight was confirmed pharmacologically using 2′, 2′-difluoro 2′deoxycytidine (dFdC), also known as gemcitabine, a clinically used nucleotide analog that is a potent inhibitor of the RNR complex. Importantly, while cisplatin exposure displayed severe, long-lasting toxicity on the hematopoietic stem and progenitor compartments in Fancg−/− mice, gemcitabine was well tolerated and had only a mild, transient impact. Taken together, our data implicate that gemcitabine-based chemoradiotherapy could serve as an alternative HNSCC treatment in Fanconi patients, and deserves clinical testing.
- Published
- 2024
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6. Elevated plasma endothelin-1 is associated with reduced weight loss post vertical sleeve gastrectomy
- Author
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Adam Dungey, Joshua S. Speed, London J Williams, Kenneth D. Vick, Haley N. Jenkins, and Bernadette E. Grayson
- Subjects
Adult ,Male ,Sleeve gastrectomy ,medicine.medical_specialty ,Time Factors ,medicine.medical_treatment ,Bariatric Surgery ,030209 endocrinology & metabolism ,Inflammation ,Gastroenterology ,Article ,Body Mass Index ,Cohort Studies ,03 medical and health sciences ,0302 clinical medicine ,Insulin resistance ,Gastrectomy ,Weight loss ,Internal medicine ,Weight Loss ,medicine ,Humans ,Endothelin-1 ,business.industry ,Middle Aged ,medicine.disease ,Endothelin 1 ,Obesity ,Obesity, Morbid ,Surgery ,Treatment Outcome ,Cohort ,Female ,030211 gastroenterology & hepatology ,medicine.symptom ,business ,Body mass index - Abstract
Background Obesity and insulin resistance are positively correlated with plasma endothelin-1 (ET-1) levels; however, the mechanisms leading to increased ET-1 are not understood. Similarly, the full physiological complexity of ET-1 has yet to be described, especially in obesity. To date, one of the best treatments available for morbid obesity is bariatric surgery to quickly reduce body fat and the factors associated with obesity-related disease; however, the effects of vertical sleeve gastrectomy (SG) on plasma ET-1 have not been described. Objectives To determine if SG will reduce plasma ET-1 levels and to determine if plasma ET-1 concentration is associated with weight loss after surgery. Setting The studies were undertaken at a University Hospital. Methods This was tested by measuring plasma ET-1 levels from 12 obese patients before and after SG. All data were collected from clinic visits before SG, 6 weeks after SG, and 6 months after surgery. Results At 6 weeks after SG, plasma ET-1 levels increased by 24%; however, after 6 months, there was a 27% decrease compared with presurgery. Average weight loss in this cohort was 11.3% ± 2.4% body weight after 6 weeks and 21.4% ± 5.7% body weight after 6 months. Interestingly, we observed an inverse relationship between baseline plasma ET-1 and percent body weight loss (R2 = .49, P = .01) and change in body mass index 6 months (R2 = .45, P = .011) post bariatric surgery. Conclusions Our results indicate that SG reduces plasma ET-1 levels, a possible mechanism for improved metabolic risk in these patients. These data also suggest that ET-1 may serve as a predictor of weight loss after bariatric surgery.
- Published
- 2019
- Full Text
- View/download PDF
7. Persistent Opioid Use and High-Risk Prescribing in Body Contouring Patients
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Vidhya Gunaseelan, Jay S. Lee, Katelyn G. Bennett, Alexis D Vick, Jennifer F. Waljee, Brian P Kelley, and Chad M. Brummett
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,Databases, Factual ,Bariatric Surgery ,030230 surgery ,Risk Assessment ,Article ,Time ,Cohort Studies ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Weight loss ,Internal medicine ,Weight Loss ,Prevalence ,medicine ,Humans ,Pain Measurement ,Retrospective Studies ,Pain, Postoperative ,Neck pain ,business.industry ,Retrospective cohort study ,Middle Aged ,Body Contouring ,Opioid-Related Disorders ,medicine.disease ,Comorbidity ,Drug Utilization ,United States ,Obesity, Morbid ,Analgesics, Opioid ,Logistic Models ,Treatment Outcome ,030220 oncology & carcinogenesis ,Multivariate Analysis ,Body contouring ,Cohort ,Female ,Surgery ,medicine.symptom ,Risk assessment ,business ,Follow-Up Studies ,Cohort study - Abstract
Background Opioid misuse occurs commonly among obese patients and after bariatric surgery. However, the risk of new persistent use following postbariatric body contouring procedures remains unknown. Methods The authors examined insurance claims from Clinformatics Data Mart (OptumInsight, Eden Prairie, Minn.) between 2001 and 2015 for opioid-naive patients undergoing five body contouring procedures: abdominoplasty/panniculectomy, breast reduction, mastopexy, brachioplasty, and thighplasty (n = 11,257). Their primary outcomes included both new persistent opioid use, defined as continued prescription fills between 90 and 180 days after surgery, and the prevalence of high-risk prescribing. They used multilevel logistic regression to assess the risk of new persistent use, adjusting for relevant covariates. Results In this cohort, 6.1 percent of previously opioid-naive patients developed new persistent use, and 12.9 percent were exposed to high-risk prescribing. New persistent use was higher in patients with high-risk prescribing (9.2 percent). New persistent use was highest after thighplasty (17.7 percent; 95 percent CI, 0.03 to 0.33). Increasing Charlson comorbidity indices (OR, 1.11; 95 percent CI, 1.05 to 1.17), mood disorders (OR, 1.27; 95 percent CI, 1.05 to 1.54), anxiety (OR, 1.41; 95 percent CI, 1.16 to 1.73), tobacco use (OR, 1.22; 95 percent CI, 1.00 to 1.49), neck pain (OR, 1.23; 95 percent CI, 1.04 to 1.46), arthritis (OR, 1.30; 95 percent CI, 1.08 to 1.58), and other pain disorders (OR, 1.36; 95 percent CI, 1.16 to 1.60) were independently associated with persistent use. Conclusions Similar to other elective procedures, 6 percent of opioid-naive patients developed persistent use, and 12 percent were exposed to high-risk prescribing practices. Plastic surgeons should remain aware of risk factors and offer opioid alternatives. Clinical question/level of evidence Risk, III.
- Published
- 2019
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8. Whole genome transcriptome analysis of the stomach resected in human vertical sleeve gastrectomy: cutting more than calories
- Author
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Bradley A. Welch, Michael R. Garrett, Kenneth D. Vick, William J. Lawson, Adam Dungey, William C Dungan, Bernadette E. Grayson, and Alexandra R Himel
- Subjects
0301 basic medicine ,Adult ,Male ,Sleeve gastrectomy ,Calorie ,Physiology ,medicine.medical_treatment ,Bariatric Surgery ,Biology ,Transcriptome ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Gastrectomy ,Genetics ,medicine ,Humans ,Esophagus ,Genome, Human ,Stomach ,Gene Expression Profiling ,Anatomy ,Middle Aged ,Curvatures of the stomach ,030104 developmental biology ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Duodenum ,Female ,Research Article - Abstract
Vertical sleeve gastrectomy (VSG) is a surgical weight loss procedure that resects 80% of the stomach, creating a tube linking the esophagus to the duodenum. Because of the efficacy and relative simplicity of VSG, it is preferred in the United States, with VSG currently at >61% of bariatric surgeries performed. Surprisingly, there has never been a complete molecular characterization of the human stomach greater curvature’s fundus and corpus. Here we compare and contrast the molecular makeup of these regions. We performed a prospective cohort study to obtain gastric tissue samples from patients undergoing elective VSG. Paired fundus and corpus samples were obtained. Whole genome transcriptome analysis was performed by RNA sequencing ( N = 10), with key findings validated by qPCR ( N = 24). Participants were primarily female (95.8%) and White (79.15%). Mean body mass index, body weight, and age were 46.1 kg/m2, 121.6 kg, and 43.29 yr, respectively. Overall, 432 gene transcripts were significantly different between the fundus and the corpus ( P < 0.05). A significant correlation was found between the RNA sequencing dataset and qPCR validation, demonstrating robust gene expression differences between the fundus and the corpus. Significant genes included progastricsin, acidic chitinase, and gastokine 1 and 2 in both the fundus and the corpus. Of the very highly expressed genes in both regions, 87% were present in both the stomach’s fundus and corpus, indicating substantial overlap. Despite significant overlap in the greater curvature gene signature, regional differences exist within the fundus and the corpus. Given that the mechanism of VSG is partly unresolved, the potential that the resected tissue may express genes that influence long-term body weight regulation is unknown and could influence VSG outcomes.
- Published
- 2021
9. NanoMi Open Source (S)TEM Platform: Initial SEM Implementation
- Author
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Darren Homeniuk, Sean Chen, Drew Price, Ray F. Egerton, Karan Kumar, Marek Malac, Misa Hayashida, Jason L. Pitters, Martin Cloutier, D. Vick, Jesus Alejandro Marin-Calzada, Mark Salomons, and Darren Wen
- Subjects
Open source ,Materials science ,Instrumentation ,Engineering physics - Published
- 2021
- Full Text
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10. G198(P) Students’ perceptions of paediatrics and the impact of a careers workshop
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D Vick, CE Roberts, and JL Oakley
- Subjects
Pediatrics ,medicine.medical_specialty ,ComputingMilieux_THECOMPUTINGPROFESSION ,business.industry ,media_common.quotation_subject ,education ,Specialty ,Workload ,Intervention group ,Positive perception ,humanities ,Perception ,General practice ,Medicine ,Medical school curriculum ,business ,Separate legal entity ,media_common - Abstract
Aims Applications to specialty training are falling and retention of trainees is increasingly challenging. Clinical placements influence students’ perceptions of a specialty and may impact on career choices. We evaluated medical students’ views of Paediatrics before and after their placement and explored the effect of a focused Careers Workshop. Methods A survey was distributed to medical students before (n=93) and after (n=74) their Child Heath block (Standard Group). Subsequently, a smaller group of students were invited to a Careers Workshop during their placement and surveyed before (n=20) and after (n=13) (Intervention Group). The workshop covered the ‘highs’ and ‘lows’ of working in Paediatrics as well as general careers advice, and a separate survey was completed to evaluate this (n=18). Results Paediatrics was a popular ‘Top 3’ careers option, second only to General Practice. Students reported that formal careers advice and clinical contact are both important for career planning. Positive perceptions of Paediatrics included working with children, clinical variety and being rewarding. Negative perceptions focused on emotional challenges, poor work-life balance and managing parents. After placement, the Intervention group were more likely to comment on the positive aspects of a ‘clinically varied’ and ‘rewarding’ workload. Following the Careers Workshop, 72% of students felt ‘well informed’ about careers in medicine generally and 94% regarding careers in Paediatrics. The workshop helped to address pre-conceptions regarding competition ratios and work-life balance. In both groups, students were more likely to consider Paediatric training following their placement, with interest increasing from 69% to 76% (Standard group) and 70% to 77% (Intervention group). Conclusion Our data demonstrates that clinical placements influence students’ perceptions of a specialty. Although the Careers Workshop improved knowledge of careers in Paediatrics, there was no measurable difference between groups in the overall number of students considering the specialty. Nevertheless, trainees and consultants should be aware of the importance of clinical placements in shaping students’ understanding and perceptions of a specialty. Careers advice should be integrated throughout the medical school curriculum and could run alongside clinical placements rather than as a separate entity.
- Published
- 2020
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11. Reply: Age at Craniosynostosis Surgery and Its Impact on Ophthalmologic Diagnoses: A Single-Center Retrospective Review
- Author
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Christian J. Vercler, Steven R. Buchman, Alexis D Vick, Steven M Archer, Katelyn G. Bennett, and Russell E Ettinger
- Subjects
medicine.medical_specialty ,business.industry ,Retrospective cohort study ,Synostosis ,Logistic regression ,medicine.disease ,Single Center ,Craniosynostosis ,Surgery ,Craniosynostoses ,Interquartile range ,Coronal plane ,Cohort ,Medicine ,Humans ,business ,Retrospective Studies - Abstract
BACKGROUND Ocular abnormalities in craniosynostosis are a persistent concern for patients and providers, and some surgeons feel that early surgical intervention for synostosis alleviates the progression of ophthalmologic abnormalities. In contradistinction, the authors hypothesize that operating early will have no bearing on postoperative ophthalmologic outcomes. METHODS Single-suture craniosynostosis patients who underwent surgical correction between 1989 and 2015 were reviewed. Patients with multisuture craniosynostosis, syndromic diagnoses, no preoperative ophthalmology evaluation, and less than 2 years of follow-up were excluded. Logistic regression was used to determine odds of preoperative and postoperative ophthalmologic abnormalities by age, while controlling for patient-level covariates. RESULTS One hundred seventy-two patients met inclusion criteria. The median age at surgery was 10 months (interquartile range, 7 to 12.9 months). Increasing age at the time of surgery was associated with increased odds of preoperative ophthalmologic diagnoses (OR, 1.06; p = 0.037) but not postoperative diagnoses (OR, 1.00; p = 0.91). Increasing age at surgery was also not associated with increased odds of ophthalmologic diagnoses, regardless of timing (OR, 1.04; p = 0.08). Patients with coronal synostosis (OR, 3.94; p = 0.036) had significantly higher odds of preoperative ophthalmologic diagnoses. Patients with metopic (OR, 5.60; p < 0.001) and coronal (OR, 7.13; p < 0.001) synostosis had significantly higher odds of postoperative ophthalmologic diagnoses. CONCLUSIONS After reviewing an expansive cohort, associations of both overall and postoperative ophthalmologic diagnoses with age at surgery were not found. The authors' findings thus run counter to the theory that early surgical intervention lessens the likelihood of postoperative ophthalmologic diagnoses and improves ophthalmologic outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE Risk, III.
- Published
- 2020
12. NanoMi: an open source (scanning) transmission electron microscope
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Drew Price, Jason L. Pitters, Misa Hayashida, Suliat Yakubu, D. Vick, Marek Malac, Marcus Leeson, Sean Chen, Mark Salomons, Ray F. Egerton, Darren Homeniuk, and Martin Cloutier
- Subjects
Optics ,Open source ,Materials science ,business.industry ,Scanning transmission electron microscopy ,business ,Instrumentation - Abstract
We are developing a modular (scanning) transmission electron microscope (S)TEM, referred to as NanoMi, which is released under an open source license by the National Research Council, Canada; see for updates. The electron microscope (EM) is a critical enabling tool in the physical, materials and biological sciences but its impact could be increased by the availability of an easy-to-build, customizable instrument capable of modest resolution and suitable for electron beam lithography, specialized experiments and for training personnel. An instrument that can be built for ~50 k$ and ~1 year of student time would fulfill these requirements in many laboratories around the world. Here we describe an initial design of such an instrument.
- Published
- 2020
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13. Bias against Latina and African American women job applicants: a field experiment
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George B. Cunningham and Astin D. Vick
- Subjects
Marketing ,African american ,Strategy and Management ,media_common.quotation_subject ,05 social sciences ,Direct effects ,Identity (social science) ,Racial group ,Race (biology) ,Interactive effects ,Tourism, Leisure and Hospitality Management ,0502 economics and business ,Business and International Management ,Psychology ,Prejudice ,Seeking employment ,Social psychology ,050203 business & management ,050212 sport, leisure & tourism ,media_common - Abstract
Purpose The purpose of this paper is to examine bias among White raters against racial minority women seeking employment in fitness organizations. Design/methodology/approach The authors conducted a 2 (applicant perceived racial identity) × 2 (applicant race) × 2 (hiring directive) factorial design experiment, with participant rater gender serving as the within-subjects variable. Adults in the USA (n=238) who had or were currently working in the fitness industry participated in the study. Findings Results indicate that applicant presumed racial identity and rater gender had direct effects, while applicant presumed racial identity, applicant race and rater gender had interactive effects, as well. Originality/value Results show that perceived racial identity affects raters’ view of job applicants, and the pattern of findings varies among racial groups.
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- 2018
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14. ECONOMIC AND FINANCIAL EFFECTS OF SPECIFIC TAXES AT THE STATE LEVEL IN THE UNITED STATES
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C. Barwegen, D. Vick, N. B. Ermasova, and Other Disorder
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State (polity) ,media_common.quotation_subject ,State government ,Economics ,Financial system ,Tax reform ,Financial policy ,Social economy ,media_common - Published
- 2018
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15. Elevated Plasma Endothelin‐1 is Associated with Reduced Weight Loss Post‐Vertical Sleeve Gastrectomy
- Author
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London J Williams, Joshua S. Speed, Haley N. Jenkins, Adam Dungey, Kenneth D. Vick, and Bernadette E. Grayson
- Subjects
Sleeve gastrectomy ,medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,University hospital ,medicine.disease ,Biochemistry ,Endothelin 1 ,Obesity ,Gastroenterology ,Insulin resistance ,Weight loss ,Internal medicine ,Cohort ,Genetics ,medicine ,medicine.symptom ,business ,Molecular Biology ,Body mass index ,Biotechnology - Abstract
Background Obesity and insulin resistance are positively correlated with plasma endothelin-1 (ET-1) levels; however, the mechanisms leading to increased ET-1 are not understood. Similarly, the full physiological complexity of ET-1 has yet to be described, especially in obesity. To date, one of the best treatments available for morbid obesity is bariatric surgery to quickly reduce body fat and the factors associated with obesity-related disease; however, the effects of vertical sleeve gastrectomy (SG) on plasma ET-1 have not been described. Objectives To determine if SG will reduce plasma ET-1 levels and to determine if plasma ET-1 concentration is associated with weight loss after surgery. Setting The studies were undertaken at a University Hospital. Methods This was tested by measuring plasma ET-1 levels from 12 obese patients before and after SG. All data were collected from clinic visits before SG, 6 weeks after SG, and 6 months after surgery. Results At 6 weeks after SG, plasma ET-1 levels increased by 24%; however, after 6 months, there was a 27% decrease compared with presurgery. Average weight loss in this cohort was 11.3% ± 2.4% body weight after 6 weeks and 21.4% ± 5.7% body weight after 6 months. Interestingly, we observed an inverse relationship between baseline plasma ET-1 and percent body weight loss (R2 = .49, P = .01) and change in body mass index 6 months (R2 = .45, P = .011) post bariatric surgery. Conclusions Our results indicate that SG reduces plasma ET-1 levels, a possible mechanism for improved metabolic risk in these patients. These data also suggest that ET-1 may serve as a predictor of weight loss after bariatric surgery.
- Published
- 2019
- Full Text
- View/download PDF
16. Consistent probe spacing in multi-probe STM experiments
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Jason L. Pitters, D. Vick, Jo Onoda, Mark Salomons, and Robert A. Wolkow
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focused ion beam ,field ion microscopy ,Materials science ,Silicon ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,01 natural sciences ,Focused ion beam ,law.invention ,electric measurements ,law ,0103 physical sciences ,semiconductor device fabrication ,Electrical measurements ,Nanoscopic scale ,surface and interface chemistry ,010302 applied physics ,business.industry ,food and beverages ,Radius ,021001 nanoscience & nanotechnology ,lcsh:QC1-999 ,Characterization (materials science) ,chemistry ,scanning tunneling microscopy ,Optoelectronics ,Scanning tunneling microscope ,0210 nano-technology ,business ,Field ion microscope ,lcsh:Physics - Abstract
Multi-probe scanning tunneling microscopy can play a role in various electrical measurements and characterization of nanoscale objects. The consistent close placement of multiple probes relies on very sharp apexes with no other interfering materials along the shank of the tip. Electrochemically etched tips can prepare very sharp apex tips; however, other asperities on the shank can cause interference and limit the close positioning of multiple tips to beyond the measured radii. Gallium focused ion beam (FIB) milling is used to remove any interfering material and allow closely spaced tips with a consistent yield. The tip apex radius is evaluated with field ion microscopy, and the probe spacing is evaluated with STM on hydrogen terminated silicon surfaces. FIB prepared tips can consistently achieve the measured probe to probe spacing distances of 25 nm–50 nm.
- Published
- 2020
17. Inflammatory marker changes following vertical sleeve gastrectomy in Black Americans and White Americans
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Bradley A. Welch, Adam Dungey, Kenneth D. Vick, Bernadette E. Grayson, and Charles L Phillips
- Subjects
medicine.medical_specialty ,Sleeve gastrectomy ,White (horse) ,business.industry ,medicine.medical_treatment ,Biochemistry ,Gastroenterology ,Inflammatory marker ,Internal medicine ,Genetics ,medicine ,business ,Molecular Biology ,Biotechnology - Published
- 2020
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18. Nanomechanical torque magnetometry of an individual aggregate of ∼350 nanoparticles
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Fatemeh Fani Sani, D.K. Potter, Miro Belov, A. McDermott, D. Vick, Tayyaba Firdous, T. Prozorov, Mark R. Freeman, Joseph Losby, and D.A. Bazylinski
- Subjects
Physics ,Aggregate (composite) ,Magnetotactic bacteria ,Magnetometer ,Physics::Optics ,General Physics and Astronomy ,Nanoparticle ,Nanotechnology ,Magnetic hysteresis ,law.invention ,Condensed Matter::Materials Science ,Magnetite Nanoparticles ,law ,Torque - Abstract
The measurements of magnetic hysteresis for aggregates of nanoparticles deposited on a surface are reported. Magnetite nanoparticles derived from magnetotactic bacteria are studied using nanomechanical torque magnetometry. The nanoparticles are deposited on high-stress Si3N4 membranes, to allow inspection by electron microscopy, followed by focused ion-beam milling of torsional resonators precisely located to capture selected aggregates within the membrane area. Torque magnetometry is performed using the resonators. We investigate also the magnetic torque-driven AC resonant modes of the modified supporting membrane. The observations are compared to numerical simulations of the mechanical modes, and to micromagnetic modeling of the hysteresis of a specific measured cluster of ∼350 nanoparticles.
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- 2015
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19. Epigenetics and Health Disparities
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Heather H. Burris and Alexis D Vick
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0301 basic medicine ,medicine.medical_specialty ,business.industry ,Cancer ,Disease ,medicine.disease ,Health equity ,Article ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Breast cancer ,030220 oncology & carcinogenesis ,Environmental health ,DNA methylation ,Immunology ,Epidemiology ,medicine ,General Earth and Planetary Sciences ,Epigenetics ,business ,Epigenomics - Abstract
African-Americans disproportionately suffer from leading causes of morbidity and mortality including cardiovascular disease (CVD), cancer, and preterm birth. Disparities can arise from multiple social and environmental exposures, but how the human body responds to these exposures to result in pathophysiologic states is incompletely understood. Epigenetic mechanisms, particularly DNA methylation, can be altered in response to exposures such as air pollution, psychosocial stress, and smoking. Each of these exposures has been linked to the above health states (CVD, cancer, and preterm birth) with striking racial disparities in exposure levels. DNA methylation patterns have also been shown to be associated with each of these health outcomes. Whether DNA methylation mediates exposure–disease relationships and can help explain racial disparities in health is not known. However, because many environmental and adverse social exposures disproportionately affect minorities, understanding the role that epigenetics plays in the human response to these exposures that often result in disease is critical to reducing disparities in morbidity and mortality.
- Published
- 2017
20. Adding concentrated solar power plants to wind farms to achieve a good utility electrical load match
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Timothy A. Moss and Brian D. Vick
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Wind power ,Electrical load ,Meteorology ,Renewable Energy, Sustainability and the Environment ,business.industry ,Thermal energy storage ,Electricity generation ,Concentrated solar power ,Parabolic trough ,Environmental science ,General Materials Science ,business ,Cost of electricity by source ,Solar power - Abstract
Texas has the greatest installed wind turbine capacity of any state in the United States, but as the percentage of wind generation approaches 10% of the utilities total electrical generation (in 2012, the total wind generated electricity in Texas was 7.4%), it becomes increasingly difficult for the utility to balance the electrical load due to the mismatch between the wind farm (WF) generated electricity and the utility electrical loading. In this paper WF output was shown to be diurnally and seasonally mismatched with the utility electrical loading in the Texas Panhandle (e.g. Texas Panhandle has the highest wind energy resource in Texas). In addition, the wind farm output in the Texas Panhandle does not normally contribute significantly at the peak hourly electrical load, and the peak hourly electrical load is a major deciding factor for a utility to add new power plants. A financial analysis was also performed on all the renewable energy systems analyzed. Various ratios of wind farm output to concentrating solar power (CSP) parabolic trough plant output (with 6 h of thermal storage) were calculated for the Texas Panhandle and compared to the utility electrical loading on an annual and peak monthly basis (each renewable energy system was analyzed at a 100 MW rating). The 67 MW wind farm and the 33 MW CSP plant with 6 h of thermal storage was approximately the best match to the utility electrical loading. The utility electrical load was also compared to: a 100 MW WF, a 100 MW CSP plant (with and without 6 h thermal storage), and finally the 67 MW WF with 33 MW CSP plant (with 6 h of thermal storage) on an annual, monthly, and peak hourly load basis. Typically for each month, the wind farm did not match the utility electrical loading except in the evening while the CSP plant (without storage) matched the utility electrical loading with the exception of in the evening. For the peak utility electrical loading months (July and August) and the days with the peak electrical loadings during those months, the 100 MW CSP plant with 6 h of thermal storage performed best in terms of supporting the utility electrical load (e.g. no wind farm). For the Texas Panhandle the estimated levelized cost of energy (LCOE) of a hybrid WF/CSP plant was in the range of $108/MW h to $129/MW h while the WF only system was estimated to be $64/MW h, but the benefits of adding CSP may justify the additional cost. Although the Texas Panhandle was the only location analyzed for combining CSP plants with WFs, the analysis described in this paper can be used for other regions, states, or countries.
- Published
- 2013
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21. Quantitative Magneto-Mechanical Detection and Control of the Barkhausen Effect
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Bradley Hauer, Mark R. Freeman, D. Vick, A. E. Fraser, John P. Davis, Jacob A. J. Burgess, and Fatemeh Fani Sani
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Magnetometer ,magnetic nanoparticle ,mechanical theory ,film ,Focused ion beam ,law.invention ,ion therapy ,symbols.namesake ,magnetometry ,law ,Condensed Matter::Superconductivity ,Barkhausen effect ,Magneto ,energy transfer ,Multidisciplinary ,quantitative analysis ,Condensed matter physics ,quantum mechanics ,ferromagnetic material ,Magnetic storage ,torsion ,Vortex ,Characterization (materials science) ,magnetic method ,Ferromagnetism ,magnetism ,symbols - Abstract
Controlling Magnetic Noise Ferromagnetic materials contain a number of magnetic domains, with individual domains switching stochastically as the field strength is increased. As magnetic memory elements shrink in size, it is important to understand, and ultimately control, this magnetic noise. Using a magnetic vortex core integrated with a nanomechanical torsion balance, Burgess et al. (p. 1051 , published online 17 January) created a two-dimensional map of the magnetic potential within the sample with nanoscale resolution. Moreover, introducing geometric defects (dimples) in the sample allowed the magnetization to be stabilized.
- Published
- 2013
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22. Torque-mixing magnetic resonance spectroscopy (Conference Presentation)
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Jacob A. J. Burgess, Douglas J. Thomson, Fatemeh Fani Sani, Dylan T. Grandmont, Kaveh Mohammad, Wayne K. Hiebert, Miro Belov, Gregory Bridges, D. Vick, Zhu Diao, Elham Salimi, Shawn Compton, Mark R. Freeman, and Joseph Losby
- Subjects
Larmor precession ,Physics ,Magnetization dynamics ,Dipole ,Condensed matter physics ,Relaxation (NMR) ,Spin echo ,Magnetic resonance force microscopy ,Resonance ,Ferromagnetic resonance - Abstract
An optomechanical platform for magnetic resonance spectroscopy will be presented. The method relies on frequency mixing of orthogonal RF fields to yield a torque amplitude (arising from the transverse component of a precessing dipole moment, in analogy to magnetic resonance detection by electromagnetic induction) on a miniaturized resonant mechanical torsion sensor. In contrast to induction, the method is fully broadband and allows for simultaneous observation of the equilibrium net magnetic moment alongside the associated magnetization dynamics. To illustrate the method, comprehensive electron spin resonance spectra of a mesoscopic, single-crystal YIG disk at room temperature will be presented, along with situations where torque spectroscopy can offer complimentary information to existing magnetic resonance detection techniques. The authors are very grateful for support from NSERC, CRC, AITF, and NINT. Reference: Science 350, 798 (2015).
- Published
- 2016
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23. Using direct normal irradiance models and utility electrical loading to assess benefit of a concentrating solar power plant
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Daryl R. Myers, Brian D. Vick, and William E. Boyson
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Insolation ,Pyranometer ,Meteorology ,Electrical load ,Renewable Energy, Sustainability and the Environment ,business.industry ,Direct insolation ,Direct normal irradiance ,Solar energy ,Solar power plant ,Environmental science ,General Materials Science ,business ,Solar power - Abstract
The objective of this paper was to determine if three different direct normal irradiance (DNI) models were sufficiently accurate to determine if concentrating solar power (CSP) plants could meet the utility electrical load. DNI data were measured at three different laboratories in the United States and compared with DNI calculated by three DNI models. In addition, utility electrical loading data were obtained for all three locations. The DNI models evaluated were: the Direct Insolation Simulation Code (DISC), DIRINT, and DIRINDEX. On an annual solar insolation (e.g. kW h/m2) basis, the accuracy of the DNI models at all three locations was within: 7% (DISC), 5% (DIRINT), and 3% (DIRINDEX). During the three highest electrical loading months at the three locations, the monthly accuracy varied from: 0% to 16% (DISC), 0% to 9% (DIRINT), and 0% to 8% (DIRINDEX). At one location different pyranometers were used to measure GHI, and the most expensive pyranometers did not improve the DNI model monthly accuracy. In lieu of actually measuring DNI, using the DIRINT model was felt to be sufficient for assessing whether to build a CSP plant at one location, but use of either the DIRINT or DIRINDEX models was felt to be marginal for the other two locations due to errors in modeling DNI for utility peak electrical loading days – especially for partly cloudy days.
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- 2012
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24. Analysis of off-grid hybrid wind turbine/solar PV water pumping systems
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Brian D. Vick and Byron A. Neal
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Water pumping ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Direct current ,Photovoltaic system ,Solar energy ,Renewable energy ,Rectifier ,Hybrid system ,Boost converter ,Optoelectronics ,General Materials Science ,business - Abstract
While many remote water pumping systems exist (e.g. mechanical windmills, solar photovoltaic, wind-electric, diesel powered), few combine both the wind and solar energy resources to possibly improve the reliability and the performance of the system. In this paper, off-grid wind turbine (WT) and solar photovoltaic (PV) array water pumping systems were analyzed individually and combined as a hybrid system. The objectives were to determine: (1) advantages or disadvantages of using a hybrid system over using a WT or a solar PV array alone; (2) if the WT or solar PV array interfered with the output of the other; and (3) which hybrid system was the most efficient for the location. The WT used in the analysis was rated at 900 W alternating current (AC). There were three different solar PV arrays analyzed, and they were rated at 320, 480, and 640 W direct current (DC). A rectifier converted the 3-phase variable voltage AC output from the WT to DC before combining it with the solar PV array DC output. The combined renewable energies powered a single helical pump. The independent variable used in the hybrid WT/PV array analysis was in units of W/m 2 . The peak pump efficiency of the hybrid systems at Bushland, TX occurred for the 900 W WT combined with the 640 W PV array. The peak pump efficiencies at a 75 m pumping depth of the hybrid systems were: 47% (WT/320 W PV array), 51% (WT/480 W PV array), and 55% (WT/640 W PV array). Interference occurred between the WT and the different PV arrays (likely due to voltage mismatch between WT and PV array), but the least interference occurred for the WT/320 W PV array. This hybrid system pumped 28% more water during the greatest water demand month than the WT and PV systems would have pumped individually. An additional controller with a buck/boost converter is discussed at end of paper for improvement of the hybrid WT/PV array water pumping system.
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- 2012
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25. Novel application of GI electrical stimulation in Roux stasis syndrome (with video)
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Christopher J. Lahr, Michelle Taylor, Thomas L. Abell, Kenneth D. Vick, John J. Sheehan, Shou-Jiang Tang, Om Amin, Giorgio M. Aru, and Sumanth R. Daram
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medicine.medical_specialty ,Abdominal pain ,Vomiting ,medicine.medical_treatment ,Jejunostomy ,Electric Stimulation Therapy ,Anastomosis ,Severity of Illness Index ,Article ,Esophagus ,Gastrectomy ,Electrogastrogram ,Severity of illness ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Gastroparesis ,Gastrointestinal Transit ,medicine.diagnostic_test ,business.industry ,Gastroenterology ,Anastomosis, Roux-en-Y ,Nausea ,Syndrome ,Middle Aged ,medicine.disease ,Abdominal Pain ,Surgery ,medicine.anatomical_structure ,Female ,medicine.symptom ,business - Abstract
Background About one-third of patients undergoing a Roux-en-Y anastomosis develop Roux stasis syndrome, likely because of disordered electrical conduction. GI electrical stimulation has been previously used successfully in the management of postsurgical gastroparesis. Objective Endoscopic placement of temporary electrodes and GI electrical stimulation in the management of severe Roux stasis syndrome in a patient with esophagojejunostomy and to determine whether the patient would be a candidate for surgical permanent electrode placement. Design Case report. Setting Academic medical center. Patients This study involved a patient with Roux stasis syndrome. Intervention Upper endoscopy was performed, followed by endoscopic placement of two temporary electrodes, one each in the two jejunal limbs. Electrical stimulation was provided by an external stimulation device. The patient was re-evaluated 5 days later. Main Outcome Measurements Electrogastrogram (EGG) parameters including frequency, amplitude, and frequency-amplitude ratio and total symptom score and health-related quality of life score. Results There was a significant improvement in EGG parameters with electrical stimulation. Also, the patient had a marked improvement in total GI symptom score, from 11 to 4, with a dramatic improvement in the health-related quality of life score from −3 to +3. Limitations Single case report. Conclusion Endoscopic placement of temporary electrodes is feasible and safe. GI electrical stimulation of the jejunal limb is a potentially effective treatment for Roux stasis syndrome.
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- 2011
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26. Experimental investigation of solar powered diaphragm and helical pumps
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R. Nolan Clark and Brian D. Vick
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Water pumping ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Hydraulics ,Photovoltaic system ,Diaphragm pump ,Diaphragm (mechanical device) ,Solar energy ,Solar irradiance ,law.invention ,Optics ,law ,Photovoltaics ,Optoelectronics ,General Materials Science ,business - Abstract
For several years, many types of solar powered water pumping systems were evaluated, and in this paper, diaphragm and helical solar photovoltaic (PV) powered water pumping systems are discussed. Data were collected on diaphragm and helical pumps which were powered by different solar PV arrays at multiple pumping depths to determine the pumping performance, efficiency, and reliability of the different systems. The highest diaphragm pump hydraulic efficiency measured was ∼48%, and the highest helical pump hydraulic efficiency measured was ∼60%. The peak total system efficiency (e.g. solar radiation to pumped water) measured for the diaphragm and helical pumps were ∼5% and ∼7%, respectively (based on PV modules with ∼12% efficiency). The daily water volume of the three-chamber high head diaphragm pump performed better than the dual-chamber high head diaphragm pump (∼5 to ∼100% depending on PV array input power and pumping depth). Use of a controller was shown to improve the quad diaphragm pump performance below a solar irradiance of 600 W/m 2 (20 m head) to 800 W/m 2 (30 m head). While diaphragm pumps made mostly of plastic demonstrated similar to much better pumping performance than diaphragm pumps made with a high proportion of metal, the metal pumps demonstrated a longer service life (>2 years) than the plastic pumps service life (
- Published
- 2011
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27. Developing Wind and/or Solar Powered Crop Irrigation Systems for the Great Plains
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B. D. Vick and Lal K. Almas
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Center pivot irrigation ,Engineering ,Offshore wind power ,Small wind turbine ,Wind power ,business.industry ,Distributed generation ,Photovoltaic system ,General Engineering ,Environmental engineering ,business ,Grid parity ,Renewable energy - Abstract
Some small scale, off-grid irrigation systems (< 2.5 ha) that are powered by wind or solar energy are cost effective, but this article discusses ways to achieve an economical renewable energy powered center pivot irrigation system for crops in the Great Plains. It was found that partitioning the center pivot irrigation system between a winter crop and a summer crop improved the match of wind turbine power generation to irrigation energy required. It was also found that a solar-photovoltaic (PV) array was a better match to the irrigation energy requirement of a winter and summer crop than using only a wind turbine, but a wind/solar hybrid was a better match than wind alone. Although solar PV systems were shown to be a better match than wind turbines for irrigation power requirements, solar PV systems are more expensive than small wind turbine systems for large-scale irrigation water requirements in the Great Plains. Including on-farm uses for the excess wind and solar electricity instead of selling the electricity back to a utility company at usually low prices, improves the profitability of a renewable energy powered irrigation system significantly. For a utility electrical price of $0.10/kWh, a wind turbine installed price of $3000/kW, no loan required (e.g. no loan costs), and the excess renewable energy generated electricity used for on-farm use only, a payback period of seven to eight years was possible with no state or federal incentives. With 55% federal incentives and the same assumptions, a payback period of four to five years was possible. Also, if the assumed operations and maintenance costs doubled, the payback period increased about two years. However, cost reductions are still required for both wind and solar energy systems in order that renewable energy systems can be competitive without the need for state or federal incentives when loans at 90% of installed cost with a 6% interest rate are required.
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- 2011
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28. Molecular Analysis of Inflammatory Markers in Trauma Patients at Risk of Postinjury Complications
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D Brian Newman, Laura R. Vick, Kenneth D. Vick, Christine C. Toevs, Lee Y. Tee, Marjolyn Brock, D. Olga McDaniel, Lynn Calcote, Gregory Timberlake, Sebron Harrison, James G. C. Hamilton, and Warren L. May
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Male ,Genotype ,medicine.medical_treatment ,Disease ,Critical Care and Intensive Care Medicine ,Polymerase Chain Reaction ,White People ,Sepsis ,Injury Severity Score ,Gene Frequency ,medicine ,Humans ,business.industry ,Patient Selection ,Interleukin ,medicine.disease ,Toll-Like Receptor 2 ,Black or African American ,Toll-Like Receptor 4 ,Cytokine ,Relative risk ,Immunology ,Cytokines ,Wounds and Injuries ,Surgery ,Tumor necrosis factor alpha ,business ,Polymorphism, Restriction Fragment Length - Abstract
Background: Genetic differences associated with individual's immune responses appear to be a major contributing factor to the development of trauma-induced sepsis. Thus, effective treatment of sepsis requires the identification of the patients who are at increased risk for sepsis. Methods: Sixty-eight patients, of which the majority had an injury severity score >15, and 118 controls from the same geographic region were genotyped. Cytokine and Toll-like receptor (TLR) genotypes and expressions were tested using polymerase chain reaction (PCR). Results: Fifty percent of African American and 42% of Caucasian patients developed posttrauma sepsis. Frequency distribution of the polymorphism for some cytokine genes such as Interleukin (IL)-10 low/high and interferon (IFN)-y low producer were statistically different between the septic and aseptic patients, for others, such as tumor necrosis factor (TNF)-a, IL-6, and IL-18, there was no statistical difference. The TLR-2 genotypes (A/G) were considered a sepsis risk marker as compared with A/A (62.5% versus 37.5%,p < 0.03; relative risk = 2.5) in African American patients. Cytokine mRNA levels correlated with genotype definition, particularly, for IL-10, IL-6, IL-18, and TNF-a. A time course study demonstrated a significant difference in cytokines expression profile in septic and aseptic patients before the development of sepsis. Conclusion: Monitoring cytokine expression levels before the disease might predict the outcome of sepsis. A large cohort study is needed to assess the diagnostic potential of the genotypes.
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- 2007
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29. Valuing weather radar benefits for winter road maintenance: A practical case example
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Sandra D Vick and Keith Smith
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Transport engineering ,Atmospheric Science ,Operations research ,law ,Service (economics) ,media_common.quotation_subject ,Weather radar ,Business ,law.invention ,media_common - Abstract
A simple decision-analysis model is used to determine the financial benefits accruing to one highway authority in Scotland from the use of weather radar imagery for u-inter-road-maintenance operations. Over a three-month period, the savings are some £23 000 greater than the benefits derived from the use of the particular OPEN ROAD forecast service employed by that authority.
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- 2007
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30. Torque-mixing magnetic resonance spectroscopy
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Joseph Losby, D. Vick, Dylan T. Grandmont, Wayne K. Hiebert, Fatemeh Fani Sani, Douglas J. Thomson, Mark R. Freeman, Greg E. Bridges, Kaveh Mohammad, Miro Belov, Shawn Compton, Jacob A. J. Burgess, Zhu Diao, and Elham Salimi
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Multidisciplinary ,Materials science ,Condensed matter physics ,Yttrium iron garnet ,Resonance ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electromagnetic induction ,Magnetization ,Dipole ,chemistry.chemical_compound ,Nuclear magnetic resonance ,chemistry ,0103 physical sciences ,Torque sensor ,010306 general physics ,0210 nano-technology ,Spin (physics) ,Spectroscopy - Abstract
Mechanically detected spin resonances The interaction of spins in a sample with a magnetic field can generate forces that can be sensed with cantilever probes. Losby et al. measured the resonance signals at room temperature with a micromechanical torque magnetometer. The difference between two applied radio-frequency signals corresponded to the mechanical frequency of the resonator. This approach revealed the vortex core dynamics of the ferri-toferro–magnetic transition in a micrometer-sized yttrium-iron-garnet single-crystal disk. Science , this issue p. 798
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- 2015
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31. Conduction anisotropy in porous thin films with chevron microstructures
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M. J. Brett and D. Vick
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Materials science ,Nanotechnology ,Surfaces and Interfaces ,Substrate (electronics) ,Chemical vapor deposition ,Conductivity ,Condensed Matter Physics ,Microstructure ,Thermal conduction ,Surfaces, Coatings and Films ,Electrical resistivity and conductivity ,Thin film ,Composite material ,Anisotropy - Abstract
Electrical conductivity measurements were performed on structurally anisotropic thin films deposited using the glancing angle deposition apparatus [K. Robbie and M. J. Brett, J. Vac. Sci. Technol. A 15, 1460 (1997); K. Robbie, J. Sit, and M. J. Brett, J. Vac. Sci. Technol. B 16, 1115 (1998); K. Robbie and M. J. Brett, US Patent No. 5,866,204 (2 February 1999)]. The films were comprised of bilayers of titanium over silica, engineered as a chevron morphology. Samples were evaporated at various incident vapor deposition angles α, in order to investigate the effects of morphology and voiding on the behavior of conductivity. A rapid decline in the conductivity, accompanied by an increase in conduction anisotropy in the plane of the substrate, was observed with increasing α. A random walk model was developed to model the transport properties of the films, and applied to microstructures predicted by a three-dimensional ballistic thin film simulator. In order to generate reasonable agreement between the modeling ...
- Published
- 2006
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32. Generation of fibrous aerosols from thin films
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M.J. Brett, Carlos F. Lange, D. Vick, Warren H. Finlay, K.E. Gilbertson, and Yung-Sung Cheng
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Fluid Flow and Transfer Processes ,Atmospheric Science ,Range (particle radiation) ,Environmental Engineering ,Materials science ,Mechanical Engineering ,Dispersity ,Nanotechnology ,Substrate (electronics) ,Pollution ,Aerosol ,Fiber ,Composite material ,Thin film ,Porous thin films - Abstract
A method of producing relatively monodisperse, small-diameter (sub-500 nm diameter) aerosol fibers is described. This method involves the separation of porous thin films from their substrate. It was found that fibers with diameters of less than several hundred nm and lengths of several micrometers can be formed that do not adhere to one-another. Two μ m thick columnar thin films were fabricated and processed, yielding aerosol fibers with lengths up to 2 μm and diameters up to 170 nm. Diameter and length distributions of a collected aerosol showed that a broad range of fiber lengths and diameters are formed by this method. Further modification of the method, however, is expected to greatly narrow the range of effective diameters and lengths obtained.
- Published
- 2005
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33. Incurable Colorectal Carcinoma: The Role of Surgical Palliation
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Erin R. Cummins, Kenneth D. Vick, and Galen V. Poole
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General Medicine - Abstract
About 20 per cent of patients with carcinoma of the colon or rectum present with metastatic disease. Surgeons are frequently asked to consider resection or other operative procedures in these patients for palliation. We performed this review to determine whether patients presenting with known metastatic colorectal cancer derive benefit from surgical intervention. We performed a retrospective review of all patients with Ml carcinoma of the colon or rectum who were identified from the University of Mississippi Medical Center Cancer Registry from April 1985 through February 2003. Patients who underwent hepatic and/or pulmonary resection with curative intent were excluded from analysis, as were patients with metachronous metastases. Eighty patients with Ml colorectal cancer who did not undergo surgery with curative intent were identified, and in 74 of these, complete medical records and follow-up were available. Forty-nine of the 74 patients (66%) underwent an operation, and 25 were managed nonoperatively. Indications for surgery included bowel obstruction, active hemorrhage, severe anemia from gastrointestinal bleeding with requirement for blood transfusions, intractable pain, and perforation of the colon. Average survival was 11.2 months for operative patients versus 6.5 months for nonoperative patients ( P < 0.05). Thirty-six patients who underwent resectional procedures had a postoperative hospitalization of 7.5 days and a median survival of 11.5 months. Thirteen patients who had a nonresectional procedure had an average postoperative stay of 9 days and a median survival of 4 months. Median survival in those who did not undergo an operation was 4.8 months. Although metastatic colorectal carcinoma cannot usually be cured by surgical intervention, many patients who present with metastatic disease will benefit from palliative operations with relatively short hospitalizations and reasonable survival. Those who are not candidates for resection of the primary tumor have shorter survival times. Surgery can alleviate many of the distressing symptoms in patients with metastatic colorectal carcinoma.
- Published
- 2004
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34. Remote Solar, Wind, and Hybrid Solar/Wind Energy Systems for Purifying Water
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Junyi Ling, Shitao Ling, Brian D. Vick, and R. Nolan Clark
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Engineering ,Wind power ,Electrical load ,Power station ,Renewable Energy, Sustainability and the Environment ,business.industry ,Wind hybrid power systems ,Photovoltaic system ,Environmental engineering ,Energy Engineering and Power Technology ,Portable water purification ,Solar energy ,Turbine ,Renewable energy ,Solar wind ,Photovoltaic thermal hybrid solar collector ,Environmental science ,Water treatment ,Grid energy storage ,business - Abstract
Solar energy, wind energy, and a combination of wind and solar energy have been used successfully to power an UV (ultraviolet) water purification system. The main reason for this success has been the design of the controllers which have been operating for almost two years with various wind and solar energy inputs. Five different solar and wind energy systems have been tested so far and although these renewable energy systems have been used for water purification, graphs contained in the paper can be used to determine the feasibility of powering various other electrical loads. Combining a 100 Watt solar system with a 900 Watt wind turbine resulted in pumping and purifying enough water to satisfy the potable water requirements of 4000 people (16000 liters/day) at an estimated equipment cost of about $4660 (approximately $1/person).
- Published
- 2003
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35. Growth behavior of evaporated porous thin films
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D. Vick, Michael J. Brett, and Tom J. Smy
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Nanostructure ,Materials science ,Mechanical Engineering ,Substrate (electronics) ,Condensed Matter Physics ,Microstructure ,Engineering physics ,Carbon film ,Mechanics of Materials ,Deposition (phase transition) ,General Materials Science ,Thin film ,Porosity ,Photonic crystal - Abstract
Recent experimental work by a number of researchers has demonstrated that unusual high porosity thin films may be obtained in physical deposition systems by combining glancing angle deposition with in situ substrate motion control. The microstructure of these films consists of isolated columns engineered into shapes such as helices, posts, or chevrons. Due to the isolated nature of the columns, the films present a unique opportunity to study fundamental thin film growth behavior and, in particular, the influence of the self-shadowing mechanism in three dimensions. Apart from this academic motivation, there is the need to characterize the physical constraints imposed on the engineering of these films. In particular, this study will have implications for the realization of isolated, periodically arranged nanostructures envisioned for certain applications such as photonic band gap crystals. Results from an ongoing study of growth dynamics, morphology, porosity, and scaling behavior, and the dependence of these features on deposition parameters are presented.
- Published
- 2002
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36. Debris reduction for copper and diamond-like carbon thin films produced by magnetically guided pulsed laser deposition
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Robert Fedosejevs, Ying Y. Tsui, D. Vick, and H. Minami
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Materials science ,Diamond-like carbon ,Metallurgy ,Analytical chemistry ,chemistry.chemical_element ,Surfaces and Interfaces ,Condensed Matter Physics ,Laser ,Copper ,Surfaces, Coatings and Films ,law.invention ,Pulsed laser deposition ,Carbon film ,chemistry ,law ,Thin film ,Carbon ,Deposition (law) - Abstract
The effectiveness of debris reduction using magnetically guided pulsed laser deposition (MGPLD) is reported here. KrF laser pulses (248 nm) of 100 mJ energy were focused to intensities of 6×109 W/cm2 onto the surface of a copper or a carbon source target and a magnetic field of 0.3 T as used to steer the plasma around a curved arc of 0.5 m length to the deposition substrate. Debris counts were compared for films produced by the MGPLD and conventional PLD (nonguided) techniques. A significant reduction in particulates of size greater than 0.1 μm was achieved using MGPLD. For the copper films, particulate count was reduced from 150 000 particles/cm2/nm to 50 particulates/cm2/nm and for diamond-like carbon thin films particulate count was reduced from 25 000 particles/cm2/nm to 1200 particles/cm2/nm.
- Published
- 2002
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37. Porous thin films for the characterization of atomic force microscope tip morphology
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K.L. Westra, D. Vick, and Michael J. Brett
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Materials science ,Silicon ,business.industry ,Scanning electron microscope ,technology, industry, and agriculture ,Metals and Alloys ,chemistry.chemical_element ,Surfaces and Interfaces ,Surface finish ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Characterization (materials science) ,Optics ,chemistry ,Physical vapor deposition ,Materials Chemistry ,Surface roughness ,Composite material ,business ,Porous medium ,Titanium - Abstract
We investigated the use of a novel class of porous thin films for the characterization of tapping mode atomic force microscope (AFM) tips. Chromium and titanium films were evaporated using the technique of glancing angle deposition (GLAD) onto rotating silicon substrates. The morphology of the resulting films consisted of isolated vertical posts of sub-micron size. These isolated topographical features are small enough to provide useful information about tip morphology and aid in assessing tip wear and damage. The films were imaged using an AFM, and previously published tip reconstruction algorithms were used to obtain three-dimensional tip functions. These compared well with envelope profiles determined from scanning electron microscope images of the tips.
- Published
- 2002
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38. Strong vortex core pinning and Barkhausen-free magnetization response in thin Permalloy disks induced by implantation of 1 × 104 Ga + ions
- Author
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D. Vick, Zhu Diao, L. C. Parsons, Mark R. Freeman, Joseph E. Losby, Fatemeh Fani Sani, Wayne K. Hiebert, and Jacob A. J. Burgess
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Permalloy ,Materials science ,Condensed matter physics ,General Physics and Astronomy ,Vortex ,Magnetization ,symbols.namesake ,Ion implantation ,Condensed Matter::Superconductivity ,symbols ,Barkhausen stability criterion ,Barkhausen effect ,Pinning force ,Saturation (magnetic) - Abstract
Artificial vortex core pinning sites are induced in thin Permalloy disks by point exposure to as few as 10 000 ions from a focused Ga+ beam. These pinning sites yield a first-order change in the magnetization response of the disk. A single site can keep the vortex core pinned over an applied field range comparable to the vortex annihilation field of the unaltered disk. Several widely separated sites can work together to keep the core pinned in one place, while the Barkhausen effect is eliminated from the magnetization curve over a range approaching the saturation moment of the disk. © 2014 AIP Publishing LLC.
- Published
- 2014
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39. Porous thin films for thermal barrier coatings
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Kenneth D. Harris, D. Vick, Michael J. Brett, Kevin Robbie, Tom J. Smy, and E.J. Gonzalez
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Materials science ,Analytical chemistry ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Thermal conduction ,Thermal diffusivity ,Electron beam physical vapor deposition ,Surfaces, Coatings and Films ,Thermal transmittance ,Thermal barrier coating ,Thermal conductivity ,Physical vapor deposition ,Materials Chemistry ,Thin film ,Composite material - Abstract
A new approach is described in the deposition of thin films for thermal barrier applications. Using controlled substrate motion, porous layers and capping layers were vacuum deposited in an alternating fashion, creating a new, multilayered film structure. Direct measurements of the thermal properties of these multilayers were made using the 3ω and Mirage techniques. In the 3ω technique, heat is introduced into the coating by an AC current flowing through an evaporated resistor with a frequency ω. A fit of resistor voltage as a function of frequency yields the thermal conductivity. In the Mirage technique, an oscillating temperature is induced immediately above the film using a pulsed laser. A second probe laser aligned parallel to the surface is deflected by these temperature variations, and the thermal diffusivity is then found by fitting amplitude and phase shift data to the solution of the three-dimensional diffusion equation. Typically, the 3ω and Mirage techniques measure thermal constants in directions normal and parallel to the substrate, respectively. Measurements using these methods led to estimates of a reduction in thermal diffusivity of as little as 9% of that of films deposited entirely at normal incidence. Thermal simulations of similar structures also predicted a substantial decrease in overall thermal conductivity. In a specific case, an improved conductivity of 18% of that of films deposited by standard techniques was estimated.
- Published
- 2001
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40. Production of porous carbon thin films by pulsed laser deposition
- Author
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Robert Fedosejevs, Michael J. Brett, D. Vick, and Ying Y. Tsui
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Materials science ,business.industry ,Metals and Alloys ,Analytical chemistry ,Surfaces and Interfaces ,Substrate (electronics) ,Microstructure ,Laser ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Pulsed laser deposition ,law ,Physical vapor deposition ,Materials Chemistry ,Optoelectronics ,Thin film ,Porous medium ,business ,Porosity - Abstract
Pulsed laser deposition (PLD) has been used together with the Glancing Angle Deposition (GLAD) technique [1,2] for the first time to produce highly porous structured films. A laser produced carbon plasma and vapour plume was deposited at a highly oblique incident angle onto rotating Si substrates, resulting in films exhibiting high bulk porosity and controlled columnar microstructure. By varying the substrate rotation rate, the shape of the microcolumns can be tailored. These results extend the versatility of the GLAD process to materials not readily deposited by means of traditional physical vapour deposition techniques.
- Published
- 1999
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41. A Design Attribute Methodology for the Identification and Ranking of Functional Integration Risk
- Author
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Jeffery D. Vick
- Subjects
Engineering ,Identification (information) ,Ranking ,Functional integration (neurobiology) ,Search theory ,business.industry ,New product development ,Product (category theory) ,Risk assessment ,business ,Heuristics ,Reliability engineering - Abstract
It is well known that applying validation methods during product development will reduce product functionality problems. Generally, the earlier an error is found, the less it costs to resolve it. The traditional amount of validation analysis applied during the detailed design of derivative commercial airplanes is being challenged due to market pressures to cut costs. Without sufficient validation, a significant number of functional integration problems can remain undetected until discovered late in development by flight tests or during airline operations – which translates into cost overruns. A tradeoff exists between making planned investments in validation analysis and incurring unplanned costs later. Having the ability to identify where in the design to focus design validation analyses is essential for assuring a functionally integrated product and minimizing total development costs. A design-attribute risk assessment methodology based upon search theory, technical risk analysis concepts, and systems heuristics was developed and applied for this purpose.
- Published
- 1999
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42. Self-shadowing and surface diffusion effects in obliquely deposited thin films
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D. Vick, Tom J. Smy, M.J. Brett, Mary W. Seto, Steven K. Dew, L. J. Friedrich, and Kevin Robbie
- Subjects
Surface diffusion ,Materials science ,business.industry ,Metals and Alloys ,Crystal growth ,Surfaces and Interfaces ,Evaporation (deposition) ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Carbon film ,Optics ,Physical vapor deposition ,Materials Chemistry ,Deposition (phase transition) ,Composite material ,Thin film ,business ,Porous medium - Abstract
The production of highly porous films by oblique deposition has attracted recent attention because of the possible applications of such films. The morphology of obliquely evaporated films is thought to be determined mainly by the mechanisms of self-shadowing and surface diffusion. The thin film process simulator GROFILMS has been used to verify the importance of these effects, and clarify some aspects of how they interact to determine the final film morphology. Good agreement between simulations and actual films has been achieved. Temperature control of the film during deposition is shown to be an important consideration for the production of structurally engineered films.
- Published
- 1999
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43. The Healing Circle: An Alternative Path to Alcoholism Recovery
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Ronald D. Vick, Linda M. Smith, and Carol Iron Rope Herrera
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Clinical Psychology ,Social Psychology ,Native american ,common ,Spirituality ,common.demographic_type ,Alcoholics Anonymous ,Religious studies ,Gender studies ,Psychology ,Social psychology ,Oglala Sioux - Abstract
Recovery from alcoholism has typically involved the program of Alcoholics Anonymous (AA). However, the values espoused by AA, especially those related to spirituality, can be in conflict with the values of traditional Native Americans. This article discusses healing methods founded in the traditions of Native American culture in general and the Oglala Lakota (also called Oglala Sioux) nation specifically. An understanding of these methods gives non-Native American counselors additional tools for guiding Native American clients to an effective program of recovery.
- Published
- 1998
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44. Sigmoid-urachal fistula presenting as an incarcerated ventral hernia
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Andrew, Gaugler, Kenneth D, Vick, and Laura R, Vick
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Sigmoid Diseases ,Fistula ,Intestinal Fistula ,Humans ,Female ,Middle Aged ,Hernia, Ventral ,Urachus - Published
- 2013
45. Untreated axillary node metastasis of occult breast primary six years after diagnosis
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J Jarrett, Corley, Kenneth D, Vick, and Laura R, Vick
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Time Factors ,Axilla ,Carcinoma ,Humans ,Breast Neoplasms ,Female ,Middle Aged ,Neoplasm Metastasis - Published
- 2013
46. Performance of Wind-Electric and Solar-PV Water Pumping Systems for Watering Livestock
- Author
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R. N. Clark and Brian D. Vick
- Subjects
Water pumping ,Engineering ,Wind power ,Renewable Energy, Sustainability and the Environment ,business.industry ,Nuclear engineering ,Photovoltaic system ,Energy Engineering and Power Technology ,Mechanical engineering ,Electric generator ,Solar energy ,Centrifugal pump ,Wind speed ,law.invention ,law ,business ,Induction motor - Abstract
The water pumping performance of two wind-electric systems is compared to the water pumping performance of two solar-PV systems. The wind-electric systems were rated at 1.0 kW and 1.5 kW at a wind speed of about 12 m/s, and the rotor diameters were 2.75 m and 3.05 m, respectively. The solar-PV systems were rated at 0.1 kW and 0.9 kW at a radiation level of about 1,000 W/m{sup 2}, and the total solar panel surface areas were 1 and 17 m{sup 2}, respectively. Both wind-electric systems powered three-phase 230 V a-c induction motors with centrifugal pumps. The smaller of the solar-PV systems powered a d-c motor with a diaphragm pump, and the larger one powered a single phase 230 V a-c induction motor with a centrifugal pump. Only a well pumping depth of 30 m was evaluated for both wind-electric and solar-PV water pumping systems. The 0.1 kW and the 0.9 kW solar water pumping systems can provide enough water for 25 and 75 cattle, respectively, if the incident solar radiation is similar to that of Bushland, TX. The 1.0 kW and 1.5 kW wind-electric water pumping systems can provide enough water for 300 and 400 cattle, respectively, if themore » wind regime is similar to that of Bushland, TX.« less
- Published
- 1996
- Full Text
- View/download PDF
47. Tunable open-access microcavities for on-chip cavity quantum electrodynamics
- Author
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M. H. Bitarafan, H. Ramp, D. Vick, Ray G. DeCorby, John P. Davis, A. Melnyk, C. A. Potts, and Lindsay LeBlanc
- Subjects
Physics ,Cavity resonance ,Quantum optics ,Mode volume ,Physics and Astronomy (miscellaneous) ,business.industry ,Cavity quantum electrodynamics ,Physics::Optics ,01 natural sciences ,Reflectivity ,010309 optics ,Finesse ,0103 physical sciences ,Atom ,Strong coupling ,Optoelectronics ,010306 general physics ,business - Abstract
We report on the development of on-chip microcavities and show their potential as a platform for cavity quantum electrodynamics experiments. Microcavity arrays were formed by the controlled buckling of SiO2/Ta2O5 Bragg mirrors and exhibit a reflectance-limited finesse of 3500 and mode volumes as small as 35λ3. We show that the cavity resonance can be thermally tuned into alignment with the D2 transition of 87Rb and outline two methods for providing atom access to the cavity. Owing to their small mode volume and high finesse, these cavities exhibit single-atom cooperativities as high as C1=65. A unique feature of the buckled-dome architecture is that the strong-coupling parameter g0/κ is nearly independent of the cavity size. Furthermore, strong coupling should be achievable with only modest improvements in mirror reflectance, suggesting that these monolithic devices could provide a robust and scalable solution to the engineering of light-matter interfaces.
- Published
- 2016
- Full Text
- View/download PDF
48. Publisher's Note: Nanoelectromechanical devices in a fluidic environment [Phys. Rev. E85, 056313 (2012)]
- Author
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Vince Sauer, Kar-Mun Cheng, Ning Liu, D. Vick, Wayne K. Hiebert, Oleksiy Svitelskiy, and Mark R. Freeman
- Subjects
Physics ,Fluidics ,Nanotechnology - Published
- 2012
- Full Text
- View/download PDF
49. Nanoelectromechanical devices in a fluidic environment
- Author
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Vince Sauer, D. Vick, Ning Liu, Wayne K. Hiebert, Mark R. Freeman, Kar-Mun Cheng, and Oleksiy Svitelskiy
- Subjects
Materials science ,lower pressures ,quality factors ,nano scale ,nanoresonators ,phenomenological models ,Quality (physics) ,fabrication technique ,Phenomenological model ,relaxation rates ,fluid damping ,Weissenberg number ,Fluidics ,Knudsen numbers ,Nanoelectromechanical systems ,mass load ,pressure regime ,mean free path ,damping ,nanotechnology ,Oscillation ,theoretical models ,Mechanics ,intermediate pressures ,high pressure ,SPHERES ,resonant response ,Knudsen number ,oscillation frequency ,micro resonators - Abstract
We present a comprehensive study of nanoelectromechanical systems in pressurized fluids. Resonant responses and quality factors are monitored in five different gases and one liquid, in pressures ranging from vacuum to 20 MPa, in order to evaluate theoretical models of device-fluid interactions at the nanoscale. The traditional Newell picture of microresonator damping in different pressure regimes is found to be inadequate in describing nanoresonators in general. Damping at intermediate pressure ranges is better physically characterized by a Weissenberg number (which compares oscillation frequencies with fluid relaxation rates) than a Knudsen number (which compares mean free paths with device widths) and most adequately described by the Yakhot and Colosqui model. At high-pressure ranges, two models are found to give good agreement with data: the phenomenological model of vibrating spheres and the Sader and Bhiladvala model for the viscous regime. The latter is also successful in explicitly predicting pressure-dependent behavior of the viscous mass load and damping. We observe significant increases in damping due to the squeezed film (SF) of gas between the device and substrate as well as due to undercut (an unavoidable artifact of the standard fabrication technique); correcting the shape of the devices with a focused ion beam allows us to differentiate these two factors. Application of the SF model accounts well for additional damping at high pressures while only qualitatively agreeing at lower pressures. The extensive data collected allow additional insight into fundamental processes underlying fluid damping at the nanoscale, particularly in the intermediate- and high-pressure regimes.
- Published
- 2012
50. Study of Thermal Smoothing by Shock Speed Measurement
- Author
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A. Nishiguchi, Kokichi Tanaka, H. Azechi, Masataka Kado, S. Nakai, H. Yamamoto, K. Mima, N. Miyanaga, D. Vick, and M. Tsukamoto
- Subjects
Shock wave ,Laser ablation ,Materials science ,business.industry ,medicine.medical_treatment ,inertial confinement fusion ,shock waves ,Thermal conduction ,Ablation ,Wavelength ,Optics ,thermal smoothing ,Physics::Plasma Physics ,medicine ,business ,Absorption (electromagnetic radiation) ,Inertial confinement fusion ,Smoothing - Abstract
Summary form only given. Intensity nonuniformities in an incident laser beam may cause corresponding variations in the ablation pressure. The variations in the ablation pressure should be less than a few percent in order for spherical targets to implode symmetrically and to be ignited in inertial confinement-fusion experiments. The uniformity requirements on the laser beam could be eased by the degree of lateral heat conduction and plasma-hydrodynamic motions occurring between the absorption and the ablation surfaces. Theoretically, the scaling of the smoothing on the standoff distance (D) between the absorption and the ablation surfaces and the intensity-modulation wavelength (L) is obtained in terms of heat conduction and plasma-fluid motions. Experiments were conducted with a 0.53-/spl mu/m, 1-ns (FWHM), Gaussian shaped laser beam focused onto thin polystyrene targets. The smoothing factor shows a clear exponential decrease as D/L increases.
- Published
- 1994
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