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Sample records for natural orifice translumenal

  1. Development of a Virtual Reality Simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) Cholecystectomy Procedure.

    Science.gov (United States)

    Ahn, Woojin; Dargar, Saurabh; Halic, Tansel; Lee, Jason; Li, Baichun; Pan, Junjun; Sankaranarayanan, Ganesh; Roberts, Kurt; De, Suvranu

    2014-01-01

    The first virtual-reality-based simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) is developed called the Virtual Translumenal Endoscopic Surgery Trainer (VTESTTM). VTESTTM aims to simulate hybrid NOTES cholecystectomy procedure using a rigid scope inserted through the vaginal port. The hardware interface is designed for accurate motion tracking of the scope and laparoscopic instruments to reproduce the unique hand-eye coordination. The haptic-enabled multimodal interactive simulation includes exposing the Calot's triangle and detaching the gall bladder while performing electrosurgery. The developed VTESTTM was demonstrated and validated at NOSCAR 2013.

  2. Natural orifice translumenal endoscopic surgery (NOTES) for innovation in hepatobiliary and pancreatic surgery: preface.

    Science.gov (United States)

    Sugimoto, Maki

    2009-01-01

    Natural orifice translumenal endoscopic surgery (NOTES) has captured the interest of interventional endoscopists and may represent the next stage of evolution of minimally invasive surgery. It provides the potential for performance of incisionless operations. It is gaining momentum both in the animal laboratory and in human case reports. Developments in the field of NOTES have led to the formation of the Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) in 2006. In this special issue, the current trends in NOTES in the field of hepatobiliary and pancreatic surgery are featured, including NOTES cholecystectomy, hepatectomy splenectomy, pancreatic necrosectomy, and the future of NOTES. In this issue, we discuss the potential benefits of these procedures in hepatobiliary and pancreatic surgery. We have just started the evaluation process for this new technology. The concept of NOTES is becoming established and is enormously advantageous for the patient. Both the surgeon and gastroenterologist should contribute to developing NOTES in making use of their specialties.

  3. The German registry for natural orifice translumenal endoscopic surgery: report of the first 551 patients.

    Science.gov (United States)

    Lehmann, Kai S; Ritz, Jörg P; Wibmer, Andreas; Gellert, Klaus; Zornig, Carsten; Burghardt, Jens; Büsing, Martin; Runkel, Norbert; Kohlhaw, Kay; Albrecht, Roland; Kirchner, Tom G; Arlt, Georg; Mall, Julian W; Butters, Michael; Bulian, Dirk R; Bretschneider, Jörgen; Holmer, Christoph; Buhr, Heinz J

    2010-08-01

    To analyze patient outcome in the first 14 months of the German natural orifice translumenal endoscopic surgery (NOTES) registry (GNR). NOTES is a new surgical concept, which permits scarless intra-abdominal operations through natural orifices, such as the mouth, vagina, rectum, or urethra. The GNR was established as a nationwide outcome database to allow the monitoring and safe introduction of this technique in Germany. The GNR was designed as a voluntary database with online access. All surgeons in Germany who performed NOTES procedures were requested to participate in the registry. The GNR recorded demographical and therapy data as well as data on the postoperative course. A total of 572 target organs were operated in 551 patients. Cholecystectomies accounted for 85.3% of all NOTES procedures. All procedures were performed in female patients using transvaginal hybrid technique. Complications occurred in 3.1% of all patients, conversions to laparoscopy or open surgery in 4.9%. In cholecystectomies, institutional case volume, obesity, and age had substantial effect on conversion rate, operation length, and length of hospital stay, but no effect on complications. Despite the fact that NOTES has just recently been introduced, the technique has already gained considerable clinical application. Transvaginal hybrid NOTES cholecystectomy is a practicable and safe alternative to laparoscopic resection even in obese or older patients.

  4. Natural orifice translumenal endoscopic surgery: Progress in humans since white paper

    Institute of Scientific and Technical Information of China (English)

    Byron F Santos; Eric S Hungness

    2011-01-01

    Since the first description of the concept of natural orifice translumenal endoscopic surgery (NOTES), a substantial number of clinical NOTES reports have appeared in the literature. This editorial reviews the available human data addressing research questions originally proposed by the white paper, including determining the optimal method of access for NOTES, developing safe methods of lumenal closure, suturing and anastomotic devices,advanced multitasking platforms, addressing the risk of infection, managing complications, addressing challengeswith visualization, and training for NOTES procedures.An analysis of the literature reveals that so far transvaginal access and closure appear to be the most feasible techniques for NOTES, with a limited, but growing transgastric, transrectal, and transesophageal NOTES experience in humans. The theoretically increased risk of infection as a result of NOTES procedures has not been substantiated in transvaginal and transgastric procedures so far. Development of suturing and anastomotic devices and advanced platforms for NOTES has progressed slowly,with limited clinical data on their use so far. Data on the optimal management and incidence of intraoperative complications remain sparse, although possible factorscontributing to complications are discussed. Finally, this editorial discusses the likely direction of future NOTES development and its possible role in clinical practice.

  5. Endoscopic management of intraoperative small bowel laceration during natural orifice translumenal endoscopic surgery: a blinded porcine study.

    Science.gov (United States)

    Fyock, Christopher J; Forsmark, Chris E; Wagh, Mihir S

    2011-01-01

    Natural orifice translumenal endoscopic surgery (NOTES) has recently gained great enthusiasm, but there is concern regarding the ability to endoscopically manage complications purely via natural orifices. To assess the feasibility of endoscopically managing enteral perforation during NOTES using currently available endoscopic accessories. Twelve pigs underwent transgastric or transcolonic endoscopic exploration. Full-thickness enterotomies were intentionally created to mimic accidental small bowel lacerations during NOTES. These lacerations were then closed with endoclips. In the blinded arm of the study, small bowel repair was performed by a second blinded endoscopist. Adequate closure of the laceration was confirmed with a leak test. Primary access sites were closed with endoclips or T-anchors. At necropsy, the peritoneal cavity was inspected for abscesses, bleeding, or damage to surrounding structures. The enterotomy site was examined for adequacy of closure, adhesions, or evidence of infection. Fifteen small bowel lacerations were performed in 12 animals. Successful closure was achieved in all 10 cases in the nonblinded arm. Survival animals had an uncomplicated postoperative course and all enterotomy sites were well healed without evidence of necrosis, adhesions, abscess, or bleeding at necropsy. Leak test was negative in all animals. In the blinded arm, both small intestinal lacerations could not be identified by the blinded endoscopist. Necropsy revealed open small bowel lacerations. Small intestinal injuries are difficult to localize with currently available flexible endoscopes and accessories. Endoscopic clips, however, may be adequate for closure of small bowel lacerations if the site of injury is known.

  6. Preoperative ultrasound measurements predict the feasibility of gallbladder extraction during transgastric natural orifice translumenal endoscopic surgery cholecystectomy.

    Science.gov (United States)

    Santos, Byron F; Auyang, Edward D; Hungness, Eric S; Desai, Kush R; Chan, Edward S; van Beek, Darren B; Wang, Edward C; Soper, Nathaniel J

    2011-04-01

    Extraction of a gallbladder through an endoscopic overtube during natural orifice translumenal endoscopic surgery (NOTES) transgastric cholecystectomy avoids potential injury to the esophagus. This study examined the rate of successful gallbladder specimen extraction through an overtube and hypothesized that preoperative ultrasound findings could predict successful specimen passage. Gallbladder specimens from patients undergoing laparoscopic cholecystectomy were measured, and an attempt was made to pull the specimens through a commercially available overtube with an inner diameter of 16.7-mm. A radiologist blinded to the outcomes reviewed the available preoperative ultrasound measurements from these patients. Ultrasound dimensions including gallbladder length, width, and depth; wall thickness; common bile duct diameter; and size of the largest gallstone (LGS) were recorded. Multiple logistic regression analysis was performed to determine whether ultrasound findings and patient characteristics (age, body mass index [BMI], and sex) could predict the ability of a specimen to pass through the overtube. Of 57 patients, 44 (77%) who had preoperative ultrasounds available for electronic review were included in the final analysis. Gallstones were present in 35 (79%) of these 44 patients. Intraoperative gallbladder perforation occurred in 18 (41%) of the 44 patients, and 16 (36%) of the 44 gallbladders could be extracted through the overtube. Measurement of LGS was possible for 23 patients, and indeterminate gallstone size (IGS) was determined for 12 patients. The rate for passage of perforated versus intact gallbladders was similar (40% vs. 23%; p = 0.054). The LGS (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.02-1.33; p = 0.021) and IGS (OR, 22.97; 95% CI, 1.99-265.63; p = 0.025) predicted failed passage on multivariate logistic regression analysis. The passage rate was 80% for LGS smaller than 10 mm or no stones present, 18% for LGS 10 mm or larger, and 8% for

  7. Educational and training aspects of new surgical techniques: experience with the endoscopic–laparoscopic interdisciplinary training entity (ELITE) model in training for a natural orifice translumenal endoscopic surgery (NOTES) approach to appendectomy.

    Science.gov (United States)

    Gillen, Sonja; Gröne, Jörn; Knödgen, Fritz; Wolf, Petra; Meyer, Michael; Friess, Helmut; Buhr, Heinz-Johannes; Ritz, Jörg-Peter; Feussner, Hubertus; Lehmann, Kai S

    2012-08-01

    Natural orifice translumenal endoscopic surgery (NOTES) is a new surgical concept that requires training before it is introduced into clinical practice. The endoscopic–laparoscopic interdisciplinary training entity (ELITE) is a training model for NOTES interventions. The latest research has concentrated on new materials for organs with realistic optical and haptic characteristics and the possibility of high-frequency dissection. This study aimed to assess both the ELITE model in a surgical training course and the construct validity of a newly developed NOTES appendectomy scenario. The 70 attendees of the 2010 Practical Course for Visceral Surgery (Warnemuende, Germany) took part in the study and performed a NOTES appendectomy via a transsigmoidal access. The primary end point was the total time required for the appendectomy, including retrieval of the appendix. Subjective evaluation of the model was performed using a questionnaire. Subgroups were analyzed according to laparoscopic and endoscopic experience. The participants with endoscopic or laparoscopic experience completed the task significantly faster than the inexperienced participants (p = 0.009 and 0.019, respectively). Endoscopic experience was the strongest influencing factor, whereas laparoscopic experience had limited impact on the participants with previous endoscopic experience. As shown by the findings, 87.3% of the participants stated that the ELITE model was suitable for the NOTES training scenario, and 88.7% found the newly developed model anatomically realistic. This study was able to establish face and construct validity for the ELITE model with a large group of surgeons. The ELITE model seems to be well suited for the training of NOTES as a new surgical technique in an established gastrointestinal surgery skills course.

  8. Taking NOTES: translumenal flexible endoscopy and endoscopic surgery.

    Science.gov (United States)

    Willingham, Field F; Brugge, William R

    2007-09-01

    To review the current state of natural orifice surgery and examine the concerns, challenges, and opportunities presented by translumenal research. Translumenal endoscopic procedures have been the focus of extensive research. Researchers have reported natural orifice translumenal endoscopic surgery in a swine model in several areas involving the abdominal cavity. Diagnostic procedures have included endoscopic peritoneoscopy, liver biopsy, lymphadenectomy, and abdominal exploration. Several gynecologic procedures including tubal ligation, oophorectomy, and partial hysterectomy have been demonstrated using current commercial endoscopes. Gastrointestinal surgical procedures, including gastrojejunostomy, cholecystectomy, splenectomy, and distal pancreatectomy have been performed successfully via transgastric and/or transcolonic approaches. There have been no studies of natural orifice translumenal endoscopic surgery procedures published in humans. While fundamental questions about the emerging technology have not been scrutinized, limitations of the large animal model will pose a challenge to the development of large randomized trials. While natural orifice translumenal endoscopic surgery may represent a paradigm shift and may offer significant benefits to patients, rigorous testing of the techniques is lacking and current data have been drawn from case series.

  9. Natural Orifice Translumenal Endoscopic Surgery for Anterior Spinal Procedures

    OpenAIRE

    Magno, Priscilla; Khashab, Mouen A.; Mas, Manuel; Giday, Samuel A.; Buscaglia, Jonathan M.; Shin, Eun Ji; Dray, Xavier; Kalloo, Anthony N.

    2012-01-01

    Background. NOTES techniques allow transesophageal access to the mediastinum. The aim of this study was to assess the feasibility of transesophageal biopsy of thoracic vertebrae. Methods. Nonsurvival experiments on four 50-kg porcine animals were performed. Transesophageal access to the mediastinum was attained using submucosal tunneling technique. Results. The posterior mediastinum was successfully accessed and navigated in all animals. Vertebral bodies and intervertebral spaces were easily ...

  10. [Natural Orifice Transluminal Endoscopic Surgery (NOTES)].

    Science.gov (United States)

    Kim, Yong Sik; Kim, Chul Young; Chun, Hoon Jai

    2008-03-01

    Recently, the field of gastrointestinal endoscopy is developing rapidly. Once limited to the gastroinstestinal lumen, the endoscopic technology is now breaking the barriers and extending its boundary to peritoneal and pleural space. In 2004, Dr. Kalloo, a gastroenterologist, observed intraperitoneal organs of a pig using a conventional endoscope through the stomach wall. Since then, new endoscopic technique of intraperitoneal intervention with transluminal approach named the Natural Orifice Transluminal Endoscopic Surgery or NOTES has been introduced. NOTES reaches the target organ by inserting the endoscope through a natural orifice (e.g. mouth, anus, vagina, urethra) and entering the peritoneal lumen by means of making an incision on the luminal wall. After a series of successful experiences in animal studies, NOTES are now being tried on human subjects. There are still many obstacles to overcome, but bright future for this new technology is expected because of its proposed advantages of less pain, lower complication rate, short recovery time, and scarless access. In this review, we plan to learn about NOTES.

  11. Cirugía endoscópica transluminal por orificios naturales: NOTES Natural orifice transluminal endoscopic surgery: NOTES

    Directory of Open Access Journals (Sweden)

    M. J. Varas Lorenzo

    2009-04-01

    Full Text Available Se presenta una revisión actual, puesta al día, y punto de vista de los autores sobre un tema sumamente novedoso y atractivo, como es la Cirugía Endoscópica Transluminal por Orificios Naturales (NOTES: Natural Orifice Translumenal Endoscopic Surgery. La mayoría de los trabajos revisados se han realizado en animales de experimentación, pero la publicación de la colecistectomía por vía transvaginal, y la aparición de editoriales y artículos de revisión sobre el tema, nos llevan a realizar una serie de preguntas no resueltas actualmente sobre este tipo de cirugía, que representa un avance potencial para conseguir "una cirugía endoscópica sin cicatrices, sin infecciones, con mínimos requerimientos de anestesia y una inmediata recuperación".A current review and update of an exceedingly novel and appealing topic, namely natural orifice transluminal endoscopic surgery (NOTES, is discussed, as well as the authors' viewpoint thereon. Most reviewed studies were performed in laboratory animals, but reports on transvaginal cholecystectomy and the emergence of editorials and review articles on this topic pose a number of as yet unanswered questions on this type of surgery, which represents a potential advance towards "endoscopic surgery with no scars, no infection, minimal anesthesia requirements, and immediate recovery".

  12. Patient and physician perception of natural orifice transluminal endoscopic appendectomy

    Czech Academy of Sciences Publication Activity Database

    Hucl, T.; Saglová, A.; Beneš, M.; Kocík, M.; Oliverius, M.; Valenta, Zdeněk; Špičák, J.

    2012-01-01

    Roč. 18, č. 15 (2012), s. 1800-1805 ISSN 1007-9327 Institutional research plan: CEZ:AV0Z10300504 Keywords : natural orifice transluminal endoscopic surgery * patient perception * physician perception * appendectomy * laparoscopy Subject RIV: FJ - Surgery incl. Transplants Impact factor: 2.547, year: 2012

  13. Surgery via natural orifices in human beings: yesterday, today, tomorrow.

    Science.gov (United States)

    Moris, Demetrios N; Bramis, Konstantinos J; Mantonakis, Eleftherios I; Papalampros, Efstathios L; Petrou, Athanasios S; Papalampros, Alexandros E

    2012-07-01

    We performed an evaluation of models, techniques, and applicability to the clinical setting of natural orifice surgery (mainly natural orifice transluminal endoscopic surgery [NOTES]) primarily in general surgery procedures. NOTES has attracted much attention recently for its potential to establish a completely alternative approach to the traditional surgical procedures performed entirely through a natural orifice. Beyond the potentially scar-free surgery and abolishment of dermal incision-related complications, the safety and efficacy of this new surgical technology must be evaluated. Studies were identified by searching MEDLINE, EMBASE, Cochrane Library, and Entrez PubMed from 2007 to February 2011. Most of the references were identified from 2009 to 2010. There were limitations as far as the population that was evaluated (only human beings, no cadavers or animals) was concerned, but there were no limitations concerning the level of evidence of the studies that were evaluated. The studies that were deemed applicable for our review were published mainly from 2007 to 2010 (see Methods section). All the evaluated studies were conducted only in human beings. We studied the most common referred in the literature orifices such as vaginal, oral, gastric, esophageal, anal, or urethral. The optimal access route and method could not be established because of the different nature of each procedure. We mainly studied procedures in the field of general surgery such as cholecystectomy, intestinal cancers, renal cancers, appendectomy, mediastinoscopy, and peritoneoscopy. All procedures were feasible and most of them had an uneventful postoperative course. A number of technical problems were encountered, especially as far as pure NOTES procedures are concerned, which makes the need of developing new endoscopic instruments, to facilitate each approach, undeniable. NOTES is still in the early stages of development and more robust technologies will be needed to achieve reliable

  14. Hybrid natural orifice transluminal endoscopic cholecystectomy: prospective human series.

    Science.gov (United States)

    Cuadrado-Garcia, Angel; Noguera, Jose F; Olea-Martinez, Jose M; Morales, Rafael; Dolz, Carlos; Lozano, Luis; Vicens, Jose-Carlos; Pujol, Juan José

    2011-01-01

    Natural orifice transluminal endoscopic surgery (NOTES) makes it possible to perform intraperitoneal surgical procedures with a minimal number of access points in the abdominal wall. Currently, it is not possible to perform these interventions without the help of abdominal wall entryways, so these procedures are hybrids fusing minilaparoscopy and transluminal endoscopic surgery. This report presents a prospective clinical series of 25 patients who underwent transvaginal hybrid cholecystectomy for cholelithiasis. The study comprised a clinical series of 25 consecutive nonrandomized women who underwent a fusion transvaginal NOTES and minilaparoscopy procedure with two trocars for cholelithiasis: one 5-mm umbilical trocar and one 3-mm trocar in the upper left quadrant. The study had no control group. The scheduled surgical intervention was performed for all 25 women. No intraoperative complications occurred. One patient had mild hematuria that resolved in less than 12 h, but no other complications occurred during an average follow-up period of 140 days. Of the 25 women, 20 were discharged in 24 h, and 5 were discharged less than 12 h after the procedure. Hybrid transvaginal cholecystectomy, combining NOTES and minilaparoscopy, is a good surgical model for minimally invasive surgery. It can be performed in surgical settings where laparoscopy is practiced regularly using the instruments normally used for endoscopy and laparoscopic surgery. Due to the reproducibility of the intervention and the ease of vaginal closure, hybrid transvaginal cholecystectomy will permit further development of NOTES in the future.

  15. Natural orifice transluminal endoscopic surgery vs laparoscopic ovariectomy: Complications and inflammatory response

    Czech Academy of Sciences Publication Activity Database

    Martínek, J.; Ryska, O.; Filípková, T.; Doležel, R.; Juhás, Štefan; Motlík, Jan; Holubová, Monika; Nosek, V.; Rotnáglová, B.; Zavoral, M.; Ryska, M.

    2012-01-01

    Roč. 18, č. 27 (2012), s. 3558-3564 ISSN 1007-9327 Institutional research plan: CEZ:AV0Z50450515 Keywords : Natural orifice transluminal endoscopic surgery * Laparoscopy * Ovariectomy Subject RIV: FP - Other Medical Disciplines Impact factor: 2.547, year: 2012

  16. Technical skill set training in natural orifice transluminal endoscopic surgery: how should we approach it?

    LENUS (Irish Health Repository)

    Nugent, Emmeline

    2011-03-01

    The boundaries in minimally invasive techniques are continually being pushed further. Recent years have brought new and exciting changes with the advent of natural orifice transluminal endoscopic surgery. With the evolution of this field of surgery come challenges in the development of new instruments and the actual steps of the procedure. Included in these challenges is the idea of developing a proficiency-based curriculum for training.

  17. In vivo microrobots for natural orifice transluminal surgery. Current status and future perspectives.

    Science.gov (United States)

    Forgione, A

    2009-06-01

    The possibility to operate inside the peritoneal cavity through small holes performed in hollow organs that is presented by Natural Orifice Transluminal Endoscopic Surgery (NOTES) represents a major paradigm shift in general surgery. While this new approach seems very appealing from patients' perspectives because it eliminates completely abdominal wall aggression and promises to reduce postoperative pain, it is very challenging for surgeons because of the major constraints imposed by both the mode of access and the limited technology currently available. For this reason NOTES applications at the present time are performed by only a few surgeons and mainly to perform non-complex procedures. While new devices are under development, many of them are trying mainly to simply improve current endoscopic platforms and seem not to offer breakthrough solutions. The numerous challenges introduced by natural orifice approaches require a radical shift in the conception of new technologies in order to make this emerging operative access safe and reproducible. The convergence of several enabling technologies in the field of miniaturization, communication and micro-mechatronics brings the possibility to realize on a large scale the revolutionary concept of miniature in vivo co-operative robots. These robots provide vision and task assistance without the constraints of the entry incision and have been shown in experimental settings to possess many qualities that could be ideal to partner with Natural Orifice Surgery. This article explores the current status of microrobotics as well as presents potential future scenarios of their applications in NOTES.

  18. Assessing transgastric Natural Orifice Transluminal Endoscopic Surgery prior to clinical implementation

    DEFF Research Database (Denmark)

    Donatsky, Anders Meller

    2014-01-01

    The objective was to investigate whether transgastric Natural Orifice Transluminal Endoscopic Surgery (NOTES) could be implemented safely in clinical practice. The experimental studies proved ultrasonography guided access through the stomach to be feasible and safe without iatrogenic complications......-abdominal abscess formation as a result of contamination from the access route was still present. To reduce this contamination, mouthwash with chlorhexidine was effective in a human randomised study. The same study also found significant higher bacterial load in the stomach of patients using proton pump inhibitor...

  19. EFFECTS OF NATURAL ORIFICE SECRETIONS IN PERITONEAL CAVITY IN THE BACKGROUND OF NATURAL ORIFICE TRANSLUMINAL ENDOSCOPIC SURGERY (NOTES AN EXPERIMENTAL STUDY IN ANIMALS

    Directory of Open Access Journals (Sweden)

    Devendra

    2015-03-01

    Full Text Available Natural Orifice Transluminal Endoscopic Surgery (NOTES is a new form of minimally invasive surgery which eliminates traditional skin incisions by accessing internal body cavities through natural orifices. In our experimental animal study, we compared the incidences intraperitoneal abscess formation , culture swab of peritoneal cavity positive for organism, intraperitoneal adhesion formation and mean adhesion score before and after lavaging the portal of entry of albino rat , i.e. transgastric and transvaginal. On vaginal route as a portal of entry into peritoneal cavity , on the 7th day , 66% rats developed abscesses , 88% rats had culture swab positive and 88% rats developed intraperitoneal adhesion (grade - 2 before any cleansing of vaginal cavity with antiseptic solution . Now after lavage with povidone iodine solution, only 11% developed abscesses , 22% were peritoneal swab culture positive and 33% had interbowel and parietal adhesion of (grade 0 - 1. On 21 st day , the complication observed was adhesion formation in pre lavage group of 66% incidence and 16% after vaginal lavage. The incidence of complications were reduced significantly after lavage with antiseptic solution as shown by p values (p<0.01 for abscess formation, p< 0.01 for culture positivity and p< 0.01 for adhesions formation. Also the mean adhesion scoring was significantly reduced (p <0.02 after vaginal lavage on the 7 th day. Gastric route as the portal of entry into the peritoneal cavity, again the same variables were compared on the 7th and the 21st day , but wash was given with antibiotic solution (Cefazolin. On the 7th day , 44% had abscesses, 77% were culture positive and 66% had adhesions (Grade 1 - 2 before gastric lavage with antibiotic solution . After wash of stomach, 11% were culture positive and 44% developed adhesions (Grade 0 - 1. Here, abscess formation (p<0.02 and mean adhesion scoring (p<0.05 were significantly reduced after stomach wash. On the 21st day

  20. NOViSE: a virtual natural orifice transluminal endoscopic surgery simulator.

    Science.gov (United States)

    Korzeniowski, Przemyslaw; Barrow, Alastair; Sodergren, Mikael H; Hald, Niels; Bello, Fernando

    2016-12-01

    Natural orifice transluminal endoscopic surgery (NOTES) is a novel technique in minimally invasive surgery whereby a flexible endoscope is inserted via a natural orifice to gain access to the abdominal cavity, leaving no external scars. This innovative use of flexible endoscopy creates many new challenges and is associated with a steep learning curve for clinicians. We developed NOViSE-the first force-feedback-enabled virtual reality simulator for NOTES training supporting a flexible endoscope. The haptic device is custom-built, and the behaviour of the virtual flexible endoscope is based on an established theoretical framework-the Cosserat theory of elastic rods. We present the application of NOViSE to the simulation of a hybrid trans-gastric cholecystectomy procedure. Preliminary results of face, content and construct validation have previously shown that NOViSE delivers the required level of realism for training of endoscopic manipulation skills specific to NOTES. VR simulation of NOTES procedures can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. In the context of an experimental technique, NOViSE could potentially facilitate NOTES development and contribute to its wider use by keeping practitioners up to date with this novel surgical technique. NOViSE is a first prototype, and the initial results indicate that it provides promising foundations for further development.

  1. Laparoscopic sleeve gastrectomy for morbid obesity with natural orifice specimen extraction (NOSE).

    Science.gov (United States)

    Gunkova, P; Gunka, I; Zonca, P; Dostalik, J; Ihnat, P

    2015-01-01

    An experience with laparoscopic sleeve gastrectomy using the natural orifice specimen extraction (NOSE) technique. Bariatric surgery is nowadays the only long term effective obesity treatment method. Twenty one consecutive patients underwent laparoscopic sleeve gastrectomy with the use of natural orifice specimen extraction (NOSE) in the Surgical Clinic of Faculty Hospital Ostrava between May 2012 and August 2012. Inclusion criteria were the body mass index (BMI) higher than 35 kg/m2 or higher than 32 kg/m2 accompanied with relevant comorbidities. Among 21 patients in this series, there were three men (14.3%) and 18 women (85.7%). Their mean age was 40.9±10.2 years. Their mean preoperative BMI was 40.4±4.6 kg/m2. No patient had previous bariatric surgery, one patient had laparoscopic fundoplication. All operations were completed laparoscopically with no conversions to an open procedure. In two cases, laparoscopic cholecystectomy was performed and the gallbladder was extracted along with the gastric specimen by transgastric approach. Laparoscopic sleeve gastrectomy is a safe and effective bariatric procedure with low morbidity and mortality. Based on our initial experiences it could be an indication for NOSE with transgastric approach. Obese patients would benefit from this approach due to the elimination of wound complications (Tab. 2, Fig. 3, Ref. 22).

  2. Two cases of laparoscopic total colectomy with natural orifice specimen extraction and review of the literature.

    Science.gov (United States)

    Gundogan, Ersin; Aktas, Aydin; Kayaalp, Cuneyt; Gonultas, Fatih; Sumer, Fatih

    2017-09-01

    We present two cases of natural orifice specimen extraction (NOSE) after laparoscopic total colectomy and ileorectal anastomosis (TC-IRA), and we also review all of the previously reported cases. Our aim was to focus on patient selection for NOSE after TC-IRA. The PubMed and Google Scholar databases were scanned. Demographic features, surgical indications, and techniques were analyzed. Basic calculations were used for statistical analysis. A total of 13 cases were detected in addition to our 2 cases. All of the specimens were removed through the natural orifices successfully. No case required a diverting ileostomy. No patients were converted to open surgery or to conventional laparoscopy. Complications were reported in three patients. Transanal extractions were performed in 12 cases (10 colonic inertia, 2 polyposis), and transvaginal extractions were performed in 3 cases (2 malignancy, 1 colonic inertia). Both transanal and transvaginal specimen extractions after laparoscopic TC-IRA can be preferred. However, transanal extraction seems to be feasible in cases of TC for benign disease with a limited mesenteric-omental resection. If the indication is a malignancy requiring a mesenteric-omental resection, a transvaginal route should be preferred for a voluminous specimen.

  3. A review on the status of natural orifice transluminal endoscopic surgery (NOTES cholecystectomy: techniques and challenges

    Directory of Open Access Journals (Sweden)

    Michael C Meadows

    2010-09-01

    Full Text Available Michael C Meadows1,3, Ronald S Chamberlain1,2,31Department of Surgery, Saint Barnabas Medical Center, Livingston, NJ, USA; 2Department of Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA; 3Saint George’s University, School of Medicine, West Indies, GrenadaIntroduction: The evolution of techniques for the performance of a cholecystectomy over the last 25 years has been swift. The laparoscopic approach is now the gold standard for removal of the gall bladder and is the most frequently performed minimally invasive procedure globally. Currently in its infancy stage, natural orifice transluminal endoscopy surgery, or NOTES, is purported to be the next leap forward in minimally invasive approaches. The safety, feasibility, and effectiveness of this procedure, as well as the significance of potential benefits to patients beyond current surgical approaches are yet undetermined.Methods: A comprehensive literature search was conducted using PubMed, a search engine ­created by the National Library of Medicine. Keywords used in the search included “natural orifice transluminal endoscopic surgery”, “NOTES”, “cholecystectomy”, “transcolonic”, “transvaginal”, and “transgastric”. The accumulated literature was critically analyzed and reviewed.Results: One-hundred and eighty-six cases of NOTES cholecystectomies have been published to date. Of these, 174 have been performed through a transvaginal approach. The remainder of the procedures were performed transgastrically. There are no published reports of ­transcolonic cholecystectomies performed in humans. Four of 186 cases (2.15% were converted to traditional laparoscopy due to intraoperative complications. No significant complications or mortalities have been reported.Conclusion: NOTES cholecystectomy appears to be a feasible procedure. However, technical, safety, and ethical issues remain relatively unresolved. Besides improved cosmesis, whether additional

  4. Feasibility study of natural orifice transluminal endoscopic surgery inguinal hernia repair.

    Science.gov (United States)

    Sherwinter, Danny A; Eckstein, Jeremy G

    2009-07-01

    A potentially less-invasive technique, transluminal surgery, may reduce or eliminate pain and decrease time to full return of activities after abdominal operations. Inguinal hernia repair is perfectly suited to the transgastric endoscopic approach and has not been previously reported. Our purpose was to evaluate the feasibility of transgastric bilateral inguinal herniorrhaphy (BIH). Feasibility study with a nonsurvival canine model. Under general anesthesia, male mongrel dogs weighing 20 to 30 kg had a dual-channel endoscope introduced into the peritoneal cavity over a percutaneously placed guidewire. An overtube with an insufflation channel was used. Peritoneoscopy was performed, and bilateral deep and superficial inguinal rings were identified. The endoscope was removed, premounted with a 4 x 6 cm acellular human dermal implant and then readvanced intraperitoneally through the overtube. The implant was then deployed across the entire myopectineal orifice and draped over the cord structures. Bioglue was then applied endoscopically, and the implant was attached to the peritoneum. After completion of bilateral repairs, the animals were killed and necropsy performed. Five dogs underwent pure natural orifice transluminal endoscopic surgery (NOTES) intraperitoneal onlay mesh (IPOM) BIH. Accurate placement and adequate myopectineal coverage was accomplished in all subjects. At necropsy no injuries to the major structures were noted but Bioglue misapplication with contamination of unintended sites did occur. Our study involved only a small number of subjects in nonsurvival experiments, and no gastric closure was used. Many of the characteristics of inguinal hernia repair are especially well suited to the transgastric approach. The repair is in line with the transgastric endoscope vector, bilateral defects are adjacent, and the IPOM technique does not require significant manipulation or novel instrumentation.

  5. Pure natural orifice transluminal endoscopic surgery (NOTES) with ultrasonography-guided transgastric access and over-the-scope-clip closure

    DEFF Research Database (Denmark)

    Donatsky, Anders Meller; Andersen, Luise; Nielsen, Ole Lerberg

    2012-01-01

    Most natural orifice transluminal endoscopic surgery (NOTES) procedures to date rely on the hybrid technique with simultaneous laparoscopic access to protect against access-related complications and to achieve adequate triangulation for dissection. This is done at the cost of the potential benefi...

  6. Complications of transvaginal natural orifice transluminal endoscopic surgery: a series of 102 patients.

    Science.gov (United States)

    Wood, Stephanie G; Panait, Lucian; Duffy, Andrew J; Bell, Robert L; Roberts, Kurt E

    2014-04-01

    To review the complications encountered in our facility and in previously published studies of transvaginal (TV) natural orifice transluminal endoscopic surgery (NOTES) to date. TV NOTES is currently observed with critical eyes from the surgical community, despite encouraging data to suggest improved short-term recovery and pain. All TV NOTES procedures performed in female patients between 18 and 65 years of age were included. The median follow-up was 90 days. The TV appendectomies and ventral hernia repairs were pure NOTES, through a SILS port in the vagina, whereas TV cholecystectomies were hybrid procedures with the addition of a 5-mm port in the umbilicus. A total of 102 TV NOTES procedures, including 72 TV cholecystectomies, 24 TV appendectomies, and 6 TV ventral hernia repairs, were performed. The average age was 37 years old and body mass index was 29 kg/m. Three major and 7 minor complications occurred. The first major complication was a rectal injury during a TV access port insertion. The second major complication was an omental vessel bleed after a TV cholecystectomy. The third complication was an intra-abdominal abscess after a TV appendectomy. Seven minor complications were urinary retention (4), transient brachial plexus injury, dislodgement of an intrauterine device, and vaginal granulation tissue. As techniques in TV surgery are adopted, inevitably, complications may occur due to the inherent learning curve. Laparoscopic instruments, although adaptable to TV approaches, have yet to be optimized. A high index of suspicion is necessary to identify complications and optimize outcomes for patients.

  7. An Intestinal Occlusion Device for Prevention of Small Bowel Distention During Transgastric Natural Orifice Transluminal Endoscopic Surgery

    OpenAIRE

    Tomasko, Jonathan M.; Mathew, Abraham; Moyer, Matthew T.; Haluck, Randy S.; Pauli, Eric M.

    2013-01-01

    Background and Objectives: Bowel distention from luminal gas insufflation reduces the peritoneal operative domain during natural orifice transluminal endoscopic surgery (NOTES) procedures, increases the risk for iatrogenic injury, and leads to postoperative patient discomfort. Methods: A prototype duodenal occlusion device was placed in the duodenum before NOTES in 28 female pigs. The occlusion balloon was inflated and left in place during the procedure, and small bowel distension was subject...

  8. Asian-Chinese patient perceptions of natural orifice transluminal endoscopic surgery cholecystectomy.

    Science.gov (United States)

    Teoh, Anthony Yuen Bun; Ng, Enders Kwok Wai; Chock, Alana; Swanstrom, Lee; Varadarajulu, Shyam; Chiu, Philip Wai Yan

    2014-05-01

    Patient and physician perceptions of natural orifice transluminal endoscopic surgery (NOTES) have been reported for the Western population. However, whether Asian-Chinese patients share the same perspectives as compared to the Western population is unknown. This was a cross-sectional survey carried out in the surgical outpatient's clinic at the Prince of Wales Hospital between June and September 2011. Patients were provided with an information leaflet and asked to complete a questionnaire regarding their perceptions of and preferences for NOTES cholecystectomy. Female patients attending the clinic were given an additional questionnaire regarding attitudes towards transvaginal surgery. Two hundred patients were recruited to complete the questionnaire(s) and the male to female ratio was 1:1. One hundred and fourteen patients (57%) preferred to undergo NOTES cholecystectomy for cosmetic reasons (P=0.009). Oral and anal routes were both acceptable for NOTES accesses in males and females. Forty-one percent of the female patients would consider transvaginal NOTES. Of these patients, significantly more patients indicated that the reason for choosing transvaginal NOTES was to minimize the risk of hernia (P=0.016) and to reduce pain associated with the procedure (P=0.017). The risk of complications (84.5%) and the cost of the procedure (58%) were considered the most important aspects when choosing a surgical approach by Asian-Chinese patients. Asian-Chinese preferred NOTES mainly for cosmetic reasons. However, the transvaginal route was less acceptable to females. Significant differences in patient perception on NOTES were observed between Asian-Chinese and Western patients. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

  9. Oophorectomy by natural orifice transluminal endoscopic surgery: feasibility study in dogs.

    Science.gov (United States)

    Freeman, Lynetta J; Rahmani, Emad Y; Sherman, Stuart; Chiorean, Michael V; Selzer, Don J; Constable, Peter D; Snyder, Paul W

    2009-06-01

    Natural orifice transluminal endoscopic surgery (NOTES) represents a potentially less-invasive alternative to conventional or laparoscopic surgery. Our purpose was to develop a canine oophorectomy model for prospective evaluation of intraoperative complications, surgical stress, and postoperative pain and recovery with NOTES. Feasibility study. Academic preclinical research. Ten healthy female dogs. NOTES procedures were performed through gastric access with an electrocautery snare to resect and retrieve the ovaries. The gastrotomy was closed with prototype T-fasteners. Operative time; complications; postoperative pain scores, and nociceptive threshold; surgical stress markers (interleukin-6 [IL-6], C-reactive protein); systemic stress parameters (cortisol, glucose); necropsy evaluation at 10 to 14 days. The mean operative time was 154 minutes (SD +/- 58 minutes) and no animals died as a result of complications from the procedure. The primary difficulty was incomplete ovarian excision and conversion to an open procedure in 1 dog. Serum glucose concentrations increased after surgery and remained elevated for at least 36 hours. The serum cortisol concentration was transiently increased from baseline at 2 hours after surgery. The serum IL-6 concentration peaked at 2 hours after surgery and returned to the baseline value by 18 hours. The serum C-reactive protein concentration increased significantly from baseline, peaked at 12 hours after surgery, and then slowly declined toward baseline but remained elevated at 72 hours after surgery. Nociceptive threshold measurements indicated increased sensitivity to pain for 2 to 24 hours after surgery. At necropsy, surgical sites were healing uneventfully with no significant damage to surrounding organs, no significant growth on bacterial cultures, and no evidence of peritonitis. Small number of animals, single center. The NOTES approach to oophorectomy in dogs appears to be a reasonable alternative to traditional surgery

  10. Current status of natural orifice trans-endoscopic surgery (NOTES and laparoendoscopic single site surgery (LESS in urologic surgery

    Directory of Open Access Journals (Sweden)

    Rafael E. Sanchez-Salas

    2010-08-01

    Full Text Available Laparoendoscopic single site surgery (LESS and natural orifice transluminal endoscopic surgery (NOTES represent novel approaches in urological surgery. To perform a review of the literature in order describe the current status of LESS and NOTES in Urology. References for this manuscript were obtained by performing a review of the available literature in PubMed from 01-01-02 to 15-05-09. Search terms included single port, single site, NOTES, LESS and single incision. A total of 412 manuscripts were initially identified. Out of these, 64 manuscripts were selected based in their urological content. The manuscript features subheadings for experimental and clinical studies, as NOTES-LESS is a new surgical technique and its future evolution will probably rely in initial verified feasibility. A subheading for reviews presents information regarding common language and consensus for the techniques. The issue of complications published in clinical series and the future needs of NOTES-LESS, are also presented.

  11. Current status and future perspectives in laparoendoscopic single-site and natural orifice transluminal endoscopic urological surgery.

    Science.gov (United States)

    Autorino, Riccardo; Stein, Robert J; Lima, Estevão; Damiano, Rocco; Khanna, Rakesh; Haber, Georges-Pascal; White, Michael A; Kaouk, Jihad H

    2010-05-01

    Objective of this study is to provide an evidence-based analysis of the current status and future perspectives of scarless urological surgery. A PubMed search has been performed for all relevant urological literature regarding natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS). In addition, experience with LESS and NOTES at our own institution has been considered. All clinical and investigative reports for LESS and NOTES procedures in the urological literature have been considered. A wide variety of clinical procedures in urology have been successfully completed by using LESS techniques. Thus far, experience with NOTES has largely been investigational, although early clinical reports are emerging. Further development of instrumentation and platforms is necessary for both techniques to become more widely adopted throughout the urological community.

  12. Comparison of pain and postoperative stress in dogs undergoing natural orifice transluminal endoscopic surgery, laparoscopic, and open oophorectomy.

    Science.gov (United States)

    Freeman, Lynetta J; Rahmani, Emad Y; Al-Haddad, Mohammad; Sherman, Stuart; Chiorean, Michael V; Selzer, Don J; Snyder, Paul W; Constable, Peter D

    2010-08-01

    Few studies are available to compare the potential benefits of natural orifice transluminal endoscopic surgery (NOTES) approaches to traditional surgery. To compare complications, surgical stress, and postoperative pain. Prospective study in dogs. Research laboratory. Thirty dogs. Oophorectomy procedures were performed via NOTES and laparoscopic and traditional open surgery. Operative time, pain scores, systemic stress parameters (cortisol, glucose), surgical stress markers (interleukin 6, C-reactive protein), 3-day observation. Median operative times were 76, 44, and 35 minutes for the NOTES, laparoscopic, and open procedures, respectively, with the NOTES procedure being significantly longer than the other 2 procedures. All ovaries were completely excised, and all the animals survived without complications. The NOTES animals had greater increases in serum cortisol concentrations at 2 hours but no statistically significant differences in glucose concentrations compared with the other groups. Serum interleukin 6 and C-reactive protein concentrations were significantly increased at specific times compared with baseline in the NOTES group, but not in the open or laparoscopic surgery groups. Based on the cumulative pain score and nociceptive thresholds, the animals in the NOTES group demonstrated less evidence of pain. Small sample size, limited follow-up. Although the NOTES oophorectomy procedures took approximately twice as long and there may be more evidence of tissue damage as judged by increases in serum cortisol and interleukin 6 concentrations, the dogs in the NOTES group had lower pain scores, especially when compared with animals undergoing open surgery. Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  13. Prospective randomized clinical trial comparing laparoscopic cholecystectomy and hybrid natural orifice transluminal endoscopic surgery (NOTES) (NCT00835250).

    Science.gov (United States)

    Noguera, José F; Cuadrado, Angel; Dolz, Carlos; Olea, José M; García, Juan C

    2012-12-01

    Natural orifice transluminal endoscopic surgery (NOTES) is a technique still in experimental development whose safety and effectiveness call for assessment through clinical trials. In this paper we present a three-arm, noninferiority, prospective randomized clinical trial of 1 year duration comparing the vaginal and transumbilical approaches for transluminal endoscopic surgery with the conventional laparoscopic approach for elective cholecystectomy. Sixty female patients between the ages of 18 and 65 years who were eligible for elective cholecystectomy were randomized in a ratio of 1:1:1 to receive hybrid transvaginal NOTES (TV group), hybrid transumbilical NOTES (TU group) or conventional laparoscopy (CL group). The main study variable was parietal complications (wound infection, bleeding, and eventration). The analysis was by intention to treat, and losses were not replaced. Cholecystectomy was successfully performed on 94% of the patients. One patient in the TU group was reconverted to CL owing to difficulty in maneuvering the endoscope. After a minimum follow-up period of 1 year, no differences were noted in the rate of parietal complications. Postoperative pain, length of hospital stay, and time off from work were similar in the three groups. No patient developed dyspareunia. Surgical time was longer among cases in which a flexible endoscope was used (CL, 47.04 min; TV, 64.85 min; TU, 59.80 min). NOTES approaches using the flexible endoscope are not inferior in safety or effectiveness to conventional laparoscopy. The transumbilical approach with flexible endoscope is as effective and safe as the transvaginal approach and is a promising, single-incision approach.

  14. Natural-orifice transluminal endoscopic surgery (NOTES) in Europe: summary of the working group reports of the Euro-NOTES meeting 2010

    DEFF Research Database (Denmark)

    Meining, A; Feussner, H; Swain, P

    2011-01-01

    The fourth Euro-NOTES workshop took place in September 2010 and focused on enabling intensive scientific dialogue and interaction between participants to discuss the state of the practice and development of natural-orifice transluminal endoscopic surgery (NOTES) in Europe. Five working groups were...... collaboration and indications, robotics and platforms, and matters related to training and education. This review summarizes consensus statements of the working groups to give an overview of what has been achieved so far and what might be relevant for research related to NOTES in the near future....

  15. Submucosal tunneling using endoscopic submucosal dissection for peritoneal access and closure in natural orifice transluminal endoscopic surgery: a porcine survival study.

    Science.gov (United States)

    Yoshizumi, F; Yasuda, K; Kawaguchi, K; Suzuki, K; Shiraishi, N; Kitano, S

    2009-08-01

    Safe peritoneal access and gastric closure are the most important concerns in the clinical application of natural orifice transluminal endoscopic surgery (NOTES). We aimed to clarify the feasibility of a submucosal tunnel technique using endoscopic submucosal dissection (ESD) for transgastric peritoneal access and subsequent closure for NOTES. Seven female pigs, each weighing about 40 kg were included in the study. The following procedures were performed: (i) after injection of normal saline into the submucosa, the mucosa was cut with a flex knife; (ii) the submucosal layer was dissected using an insulation-tipped electrosurgical knife to make a narrow longitudinal 50-mm submucosal tunnel; (iii) a small incision was made at the end of the tunnel and enlarged with a dilation balloon. After transgastric peritoneoscopy, the mucosal incision site was closed with clips. The following outcome measures were used: (a) evaluation of the technical feasibility of making a submucosal tunnel; (b) clinical monitoring for 7 days; (c) follow-up endoscopy and necropsy; and (d) peritoneal fluid culture. Natural orifice transluminal endoscopic peritoneoscopy with a submucosal tunnel was successfully carried out in all pigs. The pigs recovered well, without signs of peritonitis. Follow-up endoscopy showed healing of mucosal incision sites without open defects. Necropsy revealed no findings of peritonitis, confirming completeness of gastric closure; there was a thin scar in one pig and adhesion of the omentum in six pigs. Peritoneal fluid culture demonstrated no bacterial growth. The submucosal tunnel technique is feasible and effective for transgastric peritoneal access and closure.

  16. A novel semi-automatic snake robot for natural orifice transluminal endoscopic surgery: preclinical tests in animal and human cadaver models (with video).

    Science.gov (United States)

    Son, Jaebum; Cho, Chang Nho; Kim, Kwang Gi; Chang, Tae Young; Jung, Hyunchul; Kim, Sung Chun; Kim, Min-Tae; Yang, Nari; Kim, Tae-Yun; Sohn, Dae Kyung

    2015-06-01

    Natural orifice transluminal endoscopic surgery (NOTES) is an emerging surgical technique. We aimed to design, create, and evaluate a new semi-automatic snake robot for NOTES. The snake robot employs the characteristics of both a manual endoscope and a multi-segment snake robot. This robot is inserted and retracted manually, like a classical endoscope, while its shape is controlled using embedded robot technology. The feasibility of a prototype robot for NOTES was evaluated in animals and human cadavers. The transverse stiffness and maneuverability of the snake robot appeared satisfactory. It could be advanced through the anus as far as the peritoneal cavity without any injury to adjacent organs. Preclinical tests showed that the device could navigate the peritoneal cavity. The snake robot has advantages of high transverse force and intuitive control. This new robot may be clinically superior to conventional tools for transanal NOTES.

  17. Natural orifice transgastric endoscopic wedge hepatic resection in an experimental model using an intuitively controlled master and slave transluminal endoscopic robot (MASTER).

    Science.gov (United States)

    Phee, S J; Ho, K Y; Lomanto, D; Low, S C; Huynh, V A; Kencana, A P; Yang, K; Sun, Z L; Chung, S C Sydney

    2010-09-01

    The lack of triangulation of standard endoscopic devices limits the degree of freedom for surgical maneuvers during natural orifice transluminal endoscopic surgery (NOTES). This study explored the feasibility of adapting an intuitively controlled master and slave transluminal endoscopic robot (MASTER) the authors developed to facilitate wedge hepatic resection in NOTES. The MASTER consists of a master controller, a telesurgical workstation, and a slave manipulator that holds two end-effectors: a grasper, and a monopolar electrocautery hook. The master controller is attached to the wrist and fingers of the operator and connected to the manipulator by electrical and wire cables. Movements of the operator are detected and converted into control signals driving the slave manipulator via a tendon-sheath power transmission mechanism allowing nine degrees of freedom. Using this system, wedge hepatic resection was performed through the transgastric route on two female pigs under general anesthesia. Entry into the peritoneal cavity was via a 10-mm incision made on the anterior wall of the stomach by the electrocautery hook. Wedge hepatic resection was performed using the robotic grasper and hook. Hemostasis was achieved with the electrocautery hook. After the procedure, the resected liver tissue was retrieved through the mouth using the grasper. Using the MASTER, transgastric wedge hepatic resection was successfully performed on two pigs with no laparoscopic assistance. The entire procedure took 9.4 min (range, 8.5-10.2 min), with 7.1 min (range, 6-8.2 min) spent on excision of the liver tissue. The robotics-controlled device was able to grasp, retract, and excise the liver specimen successfully in the desired plane. This study demonstrated for the first time that the MASTER could effectively mitigate the technical constraints normally encountered in NOTES procedures. With it, the triangulation of surgical tools and the manipulation of tissue became easy, and wedge hepatic

  18. Natural orifice transluminal endoscopic surgery gastrotomy closure with an over-the-endoscope clip: a randomized, controlled porcine study (with videos).

    Science.gov (United States)

    von Renteln, Daniel; Schmidt, Arthur; Vassiliou, Melina C; Gieselmann, Maria; Caca, Karel

    2009-10-01

    Secure endoscopic closure of transgastric natural orifice transluminal endoscopic surgery (NOTES) access is of paramount importance. The over-the-scope clip (OTSC) system has previously been shown to be effective for NOTES gastrotomy closure. To compare OTSC gastrotomy closure with surgical closure. Randomized, controlled animal study. Animal facility laboratory. Thirty-six female domestic pigs. Gastrotomies were created by using a needle-knife and an 18-mm balloon. The animals were subsequently randomized to either open surgical repair with interrupted sutures or endoscopic repair with 12-mm OTSCs. In addition, pressurized leak tests were performed in ex vivo specimens of 18-mm scalpel incisions closed with suture (n = 14) and of intact stomachs (n = 10). The mean time for endoscopic closure was 9.8 minutes (range 3-22, SD 5.5). No complications occurred during either type of gastrotomy closure. At necropsy, examination of all OTSC and surgical closures demonstrated complete sealing of gastrotomy sites without evidence of injury to adjacent organs. Pressurized leak tests showed a mean burst pressure of 83 mm Hg (range 30-140, SD 27) for OTSC closures and 67 mm Hg (range 30-130, SD 27.7) for surgical sutures. Ex vivo hand-sewn sutures of 18-mm gastrotomies (n = 14) exhibited a mean burst pressure of 65 mm Hg (range 20-140, SD 31) and intact ex vivo stomachs (n = 10) had a mean burst pressure of 126 mm Hg (range 90-170, SD 28). The burst pressure of ex vivo intact stomachs was significantly higher compared with OTSC closures (P < .01), in vivo surgical closures (P < .01), and ex vivo hand-sewn closures (P < .01). There was a trend toward higher burst pressures in the OTSC closures compared with surgical closures (P = .063) and ex vivo hand-sewn closures (P = .094). In vivo surgical closures demonstrated similar burst pressures compared with ex vivo hand-sewn closures (P = .848). Nonsurvival setting. Endoscopic closure by using the OTSC system is comparable to

  19. Flow-throttling orifice nozzle

    International Nuclear Information System (INIS)

    Sletten, H.L.

    1975-01-01

    A series-parallel-flow type throttling apparatus to restrict coolant flow to certain fuel assemblies of a nuclear reactor is comprised of an axial extension nozzle of the fuel assembly. The nozzle has a series of concentric tubes with parallel-flow orifice holes in each tube. Flow passes from a high pressure plenum chamber outside the nozzle through the holes in each tube in series to the inside of the innermost tube where the coolant, having dissipated most of its pressure, flows axially to the fuel element. (U.S.)

  20. Effect of mitral orifice shape on intra-ventricular filling fluid dynamics

    Science.gov (United States)

    Okafor, Ikechukwu; Angirish, Yagna; Yoganathan, Ajit; Santhanakrishnan, Arvind

    2013-11-01

    The natural geometry of the mitral orifice is D-shaped. However, most current designs of prosthetic valves employ O-shaped orifice geometry. The goal of this study was to compare the effect of geometrical modification between the D and O orifice on the intra-ventricular fluid dynamics during diastolic filling. The different mitral orifice geometries were incorporated into an in vitro left heart simulator consisting of a flexible-walled anatomical left ventricle (LV) physical model enclosed in an acrylic housing. Physiological flow rates and pressures were obtained via tuning systemic resistance and compliance elements in the flow loop. A programmable piston pump was used to generate the LV model wall motion. 2D Particle image velocimetry measurements were conducted along multiple longitudinal planes perpendicular to the annulus plane. During peak diastole, the incoming jet width at the LV central plane was smaller for the D-orifice than that of the O-orifice. Further, the core of the vortex ring in the D-orifice was reduced in size compared to that of the O-orifice. The spatiotemporal spreading of the inflow jet as well as the propagation of the vortex ring will be discussed. This study was funded by a grant from the National Heart, Lung and Blood Institute (RO1HL70262).

  1. The penetration of aerosols through fine orifices

    International Nuclear Information System (INIS)

    Marshall, I.A.; Latham, L.J.; Ball, M.H.E.; Mitchell, J.P.

    1991-07-01

    A novel experimental technique has been extended to study the migration of gas-borne glass microspheres in the size range from about 1 to 15 μm volume equivalent diameter through orifices with bores and thicknesses in the range from 2 to 100 μm and 12.7 to 509 μm respectively. The penetration of these particles was significant with all orifices greater than 10 μm bore at a constant driving pressure of 100 kPa. However, few particles penetrated the 5 μm bore orifice, while virtually no particles penetrated the 2 μm bore orifice. Particle size distributions determined after penetration through the orifices were very similar to that of the upstream aerosol except when significant attenuation occurred. (author)

  2. Cirurgia por orifícios naturais transcolônica: acesso NOTES peri-retal (PNA para excisão mesoretal total Transcolonic natural orifice surgery: peri-rectal NOTES access (PNA for total mesorectal excision

    Directory of Open Access Journals (Sweden)

    Ricardo Zorron

    2010-03-01

    Full Text Available OBJETIVOS: Cirurgia por orifícios naturais tem sido recentemente aplicada em series clínicas para cirurgia abdominal. Apesar de potenciais vantagens do acesso NOTES transcolônico para doenças colorretais, este ainda não havia sido utilizado clinicamente. O presente trabalho descreve a primeira aplicação bem-sucedida de NOTES transcolônico da literatura, em uma nova abordagem de excisão mesoretal total (TME para cancer de reto. MÉTODOS: Foi obtida aprovação de Comitê de Ética em Pesquisa para cirurgias por orifícios naturais, e o paciente assinou termo de consentimento informado. Em um paciente de 54 anos portador de adenocarcinoma de reto, o procedimento de retossigmoidectomia e linfadenectomia, com excisão mesoretal total foi realizada utilizando um acesso posterior transcolônico pouco acima da borda anal. A dissecção mesorretal foi conseguida utilizando um colonoscópio flexível e instrumentos endoscópicos, com assistência laparoscópica. O espécime foi retirado via transanal, e anastomose foi transorificial, com estoma proximal de proteção. RESULTADOS: O tempo operatório foi de 350 min, não ocorrendo complicações operatórias. A evolução pós-operatória foi favorável, e o paciente recebeu alta no sexto dia de pós-operatório com dieta plena. CONCLUSÃO: Este primeiro relato bem sucedido de cirurgia NOTES transcolônica traz potencialmente novas fronteiras de aplicações clínicas na cirurgia minimamente invasiva. O tratamento de doenças colorretais utilizando o novo acesso flexível PNA (Perirectal NOTES Access é uma promissora nova abordagem, paralelamente à laparoscopia e cirurgia aberta, para melhoria do tratamento dos pacientes.OBJECTIVES: Clinical natural orifice surgery has been applied for abdominal surgery in recent years. Despite potential advantages of transcolonic NOTES for colorectal diseases, it was since now not yet clinically applied. The study describes the first successful human

  3. Variable orifice using an iris shutter

    International Nuclear Information System (INIS)

    Beeman, R.; Brajkovich, S.J.

    1978-01-01

    A variable orifice forming mechanism is described that utilizes shutter arrangement adapted to control gas flow, conductance in vacuum systems, as a heat shield for furnace windows, as a beam shutter in sputtering operations, and in any other application requiring periodic or continuously-variable control of material, gas, or fluid flow

  4. Sizing of high-pressure restriction orifices

    International Nuclear Information System (INIS)

    Casado Flores, E.

    1995-01-01

    Constant up-grading of power plants sometimes requires the modification of components which form part of suppliers' packages. In order to protect technology they have developed, however, the suppliers do not supply their calculation criteria. In order to reduce the costs of such improvements, and so as to be able to undertake the modification without having to rely on the original supplier, this paper describes the basic criteria applicable to the study of high-pressure restriction orifices, which can be considered to be representative of the components in question. The restriction orifices discussed are: - Insert - Multiplates in series with one perforation in each plate - Multiplates in series with several perforations in each plate For each type, an explanation of their sizing is given, together with the equations relating the corresponding flow and pressure drop. (Author)

  5. Experimental investigation of hydrodynamic cavitation through orifices of different geometries

    Science.gov (United States)

    Rudolf, Pavel; Kubina, Dávid; Hudec, Martin; Kozák, Jiří; Maršálek, Blahoslav; Maršálková, Eliška; Pochylý, František

    Hydrodynamic cavitation in single and multihole orifices was experimentally investigated to assess their hydraulic characteristics: loss coefficients, inception cavitation number, cavitation number for transition to supercavitation. Significant difference for singlehole and multihole orifices was observed in terms of the measured loss coefficient. It is significantly more effective to use multihole orifices, where energy dissipation is much lower.It was found that using scaling factor given by ratio of orifice thickness suggests linear behaviour of both loss coefficient and inception cavitation number. Orifices seem to be convenient choice as flow constriction devices inducing cavitation due to their simplicity.

  6. Experimental investigation of hydrodynamic cavitation through orifices of different geometries

    Directory of Open Access Journals (Sweden)

    Rudolf Pavel

    2017-01-01

    Full Text Available Hydrodynamic cavitation in single and multihole orifices was experimentally investigated to assess their hydraulic characteristics: loss coefficients, inception cavitation number, cavitation number for transition to supercavitation. Significant difference for singlehole and multihole orifices was observed in terms of the measured loss coefficient. It is significantly more effective to use multihole orifices, where energy dissipation is much lower.It was found that using scaling factor given by ratio of orifice thickness suggests linear behaviour of both loss coefficient and inception cavitation number. Orifices seem to be convenient choice as flow constriction devices inducing cavitation due to their simplicity.

  7. Motion of a single quantized vortex in an orifice

    International Nuclear Information System (INIS)

    Schwarz, K.W.

    1993-01-01

    Discrete phase-slip events are observed when superfluid 4 He moves through a microscopic orifice. In order to understand such behavior, one must know (a) how a quantized vortex is introduced into the orifice, and (b) how such a vortex evolves fluid dynamically so as to absorb energy from the applied flow field. To begin the study of the latter question, the authors present calculations done with an idealized orifice geometry. It is found that vortex loops larger than a critical size are carried out of the orifice and stretched by the diverging flow. As it stretches, such a vortex will cross the orifice, the energy required to stretch the vortex being absorbed from the flow field. Both a vortex loop introduced directly into the orifice and a remanent vortex extending to infinity will be discussed

  8. Gaseous Nitrogen Orifice Mass Flow Calculator

    Science.gov (United States)

    Ritrivi, Charles

    2013-01-01

    The Gaseous Nitrogen (GN2) Orifice Mass Flow Calculator was used to determine Space Shuttle Orbiter Water Spray Boiler (WSB) GN2 high-pressure tank source depletion rates for various leak scenarios, and the ability of the GN2 consumables to support cooling of Auxiliary Power Unit (APU) lubrication during entry. The data was used to support flight rationale concerning loss of an orbiter APU/hydraulic system and mission work-arounds. The GN2 mass flow-rate calculator standardizes a method for rapid assessment of GN2 mass flow through various orifice sizes for various discharge coefficients, delta pressures, and temperatures. The calculator utilizes a 0.9-lb (0.4 kg) GN2 source regulated to 40 psia (.276 kPa). These parameters correspond to the Space Shuttle WSB GN2 Source and Water Tank Bellows, but can be changed in the spreadsheet to accommodate any system parameters. The calculator can be used to analyze a leak source, leak rate, gas consumables depletion time, and puncture diameter that simulates the measured GN2 system pressure drop.

  9. A Mandibular Second Premolar with Three Canals and Atypical Orifices

    Directory of Open Access Journals (Sweden)

    Neha Agarwal

    2013-01-01

    Full Text Available Background: Mandibular second premolars with three canals (Type V, Vertucci and separate foramina are very rare. The anatomy of the pulp chamber floor in these premolars usually reveals one lingual and two buccal orifices at the same level. This case report describes a second premolar with three canals and an unusual pulpal floor anatomy with one mesiobuccal and one distobuccal orifice at the same level and an orifice on the distolingual wall. Very careful examination of the pulpal space with an optical device and preoperative spiral computed tomography is recommended to locate any unusual orifices.

  10. High Pressure Water Stripping Using Multi-Orifice Nozzles

    Science.gov (United States)

    Hoppe, David

    1999-01-01

    The use of multi-orifice rotary nozzles greatly increases the speed and stripping effectiveness of high pressure water blasting systems, but also greatly increases the complexity of selecting and optimizing the operating parameters. The rotational speed of the nozzle must be coupled with its transverse velocity as it passes across the surface of the substrate being stripped. The radial and angular positions of each orifice must be included in the analysis of the nozzle configuration. Orifices at the outer edge of the nozzle head move at a faster rate than the orifices located near the center. The energy transmitted to the surface from the impact force of the water stream from an outer orifice is therefore spread over a larger area than energy from an inner orifice. Utilizing a larger diameter orifice in the outer radial positions increases the total energy transmitted from the outer orifice to compensate for the wider distribution of energy. The total flow rate from the combination of all orifices must be monitored and should be kept below the pump capacity while choosing orifice to insert in each position. The energy distribution from the orifice pattern is further complicated since the rotary path of all the orifices in the nozzle head pass through the center section. All orifices contribute to the stripping in the center of the path while only the outer most orifice contributes to the stripping at the edge of the nozzle. Additional orifices contribute to the stripping from the outer edge toward the center section. With all these parameters to configure and each parameter change affecting the others, a computer model was developed to track and coordinate these parameters. The computer simulation graphically indicates the cumulative affect from each parameter selected. The result from the proper choices in parameters is a well designed, highly efficient stripping system. A poorly chosen set of parameters will cause the nozzle to strip aggressively in some areas

  11. Minimum wall pressure coefficient of orifice plate energy dissipater

    Directory of Open Access Journals (Sweden)

    Wan-zheng Ai

    2015-01-01

    Full Text Available Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  12. Orifice design for the control of coupled region flow

    International Nuclear Information System (INIS)

    Atherton, R.; Spadaro, P.R.; Brummerhop, F.G.

    1975-01-01

    A fluid system arrangement for nuclear reactors is described comprising a triplate orifice apparatus which simultaneously controls core flow distribution, flow rate ratio between hydraulically coupled regions of the blanket and radial static pressure gradients entering and leaving the blanket fuel region. The design of the apparatus is based on the parameters of the diameter of the orifice holes, the friction factor, and expansion, contraction and turning pressure loss coefficients of the geometry of each orifice region. These above parameters are properly matched to provide the desired pressure drop, flow split and negligible cross flow at the interface of standard and power-flattened open lattice blanket regions. (U.S.)

  13. Pressure atomizer having multiple orifices and turbulent generation feature

    Science.gov (United States)

    VanBrocklin, Paul G.; Geiger, Gail E.; Moran, Donald James; Fournier, Stephane

    2002-01-01

    A pressure atomizer includes a silicon plate having a top surface and a bottom surface. A portion of the top surface defines a turbulent chamber. The turbulent chamber is peripherally bounded by the top surface of the plate. The turbulent chamber is recessed a predetermined depth relative to the top surface. The silicon plate further defines at least one flow orifice. Each flow orifice extends from the bottom surface of the silicon plate to intersect with and open into the turbulent chamber. Each flow orifice is in fluid communication with the turbulent chamber.

  14. Periodic cavitation shedding in a cylindrical orifice

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, C.; Barber, T.; Milton, B.; Rosengarten, G. [University of New South Wales, School of Mechanical and Manufacturing Engineering, Sydney (Australia)

    2011-11-15

    Cavitation structures in a large-scale (D = 8.25 mm), plain orifice style nozzle within a unique experimental rig are investigated using high-speed visualisation and digital image processing techniques. Refractive index matching with an acrylic nozzle is achieved using aqueous sodium iodide for the test fluid. Cavitation collapse length, unsteady shedding frequency and spray angles are measured for cavitation conditions from incipient to supercavitation for a range of Reynolds numbers, for a fixed L/D ratio of 4.85. Periodic cavitation shedding was shown to occur with frequencies between 500 and 2,000 Hz for conditions in which cavitation occupied less than 30% of the nozzle length. A discontinuity in collapse length was shown to occur once the cavitation exceeded this length, coinciding with a loss of periodic shedding. A mechanism for this behaviour is discussed. Peak spray angles of approximately {theta} {approx} 14 were recorded for supercavitation conditions indicating the positive influence of cavitation bubble collapse on the jet atomisation process. (orig.)

  15. Evaluation of RF properties by orifice design for IFMIF RFQ

    International Nuclear Information System (INIS)

    Maebara, Sunao; Sugimoto, Masayoshi

    2005-03-01

    Orifices for the IFMIF RFQ have been designed and fabricated, and RF properties have been evaluated by a network analyzer. The designed orifices were installed into a vacuum port of the 1.1m-long RFQ mock-up module, and the resonant frequency and the phase difference between cavities were measured for a quadrupole operation mode of TE 210 . It was found that the RF properties are not affected on condition that slit direction with the same direction of current flow at the RFQ wall. Orifice conductance from 0.22 to 0.25 m 3 /sec by nitrogen conversion at room temperature was designed, and an ultimate pressure level of 5x10 -7 [Pa] was evaluated for the 4.1m-long central module for the IFMIF RFQ. It was concluded that the designed orifices are effective for RF properties and vacuum conductance in the IFMIF RFQ. (author)

  16. Investigation of wall mass transfer characteristics downstream of an orifice

    International Nuclear Information System (INIS)

    El-Gammal, M.; Ahmed, W.H.; Ching, C.Y.

    2012-01-01

    Highlights: ► Numerical simulations were performed for the mass transfer downstream of an orifice. ► The Low Reynolds Number K-ε turbulence model was used. ► The numerical results were in good agreement with existing experimental results. ► The maximum Sherwood number downstream of the orifice was significantly affected by the Reynolds number. ► The Sherwood number profile was well correlated with the turbulence kinetic energy profile close to the wall. - Abstract: Numerical simulations were performed to determine the effect of Reynolds number and orifice to pipe diameter ratio (d o /d) on the wall mass transfer rate downstream of an orifice. The simulations were performed for d o /d of 0.475 for Reynolds number up to 70,000. The effect of d o /d was determined by performing simulations at a Reynolds number of 70,000 for d o /d of 0.375, 0.475 and 0.575. The momentum and mass transport equations were solved using the Low Reynolds Number (LRN) K-ε turbulence model. The Sherwood number (Sh) profile downstream of the orifice was in relatively good agreement with existing experimental results. The Sh increases sharply downstream of the orifice, reaching a maximum within 1–2 diameters downstream of the orifice, before relaxing back to the fully developed pipe flow value. The Sh number well downstream of the orifice was in good agreement with results for fully developed pipe flow estimated from the correlation of . The peak Sh numbers from the simulations were higher than that predicted from and .

  17. Fabrication of small-orifice fuel injectors for diesel engines.

    Energy Technology Data Exchange (ETDEWEB)

    Woodford, J. B.; Fenske, G. R.

    2005-04-08

    Diesel fuel injector nozzles with spray hole diameters of 50-75 {micro}m have been fabricated via electroless nickel plating of conventionally made nozzles. Thick layers of nickel are deposited onto the orifice interior surfaces, reducing the diameter from {approx}200 {micro}m to the target diameter. The nickel plate is hard, smooth, and adherent, and covers the orifice interior surfaces uniformly.

  18. Calibration and use of filter test facility orifice plates

    Science.gov (United States)

    Fain, D. E.; Selby, T. W.

    1984-07-01

    There are three official DOE filter test facilities. These test facilities are used by the DOE, and others, to test nuclear grade HEPA filters to provide Quality Assurance that the filters meet the required specifications. The filters are tested for both filter efficiency and pressure drop. In the test equipment, standard orifice plates are used to set the specified flow rates for the tests. There has existed a need to calibrate the orifice plates from the three facilities with a common calibration source to assure that the facilities have comparable tests. A project has been undertaken to calibrate these orifice plates. In addition to reporting the results of the calibrations of the orifice plates, the means for using the calibration results will be discussed. A comparison of the orifice discharge coefficients for the orifice plates used at the seven facilities will be given. The pros and cons for the use of mass flow or volume flow rates for testing will be discussed. It is recommended that volume flow rates be used as a more practical and comparable means of testing filters. The rationale for this recommendation will be discussed.

  19. Noise generated by cavitating single-hole and multi-hole orifices in a water pipe

    NARCIS (Netherlands)

    Testud, P.; Moussou, P.; Hirschberg, A.; Aurégan, Y.

    2007-01-01

    This paper presents an experimental study of the acoustical effects of cavitation caused by a water flow through an orifice. A circular-centered single-hole orifice and a multi-hole orifice are tested. Experiments are performed under industrial conditions: the pressure drop across the orifice varies

  20. The influence of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices

    International Nuclear Information System (INIS)

    Idris, A; Pullen, K

    2013-01-01

    The effects of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices are presented in this paper. Both experimental and CFD results show that chamfering and corner radiusing improve the discharge coefficient of rotating orifices. For non-inclined rotating orifices, the discharge coefficient reduces with increasing speed, but chamfered and radiused orifices manage to have higher discharge coefficient (C d ) than the straight edge orifices. Comparing between chamfering and corner radiusing, the radiused corner orifice has the highest C d at every rotational speed. This is because the inlet radius helps guiding the flow into the orifice and avoiding flow separation at the inlet.

  1. International Conference on Natural Orifice Transluminal Endoscopic Surgery (NOTES)

    Science.gov (United States)

    2006-06-01

    hemangiomas, and one simple cyst), five were malignant in five patients (five hepatocarcinoma ). and four patients had an uncertain preoperative diagnosis...In the first three cases [ hepatocarcinoma (HCO of segment II, hydatid cyst of segment VI. and hemangioma of segment II], we used the Kellyclasia...HCC HCC HCC HCC HCC Hemangiomab l-’NH vs adenoma FNH vs adenoma FNH vs adenoma FHN. focal nodular hyperplasia; HCC, hepatocarcinoma 1

  2. Energy dissipation characteristics of sharp-edged orifice plate

    Directory of Open Access Journals (Sweden)

    Ai Wanzheng

    2015-08-01

    Full Text Available The energy loss coefficient, relating directly to the energy dissipation ratio, is an important index of this energy dissipater. In this article, this coefficient and its affecting parameters were analyzed by theoretical considerations, and their relationships were obtained by numerical simulations. It could be concluded that the energy loss coefficient of sharp-edged orifice plate and its backflow region length were mainly dominated by the contraction ratio of the orifice plate. Sharp-edged orifice plate’s energy loss coefficient and its backflow region length all increase slightly with the increase in its thickness. When Reynolds number is in the range of 9.00×104–10.3×106, Reynolds number has little impacts on energy loss coefficient and backflow region length. Two empirical expressions, relating to backflow region length and energy loss coefficient, respectively, were presented.

  3. A pulse-tube refrigerator using variable-resistance orifice

    Science.gov (United States)

    Huang, B. J.; Sun, B. W.

    2003-01-01

    In the present study, we propose a new design of orifice pulse-tube refrigerator (VROPT) using a variable-resistance valve to replace the conventional orifice. The variable-resistance orifice (VRO) is basically a high-speed solenoidal valve similar to the fuel jet device widely used in automobile engines. By changing the frequency and periods of ON and OFF of the valve through an electronic device, we can change the flow resistance of the VRO. This thus provides a possibility for an OPT to be controlled on-line during operation. From the results obtained in the present study, we have shown that VROPT is able to achieve on-line control by regulating the duty cycle d or frequency fv of the VRO. We also show that VROPT will not loss its thermal performance as compared to conventional OPT.

  4. Orifice jet brazing process development, qualification, and initial application

    International Nuclear Information System (INIS)

    1971-05-01

    Experiments were carried out to develop acceptable procedures for brazing molybdenum alloy orifices to fuel element channel inlets of the NERVA R-1 reactor core. Results achieved with various procedures are described, and qualification tests of the selected process are documented. The recommended procedure includes preplacing of Au-Ni-Cr alloy washers and induction heating to 1600 0 F, holding two minutes, heating further to 2400 0 F, holding one minute, and allowing to cool. Inert atmosphere is used, and fixturing maintains proper positioning of the orifices. Leak testing of the joints has demonstrated reproducibly satisfactory sealing. Repair brazing is feasible if needed. (auth)

  5. Effect of plate shapes in orifice plate type flowmeters

    International Nuclear Information System (INIS)

    Moeller, S.V.

    1984-01-01

    The study of unusual plate shapes in orifice plate type flowmeters is presented, with a view to providing data for the substitution of the plate with one centered circular orifice in those applications where its use is not possible. For this purpose, six pairs of plates with different forms, with and without chamfered edges, were made and tested in a closed water loop. Results show that, generally, the use of chamfers improves the results and, in the case of perforated and slotlike orificed plates, the narrow-ness of the fluid passage tends to make unnecessary its use. (Author) [pt

  6. Design and analysis of throttle orifice applying to small space with large pressure drop

    International Nuclear Information System (INIS)

    Li Yan; Lu Daogang; Zeng Xiaokang

    2013-01-01

    Throttle orifices are widely used in various pipe systems of nuclear power plants. Improper placement of orifices would aggravate the vibration of the pipe with strong noise, damaging the structure of the pipe and the completeness of the system. In this paper, effects of orifice diameter, thickness, eccentric distance and chamfering on the throttling are analyzed applying CFD software. Based on that, we propose the throttle orifices which apply to small space with large pressure drop are multiple eccentric orifices. The results show that the multiple eccentric orifices can effectively restrain the cavitation and flash distillation, while generating a large pressure drop. (authors)

  7. The effect of orifice plate insertion on low NOx radial swirl burner performances (simulated variable area burner)

    International Nuclear Information System (INIS)

    Mohammad Nazri Mohd Jaafar

    2000-01-01

    The effect of inserting an outlet orifice plate of different sizes at the exit plane of the swirler outlet were studied for small radial swirler with fixed curves vanes. Tests were carried out using two different sizes flame tubes of 76 mm and 140 mm inside diameter, respectively and 330 mm in length. The system was fuelled via eight vane passage fuel nozzles of 3.5 mm diameter hole. This type of fuel injection helps in mixing the fuel and air better prior to ignition. Tests were carried out at 20 mm W.G. pressure loss which is representative of gas burners for domestic central heating system operating conditions. Tests were also carried out at 400 K preheated inlet air temperature and using only natural gas as fuel. The aim of the insertion of orifice plate was to create the swirler pressure loss at the swirler outlet phase so that the swirler outlet shear layer turbulence was maximize to assist with fuel/air mixing. For the present work, the smallest orifice plate exhibited a very low NO x emissions even at 0.7 equivalence ratio were NO x is well below 10 ppm corrected at 0% oxygen at dry basis. Other emissions such as carbon monoxide and unburned hydrocarbon were below 10 ppm and 100 ppm, respectively, over a wide range of operating equivalence ratios. The implies that good combustion was achieved using the smallest orifice plate. (Author)

  8. Cavitating Orifice: Flow regime transitions and low frequency sound production

    NARCIS (Netherlands)

    Testud, P.; Moussou, P.; Hirschberg, A.; Aurégan, Y.

    2005-01-01

    Detailed data are provided for the broadband noise in a cavitating pipe flow through a circular orifice in water. Experiments are performed under industrial conditions, i.e., with a pressure drop varying from 3 to 30 bars and a cavitation number in the range 0.10 = s = 0.77. The speed of sound

  9. Energy Efficiency for Biodiesel Production by Combining Two Orifices in Hydrodynamic Cavitation Reactor

    OpenAIRE

    Mahlinda, Mahlinda; Djafar, Fitriana

    2014-01-01

    Research of energy efficiency for biodiesel production process by combining two orifices on  hydrodynamic cavitation reactor had been carried out. The aim of this reseach was to studied effect of the number of orifices toward increasing temperature without using external energy source to produce biodiesel that generated by cavitation effects on orifices. The results of preliminary research showed by combining two orifices arranged in series can produce the highest thermal energy reached 48oC....

  10. Laboratory evaluation of a vibrating orifice monodisperse aerosol generator

    International Nuclear Information System (INIS)

    Everitt, N.M.; Snelling, K.W.

    1985-02-01

    The Berglund-Liu vibrating orifice aerosol generator is capable of producing monodisperse particles in the diameter range 5 to 50 μm. Experiments have been carried out to set up and evaluate such a generator for the preparation of standard liquid (olive oil) and solid (methylene blue) aerosols in the size range 8 to 13 μm. Modifications have been made to the apparatus to improve its performance and increase its particle output. (author)

  11. Preparation of spherical particles by vibrating orifice technique

    Science.gov (United States)

    Shibata, Shuichi; Tomizawa, Atsushi; Yoshikawa, Hidemi; Yano, Tetsuji; Yamane, Masayuki

    2000-05-01

    Preparation of micrometer-sized spherical particles containing Rhodamine 6G (R6G) has been investigated for the spherical cavity micro-laser. Using phenyl triethoxy silane (PTES) as a starting material, R6G-doped monodisperse spherical particles were prepared by the vibrating orifice technique. Processing consists of two major processes: (1) Hydrolysis and polymerization of PTES and (2) Droplet formation from PTES oligomers by vibrating orifice technique. A cylindrical liquid jet passing through the orifice of 10 and 20 micrometers in diameter breaks up into equal- sized droplets by mechanical vibration. Alcohol solvent of these droplets was evaporated during flying with carrier gas and subsequently solidified in ammonium water trap. For making smooth surface and god shaped particles, control of molecular weight of PTES oligomer was essential. R6G-doped hybrid spherical particles of 4 to 10 micrometers size of cavity structure were successfully obtained. The spherical particles were pumped by a second harmonic pulse of Q- switched Nd:YAG laser and laser emission peaks were observed at wavelengths which correspond to the resonance modes.

  12. Killing rate of colony count by hydrodynamic cavitation due to square multi-orifice plates

    Science.gov (United States)

    Dong, Zhiyong; Zhao, Wenqian

    2018-02-01

    Currently,in water supply engineering, the conventional technique of disinfection by chlorination is employed to kill pathogenic microorganisms in raw water. However, chlorine reacts with organic compounds in water and generates disinfection byproducts (DBPs), such as trihalomethanes (THMs), haloacetic acids (HAAs) etc. These byproducts are of carcinogenic, teratogenic and mutagenic effects, which seriously threaten human health. Hydrodynamic cavitation is a novel technique of drinking water disinfection without DBPs. Effects of orifice size, orifice number and orifice layout of multi-orifice plate, cavitation number, cavitation time and orifice velocity on killing pathogenic microorganisms by cavitation were investigated experimentally in a self-developed square multi-orifice plate-type hydrodynamic cavitation device. The experimental results showed that cavitation effects increased with decrease in orifice size and increase in orifice number, cavitation time and orifice velocity. Along with lowering in cavitation number, there was an increase in Reynolds shear stress,thus enhancing the killing rate of pathogenic microorganism in raw water. In addition, the killing rate by staggered orifice layout was greater than that by checkerboard-type orifice layout.

  13. Development of honeycomb type orifices for flow zoning in PFBR

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, G.K., E-mail: gkpandey@igcar.gov.in; Ramdasu, D.; Padmakumar, G.; Prakash, V.; Rajan, K.K.

    2013-09-15

    Highlights: • Cavitation free flow zoning devices are developed for reactor core in PFBR. • These devices are experimentally investigated for their hydraulic characteristics. • Pressure drop and cavitation are two main characteristics to be investigated. • Various configurations of devices utilized in different zones are discussed. • Loss coefficient for each configuration is compared and reported. -- Abstract: The prototype fast breeder reactor (PFBR) is in its advanced phase of construction at Kalpakkam, India. It is a sodium cooled, pool type reactor with two loop concept where each loop have one primary sodium pump (PSP), one secondary sodium pump (SSP) and two intermediate heat exchangers (IHX). PFBR core subassemblies (SA) are supported vertically inside the sleeves provided in the grid plate (GP). The GP acts as a coolant header through which flow is distributed among the SA to remove fission heat. Since the power profile of the reactor core is not uniform, it is necessary to distribute the coolant flow (called flow zoning) to each subassembly according to their power levels to get maximum mean outlet temperature of sodium at core outlet. To achieve this, PFBR core is divided into 15 zones such as fuel, blanket, reflector, storage, etc. according to their respective power levels. The flow zoning in the different SAs of the reactor core is achieved by installing permanent pressure dropping devices in the foot of the subassembly. Orifices having honey-comb type geometry were developed to meet the flow zoning requirements of fuel zone. These orifices being of very complex geometry requires precision methods of manufacturing to achieve the desired shape under specified tolerances. Investment casting method was optimized to manufacture this orifice plate successfully. Hydraulics of these orifices is important in achieving the required pressure drop without cavitation. The pressure drop across these orifice geometries depends mainly on geometrical

  14. The Impact of Manifold-to-Orifice Turning Angle on Sharp-Edge Orifice Flow Characteristics in both Cavitation and Non-Cavitation Turbulent Flow Regimes (Preprint)

    Science.gov (United States)

    2007-06-01

    varies as the cavitation number is lowered. The third is supercavitation where the vapor pocket attachment has moved to the orifice exit and beyond but...the flow still acts as attached. For this study only the 90 degree orifice angle configuration experienced supercavitation . For all other angles

  15. Pressure heat pumping in the orifice pulse-tube refrigerator

    International Nuclear Information System (INIS)

    Boer, P.C.T. de

    1996-01-01

    The mechanism by which heat is pumped as a result of pressure changes in an orifice pulse-tube refrigerator (OPTR) is analyzed thermodynamically. The thermodynamic cycle considered consists of four steps: (1) the pressure is increased by a factor π 1 due to motion of a piston in the heat exchanger at the warm end of the regenerator; (2) the pressure is decreased by a factor π 2 due to leakage out of the orifice; (3) the pressure is further decreased due to motion of the piston back to its original position; (4) the pressure is increased to its value at the start of the cycle due to leakage through the orifice back into the pulse tube. The regenerator and the heat exchangers are taken to be perfect. The pressure is assumed to be uniform during the entire cycle. The temperature profiles of the gas in the pulse tube after each step are derived analytically. Knowledge of the temperature at which gas enters the cold heat exchanger during steps 3 and 4 provides the heat removed per cycle from this exchanger. Knowledge of the pressure as a function of piston position provides the work done per cycle by the piston. The pressure heat pumping mechanism considered is effective only in the presence of a regenerator. Detailed results are presented for the heat removed per cycle, for the coefficient of performance, and for the refrigeration efficiency as a function of the compression ratio π 1 and the expansion ratio π 2 . Results are also given for the influence on performance of the ratio of specific heats. The results obtained are compared with corresponding results for the basic pulse-tube refrigerator (BPTR) operating by surface heat pumping

  16. Characterization of surface position in a liquid dispensing orifice

    Energy Technology Data Exchange (ETDEWEB)

    Farahi, R H [ORNL; Passian, Ali [ORNL; Thundat, Thomas George [ORNL; Lereu, Aude L [ORNL; Tetard, Laurene [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Jones, Yolanda [ORNL

    2009-01-01

    Precision microdispencing technology delivers picoliter amounts of fluid for printing, electronic, optical, chemical and biomedical applications. In particular, microjetting is capable of accurate, flexible, and non-contact coating with polymers, thus allowing the functionalization of delicate microsensors such as microcantilevers. Information on various phases of droplet formation are important to control volume, uniformity, velocity and rate. One such aspect is the ringing of the meniscus after droplet breakoff which can affect subsequent drop formation. We present analysis of an optical characterization technique and experimental results on the behaviour of menisus oscillations in an orifice of a piezoelectric microjet.

  17. Numerical simulation of progressive BWR fuel inlet orifices

    International Nuclear Information System (INIS)

    Sara Lundgren; Hernan Tinoco; Aleksander Pohl; Wiktor Frid

    2005-01-01

    Full text of publication follows: A 'progressive' orifice is characterized by an edge-shaped hole that gives a Reynolds number dependent resistance coefficient. For Reynolds numbers smaller than a critical one, the resistance coefficient has a high constant value that drops to a much lower value for Reynolds numbers greater than this critical value. A similar effect is widely known for external flows around bodies of different shapes, i. e. spheres, cylinders, etc., and the sudden drop in drag coefficient is due to the shift from laminar to turbulent boundary-layer flow. Experimentally, progressive orifices have been investigated under high-pressure and high-temperature conditions by Akiba et al. (2001) for a reduced set of geometrical parameters. Using the sparse experimental data, a core stability study was carried out by Forsmaks Kraftgrupp AB that showed an improvement in core stability but without the expected reduction in pump power at normal operation. The reason for this partial success was the impossibility of optimizing the fuel inlet pressure drop owing to the limited amount of available data. Due to the high costs associated with the experimental generation of high-pressure, high-temperature data, it was considered that, if possible, the lacking data could be generated numerically at much lower cost. Therefore, the present work deals with the possibility of numerically simulate the flow through progressive orifices, and with the conditions under which to reproduce and generate resistance coefficient data by means of a commercial CFD-code. The results obtained with a two-dimensional, axisymmetric approximation show that Reynolds Averaged Navier-Stokes (RANS) turbulence models are able to qualitatively capture the physics of the phenomenon but with an earlier transition to turbulent boundary-layer flow and with an underestimation of the resistance coefficient by approximately 20 %. This underestimation of the resistance coefficient is related to the two

  18. Numerical simulation of progressive BWR fuel inlet orifices

    Energy Technology Data Exchange (ETDEWEB)

    Sara Lundgren; Hernan Tinoco [Forsmarks Kraftgrupp AB, 742 03 Oesthammar (Sweden); Aleksander Pohl; Wiktor Frid [The Royal Institute of Technology, Dept. Energy Technology, SE-100 44 Stockholm (Sweden)

    2005-07-01

    Full text of publication follows: A 'progressive' orifice is characterized by an edge-shaped hole that gives a Reynolds number dependent resistance coefficient. For Reynolds numbers smaller than a critical one, the resistance coefficient has a high constant value that drops to a much lower value for Reynolds numbers greater than this critical value. A similar effect is widely known for external flows around bodies of different shapes, i. e. spheres, cylinders, etc., and the sudden drop in drag coefficient is due to the shift from laminar to turbulent boundary-layer flow. Experimentally, progressive orifices have been investigated under high-pressure and high-temperature conditions by Akiba et al. (2001) for a reduced set of geometrical parameters. Using the sparse experimental data, a core stability study was carried out by Forsmaks Kraftgrupp AB that showed an improvement in core stability but without the expected reduction in pump power at normal operation. The reason for this partial success was the impossibility of optimizing the fuel inlet pressure drop owing to the limited amount of available data. Due to the high costs associated with the experimental generation of high-pressure, high-temperature data, it was considered that, if possible, the lacking data could be generated numerically at much lower cost. Therefore, the present work deals with the possibility of numerically simulate the flow through progressive orifices, and with the conditions under which to reproduce and generate resistance coefficient data by means of a commercial CFD-code. The results obtained with a two-dimensional, axisymmetric approximation show that Reynolds Averaged Navier-Stokes (RANS) turbulence models are able to qualitatively capture the physics of the phenomenon but with an earlier transition to turbulent boundary-layer flow and with an underestimation of the resistance coefficient by approximately 20 %. This underestimation of the resistance coefficient is related to

  19. Return to axi-symmetry for pipe flows generated after a fractal orifice

    Energy Technology Data Exchange (ETDEWEB)

    Nicolleau, F C G A, E-mail: F.Nicolleau@Sheffield.ac.uk [SFMG, Department of Mechanical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2013-12-15

    We present experimental results obtained from pipe flows generated by fractal shaped orifices or openings. We compare different fractal orifices and their efficiencies to re-generate axi-symmetric flows and to return to the standard flow generated by a perforated plate or a circular orifice plate. We consider two families of fractal openings: mono-orifice and complex orifice and emphasize the differences between the two fractal families. For the Reynolds number we used, we found that there is an optimum iteration for the fractal level above which no improvement for practical applications such as flowmetering is to be expected. The main parameters we propose for the characterization of the fractal orifice are the connexity parameter, the symmetry angle and the gap to the wall {delta}*{sub g}. The results presented here are among the first for flows forced through fractal openings and will serve as a reference for future studies and benchmarks for numerical applications. (paper)

  20. Return to axi-symmetry for pipe flows generated after a fractal orifice

    International Nuclear Information System (INIS)

    Nicolleau, F C G A

    2013-01-01

    We present experimental results obtained from pipe flows generated by fractal shaped orifices or openings. We compare different fractal orifices and their efficiencies to re-generate axi-symmetric flows and to return to the standard flow generated by a perforated plate or a circular orifice plate. We consider two families of fractal openings: mono-orifice and complex orifice and emphasize the differences between the two fractal families. For the Reynolds number we used, we found that there is an optimum iteration for the fractal level above which no improvement for practical applications such as flowmetering is to be expected. The main parameters we propose for the characterization of the fractal orifice are the connexity parameter, the symmetry angle and the gap to the wall δ* g . The results presented here are among the first for flows forced through fractal openings and will serve as a reference for future studies and benchmarks for numerical applications. (paper)

  1. Numerical analysis for the flow field past a two-staged conical orifice

    International Nuclear Information System (INIS)

    Kim, Yeon Soo; Kim, You Gon

    2001-01-01

    The objective of the paper was to measure the pressure drop and to investigate the recirculation region of the conical orifices used in Kwang-yang Iron and Steel Company. The flow field with water used as a working fluid was the turbulent flow for Reynolds number of 2x10 4 . The effective parameters for the pressure drop and the recirculation region were the conical orifice's inclined angle (θ) against the wall, the interval(L) between orifices, the relative angle of rotation(α) of the orifices, the shape of the orifice's hole(circle, rectangle, triangle) having the same area. It was found that the shape of the orifice's hold affected the pressure drop and the flow field a lot. But the other parameters did not make much differences to the pressure drop. The PISO algorithm with FLUENT code was employed

  2. Transport phenomena of macro and micro flows behind orifice and flow accelerated corrosion

    International Nuclear Information System (INIS)

    Fujisawa, Nobuyuki; Hayase, Toshiyuki; Ohara, Taku; Ikohagi, Toshiaki

    2008-01-01

    This paper describes experiment and numerical simulations for macro and micro flows behind an orifice model in a square pipe, which are carried from the viewpoint of flow accelerated corrosion (FAC). The measurements of velocity field behind the orifice model were carried out using particle image velocimetry, and the variations of velocity field with respect to the accuracy of the orifice position were studied. It is found that the reattachment behavior of the flow is highly influenced by the orifice position, which is a critical problem for predicting the pipe thinning phenomena by FAC. The DNS simulation was also conducted for calculating the macro flow behind the orifice. The result suggests that the DNS simulation is applicable to the prediction of pipe thinning macro flow for highly aged nuclear plant. The micro flow simulation can predict the pipe thinning phenomena near the wall. (author)

  3. Occurrence and prevention of enhanced oxide deposition in boiler flow control orifices

    International Nuclear Information System (INIS)

    Woolsey, I.S.; Thomas, D.M.; Garbett, K.; Bignold, G.J.

    1989-10-01

    Once-through boilers, such as those of the AGRs, incorporate flow control orifices at the boiler inlet to ensure a satisfactory flow distribution and stability in the parallel flow paths of the boiler. Deposition of corrosion products in the flow control orifice leads to changes in the orifice pressure loss characteristics, which could lead to problems of flow maldistribution within the boiler, and any adverse consequences resulting from this, such as tube overheating. To date, AGR boiler inlet orifices have not suffered significant fouling due to corrosion products in the boiler feedwater. However, oxide deposition in orifices has been observed in other plants, and in experimental loops operating under conditions very similar to those at inlet to AGR boilers. The lack of deposition in AGR flow control orifices is therefore somewhat surprising. This Report describes studies carried out to examine the factors controlling oxide deposition in flow control orifices, the intention of the work being to explain why deposition has not occurred in AGR boilers to date, and to provide means of preventing deposition in the future should this prove necessary. (author)

  4. Inactivation of Heterosigma akashiwo in ballast water by circular orifice plate-generated hydrodynamic cavitation.

    Science.gov (United States)

    Feng, Daolun; Zhao, Jie; Liu, Tian

    2016-01-01

    The discharge of alien ballast water is a well-known, major reason for marine species invasion. Here, circular orifice plate-generated hydrodynamic cavitation was used to inactivate Heterosigma akashiwo in ballast water. In comparison with single- and multihole orifice plates, the conical-hole orifice plate yielded the highest inactivation percentage, 51.12%, and consumed only 6.84% energy (based on a 50% inactivation percentage). Repeating treatment, either using double series-connection or circling inactivation, elevated the inactivation percentage, yet consumed much more energy. The results indicate that conical-hole-generated hydrodynamic cavitation shows great potential as a pre-inactivation method for ballast water treatment.

  5. CFD study of a simple orifice pulse tube cooler

    Science.gov (United States)

    Zhang, X. B.; Qiu, L. M.; Gan, Z. H.; He, Y. L.

    2007-05-01

    Pulse tube cooler (PTC) has the advantages of long-life and low vibration over the conventional cryocoolers, such as G-M and Stirling coolers because of the absence of moving parts in low temperature. This paper performs a two-dimensional axis-symmetric computational fluid dynamic (CFD) simulation of a GM-type simple orifice PTC (OPTC). The detailed modeling process and the general results such as the phase difference between velocity and pressure at cold end, the temperature profiles along the wall as well as the temperature oscillations at cold end with different heat loads are presented. Emphases are put on analyzing the complicated phenomena of multi-dimensional flow and heat transfer in the pulse tube under conditions of oscillating pressure. Swirling flow pattern in the pulse tube is observed and the mechanism of formation is analyzed in details, which is further validated by modeling a basic PTC. The swirl causes undesirable mixing in the thermally stratified fluid and is partially responsible for the poor overall performance of the cooler, such as unsteady cold-end temperature.

  6. Estimation of the measurement error of eccentrically installed orifice plates

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Neil; Hodgkinson, Edwin; Reader-Harris, Michael

    2005-07-01

    The presentation discusses methods for simulation and estimation of flow measurement errors. The main conclusions are: Computational Fluid Dynamics (CFD) simulation methods and published test measurements have been used to estimate the error of a metering system over a period when its orifice plates were eccentric and when leaking O-rings allowed some gas to bypass the meter. It was found that plate eccentricity effects would result in errors of between -2% and -3% for individual meters. Validation against test data suggests that these estimates of error should be within 1% of the actual error, but it is unclear whether the simulations over-estimate or under-estimate the error. Simulations were also run to assess how leakage at the periphery affects the metering error. Various alternative leakage scenarios were modelled and it was found that the leakage rate has an effect on the error, but that the leakage distribution does not. Correction factors, based on the CFD results, were then used to predict the system's mis-measurement over a three-year period (tk)

  7. [Fourth branchial cleft deformity with skin orifice: a series of 10 cases].

    Science.gov (United States)

    Huang, S L; Zhang, B; Chen, L S; Liang, L; Luo, X N; Lu, Z M; Zhang, S Y

    2016-10-07

    Objective: To report rare cases of congenital neck cutaneous sinus with an orifice near the sternoclavicular joint and to investigate their origins and managements. Methods: A total of ten patients with congenital neck cutaneous sinus having an orifice near the sternoclavicular joint treated in the Guangdong General Hospital from January 2010 to June 2015 were retrospectively analyzed. Results: There four boys and six girls, aging from 11 months to 96 months with an average of 33.4 months, and they had a common feature showing a congenital cutaneous sinus with an orifice near sternoclavicular joint. Discharge of pus from the orifice or abscess formation was commonly seen soon after infection. With bacteriological study, staphylococcus aureus was positive in five cases and klebsiella pneumonia in a case. Another orifice of fistula/sinus was not depicted in pyriform with barium swallow X-ray in five cases Ultrasound studies of three cases demonstrated anechoic (i.e., nearly black) and solid-cystic lesion near sternoclavicular joint with posterior acoustic enhancement. Magnetic resonance imaging (MRI) showed isointensity of the lesion on T1 and T2 weighted images with heterogeneous enhancement and a close relationship with sternoclavicular joint. All patients underwent laryngoscopic examination, which showed no orifice of sinus in pyriform at same side. Surgical resection of fistula/sinus was performed in all cases. The lengths of the fistula varied from 5 mm to 22 mm with an average of 11 mm. Postoperative pathological examination showed all specimens were accordance with fistula. No complications were noticed. Recurrence was not observed in the cases by following-up of 6 months to 70 months (median: 33 months). Conclusion: Congenital neck cutaneous sinus with orifice near the sternoclavicular joint maybe a special clinical phenotype of the fourth branchial cleft sinus with skin orifice in cervicothoracic junction. Differential diagnoses between low cervical diseases

  8. The impact assessment of eccentric installation and roughness change in piping on the orifice flow measurement

    International Nuclear Information System (INIS)

    Nishi, Y.; Eguchi, Y.; Nishihara, T.; Kanai, T.; Kondo, M.

    2012-01-01

    In orifice flowmeters used in nuclear power plants, requirements for the inner surface roughness of upstream piping and eccentric installation exist depending on certain standards. If these cannot be satisfied based on the installation condition, an appropriate error margin must be considered, although this remains to be clarified. In this research, quantitative data concerning the relative error of orifice flowmeters were obtained during experiments with the parameters of the inner surface roughness of upstream piping and the installation eccentricity of the orifice hole. The maximum Reynolds number of the experimental facility is about 1.6x10 6 . In orifice flowmeters, the flow rate is calculated based on the differential pressure between upstream and downstream orifices and the peculiar discharge coefficient C. The latter value shows an upward trend with increasing roughness of piping, while change of 0.3% of C was observed in terms of roughness (case 2), which approaches the limits of the JIS standard. With significant roughness (Case 3) that exceeds five times the JIS standard, C is shown to have increased by about 1%. No influence was observed by varying the direction of eccentric installation, hence this was fixed and the amount of eccentricity was considered. Change in C of about 0.25% was observed when around twice the standard level of eccentricity was applied. The error margin data under conditions exceeding the JIS standard for the orifice flowmeter was obtained. (authors)

  9. Choked flow mechanism of HFC-134a flowing through short-tube orifices

    Energy Technology Data Exchange (ETDEWEB)

    Nilpueng, Kitti; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok (Thailand)

    2011-02-15

    This paper is a continuation of the author's previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube orifices under choked flow condition are presented. Short-tube orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a miniature vapour-compression refrigeration system are examined. The experimental results indicated that the occurrence of choked flow phenomena inside short-tube orifices is different from that obtained from short-tube orifice diameters of greater than 1 mm, which are typically used in air-conditioner. The beginning of choked flow is dependent on the downstream pressure, degree of subcooling, and length-to-diameter ratio. Under choked flow condition, the mass flow rate is greatly varied with the short-tube orifice dimension, but it is slightly affected by the operating conditions. A correlation of mass flow rate through short-tube orifices is proposed in terms of the dimensionless parameters. The predicted results show good agreement with experimental data with a mean deviation of 4.69%. (author) transfer coefficient was also proposed. (author)

  10. Orifice Mass Flow Calculation in NASA's W-8 Single Stage Axial Compressor Facility

    Science.gov (United States)

    Bozak, Richard F.

    2018-01-01

    Updates to the orifice mass flow calculation for the W-8 Single Stage Axial Compressor Facility at NASA Glenn Research Center are provided to include the effect of humidity and incorporate ISO 5167. A methodology for including the effect of humidity into the inlet orifice mass flow calculation is provided. Orifice mass flow calculations provided by ASME PTC-19.5-2004, ASME MFC-3M-2004, ASME Fluid Meters, and ISO 5167 are compared for W-8's atmospheric inlet orifice plate. Differences in expansion factor and discharge coefficient given by these standards give a variation of about +/- 75% mass flow except for a few cases. A comparison of the calculations with an inlet static pressure mass flow correlation and a fan exit mass flow integration using test data from a 2017 turbofan rotor test in W-8 show good agreement between the inlet static pressure mass flow correlation, ISO 5167, and ASME Fluid Meters. While W-8's atmospheric inlet orifice plate violates the pipe diameter limit defined by each of the standards, the ISO 5167 is chosen to be the primary orifice mass flow calculation to use in the W-8 facility.

  11. A Study of System Pressure Transients Generated by Isolation Valve Open/Closure in Orifice Manifold

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. [KEPCO, Daejeon (Korea, Republic of); Bae, S. W.; Kim, J. I.; Park, S. J. [KHNP, Abu Dhabi (United Arab Emirates)

    2016-05-15

    In this study, we explore the effects of pressure transients on peak and minimal pressures caused by the actuation of isolation valve and control valve reacting to the combined orifice operation of orifice manifold with motor-operated valve installed in the rear of the orifice. We then use the collected data to direct our effort towards cause analysis and propose improvements to efficiency and safety of operation. This formation is used to by domestic and foreign nuclear power plants as a mean to control flow rate, producing required flow rate jointly together by combination of the orifices. No significant impacts on the internals of manifold orifice due to peak pressure has been observed, although chance of cavitation at the outlet of control valve is significant. Considering the peak pressure, as well as minimum pressure occurs in low flow rate conditions, the pressure transient is more so affected by the characteristics (modified equal percentage) of control valve. Isolation valve of the orifice and control valve operate organically, therefore stroke time for valves need to be applied in order for both valves to cooperatively formulate an optimized operation.

  12. Experimental otitis media with effusion induced by electron beam irradiation to pharyngeal orifice of auditory tube in guinea pig

    International Nuclear Information System (INIS)

    Kokubu, Michiyo; Amatsu, Mutsuo

    1984-01-01

    The purpose of the present study was to obtain a more natural tubal insufficiency than that obtained by the conventional methods to clarify the middle ear pathology associated with tubal dysfunction. For this purpose, the pharyngeal orifice of the auditory tube in the guinea pigs was irradiated with electron beam with a dose of 2,000 rad following the preliminary experiments to determine the appropriate dose. The guinea pigs with intact drum and normal Pryer reflex were used for the present experiment series. A specially devised apparatus was used for avoiding the dipersing beam. Histopathological changes of the middle ear and auditory tube were observed in a series of single specimen with H-E staining 1, 2, 3, 6, 12 months after irradiation. In this study, middle ear with effusion was used to clarify the dynamic process of the pathological changes between the auditory tube and the middle ear. In summary, the present study revealed that the electron beam irradiation to the pharyngeal orifice caused various grades of otitis media with effusion which could be classified into three groups. Of these groups 1) and 2), 3) were likely to be corresponding with so-called serous and purulent otitis media with effusion in human respectively. Infection due to the malfunction caused by the epithelial damage of the auditory tube was an important promoting factor to change the serous type effusion for the purulent type effusion. (J.P.N.)

  13. Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

    International Nuclear Information System (INIS)

    Papell, S.S.; Nyland, T.W.; Saiyed, N.H.

    1992-07-01

    Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomson devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1-X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band. 3 refs

  14. Localization of root canal orifices in mandibular second molars in relation to occlusal dimension.

    Science.gov (United States)

    Gorduysus, O; Nagas, E; Cehreli, Z C; Gorduysus, M; Yilmaz, Z

    2009-11-01

    To evaluate the localization and distribution of canal orifices of mandibular second molar teeth in relation to the mesio-distal and bucco-lingual dimensions of coronal tissue. Fifty extracted mandibular second molar teeth were embedded into plaster blocks with their vertical axes aligned perpendicular to the horizontal plane. The teeth were photographed digitally from the occlusal aspect under 12 x magnification. Thereafter, the occlusal halves of crowns were sectioned off to expose the root canal orifices. The teeth were than photographed under the same magnification, after which the pre- and post-sectioning images of each specimen were stacked into a single file. To plot the coordinate of each canal orifice, a 0.5-mm grid analytical plane was mounted digitally on the stack so that the x- and y-axes of the plane were superimposed on the mesiodistal and buccolingual axes (bisectors) of the tooth crowns. Localization and distribution of the coordinates of the canal orifices were evaluated using the chi-square test (P = 0.05). Only one tooth displayed a single root canal orifice, located in the mesiobuccal-distolingual 'centre' of the occlusal surface. The majority of mandibular second molars had three orifices (72%), followed by those with two (16%) and four (10%). The distal canal was located lingual to the centre of the occlusal plane. The distal canal was located lingual to the centre of the occlusal plane of mandibular second molars. The possibility of observing more divergent localizations and orifice numbers should not be overlooked in clinical practice.

  15. Optimization of Orifice Geometry for Cross-Flow Mixing in a Cylindrical Duct

    Science.gov (United States)

    Kroll, J. T.; Sowa, W. A.; Samuelsen, G. S.

    1996-01-01

    Mixing of gaseous jets in a cross-flow has significant applications in engineering, one example of which is the dilution zone of a gas turbine combustor. Despite years of study, the design of the jet injection in combustors is largely based on practical experience. The emergence of NO(x) regulations for stationary gas turbines and the anticipation of aero-engine regulations requires an improved understanding of jet mixing as new combustor concepts are introduced. For example, the success of the staged combustor to reduce the emission of NO(x) is almost entirely dependent upon the rapid and complete dilution of the rich zone products within the mixing section. It is these mixing challenges to which the present study is directed. A series of experiments was undertaken to delineate the optimal mixer orifice geometry. A cross-flow to core-flow momentum-flux ratio of 40 and a mass flow ratio of 2.5 were selected as representative of a conventional design. An experimental test matrix was designed around three variables: the number of orifices, the orifice length-to- width ratio, and the orifice angle. A regression analysis was performed on the data to arrive at an interpolating equation that predicted the mixing performance of orifice geometry combinations within the range of the test matrix parameters. Results indicate that the best mixing orifice geometry tested involves eight orifices with a long-to-short side aspect ratio of 3.5 at a twenty-three degree inclination from the center-line of the mixing section.

  16. Neutron Imaging study of bubble behaviors in Nanofluid Through Engineered Orifices

    International Nuclear Information System (INIS)

    Seo, Seok Bin; Bang, In Cheol; Kim, Tae Joo

    2014-01-01

    Most studies focused on the change of surface parameters through deposited nanoparticles, while Vafaei and Wen firstly discussed modification of bubble dynamics by dispersed nanoparticles in fluid as well as deposited ones. The boiling mechanism, as an effective heat transfer mode, includes bubble generation, growth, departure, and coalescence. Therefore the change of bubble dynamics can lead to the change of boiling heat transfer condition. That is, not only surface characteristics but the dispersed nanoparticles would be the essential parameters of boiling mechanism in terms of bubble dynamics. For advanced visualization of opaque fluids, the neutron imaging technique is introduced. In the present study, the bubble dynamics in nanofluid through engineered orifices was studied. The main parameters of engineered orifices are size and geometry. Photographic analysis of bubble departure frequency and averaged bubble departure volume provides as follows: With increasing orifice diameter, averaged bubble departure volume increases, while bubble departure frequency decreases. The results are attributed to enhanced capillary force by increasing contact perimeter. Averaged bubble departure volume and bubble departure frequency remain similar for three different types of orifices. But edges of the triangle and square orifice produce small bubbles which interrupts bubble generation. The converged triple contact line due to the edge may be a reason for the emerged baby bubbles. Nanofluid shows less averaged bubble departure volume and higher bubble departure frequency. Considering little change in physical properties of the fluid, interaction between bubble interface and nanoparticles may be in charge of the results

  17. Comparison of turbulent flow through hexagram and hexagon orifices in circular pipes using large-eddy simulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Nicolleau, Franck C G A; Qin, Ning, E-mail: n.qin@sheffield.ac.uk [Department of Mechanical Engineering, The University of Sheffield, Sheffield, S1 3JD (United Kingdom)

    2016-04-15

    Characteristics of turbulent flow through a circular, a hexagon and a hexagram orifice with the same flow area in circular pipes are investigated using wall-modelled large-eddy simulation. Good agreements to available experimental data were obtained in both the mean velocity and turbulent kinetic energy. The hexagram orifice with alternating convex and concave corners introduces outwards radial velocity around the concave corners downstream of the orifice plate stronger than the hexagon orifice. The stronger outwards radial velocity transfers high momentum from the pipe centre towards the pipe wall to energize the orifice-forced vortex sheet rolling-up and leads to a delayed vortex break-down. Correspondingly, the hexagram has a more gradual flow recovery to a pipe flow and a reduced pressure drop than the hexagon orifice. Both the hexagon and hexagram orifices show an axis-switching phenomenon, which is observed from both the streamwise velocity and turbulent kinetic energy contours. To the best knowledge of the authors, this is the first comparison of orifice-forced turbulence development, mixing and flow dynamics between a regular and a fractal-based polygonal orifice. (paper)

  18. Simulation of Micro-Channel and Micro-Orifice Flow Using Lattice Boltzmann Method with Langmuir Slip Model

    Directory of Open Access Journals (Sweden)

    A. R. Rahmati

    2016-12-01

    Full Text Available Because of its kinetic nature and computational advantages, the Lattice Boltzmann method (LBM has been well accepted as a useful tool to simulate micro-scale flows. The slip boundary model plays a crucial role in the accuracy of solutions for micro-channel flow simulations. The most used slip boundary condition is the Maxwell slip model. The results of Maxwell slip model are affected by the accommodation coefficient significantly, but there is not an explicitly relationship between properties at wall and accommodation coefficient. In the present wok, Langmuir slip model is used beside LBM to simulate micro-channel and micro-orifice flows. Slip velocity and nonlinear pressure drop profiles are presented as two major effects in such flows. The results are in good agreement with existing results in the literature.

  19. Microcomputed tomography analysis of mesiobuccal orifices and major apical foramen in first maxillary molars.

    Science.gov (United States)

    Spagnuolo, Gianrico; Ametrano, Gianluca; D'Antò, Vincenzo; Formisano, Anna; Simeone, Michele; Riccitiello, Francesco; Amato, Massimo; Rengo, Sandro

    2012-01-01

    Aim of the study was to determined by microcomputed tomography (µCT) the horizontal distance between the main (MB1) and the second mesiobuccal canal (MB2) orifices, the vertical distance between the MB1 and MB2 orifices planes, and the distance between the anatomic apex and major apical foramen (AF). Furthermore, we characterized the entire internal and external anatomy of the MB, distalbuccal (DB) and palatal (P) maxillary first molars roots. Twenty-two intact extracted first maxillary molars were scanned by X-ray computed transaxial µCT and then 2D and 3D images were processed and analyzed. The results showed that 77.27% of the mesiobuccal (MB) roots presented a second MB canal, and 29.41% of the MB2 were independent from the MB1 canals. In 15 teeth, there were three root canal orifices on the chamber floor, and 10 of these teeth presented MB2 canals. The mean vertical distance between the MB1 and MB2 planes was 1.68 ± 0.83 mm. Seven teeth had four orifices. The mean horizontal interorificial distance between the MB1 and MB2 orifices was 1.21 ± 0.5 mm. Accessory canals were observed in 33.33% of the roots, loops in 6.06%, while isthmuses were found in 15 of the 22 MB roots. Of the total roots, 74.24% presented one foramen, while all of the roots showed a major apical foramen that was not coincident with the anatomic apex. Our µCT analysis provided interesting features on the horizontal and vertical distance between the MB1 and MB2 orifices and on the distance of AF and anatomic apex. These results have an important clinical value because might support the endodontist in the recruitment, negotiation and obturation of maxillary first molar canal system.

  20. MR imaging of the entry, the abdominal communicating orifice, and the retrograde dissection in aortic dissections

    International Nuclear Information System (INIS)

    Yoshida, Y.; Mukohara, N.; Nakamura, K.; Sugimura, K.; Kono, M.

    1986-01-01

    MR imaging (1.5 T) was performed on 41 patients with aortic dissection. Entries were clearly visualized on the MR images as partial defects of the intimal flap in 18 of 21 patients (85.7%). In eight of ten patients, the locations of abdominal communicating orifices corresponded to the lowest signal intensities of the false lumina. Retrograde disections were diagnosed in all six patients from gradual increases in signal intensities of the false lumina toward the heart. MR imaging was very useful in diagnosing entries of the thoracic aorta, abdominal communicating orifices between true and false lumina, and retrograde dissections

  1. Detectability of Middle Mesial Root Canal Orifices by Troughing Technique in Mandibular Molars: A Micro-computed Tomographic Study.

    Science.gov (United States)

    Keleş, Ali; Keskin, Cangül

    2017-08-01

    The objective of the present study was to measure the orifice depth of middle mesial canals (MMCs) and evaluate the detectability of orifices using troughing preparation. For this study, 85 mandibular molar teeth with MMCs were selected from the scanned micro-computed tomographic images. The MMCs were categorized, and the distances between the MMC orifices and the cementoenamel junctions (CEJ) were recorded as the depth of the orifice. Data were evaluated with frequency analysis and a chi-square test using SPSS (SPSS Inc, Chicago, IL), and the results indicated a 5% significance level. It was found that 77.41% of the MMC orifices were at the CEJ level, whereas 5.38% and 9.69% of the MMC orifices were detectable within 1-mm and 2-mm depths from the CEJ, respectively. Of the specimens, 7.52% had MMC orifices deeper than 2 mm from the CEJ. Confluent anatomy was the most frequent configuration. No significant relation was detected between the orifice depth and MMC configuration (P > .05). It was concluded that 77.41% of the specimens did not require troughing preparation, the remaining 15.07% would require troughing, and 7.52% could not be accessed even with the troughing preparation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Requirements for Vertically Installed Runoff Control Boards for the “Paddy Field Dam” and Appropriate Orifice Shapes

    Science.gov (United States)

    Natsuki, Yoshikawa; Hideyuki, Koide; Shin-Ichi, Misawa

    While the “Paddy Field Dam” project has been recognized as an effective flood control measure, there are some cases in which the runoff control boards are vertically installed on the opening of the drainage boxes without careful consideration of the orifice shape and size. The important criteria for the runoff control boards to be satisfied are: 1. to maintain a sufficient peak runoff control function, 2. to avoid excessive ponding causing overflow, 3. to minimize the influence to the ordinary water management, and 4. to reserve sufficient orifice area to avoid blockage of the orifice with floating litters. The purpose of this study is to examine proper shapes and sizes of the orifice to satisfy the criteria for the vertically installed runoff control boards through experiments and simulations. Given the condition that the orifice has sufficient area to avoid overflow with 10 and 20 year return period rainfall event (criteria 2), the simulation results show that the orifice with horizontally wider shapes has advantages over the square or circular shapes in terms of the criteria 1 and 3. The disadvantage of the horizontally wider shapes is the blockage of the orifice with floating litters (criteria 4). In conclusion, we proposed to secure sufficient vertical distance to avoid this problem by setting a lower limit on the vertical distance and then determine the widest horizontal distance to optimize all the criteria. In addition, we have constructed the “Orifice Design Assist Tool” on the basis of the examinations in this study.

  3. Software development for a orifice plate characterization used in the oil and gas industry; Desenvolvimento de um 'software' para caracterizacao de placas de orificio utilizadas na industria do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Andreas, N. Andreas [Universidade Federal de Itajuba (UNIFEI), MG (Brazil)

    2008-07-01

    The petroleum industry is an economic area that has a strong impact, because this, the information precision is one of the most important facts and it is able to be defined with software simulation. The knowledge of the exactly quantify of petroleum is fundamental, and then the instrumentation is essential for this measurement. There are many mechanisms to measure the volume flow, and one of the most used is the Orifice Plates, which has been more common in the Natural Gas Industry. The software development goal is the characterization of these Orifice Plates, allowing that the constant, which characterizes certain Plate, to be determined without Labor instruments, for that the software has an actualized database. But, the software needs some variables, that are responsible for the environment characteristics and the used material, to calculate the constant of the Orifice Plate, for example, fluid viscosity, environment temperature and kind of the Orifice Plate. The utilized equations in this software are based on the Stolz II equations. This tool is able to facilitate the work in petroleum industry, besides it is done for mobile applications, allowing analyses in real time. (author)

  4. Cavitation in flow through a micro-orifice inside a silicon microchannel

    Science.gov (United States)

    Mishra, Chandan; Peles, Yoav

    2005-01-01

    Hydrodynamic cavitation in flows through a micro-orifice entrenched in a microchannel has been detected and experimentally investigated. Microfabrication techniques have been employed to design and develop a microfluidic device containing an 11.5μm wide micro-orifice inside a 100.2μm wide and 101.3μm deep microchannel. The flow of de-ionized water through the micro-orifice reveals the presence of multifarious cavitating flow regimes. This investigation divulges both similarities and differences between cavitation in micro-orifices and cavitation in their macroscale counterparts. The low incipient cavitation number obtained from the current experiments suggests a dominant size scale effect. Choking cavitation is observed to be independent of any pressure or velocity scale effects. However, choking is significantly influenced by the small stream nuclei residence time at such scales. Flow rate choking leads to the establishment of a stationary cavity. Large flow and cavitation hysteresis have been detected at the microscale leading to very high desinent cavitation numbers. The rapid transition from incipient bubbles to choking cavitation and subsequent supercavitation suggests the presence of radically different flow patterns at the microscale. Supercavitation results in a thick cavity, which extends throughout the microchannel, and is encompassed by the liquid. Cavitation at the microscale is expected to considerably influence the design of innovative high-speed microfluidic systems.

  5. A double parameters measurement of steam-water two-phase flow with single orifice

    International Nuclear Information System (INIS)

    Zhong Shuoping; Tong Yunxian; Yu Meiying

    1992-08-01

    A double parameters measurement of steam-water two-phase flow with single orifice is described. An on-line measurement device based on micro-computer has been developed. The measured r.m.s error of steam quality is less than 6.5% and the measured relative r.m.s. error of mass flow rate is less than 9%

  6. Orifice microreactor for the production of an organic peroxide – non-reactive and reactive characterization

    NARCIS (Netherlands)

    Illg, T.; Hessel, V.; Löb, P.; Schouten, J.C.

    2012-01-01

    In this article, the transfer of a two-step, biphasic, and exothermic peroxide synthesis into a microreactor assisted process is discussed as well as the non-reactive and reactive characterization of the developed orifice microreactor. Residence time distribution measurements showed nearly ideal

  7. A case of ectopic ureteral orifice with hypoplastic kidney diagnosed by enhanced computed tomography

    International Nuclear Information System (INIS)

    Kishi, Mikio; Yoshimoto, Jun; Matsumura, Yosuke; Ohmori, Hiroyuki

    1983-01-01

    A case of ectopic ureteral orifice, 6 year old girl with urinary incontinece, is herein reported. Cystoscopy and excretory urogram showed absense of right half of trigone and non visualizing kidney. By enhanced computed tomography, right hypoplastic kidney was found and right nephrectomy was performed. We emphasize that enhanced computed tomography is very usefull for diagnosis of localization of hypoplastic kidney. (author)

  8. Flow through a cylindrical pipe with a periodic array of fractal orifices

    NARCIS (Netherlands)

    van Melick, P.A.J.; Geurts, Bernardus J.

    2013-01-01

    We apply direct numerical simulation (DNS) of the incompressible Navier–Stokes equations to predict flow through a cylindrical pipe in which a periodic array of orifice plates with a fractal perimeter is mounted. The flow is simulated using a volume penalization immersed boundary method with which

  9. Flow through a cylindrical pipe with a periodic array of fractal orifices

    NARCIS (Netherlands)

    van Melick, P.A.J.; Geurts, B.J.

    2013-01-01

    We apply direct numerical simulation (DNS) of the incompressible Navier-Stokes equations to predict flow through a cylindrical pipe in which a periodic array of orifice plates with a fractal perimeter is mounted. The flow is simulated using a volume penalization immersed boundary method with which

  10. Energy Efficiency for Biodiesel Production by Combining Two Orifices in Hydrodynamic Cavitation Reactor

    Directory of Open Access Journals (Sweden)

    Mahlinda Mahlinda

    2014-12-01

    Full Text Available Research of energy efficiency for biodiesel production process by combining two orifices on  hydrodynamic cavitation reactor had been carried out. The aim of this reseach was to studied effect of the number of orifices toward increasing temperature without using external energy source to produce biodiesel that generated by cavitation effects on orifices. The results of preliminary research showed by combining two orifices arranged in series can produce the highest thermal energy reached 48oC. Result of biodiesel production showed that yield of the highest biodiesel was 96.34% using molar ratio a methanol:oil with comparison 6:1, KOH as catalyst (1% for 50 minutes processing time. For biodiesel quality testing showed all selected parameter met the requirements of the Indonesian National Standard (SNI 04-7182:2006. Identification of biodiesel compound using GCMS showed the biodiesel compounds consisted of methyl oleate, methyl palmitate, acid linoleid, methyl stearate, palmitic acid and oleic acid with the total contents 98.39%.

  11. Experiment of cavitation erosion at the exit of a long orifice

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Yoshinori; Murase, Michio [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

    2002-09-01

    We performed experiments to clarify mechanism of cavitation erosion and to predict cavitation erosion rate at the exit of a long orifice equipped at the chemical and volume control system in a pressurized water reactor (PWR). In order to find this mechanism, we used a high speed video camera. As the result, we observed bubble collapses near the exit of the orifice when flow condition was oscillating. So the bubble collapses due to the oscillation might cause the first stage erosion at the exit of the orifice. Using the orifice which had the cone-shaped exit, we observed that bubbles collapsed near the exit and then they collapsed at the upstream like a chain reaction. So this bubble collapse mechanism could be explained as follows: shock wave was generated by the bubble collapse near the exit, then it propagated upwards, consequently it caused the bubble collapse at the upstream. And we predicted erosion rate by evaluating the effect of the velocity and comparing the erosion resistance between the test speciment (aluminum) and the plant material (stainless steel) by means of vibratory tests. We compared the predicted erosion rate with that of the average value estimated from plant investigation, then we examined the applicability of these method to the plant evaluations. (author)

  12. A comphrehensive model for the amplification of acoustic pressure waves by single hole orifices

    NARCIS (Netherlands)

    Moussou, P.; Testud, Ph.; Auregan, Y.; Hirschberg, A.

    2008-01-01

    Using a parallel flow approximation, a simple model of hydrodynamic instability is proposed for describing the behavior of an orifice as an acoustic amplifier. It is shown that the growing of perturbations in the vena contracta can generate negative damping for Strouhal numbers of the order of

  13. The whistling potentiality of an orifice in a confined flow using an energetic criterion

    NARCIS (Netherlands)

    Testud, P.; Aurégan, Y.; Moussou, P.; Hirschberg, A.

    2009-01-01

    Using a two-source method, the scattering matrices of 10 sharp-edged thin orifices are measured under different subsonic flow conditions. The data are analysed in terms of net acoustical energy balance: the potential whistling frequency range is defined as the one associated with acoustical energy

  14. Fabrication and Characterization of Device Pressure Regulation System Orifice of Manufacturing Process Gel Uranium Column Gelation External

    International Nuclear Information System (INIS)

    Triyono; Sutarni; Indra Suryawan

    2009-01-01

    The device pressure regulation orifice system of manufacturing process gel uranium on external column gelation has been made and characterized. The device consists : compressor 5.75-6.75 kg / cm 2 , air container tank, power supply 24 volts dc, solenoid valve 24 volts dc, pressure indicator 0-100 mbar, pressure indicator 0-250 mbar, mechanical valve and power electric 380 volts 50 Hz. The activity includes: installation device system and characterization with pressure variation orifice 5-75 mbar on the compressor 5.75-6.5 kg/cm 2 continuously for 1 minute. The method of installation i.e: wiring and piping to first component and support component (compressor and pressure air indicator, air container tank and pressure air indicator, solenoid valve, power supply 220 volts / 24 volts dc and orifice). After apparatus installed has been tested by the characterization without feed under air pressure varied to orifice of 5-75 mbar and device characterization with variation diameter orifice of 0.5-1 mm and orifice pressure of 5-75 mbar. The result in the characterization an every component good function, can be operation by input pressure range of 15-185 mbar orifice pressure range of 5-75 mbar. The characterization result device pressure regulation orifice system showed that: the system can be good operation of air pressure regulation orifice between 5-75 mbar with diameter orifice 0.5 mm to result gelation range of 10-25 piece / minute with variation air pressure input between 15-185 mbar of air pressure compressor 5.75-6.5 kg cm 2 . (author)

  15. The Double-Orifice Valve Technique to Treat Tricuspid Valve Incompetence.

    Science.gov (United States)

    Hetzer, Roland; Javier, Mariano; Delmo Walter, Eva Maria

    2016-01-01

    A straightforward tricuspid valve (TV) repair technique was used to treat either moderate or severe functional (normal valve with dilated annulus) or for primary/organic (Ebstein's anomaly, leaflet retraction/tethering and chordal malposition/tethering, with annular dilatation) TV incompetence, and its long-term outcome assessed. A double-orifice valve technique was employed in 91 patients (mean age 52.6 ± 23.2 years; median age 56 years; range: 0.6-82 years) with severe tricuspid regurgitation. Among the patients, three had post-transplant iatrogenic chordal rupture, five had infective endocarditis, 11 had mitral valve insufficiency, 23 had Ebstein's anomaly, and 47 had isolated severe TV incompetence. The basic principle was to reduce the distance between the coapting leaflets, wherein the most mobile leaflet could coapt to the opposite leaflet, by creating two orifices, ensuring valve competence. The TV repair was performed through a median sternotomy or right anterior thoracotomy in the fifth intercostal space under cardiopulmonary bypass. The degree and extent of creating a double-valve orifice was determined by considering the minimal body surface area (BSA)-related acceptable TV diameter. Repair was accomplished by passing pledgeted mattress sutures from the middle of the true anterior annulus to a spot on the opposite septal annulus, located approximately two-thirds of the length of the septal annulus to avoid injury to the bundle of His. The annular apposition divides the TV into a larger anterior and a smaller posterior orifices, enabling valve closure, on both sides. In adults, the diameter of the anterior valve orifice should be 23-25 mm, and the posterior orifice 15-18 mm; thus, the total valve orifice area is 5-6 cm2. In children, the total valve orifice should be a standard deviation of 1.7 mm for a BSA of 1.0m2. During a mean follow up of 8.7 ± 1.34 years (median 10 years; range: 1.5-25.9 years) there have been no reoperations for TV insufficiency

  16. Natural orifice transluminal endoscopic surgery for patients with perforated peptic ulcer.

    Science.gov (United States)

    Bonin, Eduardo A; Moran, Erica; Gostout, Christopher J; McConico, Andrea L; Zielinski, Martin; Bingener, Juliane

    2012-06-01

    Perforation accounts for 70% of deaths attributed to peptic ulcers. Laparoscopic repair is effective but infrequently used. Our aim was to assess how many patients with perforated peptic ulcer could be candidates for a transluminal endoscopic omental patch closure. This retrospective study reviewed patients with perforated peptic ulcer from 2005 to 2010. Demographics, ulcer characteristics, operative procedure, and outcomes were recorded. Candidates for endoscopic transluminal repair were defined as those having undergone omental patch closure of an ulcer of appropriate size and no contraindications to laparoscopy or endoscopy. In the retrospective review, a total of 104 patients were identified; 62% female, mean age = 68 years, mean ASA of 3, and 63% medication-related ulcers. Fifty-nine (63%) had an omental patch (80% open), and 35 (37%) had other procedures. Ten patients had nonoperative management. Thirty-day mortality was 14% and 1 year mortality was 35%. Forty-nine patients (52%) were considered potential candidates for transluminal repair. Sixty-three percent of our patients sustained a medication-related perforation with 1 year mortality of 35%. The majority of patients were treated using open omental patch repair. Transluminal endoscopic repair may provide an additional situation for a minimally invasive approach for a number of these patients.

  17. Impact of body image on patients' attitude towards conventional, minimal invasive, and natural orifice surgery.

    Science.gov (United States)

    Lamadé, Wolfram; Friedrich, Colin; Ulmer, Christoph; Basar, Tarkan; Weiss, Heinz; Thon, Klaus-Peter

    2011-03-01

    A series of investigations proposed that patients' preference on minimal invasive and scarless surgery may be influenced by age, sex, and surgical as well as endoscopic history of the individual patient. However, it is unknown which psychological criteria lead to the acceptance of increased personal surgical risk or increased personal expenses in patients demanding scarless operations. We investigated whether individual body image contributes to the patient's readiness to assume higher risk in favor of potentially increased cosmesis. We conducted a nonrandomized survey among 63 consecutive surgical patients after receiving surgery. Individual body image perception was assessed postoperatively applying the FKB-20 questionnaire extended by four additional items. The FKB-20 questionnaire is a validated tool for measuring body image disturbances resulting in a two-dimensional score with negative body image (NBI) and vital body dynamics (VBD) being the two resulting scores. A subgroup analysis was performed according to the conducted operations: conventional open surgery = group 1, traditional laparoscopic surgery = group 2, and no scar surgery = group 3. There was a significant correlation between a negative body image and the preference for scar sparing and scarless surgery indicated by a significantly increased acceptance of surgical risks and the willingness to spend additional money for receiving scarless surgery (r = 0.333; p = 0.0227). Allocated to operation subgroups, 17 of 63 patients belonged to group 1 (OS), 29 to group 2 (minimally invasive surgery), and 17 patients to group 3 (no scar). Although age and sex were unequally distributed, the groups were homogenous regarding body mass index and body image (NBI). Subgroup analysis revealed that postoperative desire for scar sparing approaches was most frequently expressed by patients who received no scar operations. Patients with an NBI tend towards scarless surgery and are willing to accept increased operative risk and to spend additional money for improved postoperative cosmesis.

  18. Natural Modes of Multi-Orifice Bubbling from a Common Plenum

    Czech Academy of Sciences Publication Activity Database

    Růžička, Marek; Drahoš, Jiří; Zahradník, Jindřich; Thomas, N. H.

    1999-01-01

    Roč. 54, č. 21 (1999), s. 5223-5229 ISSN 0009-2509 R&D Projects: GA AV ČR KSK2040602 Grant - others:CEC(XE) INCO-COPERNICUS:ERB IC15-CT98-0904 Institutional research plan: CEZ:AV0Z4072921 Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.218, year: 1999

  19. Single-incision laparoscopic surgery through an ostomy site: a natural approach by an unnatural orifice.

    Science.gov (United States)

    Lopez, Nicole E; Peterson, Carrie Y; Ramamoorthy, Sonia L; McLemore, Elisabeth C; Sedrak, Michael F; Lowy, Andrew M; Horgan, Santiago; Talamini, Mark A; Sicklick, Jason K

    2015-02-01

    Single-incision laparoscopic surgery (SILS) is gaining popularity for a wide variety of surgical operations and capitalizes on the benefits of traditional laparoscopic surgery without incurring multiple incision sites. Traditionally, SILS is performed by a midline periumbilical approach. However, such a minimally invasive approach may be utilized in patients who already have an abdominal incision. Our series retrospectively reviews 7 cases in which we utilized the fascial defect at the time of after ostomy reversal as our SILS incision site. In turn, we performed a variety of concurrent intra-abdominal procedures with excellent technical success and outcomes. Our study is the largest single-institution case series of this novel approach and suggests that utilizing an existing ostomy-site abdominal incision is a safe and effective location for SILS port placement and should be considered in patients undergoing concurrent procedures.

  20. Flow and mass transfer downstream of an orifice under flow accelerated corrosion conditions

    International Nuclear Information System (INIS)

    Ahmed, Wael H.; Bello, Mufatiu M.; El Nakla, Meamer; Al Sarkhi, Abdelsalam

    2012-01-01

    Highlights: ► Mass transfer downstream of orifices was numerically and experimentally investigated. ► The surface wear pattern is measured and used to validate the present numerical results. ► The maximum mass transfer coefficient found to occur at approximately 2–3 pipe diameters downstream of the orifice. ► The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. ► The current study offered very useful information for FAC engineers for better preparation of nuclear plant inspection scope. - Abstract: Local flow parameters play an important role in characterizing flow accelerated corrosion (FAC) downstream of sudden area change in power plant piping systems. Accurate prediction of the highest FAC wear rate locations enables the mitigation of sudden and catastrophic failures, and the improvement of the plant capacity factor. The objective of the present study is to evaluate the effect of the local flow and mass transfer parameters on flow accelerated corrosion downstream of an orifice. In the present study, orifice to pipe diameter ratios of 0.25, 0.5 and 0.74 were investigated numerically by solving the continuity and momentum equations at Reynolds number of Re = 20,000. Laboratory experiments, using test sections made of hydrocal (CaSO 4 ·½H 2 O) were carried out in order to determine the surface wear pattern and validate the present numerical results. The numerical results were compared to the plants data as well as to the present experiments. The maximum mass transfer coefficient found to occur at approximately 2–3 pipe diameters downstream of the orifice. This location was also found to correspond to the location of elevated turbulent kinetic energy generated within the flow separation vortices downstream of the orifice. The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. The current study found to offer very

  1. High Viscosity Liquid Flow through the Round Orifices at Small Reynold’s Numbe rs

    Directory of Open Access Journals (Sweden)

    V. N. Pil'gunov

    2015-01-01

    Full Text Available The paper presents research results of the mineral oil flow process with viscosity of 30 cSt through a round orifice with the sharp inlet edge of 0.9 mm in diameter. Pilot studies were conducted using a module from the transparent plexiglas that allowed to visualize hydrodynamic processes. The intake and off-take channels of the module with their sufficient extension had diameter of 20 mm (24 diameters of an orifice that allows us to consider compression of a stream as perfect. Drawing the enameled nichrome wire with a mark as a stripping isolation of 0.1 mm width enabled sounding of electric processes in the stream sections. Intensive high- frequency electric processes were revealed in cavitation stream. The paper gives experimental values of coefficientsof volumetric and mass flow at low (150 orifice. Free jet at a speed exceeding 50 m/s strikes a wall, barrier, installed at a distance of 100 diameters of the orifice: the reflection from walls, barriers shot blast, which caused intense foaming and conversion of oil into the two-phase mixture "fluid- combined air." We investigate the "life cycle" of a two-phase mixture: flotation bubbles in a viscous medium, and there was no air passes completely evolved in the dissolved state in a time not exceeding 30 minutes. Volumetric analysis of the foam allowed us to estimate the percentage of volumetric gas content of oil, which was 9% at 240С and atmospheric pressure of 97.5 kPa. An explanation of the possible cause cavitation edge at the end of a viscous fluid through an orifice with a sharp edge - appearance in fluid large tensile forces due to the centrifugal force on the particles of the fluid streams in passing peripheral sharp edge. Experimental research data flow of a viscous fluid in the annular orifice formed sharp edge and the surface of the string. Detected failure mode expiration free jet and conversion shareware transparent

  2. Organic compounds generated after the flow of water through micro-orifices: Were they synthesized?

    Directory of Open Access Journals (Sweden)

    Tomiichi Hasegawa

    2017-08-01

    Full Text Available Micro-fluid mechanics is an important area of research in modern fluid mechanics because of its many potential industrial and biological applications. However, the field is not fully understood yet. In previous work, when passing ultrapure water (UPW in which air was dissolved (UPW* through micro-orifices, we found that the flow velocity decreased and stopped over time, and membranes were frequently formed in the orifice when the flow stopped. The membrane came from the dissolved air in UPW*, and membrane formation was closely related to electric charges generated in orifices by the flow. In the present paper, we clarified the components of the membrane and suggested a mechanism for membrane formation. We examined the effect of contaminants on the membrane formation and confirmed our previous results. We identified the chemical components of the membrane and those present in the UPW* itself by using an electron probe microanalyzer and found that the proportion of each element differed between the membrane and UPW*. Raman and infrared (IR spectroscopy showed that the membrane consisted of organic substances such as carotenoids, amides, esters, and sugars. We irradiated UPW* with ultraviolet light to cut organic chains that may be left in UPW* as contaminants. We found a similar membrane and organic compounds as in nonirradiated UPW*. Furthermore, although the UPW that was kept from contact with air after it was supplied from the UPW maker (UPW0 and bubbled with Ar gas (UPW0 bubbled with Ar formed no membrane, the UPW0 bubbled with CO2 formed thin membranes, and Raman and IR analysis showed that this membrane contained carboxylic acid salts, carotenoids, or a mixture of both. We found that electric grounding of the orifice reduces the probability of membrane formation and that the jets issuing from an aperture bear negative charges, and we assumed that the micro-orifices possess positive charges generated by flows. Consequently, we suggest that

  3. Repair of Double Orifice Left AV Valve (DOLAVV with Endocardial Cushion Defect in Adult

    Directory of Open Access Journals (Sweden)

    Vivek Velayudhan Pillai

    Full Text Available Abstract Double orifice left atrioventricular valve (DOLAVV or double orifice mitral valve (DOMV is a rare congenital cardiac anomaly manifesting either as an isolated lesion (mitral stenosis or mitral insufficiency or in association with other congenital cardiac defects. Signs of mitral valve disease are usually present along with the symptoms of associated coexistent congenital heart diseases. Mitral insufficiency due to annular dilatation is seen when DOLAVV is associated with endocardial cushion defects. Surgical intervention like mitral valve repair or replacement is required in 50% of patients and yields good results. We report a case of a 56-year-old lady who successfully underwent surgical correction of DOLAVV with partial atrioventricular canal defect.

  4. Burnout experiments in freon 12 using different types of orifices to simulate the core grids

    International Nuclear Information System (INIS)

    Ladeira, L.; Katsaounis, A.; Orlowski, R.; Fulfs, H.; Hofmann, K.

    1978-01-01

    This paper will report on burnout experiments carried out in freon 12 mainly at steady state and further at mass flow or power transient conditions with annular test sections axially uniformly heating either the inside or both the inside and outside rod. The runs are performed without orifice and using three different types of orifices simulating the reactor spacer grid. An important influence of the flow restriction on burnout position and value is measured. Furthermore, the comparison between the burnout correlations W2, W3, B and W2 and GE and experimental results from the literature using simple test section geometries in water and freon 12 demonstrate, that the accuracy is more or less comparable for both fluids. (orig.) [de

  5. Method for generating small and ultra small apertures, slits, nozzles and orifices

    Science.gov (United States)

    Khounsary, Ali M [Hinsdale, IL

    2012-05-22

    A method and device for one or more small apertures, slits, nozzles and orifices, preferably having a high aspect ratio. In one embodiment, one or more alternating layers of sacrificial layers and blocking layers are deposited onto a substrate. Each sacrificial layer is made of a material which preferably allows a radiation to substantially pass through. Each blocking layer is made of a material which substantially blocks the radiation.

  6. Coronal microleakage of three different dental biomaterials as intra-orifice barrier during nonvital bleaching

    Directory of Open Access Journals (Sweden)

    Nafiseh Zarenejad

    2015-01-01

    Full Text Available Background: This study was designed to assess the microleakage of glass-ionomer (GI, mineral trioxide aggregate (MTA, and calcium-enriched mixture (CEM cement as coronal orifice barrier during walking bleaching. Materials and Methods: In this experimental study, endodontic treatment was done for 70 extracted human incisors without canal calcification, caries, restoration, resorption, or cracks. The teeth were then divided into three experimental using "Simple randomization allocation" (n = 20 and two control groups (n = 5. The three cements were applied as 3-mm intra-orifice barrier in test groups, and bleaching process was then conducted using a mixture of sodium perborate powder and distilled water, for 9 days. For leakage evaluation, bovine serum albumin marker was traced in a dual-chamber technique with Bradford indicator. The Kruskal-Wallis and Mann-Whitney tests were used for statistical analysis. Results: The mean ± standard deviation leakage of samples from negative control, positive control, GI, MTA, and CEM cement groups were 0.0, 8.9 ± 0.03, 0.47 ± 0.02, 0.48 ± 0.02, and 0.49 ± 0.02 mg/mL, respectively. Statistical analysis showed no significant difference between three experimental groups (P > 0.05. Conclusion: It is concluded that GI, MTA, and CEM cements are considered as suitable intra-orifice barrier to provide coronal seal during walking bleaching.

  7. Performance of an Orifice Compensated Two-Lobe Hole-Entry Hybrid Journal Bearing

    Directory of Open Access Journals (Sweden)

    J. Sharana Basavaraja

    2008-01-01

    Full Text Available The work presented in this paper aims to study the performance of a two-lobe hole-entry hybrid journal bearing system compensated by orifice restrictors. The Reynolds equation governing the flow of lubricant in the clearance space between the journal and bearing together with the equation of flow through an orifice restrictor has been solved using FEM and Galerkin's method. The bearing performance characteristics results have been simulated for an orifice compensated nonrecessed two-lobe hole-entry hybrid journal bearing symmetric configuration for the various values of offset factor (, restrictor design parameter (2, and the value of external load (0. Further, a comparative study of the performance of a two-lobe hole-entry hybrid journal bearing system with a circular hole-entry symmetric hybrid journal bearing system has also been carried out so that a designer has a better flexibility in choosing a suitable bearing configuration. The simulated numerical results indicate that for the two-lobe symmetric hole-entry hybrid journal bearing system with an offset factor ( greater than one provides 30 to 50 percent larger values of direct stiffness and direct damping coefficients as compared to a circular symmetric hole-entry hybrid journal bearing system.

  8. Evaluation of the flow-accelerated corrosion downstream of an orifice. 1. Measurements and numerical analysis of flow field

    International Nuclear Information System (INIS)

    Utanohara, Yoichi; Nagaya, Yukinori; Nakamura, Akira; Murase, Michio

    2008-01-01

    In this study, in order to evaluate the effects of flow field on corrosion rate due to flow accelerated corrosion (FAC), an orifice flow was measured and calculated. The diameter of pipe is 50 mm and that of the orifice is 24.3 mm, and flow velocity in a water loop was set at 2.41 m/s. Flow field was measured by laser Doppler velocimetry (LDV) and particle image velocimetry (PIV), and compared with a calculation for the same flow conditions. Measurements of wall shear stress downstream of the orifice was also planed. The calculated velocity distribution of standard k-□ agreed qualitatively with PIV data and quantitatively with LDV data. Instantaneous flow field measured by PIV showed vortices around the jet from the orifice and some of them reached near the pipe wall. (author)

  9. Impact of L/D on 90 Degree Sharp-Edge Orifice Flow with Manifold Passage Cross Flow (Preprint)

    Science.gov (United States)

    2007-04-30

    that are observed by measurement as the flow transitions from non-cavitation to cavitation (turbulent flow), supercavitation , and finally separation in...include inception of cavitation, supercavitation , and separation. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...cavitation to cavitation (turbulent flow), supercavitation , and finally separation in sharp-edge 90 degree orifices. This study includes orifice L/D from

  10. Numerical simulation of progressive inlet orifices in boiling water reactor fuel

    International Nuclear Information System (INIS)

    Lundgren, Sara

    2004-07-01

    This thesis was carried out at Forsmark Nuclear Power Plant. The power plant in Forsmark consists of three boiling water reactors (BWR) which produce about 17% of Swedish electricity. In a BWR the nuclear reactions are used to boil water inside the reactor vessel. The water works both as a coolant and as a moderator and the resulting steam is used directly to run the turbines. A problem when running a BWR at low flow conditions is the density wave oscillations that might occur to the water flow inside the fuel assemblies. These oscillations arise due to the connection between power and flow rate in a heated channel with two-phase flow. In order to improve the stability performance of the channel an orifice plate is placed at the inlet of each fuel assembly. Today these orifice plates have sharp edges and a constant resistance coefficient. Experimental work has been done with progressive orifices, the edge of which is half-oval in shape. The advantage of progressive orifices is the lower pressure losses with an increase of the Reynolds number, a similar phenomenon that appears in external flow around curved bodies. Since there are high costs associated with experimental generation of high- temperature and high-pressure data, it is of some interest to be able to reproduce and generate data using Computational Fluid Dynamics (CFD). This work deals with the possibility to use the CFD-code Fluent to do numerical simulations of the flow through progressive orifices. The following conclusions may be drawn from the numerical results: All simulations using Reynolds-Averaged Navier-Stokes (RANS) turbulence models, two-dimensional and three-dimensional, capture an abrupt decrease of the resistance coefficient at higher Reynolds numbers. Two-equation models seem to under-predict the critical Reynolds number. The five-equation Reynolds Stress Model (RSM) gives a critical Reynolds number of the same order of magnitude of that measured in experiments. No major differences have

  11. Mass transfer coefficient in disturbed flow due to orifice for flow accelerated corrosion in nuclear power plant

    International Nuclear Information System (INIS)

    Prasad, Mahendra; Gaikwad, Avinash J.; Sridharan, Arunkumar; Parida, Smrutiranjan

    2015-01-01

    The flow of fluid in pipes cause corrosion wherein the inner surface of pipe becomes progressively thinner and susceptible to failure. This form of corrosion dependent on flow dynamics is called Flow Accelerated Corrosion (FAC) and has been observed in Nuclear Power Plants (NPPs). Mass transfer coefficient (MTC) is related to extent of wall thinning and it changes from its value in a straight pipe (with same fluid parameters) for flow in orifices, bends, junctions etc. due to gross disturbance of the velocity profile. This paper presents two-dimensional computational fluid dynamics (CFD) simulations for an orifice configuration in a straight pipe. Turbulent model K- ω with shear stress transport and transition flow was the model used for simulation studies. The mass transfer boundary layer (MTBL) thickness δ mtbl is related to the Schmidt number (Sc) and hydrodynamic boundary layer thickness δ h , as δ mtbl ~ δh/(Sc 1/3 ). MTBL is significantly smaller than δ h and hence boundary layer meshing was carried out deep into δ mtbl . Uniform velocity profile was applied at the inlet. Post orifice fluid shows large recirculating flows on the upper and lower wall. At various locations after orifice, mass transfer coefficient is calculated and compared with the value in straight pipe with fully developed turbulent flow. The MTC due to the orifice increases and it is correlated with enhanced FAC in region after orifice. (author)

  12. The Performance Test for Reactor Coolant Pump (RCP) adopting Variable Restriction Orifice Type Control Valve

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.; Bae, B. U.; Cho, Y. J. and others

    2014-05-15

    The design values of the RCPTF are 17.2 MPa, 343 .deg. C, 11.7 m{sup 3}/s, and 13 MW in the maximum pressure, temperature, flow rate, and electrical power, respectively. In the RCPTF, various types of tests can be performed including a hydraulic performance test to acquire a H-Q curve as well seal transient tests, thrust bearing transient test, cost down test, NPSHR verification test, and so on. After a commissioning startup test was successfully perfomed, mechanical structures are improved including a flow stabilizer and variable restriction orifice. Two- branch pipe (Y-branch) was installed to regulate the flow rate in the range of performance tests. In the main pipe, a flow restrictor (RO: Restriction Orifice) for limiting the maximum flow rate was installed. In the branch pipe line, a globe valve and a butterfly valves for regulating the flow rate was located on the each branch line. When the pressure loss of the valve side is smaller than that of the RO side, the flow rate of valve side was increasing and the flow disturbance was occurred in the lower pipe line. Due to flow disturbnace, it is to cause an error when measuring RCP head and flow measurement of the venturi flow meter installed in the lower main pipe line, and thus leading to a decrease in measurement accuracy as a result. To increase the efficiency of the flow control availability of the test facility, the variable restriction orifice (VRO) type flow control valve was designed and manufactured. In the RCPTF in KAERI, the performance tests and various kinds of transient tests of the RCP were successfully performed. In this study, H-Q curve of the pump using the VRO revealed a similar trend to the result from two ROs. The VRO was confirmed to effectively cover the full test range of the flow rate.

  13. Numerical simulation of trans-critical carbon dioxide (R744) flow through short tube orifices

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Valladares, O. [Centro de Investigacion en Energia de la Universidad Nacional Autonoma de Mexico, Privada Xochicalco S/N, Apdo. Postal 34, 62580 Temixco, Morelos (Mexico)

    2006-02-01

    A detailed one-dimensional numerical simulation of the fluid-dynamic behaviour of short tube orifices expansion devices working with trans-critical carbon dioxide (CO{sub 2} or R744) has been developed. The discretized governing equations are coupled using an implicit step by step method. A special treatment has been implemented in order to consider transitions (subcooled liquid region and equilibrium two-phase region). The numerical model allows analysis of aspects such as geometry, different working conditions, critical or non-critical flow conditions, etc. Comparison of the numerical simulation with experimental data presented in the technical literature will be shown in the present article. (author)

  14. Disinfection of Escherichia coli bacteria using hybrid method of ozonation and hydrodynamic cavitation with orifice plate

    Science.gov (United States)

    Karamah, Eva F.; Ghaudenson, Rioneli; Amalia, Fitri; Bismo, Setijo

    2017-11-01

    This research aims to evaluate the performance of hybrid method of ozonation and hydrodynamic cavitation with orifice plate on E.coli bacteria disinfection. In this research, ozone dose, circulation flowrate, and disinfection method were varied. Ozone was produced by commercial ozonator with ozone dose of 64.83 mg/hour, 108.18 mg/hour, and 135.04 mg/hour. Meanwhile, hydrodynamic cavitation was generated by an orifice plate. The disinfection method compared in this research were: hydrodynamic cavitation, ozonation, and the combination of both. The best result on each method was achieved on the 60th minutes and with a circulation flowrate of 7 L/min. The hybrid method attained final concentration of 0 CFU/mL from the initial concentration of 2.10 × 105 CFU/mL. The ozonation method attained final concentration of 0 CFU/mL from the initial concentration of 1.32 × 105 CFU/mL. Cavitation method gives the least disinfection with final concentration of 5.20 × 104 CFU/mL from the initial concentration of 2.17 × 105 CFU/mL. In conclusion, hybrid method gives a faster and better disinfection of E.coli than each method on its own.

  15. Dual discharge from a stratified two-phase region through side orifices oriented horizontally

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, I G; Soliman, H M; Sims, G E [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Mechanical Engineering; Kowalski, J E [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

    1996-12-31

    Experimental data are presented for the mass flow rate and quality of two-phase (air-water) discharge from a stratified region through two side orifices (6.35 mm i.d.) with their parallel centre lines located in a horizontal plane. These data correspond to different values of the interface level between the onsets of gas and liquid entrainments for test-section pressures of 316 and 517 kPa, test-section-to-separators pressure difference ranging from 40 to 235 kPa, orifice separating distance to diameter ratio ranging from 1.5 to 8 and different hydraulic resistances of the lines connecting the test section to the separators. Influences of these independent variables on the deviation between the present results (of mass flow rate and quality) and those corresponding to a single discharge are presented and discussed. Normalized plots are presented showing that the present data of dual discharge and those of a single discharge can be collapsed for the whole test range when specific definition for the dimensionless height of the interface and mass flow rate are used. Excellent agreement is demonstrated between single-discharge correlations and the present data using these dimensionless quantities. (author). 12 refs., 1 tab., 16 figs.

  16. Dual discharge from a stratified two-phase region through side orifices oriented horizontally

    International Nuclear Information System (INIS)

    Hassan, I.G.; Soliman, H.M.; Sims, G.E.; Kowalski, J.E.

    1995-01-01

    Experimental data are presented for the mass flow rate and quality of two-phase (air-water) discharge from a stratified region through two side orifices (6.35 mm i.d.) with their parallel centre lines located in a horizontal plane. These data correspond to different values of the interface level between the onsets of gas and liquid entrainments for test-section pressures of 316 and 517 kPa, test-section-to-separators pressure difference ranging from 40 to 235 kPa, orifice separating distance to diameter ratio ranging from 1.5 to 8 and different hydraulic resistances of the lines connecting the test section to the separators. Influences of these independent variables on the deviation between the present results (of mass flow rate and quality) and those corresponding to a single discharge are presented and discussed. Normalized plots are presented showing that the present data of dual discharge and those of a single discharge can be collapsed for the whole test range when specific definition for the dimensionless height of the interface and mass flow rate are used. Excellent agreement is demonstrated between single-discharge correlations and the present data using these dimensionless quantities. (author). 12 refs., 1 tab., 16 figs

  17. Experimental study of cooling performance of pneumatic synthetic jet with singular slot rectangular orifice

    Science.gov (United States)

    Yu, Roger Ho Zhen; Ismail, Mohd Azmi bin; Ramdan, Muhammad Iftishah; Mustaffa, Nur Musfirah binti

    2017-03-01

    Synthetic Jet generates turbulence flow in cooling the microelectronic devices. In this paper, the experiment investigation of the cooling performance of pneumatic synthetic jet with single slot rectangular orifices at low frequency motion is presented. The velocity profile at the end of the orifice was measured and used as characteristic performance of synthetic jet in the present study. Frequencies of synthetic jet and the compressed air pressure supplied to the pneumatic cylinder (1bar to 5bar) were the parameters of the flow measurement. The air velocity of the synthetic jet was measured by using anemometer air flow meter. The maximum air velocity was 0.5 m/s and it occurred at frequency motion of 8 Hz. The optimum compressed air supplied pressure of the synthetic jet study was 4 bar. The cooling performance of synthetic jet at several driven frequencies from 0 Hz to 8 Hz and heat dissipation between 2.5W and 9W were also investigate in the present study. The results showed that the Nusselt number increased and thermal resistance decreased with both frequency and Reynolds number. The lowest thermal resistance was 5.25°C/W and the highest Nusselt number was 13.39 at heat dissipation of 9W and driven frequency of 8Hz.

  18. Flow resistance of orifices and spacers of BWR thermal-hydraulic and neutronic coupling loop

    International Nuclear Information System (INIS)

    Iguchi, Tadashi; Asaka, Hideaki; Nakamura, Hideo

    2002-03-01

    Authors are performing THYNC experiments to study thermal-hydraulic instability under neutronic and thermal-hydraulic coupling. In THYNC experiments, the orifices are installed at the exit of the test section and the spacers are installed in the test section, in order to properly simulate in-core thermal-hydraulics in the reactor core. It is necessary to know the flow resistance of the orifices and spacers for the analysis of THYNC experimental results. Consequently, authors measured the flow resistance of orifice and spacer under single-phase and two-phase flows. Using the experimental results, authors investigated the dependency of the flow resistances on the parameters, such as pressure, mass flux, an geometries. Furthermore, authors investigated the applicability of the basic two-phase flow models, for example the separate flow model, to the two-phase flow multiplier. As the result of the investigation on the single-phase flow experiment, it was found (1) that the effects of pressure and mass flux flow resistance are described by a function of Reynolds number, and (2) that flow resistances of the orifice and the spacer are calculated with the previous prediction methods. However, it was necessary to introduce an empirical coefficient, since it was difficult to predict accurately the flow resistance only with the previous prediction method due to the complicated geometry dependency, for example a flow area blockage ratio. On the other hand, according to the investigation on two-phase flow experiment, the followings were found. (1) Relation between the two-phase flow multiplier and the quality is regarded to be linear under pressure of 2MPa - 7MPa. The relation is dependent on pressure and geometry, and is little dependent on mass flux. (2) Relation between the two-phase flow multiplier and void fraction is little dependent on pressure, mass flux, and geometry under pressure of 0.2MPa - 7MPa and void fraction less than 0.6. The relation is less dependent on

  19. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  20. Effect of Orifice Nozzle Design and Input Power on Two-Phase Flow and Mass Transfer Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hei Cheon [Chonnam Nat’l Univ., Gwangju (Korea, Republic of)

    2016-04-15

    It is necessary to investigate the input power as well as the mass transfer characteristics of the aeration process in order to improve the energy efficiency of an aerobic water treatment. The objective of this study is to experimentally investigate the effect of orifice nozzle design and input power on the flow and mass transfer characteristics of a vertical two-phase flow. The mass ratio, input power, volumetric mass transfer coefficient, and mass transfer efficiency were calculated using the measured data. It was found that as the input power increases the volumetric mass transfer coefficient increases, while the mass ratio and mass transfer efficiency decrease. The mass ratio, volumetric mass transfer coefficient, and mass transfer efficiency were higher for the orifice configuration with a smaller orifice nozzle area ratio. An empirical correlation was proposed to estimate the effect of mass ratio, input power, and Froude number on the volumetric mass transfer coefficient.

  1. [Urethroplasty with transection of urethral orifice and preservation and lengthening of urethral plate: highly applicable to the treatment of hypospadias].

    Science.gov (United States)

    Wang, Wen-Min; Qiu, Wei-Feng; Qian, Chong

    2010-07-01

    To explore the feasibility of urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate in the treatment of hypospadias. Forty-eight patients with hypospadias (18 of the coronal type, 21 the penile type, 8 the penoscrotal type and 1 the perineal type) underwent urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate. The surgical effects were observed by following up the patients for 3-27 months. One-stage surgical success was achieved in 44 of the cases, with satisfactory functional and cosmetic results but no complications. Two cases developed urinary fistula and another 2 urethral stricture, but all cured by the second surgery. Urethroplasty with transection of the urethral orifice and preservation and lengthening of the urethral plate is a simple, safe and effective surgical procedure for the treatment of hypospadias.

  2. Impact of valve prosthesis-patient mismatch estimated by echocardiographic-determined effective orifice area on long-term outcome after aortic valve replacement.

    Science.gov (United States)

    Florath, Ines; Albert, Alexander; Rosendahl, Ulrich; Ennker, Ina Carolin; Ennker, Jrgen

    2008-06-01

    The impact of valve prosthesis-patient mismatch on long-term outcome after aortic valve replacement estimated by various variables such as projected indexed effective orifice area and internal geometric orifice area obtained from in vivo or in vitro published data is still controversial. The effective orifice area was measured by echocardiography in 533 patients. The mean age of the patients was 71 +/- 9 years; mean follow-up time was 4.7 +/- 2.2 years. The impact of severe (indexed effective orifice area regression. Severe mismatch (hazard ratio: 1.9 [1.08-3.21]) was a significant predictor of survival time after adjustment for age, left ventricular ejection fraction, atrial fibrillation, New York Heart Association class, serum creatinine, and hemoglobin level. The 5- and 7-year survival rates were 71% +/- 4% and 54% +/- 8% for patients with severe mismatch and 83% +/- 4% and 80% +/- 8% for patients with mild mismatch, respectively. The correlation between projected and measured indexed effective orifice area was of medium strength (r = 0.49), and the frequency of observed mismatch depended linearly on the projected indexed effective orifice area. Although projected indexed effective orifice area and indexed internal geometric orifice area were significant predictors of severe mismatch, the sensitivity and specificity for severe prosthesis-patient mismatch were only 75% and 52%, using an optimal threshold of projected indexed effective orifice area defined by the Youden index. Severe prosthesis-patient mismatch estimated by effective orifice area measured within 10 days was an independent risk factor of survival time. Projected indexed effective orifice area determined at surgery does not sufficiently predict mismatch.

  3. Fabrication and Application of Mono-sized Spherical Micro Particles by Pulsated Orifice Ejection Method

    Directory of Open Access Journals (Sweden)

    DONG Wei

    2018-02-01

    Full Text Available A novel technology called pulsated orifice ejection method(POEM and used for preparing mono-sized and high-precision spherical micro particles was introduced in this article. The working principle of the technique was illustrated and it was in two modes:low-melting point diaphragm mode and high-melting point rod mode, depending on the different melting points of materials. The particles prepared by POEM have the advantages of mono-sized, uniform and controllable particle size, high sphericity, and consistent thermal history. By introducing the application of particles prepared by this method, showing the huge application prospects of this technology in electronic packaging, bioengineering, micro-fabrication, rapid solidification analysis of metal droplets, additive manufacturing and so on.With the development of POEM, this technology is predicted to have wider prospects due to its unique characteristics.

  4. Restenosis after stenting in symptomatic vertebral arterial orifice disease and considerations for better outcome

    Science.gov (United States)

    Chang, Jun Young; Park, Hyun; Kwon, Oki

    2017-01-01

    We have performed stenting in 11 patients with symptomatic vertebral arterial orifice stenosis refractory to medical treatment or impairment in anterior circulation. Three of the 11 patients experienced asymptomatic severe in-stent restenosis or occlusion. Bare metal stents were used in those three patients, two of whom received revascularization therapy. Development of sufficient cervical collateral channels reconstituting the distal vertebral artery was the common feature in patients with asymptomatic in-stent restenosis. In selecting appropriate stents, consideration of mechanical strength and drug-eluting properties of a stent according to characteristics of the target vessel is important to reduce the risk of in-stent restenosis. Any decision to perform revascularization should be based on the presence of abundant cervical collaterals as well as clinical symptoms of vertebrobasilar ischemia. PMID:28304206

  5. Evaluation of effective regurgitant orifice area of mitral valvular regurgitation by multislice cardiac computed tomography

    International Nuclear Information System (INIS)

    Vural, M.; Ucar, O.; Celebi, O.O.; Cicekcioglu, H.; Durmaz, H.A.; Selvi, N.A.; Koparal, S.; Aydogdu, S.

    2010-01-01

    The purpose of our study was to assess the diagnostic accuracy of multislice computed tomography (MSCT) for the identification and quantification of mitral valve regurgitation in comparison with transthoracic echocardiography (TTE). Twenty-six patients (15 females, 11 males with a mean age of 44.6±14.1 years) who were in follow-up with the diagnosis of mitral regurgitation and those who were referred for MSCT were enrolled. MSCT results were compared with TTE measurements. The mean effective mitral regurgitant orifice area at MSCT was 23.1±13.0 mm 2 and at echocardiography was 24.4±16.0mm 2 . Bland-Altman analysis showed good agreement between the two imaging methods. MSCT provides reliable and good results for the evaluation of mitral regurgitation. (author)

  6. A mathematical model for erosion-corrosion downstream of an orifice

    International Nuclear Information System (INIS)

    Thomas, R.M.

    1989-08-01

    In certain types of nuclear plant, the internal surfaces of the steel high-pressure boiler tubes become covered with magnetite. This normal growth of protective magnetite may, in unfavourable circumstances, be replaced by rapid attack on the tube wall. Particularly at risk are the regions downstream of the orifice plates commonly fitted near the boiler inlet. An attempt is made to construct a mathematical model for this erosion-corrosion which is considerably more complete than those available hitherto. A systematic synthesis is developed of the various aspects of the phenomenon, namely the mechanism of the topotactic oxidation at the interface between magnetite and metal, the kinetics of the electrode reactions at the magnetite/solution interface, the thermodynamics of magnetite solubility and the calculation of mass transfer in solution. With one choice of parameters and some simplification, the treatment reduces to the original theory of Bignold. (author)

  7. The counter-current flooding limit in vertical tubes with and without orifices

    International Nuclear Information System (INIS)

    Tye, P.; Davidson, M.; Teyssedou, A.; Tapucu, A.; Matuszkiewicz, A.; Midvidy, W.

    1993-01-01

    For hypothetical loss of coolant accidents in nuclear reactors, rapid reflooding of the core is desirable. In CANDU reactors the cooling water is injected into the headers which are connected to the fuel channels by the feeder pipes. These pipes consist of vertical and horizontal runs; in some feeders, orifices and/or venturi flow meters are installed for flow adjustments and measurements respectively. For certain postulated accident scenarios, steam coming from the fuel channels and/or generated in the hot feeders may flow in the direction opposite to that of the cooling water thereby, creating a vertical or horizontal counter-current two-phase flow. Under these conditions, the rate at which cooling water can enter the fuel channels may be limited by the flooding phenomena. This phenomena is greatly affected by the geometry of the feeder pips, shape and number of fittings, and the flow area restrictions located in the feeders. In this paper the influence that orifice type flow area restrictions have on the counter-current flooding limit (CCFL) in a vertical tube is examined. air and water at close to atmospheric conditions are used as the working fluids. The data collected on the counter-current flooding limit in a vertical tube both with and without flow area restrictions is compared against some of the most commonly used correlations that are available in the open literature. Data on the two-phase counter-current pressure drop below the flooding point are also presented. 12 refs., 10 figs., 1 tab

  8. Continuous synthesis of tert.-butyl peroxypivalate using a single channel micro reactor equipped with orifices as emulsification units

    NARCIS (Netherlands)

    Illg, T.; Hessel, V.; Löb, P.; Schouten, J.C.

    2011-01-01

    The two-step synthesis of tert-butyl peroxypivalate is performed in a single-channel microreactor. The first step, the deprotonation of tert-butyl hydroperoxide, is done in a simple mixer tube setup. The residence time section for the second reaction step is equipped with orifices for interfacial

  9. Shear flow over a plane wall with an axisymmetric cavity or a circular orifice of finite thickness

    International Nuclear Information System (INIS)

    Pozrikidis, C.

    1994-01-01

    Shear flow over a plane wall that contains an axisymmetric depression or pore is studied using a new boundary integral method which is suitable for computing three-dimensional Stokes flow within axisymmetric domains. Numerical results are presented for cavities in the shape of a section of a sphere or a circular cylinder of finite length, and for a family of pores or orifices with finite thickness. The results illustrate the distribution of shear stresses over the plane wall and inside the cavities or pores. It is found that in most cases, the distribution of shear stresses over the plane wall, around the depressions, is well approximated with that for flow over an orifice of infinitesimal thickness for which an exact solution is available. The kinematic structure of the flow is discussed with reference to eddy formation and three-dimensional flow reversal. It is shown that the thickness of a circular orifice or depth of a pore play an important role in determining the kinematical structure of the flow underneath the orifice in the lower half-space

  10. Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, V.G.; Goncalves, J.A.S. [Department of Chemical Engineering, Federal University of Sao Carlos, Via Washington Luiz, Km. 235, 13565-905 Sao Carlos, SP (Brazil); Coury, J.R. [Department of Chemical Engineering, Federal University of Sao Carlos, Via Washington Luiz, Km. 235, 13565-905 Sao Carlos, SP (Brazil)], E-mail: jcoury@ufscar.br

    2009-01-15

    Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

  11. Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber

    International Nuclear Information System (INIS)

    Guerra, V.G.; Goncalves, J.A.S.; Coury, J.R.

    2009-01-01

    Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets

  12. Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber.

    Science.gov (United States)

    Guerra, V G; Gonçalves, J A S; Coury, J R

    2009-01-15

    Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

  13. Appendiceal Abscesses Reduced in Size by Drainage of Pus from the Appendiceal Orifice during Colonoscopy: A Report of Three Cases

    Directory of Open Access Journals (Sweden)

    Shinjiro Kobayashi

    2014-11-01

    Full Text Available Interval appendectomy (IA for appendiceal abscesses is useful for avoiding extended surgery and preventing postoperative complications. However, IA has problems in that it takes time before an abscess is reduced in size in some cases and in that elective surgery may result in a delay in treatment in patients with a malignant tumor of the appendix. In order to rule out malignancy, we performed colonoscopy on three patients with an appendiceal abscess that did not decrease in size 5 or more days after IA. After malignancy had been ruled out by examination of the area of the appendiceal orifice, the appendiceal orifice was compressed with a colonoscope, and a catheter was inserted through the orifice. Then, drainage of pus was observed from the appendiceal orifice into the cecal lumen. Computed tomography performed 3 days after colonoscopy revealed a marked reduction in abscess size in all patients. No endoscopy-related complication was noted. Colonoscopy in patients with an appendiceal abscess may not only differentiate malignant tumors, but also accelerate reduction in abscess size.

  14. Simplified one-orifice venoplasty for middle hepatic vein reconstruction in adult living donor liver transplantation using right lobe grafts.

    Science.gov (United States)

    Kim, Joo Dong; Choi, Dong Lak; Han, Young Seok

    2014-05-01

    Middle hepatic vein (MHV) reconstruction is often essential to avoid hepatic congestion and serious graft dysfunction in living donor liver transplantation (LDLT). The aim of this report was to introduce evolution of our MHV reconstruction technique and excellent outcomes of simplified one-orifice venoplasty. We compared clinical outcomes with two reconstruction techniques through retrospective review of 95 recipients who underwent LDLT using right lobe grafts at our institution from January 2008 to April 2012; group 1 received separate outflow reconstruction and group 2 received new one-orifice technique. The early patency rates of MHV in group 2 were higher than those in group 1; 98.4% vs. 88.2% on postoperative day 7 (p = 0.054) and 96.7% vs. 82.4% on postoperative day 14, respectively (p = 0.023). Right hepatic vein (RHV) stenosis developed in three cases in group 1, but no RHV stenosis developed because we adopted one-orifice technique (p = 0.043). The levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in group 2 were significantly lower than those in group 1 during the early post-transplant period. In conclusion, our simplified one-orifice venoplasty technique could secure venous outflow and improve graft function during right lobe LDLT. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Transcatheter pledget-assisted suture tricuspid annuloplasty (PASTA) to create a double-orifice valve.

    Science.gov (United States)

    Khan, Jaffar M; Rogers, Toby; Schenke, William H; Greenbaum, Adam B; Babaliaros, Vasilis C; Paone, Gaetano; Ramasawmy, Rajiv; Chen, Marcus Y; Herzka, Daniel A; Lederman, Robert J

    2018-02-06

    Pledget-assisted suture tricuspid valve annuloplasty (PASTA) is a novel technique using marketed equipment to deliver percutaneous trans-annular sutures to create a double-orifice tricuspid valve. Tricuspid regurgitation is a malignant disease with high surgical mortality and no commercially available transcatheter solution in the US. Two iterations of PASTA were tested using trans-apical or trans-jugular access in swine. Catheters directed paired coronary guidewires to septal and lateral targets on the tricuspid annulus under fluoroscopic and echocardiographic guidance. Guidewires were electrified to traverse the annular targets and exchanged for pledgeted sutures. The sutures were drawn together and knotted, apposing septal and lateral targets, creating a double orifice tricuspid valve. Twenty-two pigs underwent PASTA. Annular and chamber dimensions were reduced (annular area, 10.1 ± 0.8 cm 2 to 3.8 ± 1.5 cm 2 (naïve) and 13.1 ± 1.5 cm 2 to 6.2 ± 1.0 cm 2 (diseased); septal-lateral diameter, 3.9 ± 0.3 mm to 1.4 ± 0.6 mm (naïve) and 4.4 ± 0.4 mm to 1.7 ± 1.0 mm (diseased); and right ventricular end-diastolic volume, 94 ± 13 ml to 85 ± 14 ml (naïve) and 157 ± 25 ml to 143 ± 20 ml (diseased)). MRI derived tricuspid regurgitation fraction fell from 32 ± 12% to 4 ± 5%. Results were sustained at 30 days. Pledget pull-through force was five-fold higher (40.6 ± 11.7N vs 8.0 ± 2.6N, P PASTA reduces annular dimensions and tricuspid regurgitation in pigs. It may be cautiously applied to selected patients with severe tricuspid regurgitation and no options. This is the first transcatheter procedure, to our knowledge, to deliver standard pledgeted sutures to repair cardiac pathology. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

  16. Investigation on Hydrodynamic Cavitation of a Restriction Orifice and Static Mixer on Crud-like Deposits

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Man; Lee, Seung Won; Park, Seong Dae; Kang, Sa Rah; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2012-05-15

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core have shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice and static mixer fundamentally

  17. Effects of Hydrodynamic Cavitation of a Restriction Orifice on Crud-like Deposits

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Man; Lee, Seung Won; Park, Sung Dae; Kang, Sarah; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2011-10-15

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core has shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice fundamentally

  18. Urethral orifice hyaluronic acid injections: a novel animal model of bladder outlet obstruction.

    Science.gov (United States)

    Wang, Yongquan; Xiong, Zhiyong; Gong, Wei; Zhou, Zhansong; Lu, Gensheng

    2015-02-21

    We produced a novel model of bladder outlet obstruction (BOO) by periurethral injection of hyaluronic acid and compared the cystometric features, postoperative complications, and histopathological changes of that model with that of traditional open surgery. Forty female Sprague-Dawley rats were divided into three groups. Fifteen rats were subcutaneously injected with 0.2 ml hyaluronic acid at 5, 7, and 12 o'clock around the urethral orifice. Another fifteen rats underwent traditional open partial proximal urethral obstruction surgery, and 10 normal rats used as controls. After 4 weeks, filling cystometry, postoperative complications, and histopathological features were evaluated in each group. Three rats were also observed for 12 weeks after hyaluronic acid injection to evaluate the long-term effect. Hyaluronic acid periurethral injection caused increased maximum cystometric capacity, maximum bladder pressure, micturition interval, and post-void residual urine volume compared with control (p injection group had significantly shorter operative time, less incidence of incision infection and bladder stone formation compared with the surgery group (p injection and surgery bladders; these were not observed in the control group. Bladder weight and thickness of smooth muscle in the injection and surgery groups were significantly greater than those in the control group (p injection or control groups. Rats periurethrally injected hyaluronic acid were stable the compound was not fully absorbed in any rat after 12 weeks. Hyaluronic acid periurethral injection generates a simple, effective, and persistent animal model of BOO with lower complications, compared with traditional surgery.

  19. Investigation on Hydrodynamic Cavitation of a Restriction Orifice and Static Mixer on Crud-like Deposits

    International Nuclear Information System (INIS)

    Kim, Seong Man; Lee, Seung Won; Park, Seong Dae; Kang, Sa Rah; Seo, Han; Bang, In Cheol

    2012-01-01

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core have shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice and static mixer fundamentally

  20. Effects of Hydrodynamic Cavitation of a Restriction Orifice on Crud-like Deposits

    International Nuclear Information System (INIS)

    Kim, Seong Man; Lee, Seung Won; Park, Sung Dae; Kang, Sarah; Seo, Han; Bang, In Cheol

    2011-01-01

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core has shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice fundamentally

  1. THE PERFORMANCE ANALYSIS OF A PACKED COLUMN : CALIBRATION OF AN ORIFICE

    Directory of Open Access Journals (Sweden)

    Aynur ŞENOL

    2003-01-01

    Full Text Available Investigations to develop data for this study were made using a pilot scale glass column of 9 cm inside diameter randomly filled to a depth of 1.90 cm with a Raschig type ring at a slightly modified geometry. The geometrical characteristics of packing are: the total area of a single particle ad = 2.3 cm2; specific area ap = 10.37 cm2/cm3; voidage ? = 0.545 m3/m3. The efficiency tests were run using trichloroethylene/n-heptane system under total reflux conditions. Using the modified versions of the Eckert flooding model and the Bravo effective area (ae approach, as well as the Onda wetted area (aw and individual mass transfer coefficient models, it has been attempted to estimate the packing efficiency theoretically. This article also deals with the design strategies attributed to a randomly packed column. Emphasis is mainly placed on the way to formulate an algorithm of designing a pilot scale column through the models being attributed to the film theory. Using the column dry pressure drop properties based on the air flowing it has been achieved a generalized flow rate approach for calibrating of an orifice through which the air passes.

  2. Oxide deposition in the orifices of AGR boiler inlet ferrule assemblies

    International Nuclear Information System (INIS)

    Thomas, D.M.

    1988-08-01

    In experiments designed to study the erosion-corrosion behaviour of AGR boiler inlet ferrules using the CERL high velocity circulating isothermal water rig, oxide deposition was frequently found within the flow control orifices. The present investigation was carried out as a preliminary to a programme of experiments addressed specifically to this problem. Analysis shows the deposits to be predominantly magnetite (or possible maghemite) with traces of α-haematite. Calculations indicate that the maximum rate of magnetite deposition is mass transfer limited, although in some experiments no deposition occurred in cases where mass transfer would have allowed substantial deposition. Thus the occurrence of deposition is thought to depend on the rig potential as this varies with experimental conditions. In these experiments the surface potential is not found to be governed by the hydrogen level. Metallographic cross-sections through the ferrule control bores show the deposits to be found in regions of separated flow, and the flow markings in the deposits show that the flow is turbulent in these zones. The exact morphology is thought to be influenced by machining marks within the control bore. (author)

  3. Does bladder outlet obstruction affect distance between the ureteric orifices in patients with benign prostate hyperplasia?

    Directory of Open Access Journals (Sweden)

    Cüneyt Özden

    2009-01-01

    Full Text Available Objectives: Many morphological changes occur in the bladder due to bladder outlet obstruction (BOO in pa-tients with benign prostate hyperplasia (BPH. In the present study we evaluated the relationship between in-terureteric distance (IUD of the orifices and BOO in BPH patients.Materials and methods: Thirty-seven consecutive pa-tients with lower urinary tract symptoms at the urology polyclinic included in the study. Patients divided into 2 groups according to maximal flow rate (Qmax. The first group constituted of 18 patients with Qmax 15ml/s. The IUD measurement was performed with Doppler ultrasonography.Results: There was no significant difference between the groups regarding mean age and prostate volume. Mean IUD in the first group was 32.7±5.4 mm and mean IUD in the second group was 31.5±5.1 mm. There was no statistically significant difference between the groups regarding the IUD.Conclusions: Data obtained from the study revealed that measurement of IUD with Doppler ultrasonography not significantly related to BOO.

  4. Experimental study of mixed convection flow through a horizontal orifice or vent linking two compartments

    International Nuclear Information System (INIS)

    Varrall, Kevin

    2016-01-01

    To answer building issues and fire safety challenges, this thesis deals with the mixed convection flow through a horizontal orifice or vent linking two compartments. The aim is to improve the understanding and the modeling of the exchange of gas through the opening. A small scale experimental study and a theoretical approach are proposed. The study focuses first on the influence of the geometrical ratio L/D of the opening on the flow rate at the vent for free convection regime. Non-intrusive measurements, via the tracking of the interface between two non miscible liquids in an isothermal approach, and thanks to the SPIV in a thermal approach, permit to describe the bidirectional exchange process and to consolidate existing correlations. Experiments for mixed convection regime aim to study the impact of mechanical ventilation (in blowing and extracting modes) on the exchanged flow rates. The comparison between existing correlations and experimental data shows large differences. A modification of the correlation of Cooper is proposed. A theoretical approach from the simplified Navier Stokes equations and with the Boussinesq approximation permits to discuss the construction of existing correlations. From this theory, a more accurate model than those available in the literature is proposed thanks to an adjustment of discharge coefficients from experimental data. (author)

  5. Evaluation of the flow-accelerated corrosion downstream of an orifice. 2. Measurement of corrosion rate and evaluation on the effects of the flow field

    International Nuclear Information System (INIS)

    Nagaya, Yukinori; Utanohara, Yoichi; Nakamura, Akira; Murase, Michio

    2008-01-01

    In this study, in order to evaluate the effects of flow field on corrosion rate due to flow accelerated corrosion (FAC), a corrosion rate downstream of an orifice was measured using the electric resistance method. The diameter of the pipe is 50 mm and that of the orifice is 24.3 mm, and flow velocity of the experimental loop was set at 5m/s, and the temperature of water was controlled within ±1 at 150deg-C. There were no significant circumferential difference in measured corrosion rate, and the maximum corrosion rate was observed at 1D or 2D downstream from the orifice. The ratios of the measured corrosion rate and the calculated wall shear stress at the 1D downstream from the orifice to the value at upstream under well developed flow agreed well. (author)

  6. Mechanisms of natural ventilation in livestock buildings

    DEFF Research Database (Denmark)

    Rong, Li; Bjerg, Bjarne; Batzanas, Thomas

    2016-01-01

    Studies on the mechanisms of natural ventilation in livestock buildings are reviewed and influences on discharge and pressure coefficients are discussed. Compared to studies conducted on buildings for human occupation and industrial buildings which focus on thermal comfort, ventilation systems......, indoor air quality, building physics and energy etc., our understanding of the mechanisms involved in natural ventilation of livestock buildings are still limited to the application of the orifice equation. It has been observed that the assumptions made for application of the orifice equation...... are not valid for wind-induced cross ventilation through large openings. This review identifies that the power balance model, the concept of stream tube and the local dynamic similarity model has helped in the fundamental understanding of wind-induced natural ventilation in buildings for human occupation...

  7. A computational investigation on the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development in diesel injector nozzles

    International Nuclear Information System (INIS)

    Molina, S.; Salvador, F.J.; Carreres, M.; Jaramillo, D.

    2014-01-01

    Highlights: • The influence of elliptical orifices on the inner nozzle flow is compared. • Five nozzles with different elliptical and circular orifices are simulated. • Differences in the flow coefficients and cavitation morphology are observed. • Horizontal axis orifices are ease to cavitate, with a higher discharge coefficient. • A better mixing process quality is expected for the horizontal major axis nozzles. - Abstract: In this paper a computational study was carried out in order to investigate the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development. With this aim, a large number of injection conditions have been simulated and analysed for 5 different nozzles: four nozzles with different elliptical orifices and one standard nozzle with circular orifices. The four elliptical nozzles differ from each other in the orientation of the major axis (vertical or horizontal) and in the eccentricity value, but keeping the same outlet section in all cases. The comparison has been made in terms of mass flow, momentum flux and other important non-dimensional parameters which help to describe the behaviour of the inner nozzle flow: discharge coefficient (C d ), area coefficient (C a ) and velocity coefficient (C v ). The simulations have been done with a code able to simulate the flow under either cavitating or non-cavitating conditions. This code has been previously validated using experimental measurements over the standard nozzle with circular orifices. The main results of the investigation have shown how the different geometries modify the critical cavitation conditions as well as the discharge coefficient and the effective velocity. In particular, elliptical geometries with vertically oriented major axis are less prone to cavitate and have a lower discharge coefficient, whereas elliptical geometries with horizontally oriented major axis are more prone to cavitate and show a higher discharge coefficient

  8. Long-term survival in children with atrioventricular septal defect and common atrioventricular valvar orifice in Sweden.

    Science.gov (United States)

    Frid, Christina; Björkhem, Gudrun; Jonzon, Anders; Sunnegårdh, Jan; Annerén, Göran; Lundell, Bo

    2004-02-01

    The survival for patients with atrioventricular septal defect has improved markedly over the last decades and, during the same period, the survival of children with Down's syndrome has also increased. The aim of our study was to investigate long-term survival in patients having atrioventricular septal defect with common valvar orifice, but without associated significant congenital heart defects, in the setting of Down's syndrome, comparing the findings to those in chromosomally normal children with the same malformation. In a population-based retrospective study, we scrutinised the medical records from 801 liveborn children with atrioventricular septal defect born in Sweden during the period 1973 through 1997. Data on gender, presence or absence of Down's syndrome, associated congenital heart defects, date of birth, operation and death were recorded and followed up until 2001. An isolated atrioventricular septal defect with common atrioventricular valvar orifice was present in 502 children, of whom 86% had Down's syndrome. We found a significant reduc tion over time in age at operation, and in postoperative mortality at 30 days, from 28 to 1%. Using a multiple logistic regression model, we found no significant differences in mortality between genders, nor between those with or without Down's syndrome. Early corrective surgery could not be identified as a significant independent factor for survival. The 5-year postoperative survival in patients with Down's syndrome increased from 65% over the period from 1973 through 1977, to about 90% in the period 1993 through 1997, and the same trend was observed in chromosomally normal patients. Survival in uncomplicated atrioventricular septal defect with common atrioventricular valvar orifice has greatly increased, and surgical correction is now equally successful in patients with Down's syndrome and chromosomally normal patients, and for both genders. Death in connection with surgery is no longer the major threat, and focus

  9. Pressure drop calculation using a one-dimensional mathematical model for two-phase flow through an orifice

    DEFF Research Database (Denmark)

    Petkov, K.P.; Puton, M; Madsen, Søren Peder

    2014-01-01

    are accounted for through both friction and acceleration as in a conventional formulation. However, in this analysis the acceleration term is both attributed geometrical effects through the area change and fluid dynamic effects through the expansion of the two-phase flow. The comparison of numerical...... is a one dimensional formulation in space and the equations incorporates the change in tubes and orifice diameter as formulated in (S. Madsen et.al., Dynamic Modeling of Phase Crossings in Two-Phase Flow, Communications in Computational Physics 12 (4), 1129-1147). The pressure changes in the flow...

  10. Advanced ultrasonic technology for natural gas measurement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-11-15

    In recent years, due to rising environmental and safety concerns, increasing commodity prices, and operational inefficiencies, a paradigm shift has been taking place with respect to gas measurement. The price of natural gas depends on the location, time of the year, and type of consumer. There is wide uncertainty associated with an orifice meter. This paper presents the use of advanced ultrasonic technology for the measurement of natural gas. For many years, multi-path ultrasonic meters with intelligent sensor technology have been used for gas measurement. This paper gives the various applications of ultrasonic technology along with their advantages and a draws a comparison with orifice meters. From the study it can be concluded that extensive advances in the use of ultrasonic technology for gas measurement have widened the areas of application and that varying frequencies combined with sealed transducer designs make it possible to measure atmospheric and sour gas in custody transfer process control and flaring accurately.

  11. Quantitative characterization of near-field fuel sprays by multi-orifice direct injection using ultrafast x-tomography technique

    International Nuclear Information System (INIS)

    Liu, X.; Im, K.S.; Wang, Y.; Wang, J.; Hung, D.L.S.; Winkelman, J.R.; Tate, M.W.; Ercan, A.; Koerner, L.J.; Caswell, T.; Chamberlain, D.; Schuette, D.R.; Philipp, H.; Smilgies, D.M.; Gruner, S.M.

    2006-01-01

    A low-pressure direct injection fuel system for spark ignition direct injection engines has been developed, in which a high-turbulence nozzle technology was employed to achieve fine fuel droplet size at a low injection pressure around 2 MPa. It is particularly important to study spray characteristics in the near-nozzle region due to the immediate liquid breakup at the nozzle exit. By using an ultrafast x-ray area detector and intense synchrotron x-ray beams, the interior structure and dynamics of the direct injection gasoline sprays from a multi-orifice turbulence-assisted nozzle were elucidated for the first time in a highly quantitative manner with μs-temporal resolution. Revealed by a newly developed, ultrafast computed x-microtomography technique, many detailed features associated with the transient liquid flows are readily observable in the reconstructed spray. Furthermore, an accurate 3-dimensional fuel density distribution, in the form of fuel volume fraction, was obtained by the time-resolved computed tomography. The time-dependent fuel density distribution revealed that the fuel jet is well broken up immediately at the nozzle exits. These results not only reveal the near-field characteristics of the partial atomized fuel sprays with unprecedented detail, but also facilitate the development of an advanced multi-orifice direct injector. This ultrafast tomography capability also will facilitate the realistic computational fluid dynamic simulations in highly transient and multiphase fuel spray systems.

  12. Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

    Energy Technology Data Exchange (ETDEWEB)

    Benhamadouche, S., E-mail: sofiane.benhamadouche@edf.fr; Arenas, M.; Malouf, W.J.

    2017-02-15

    Highlights: • Wall-resolved LES can predict the flow through a square-edged orifice at Re = 25,000. • LES results are compared with the available experimental data and ISO 5167-2. • Pressure loss and discharge coefficients are in very good agreement with ISO 5167-2. • The present wall-resolved LES could be used as reference data for RANS validation. - Abstract: The orifice plate is a pressure differential device frequently used for flow measurements in pipes across different industries. The present study demonstrates the accuracy obtainable using a wall-resolved Large Eddy Simulation (LES) approach to predict the velocity, the Reynolds stresses, the pressure loss and the discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number of 25,000. The ratio of the orifice diameter to the pipe diameter is β = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11. The mesh is sized using refinement criteria at the wall and preliminary RANS results to ensure that the solution is resolved beyond an estimated Taylor micro-scale. The inlet condition is simulated using a recycling method, and the LES is run with a dynamic Smagorinsky sub-grid scale (SGS) model. The sensitivity to the SGS model and to the pressure–velocity coupling is shown to be small in the present study. The LES is compared with the available experimental data and ISO 5167-2. In general, the LES shows good agreement with the velocity from the experimental data. The profiles of the Reynolds stresses are similar, but an offset is observed in the diagonal stresses. The pressure loss and discharge coefficients are shown to be in very good agreement with the predictions of ISO 5167-2. Therefore, the wall-resolved LES is shown to be highly accurate in simulating the flow across a square-edged orifice.

  13. Quantitative analysis of the side-branch orifice after bifurcation stenting using en-face processing of OCT images: a comparison between Xience V and Resolute Integrity stents.

    Science.gov (United States)

    Minami, Yoshiyasu; Wang, Zhao; Aguirre, Aaron D; Lee, Stephen; Uemura, Shiro; Soeda, Tsunenari; Vergallo, Rocco; Raffel, Owen C; Barlis, Peter; Itoh, Tomonori; Lee, Hang; Fujimoto, James; Jang, Ik-Kyung

    2016-01-01

    Methods for intravascular assessment of the side-branch (SB) orifice after stenting are not readily available. The aim of this study was to assess the utility of an en-face projection processing for optical coherence tomography (OCT) images for SB evaluation. Measurements of the SB orifice obtained using en-face OCT images were validated using a phantom model. Linear regression modeling was applied to estimated area measurements made on the en-face images. The SB orifice was then analyzed in 88 patients with bifurcation lesions treated with either Xience V (everolimus-eluting stent) or Resolute Integrity [zotarolimus-eluting stent (ZES)]. The SB orifice area (A) and the area obstructed by struts (B) were calculated, and the %open area was evaluated as (A-B)/A*100. Linear regression modeling demonstrated that the observed departures of the intercept and slope were not significantly different from 0 (-0.12 ± 0.22, P=0.59) and 1 (1.01 ± 0.06, R(2)=0.88, P=0.87), respectively. In cases without SB dilatation, the %open area was significantly larger in the everolimus-eluting stent group (n=25) than in the ZES group [n=32; 89.2% (83.7-91.3) vs. 84.3% (78.9-87.8), P=0.04]. A significant difference in %open area between cases with and those without SB dilatation was demonstrated in the ZES group [91.4% (86.1-94.0) vs. 84.3% (78.9-87.8), P=0.04]. The accuracy of SB orifice measurement on an en-face OCT image was validated using a phantom model. This novel approach enables quantitative evaluation of the differences in SB orifice area free from struts among different stent types and different treatment strategies in vivo.

  14. Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

    International Nuclear Information System (INIS)

    Benhamadouche, S.; Arenas, M.; Malouf, W.J.

    2017-01-01

    Highlights: • Wall-resolved LES can predict the flow through a square-edged orifice at Re = 25,000. • LES results are compared with the available experimental data and ISO 5167-2. • Pressure loss and discharge coefficients are in very good agreement with ISO 5167-2. • The present wall-resolved LES could be used as reference data for RANS validation. - Abstract: The orifice plate is a pressure differential device frequently used for flow measurements in pipes across different industries. The present study demonstrates the accuracy obtainable using a wall-resolved Large Eddy Simulation (LES) approach to predict the velocity, the Reynolds stresses, the pressure loss and the discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number of 25,000. The ratio of the orifice diameter to the pipe diameter is β = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11. The mesh is sized using refinement criteria at the wall and preliminary RANS results to ensure that the solution is resolved beyond an estimated Taylor micro-scale. The inlet condition is simulated using a recycling method, and the LES is run with a dynamic Smagorinsky sub-grid scale (SGS) model. The sensitivity to the SGS model and to the pressure–velocity coupling is shown to be small in the present study. The LES is compared with the available experimental data and ISO 5167-2. In general, the LES shows good agreement with the velocity from the experimental data. The profiles of the Reynolds stresses are similar, but an offset is observed in the diagonal stresses. The pressure loss and discharge coefficients are shown to be in very good agreement with the predictions of ISO 5167-2. Therefore, the wall-resolved LES is shown to be highly accurate in simulating the flow across a square-edged orifice.

  15. Prediction of flow rates through an orifice at pressures corresponding to the transition between molecular and isentropic flow

    International Nuclear Information System (INIS)

    DeMuth, S.F.; Watson, J.S.

    1985-01-01

    A model of compressible flow through an orifice, in the region of transition from free molecular to isentropic expansion flow, has been developed and tested for accuracy. The transitional or slip regime is defined as the conditions where molecular interactions are too many for free molecular flow modeling, yet not great enough for isentropic expansion flow modeling. Due to a lack of literature establishing a well-accepted model for predicting transitional flow, it was felt such work would be beneficial. The model is nonlinear and cannot be satisfactorily linearized for a linear regression analysis. Consequently, a computer routine was developed which minimized the sum of the squares of the residual flow for the nonlinear model. The results indicate an average accuracy within 15% of the measured flow throughout the range of test conditions. Furthermore, the results of the regression analysis indicate that the transitional regime lies between Knudsen numbers of approximately 2 and 45. 4 refs., 3 figs., 1 tab

  16. Office hysteroscopic treatment of a vanishing external uterine orifice in a postmenopausal woman with an obstetrical history of 44 abortions

    Directory of Open Access Journals (Sweden)

    Maurizio Guida

    2015-11-01

    Full Text Available Cervical stenosis, defined as cervical scarring of variable degree, represents a significant anatomical impediment to hysteroscopic procedures. Acquired cervical stenoses are more common than congenital forms and they are mainly associated with aging, estrogen–progesteron drugs, cervical trauma or carcinoma. The overcoming of cervical stenosis at office hysteroscopy is challenging and it often fails requiring the scheduling of the patient for an in-patient treatment under general anesthesia. We report the office hysteroscopy treatment of a vanishing external uterine orifice in a postmenopausal woman with an ultrasonographic report of a heterogeneous and thick endometrium suggestive of endometrial pathology, focusing on the main surgical steps to perform an adequate management.

  17. Distortion of plasma due to installation of an orifice in helium discharge positive column

    International Nuclear Information System (INIS)

    Moslehi- Fard, M.; Bidadi, H.; Khorram, S.; Sobhanian, S.; Muradov, A.H.; Jallali, H.; Shirin Pour, M.

    2003-01-01

    Complicated potential structure formed at a constriction of positive column of a DC discharge with heated cathode in He at low discharge currents is investigated. According to the potential structure, electrons and ions are accelerated by the electric field and their energy distribution functions acquire multi humped shapes. Additional maximums on distribution function quickly disappear due to collisions and radial losses. The nature of current passing through the potential structure is cleared up on the base of measured distributions. Attempt was made to calculate potential drop in DL tacking into account electron energy distribution variations

  18. A three-dimensional semi-analytical solution for predicting drug release through the orifice of a spherical device.

    Science.gov (United States)

    Simon, Laurent; Ospina, Juan

    2016-07-25

    Three-dimensional solute transport was investigated for a spherical device with a release hole. The governing equation was derived using the Fick's second law. A mixed Neumann-Dirichlet condition was imposed at the boundary to represent diffusion through a small region on the surface of the device. The cumulative percentage of drug released was calculated in the Laplace domain and represented by the first term of an infinite series of Legendre and modified Bessel functions of the first kind. Application of the Zakian algorithm yielded the time-domain closed-form expression. The first-order solution closely matched a numerical solution generated by Mathematica(®). The proposed method allowed computation of the characteristic time. A larger surface pore resulted in a smaller effective time constant. The agreement between the numerical solution and the semi-analytical method improved noticeably as the size of the orifice increased. It took four time constants for the device to release approximately ninety-eight of its drug content. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. An Assessment on Temperature Profile of Jet-A/Biodiesel Mixture in a Simple Combustion Chamber with Plain Orifice Atomiser

    Science.gov (United States)

    Ng, W. X.; Mazlan, N. M.; Ismail, M. A.; Rajendran, P.

    2018-05-01

    The preliminary study to evaluate influence of biodiesel/kerosene mixtures on combustion temperature profile is explored. A simple cylindrical combustion chamber configuration with plain orifice atomiser is used for the evaluation. The evaluation is performed under stoichiometric air to fuel ratio. Six samples of fuels are used: 100BD (pure biodiesel), 100KE (pure Jet-A), 20KE80BD (20% Jet-A/80% Biodiesel), 40KE60BD (40% Jet-A/60% Biodiesel), 60KE40BD (60% Jet-A/40% Biodiesel), and 80KE20BD (80% Jet-A/20% Biodiesel). Results showed that the oxygen content, viscosity, and lower heating value are key parameters in affecting the temperature profile inside the chamber. Biodiesel is known to have higher energy content, higher viscosity and lower heating value compared to kerosene. Mixing biodiesel with kerosene improves viscosity and caloric value but reduces oxygen content of the fuel. High oxygen content of the biodiesel resulted to the highest flame temperature. However the flame temperature reduce as the percentage of biodiesel in the fuel mixture reduces.

  20. Burnout experiments in freon 12 using different types of orifices to simulate the core grids - comparision between measured and predicted burnout values

    International Nuclear Information System (INIS)

    Katsaounis, A.; Orlowski, R.; Fulfs, H.; Hofmann, K.; Ladeira, L.C.D.

    1978-06-01

    This paper will report on burnout experiments carried out in freon 12 mainly at steady state and further at mass flow or power transient conditions with annular test sections axially uniformly heating either the inside or both the inside and outside rod. The runs are performed without orifice and using three different types of orifices simulating the reactor spacer grid. An important influence of the flow restriction on burnout position and value is measured. Furthermore, the comparison between the burnout correlations W2, W3, BandW2 and GE and experimental results from the literature using simple test section geometries in water and freon 12 demonstrate, that the accuracy is more or less comparable for both fluids

  1. The Influence of Swirl Brakes and a Tip Discharge Orifice on the Rotordynamic Forces Generated by Discharge-to-Suction Leakage Flows in Shrouded Centrifugal Pumps

    Science.gov (United States)

    Sivo, Joseph M.; Acosta, A. J.; Brennen, C. E.; Caughey, T. K.

    1993-01-01

    Recent experiments conducted in the Rotor Force Test Facility at the California Institute of Technology have examined the effects of a tip leakage restriction and swirl brakes on the rotordynamic forces due to leakage flows on an impeller undergoing a prescribed circular whirl. The experiments simulate the leakage flow conditions and geometry of the Alternate Turbopump Design (ATD) of the Space Shuttle High Pressure Oxygen Turbopump and are critical to evaluating the pump's rotordynamic instability problems. Previous experimental and analytical results have shown that discharge-to-suction leakage flows in the annulus of a shrouded centrifugal pump contribute substantially to the fluid induced rotordynamic forces. Also, previous experiments have shown that leakage inlet (pump discharge) swirl can increase the cross-coupled stiffness coefficient and hence increase the range of positive whirl for which the tangential force is destabilizing. In recent experimental work, the present authors demonstrated that when the swirl velocity within the leakage path is reduced by the introduction of ribs or swirl brakes, then a substantial decrease in both the destabilizing normal and tangential forces could be achieved. Motivation for the present research is that previous experiments have shown that restrictions such as wear rings or orifices at pump inlets affect the leakage forces. Recent pump designs such as the Space Shuttle Alternate Turbopump Design (ATD) utilize tip orifices at discharge for the purpose of establishing axial thrust balance. The ATD has experienced rotordynamic instability problems and one may surmise that these tip discharge orifices may also have an important effect on the normal and tangential forces in the plane of impeller rotation. The present study determines if such tip leakage restrictions contribute to undesirable rotordynamic forces. Additional motivation for the present study is that the widening of the leakage path annular clearance and the

  2. Comparative Performance of a Non-recessed Hole-entry Hybrid/Hydrostatic Conical Journal Bearing Compensated with Capillary and Orifice Restrictors

    Directory of Open Access Journals (Sweden)

    P.G. Khakse

    2016-06-01

    Full Text Available This research paper deals with the theoretical study of comparison of capillary and orifice compensated non-recess hole-entry hydrostatic/ hybrid conical journal bearing. Modified Reynolds equation governing the flow of lubricant in the clearance space of conical journal and bearing has been solved using FEM, Newton-Raphson method and Gauss elimination method. Spherical coordinate system has been employed to obtain the results. The results have been computed for uniform distribution of holes in the circumferential direction with the range of restrictor design parameter C ̅_s2 = 0.02 - 0.1. The numerically simulated result shows, the use of orifice restrictor is to increase bearing stiffness, threshold speed and maximum pressure compared to capillary restrictor for applied radial load.

  3. Combined experimental and computational investigation of the cavitating flow in an orifice plate with special emphasis on surrogate-based optimization method

    International Nuclear Information System (INIS)

    Li, XianLin; Huang, Biao; Chen, Tairan; Liu, Ying; Qiu, Si Cong; Zhao, Jing

    2017-01-01

    We investigated the influence of geometrical parameters of the orifice plate on the cavitation structures, and optimized these parameters by using a surrogate-based model with special emphasis on the concentration of hydroxyl radical released. The results show that for the orifice plate of the hydrodynamic cavitation system, the possible location of the inception of the cavity spreads to throat and divergent section of the venturi geometry. Based on the surrogate model and global sensitivity assessment, the diameter of throat Dt and diameter of inlet Din significantly influenced the size of the cavity, while the length of throat Lt had little effect on both cavitation intensity and flow rate. It should be noted that when Lt is decreased, the size of cavity would be slightly decreased but the flow rate increased clearly. The increase of the diverging section is in favor of the size of cavity. By comparing the experimental measurements on the concentration of Methylene blue, the optimum geometry of the orifice plate for best cavitational activity is proposed

  4. Combined experimental and computational investigation of the cavitating flow in an orifice plate with special emphasis on surrogate-based optimization method

    Energy Technology Data Exchange (ETDEWEB)

    Li, XianLin; Huang, Biao; Chen, Tairan; Liu, Ying; Qiu, Si Cong [School of Mechanical and Vehicular Engineering, Beijing Institute of Technology, Beijing (China); Zhao, Jing [China Academy of Launch Vehicle Technology, Beijing (China)

    2017-01-15

    We investigated the influence of geometrical parameters of the orifice plate on the cavitation structures, and optimized these parameters by using a surrogate-based model with special emphasis on the concentration of hydroxyl radical released. The results show that for the orifice plate of the hydrodynamic cavitation system, the possible location of the inception of the cavity spreads to throat and divergent section of the venturi geometry. Based on the surrogate model and global sensitivity assessment, the diameter of throat Dt and diameter of inlet Din significantly influenced the size of the cavity, while the length of throat Lt had little effect on both cavitation intensity and flow rate. It should be noted that when Lt is decreased, the size of cavity would be slightly decreased but the flow rate increased clearly. The increase of the diverging section is in favor of the size of cavity. By comparing the experimental measurements on the concentration of Methylene blue, the optimum geometry of the orifice plate for best cavitational activity is proposed.

  5. Characterization of Gatewell Orifice Lighting at the Bonneville Dam Second Powerhouse and Compendium of Research on Light Guidance with Juvenile Salmonids

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Robert P.; Simmons, Mary Ann

    2007-12-29

    The goal of the study described in this report is to provide U.S. Army Corps of Engineers (USACE) biologists and engineers with general design guidelines for using artificial lighting to enhance the passage of juvenile salmonids into the collection channel at the Bonneville Dam second powerhouse (B2). During fall 2007, Pacific Northwest National Laboratory (PNNL) researchers measured light levels in the field at one powerhouse orifice through which fish must pass to reach the collection channel. Two light types were evaluated—light-emitting diode (LED) lights and halogen spot lights. Additional measurements with mercury lamps were made at the PNNL Aquatic Research Laboratory to determine baseline intensity of the current lighting. A separate chapter synthesizes the relevant literature related to light and fish guidance for both field and laboratory studies. PNNL will also review the Corps plans for existing lighting protocol at all of the Portland District projects and help develop a uniform lighting scheme which could be implemented. The specific objectives for this study are to 1. Create a synthesis report of existing lighting data for juvenile salmonid attraction and deterrence and how the data are used at fish bypass facilities. 2. Evaluate current B2 orifice lighting conditions with both LED and halogen sources. 3. Make recommendations as to what lighting intensity, source, and configuration would improve passage at the B2 orifices. 4. Review USACE plans for retrofit of existing systems (to be assessed at a later date).

  6. Robotics in endoscopy.

    Science.gov (United States)

    Klibansky, David; Rothstein, Richard I

    2012-09-01

    The increasing complexity of intralumenal and emerging translumenal endoscopic procedures has created an opportunity to apply robotics in endoscopy. Computer-assisted or direct-drive robotic technology allows the triangulation of flexible tools through telemanipulation. The creation of new flexible operative platforms, along with other emerging technology such as nanobots and steerable capsules, can be transformational for endoscopic procedures. In this review, we cover some background information on the use of robotics in surgery and endoscopy, and review the emerging literature on platforms, capsules, and mini-robotic units. The development of techniques in advanced intralumenal endoscopy (endoscopic mucosal resection and endoscopic submucosal dissection) and translumenal endoscopic procedures (NOTES) has generated a number of novel platforms, flexible tools, and devices that can apply robotic principles to endoscopy. The development of a fully flexible endoscopic surgical toolkit will enable increasingly advanced procedures to be performed through natural orifices. The application of platforms and new flexible tools to the areas of advanced endoscopy and NOTES heralds the opportunity to employ useful robotic technology. Following the examples of the utility of robotics from the field of laparoscopic surgery, we can anticipate the emerging role of robotic technology in endoscopy.

  7. Effects of Burner Configurations on the Natural Oscillation Characteristics of Laminar Jet Diffusion Flames

    Directory of Open Access Journals (Sweden)

    K. R. V. Manikantachari

    2015-09-01

    Full Text Available In this work, effects of burner configurations on the natural oscillations of methane laminar diffusion flames under atmospheric pressure and normal gravity conditions have been studied experimentally. Three regimes of laminar diffusion flames, namely, steady, intermittent flickering and continuous flickering have been investigated. Burner configurations such as straight pipe, contoured nozzle and that having an orifice plate at the exit have been considered. All burners have the same area of cross section at the exit and same burner lip thickness. Flame height data has been extracted from direct flame video using MATLAB. Shadowgraph videos have been captured to analyze the plume width characteristics. Results show that, the oscillation characteristics of the orifice burner is significantly different from the other two burners; orifice burner produces a shorter flame and wider thermal plume width in the steady flame regime and the onset of the oscillation/flickering regimes for the orifice burner occurs at a higher fuel flow rate. In the natural flickering regime, the dominating frequency of flame flickering remains within a small range, 12.5 Hz to 15 Hz, for all the burners and for all fuel flow rates. The time-averaged flame length-scale parameters, such as the maximum and the minimum flame heights, increase with respect to the fuel flow rate, however, the difference in the maximum and the minimum flame heights remains almost constant.

  8. Novel challenges of multi-society investigator-initiated studies: a paradigm shift for technique and technology evaluation.

    Science.gov (United States)

    Schwaitzberg, Steven D; Hawes, Robert H; Rattner, David W; Kochman, Michael L

    2013-08-01

    The introduction of innovative techniques and novel technologies into clinical practice is a challenge that confronts all aspects of healthcare delivery. Upheaval from shrinking research funding and declining healthcare reimbursements now forces patients, doctors, hospitals, payers, regulators, and even health systems into conflict as new therapies struggle to find a place in the therapeutic armamentarium. The escalating costs of healthcare force all parties to consider both the medical risks/benefits as well as the economic efficiency of proposed tools and therapies. We highlight these challenges by examining the process of initiating and conducting a "society-as-investigator" clinical trial to assess the safety of the natural orifice translumenal endoscopic surgery (NOTES) approach to cholecystectomy in the context of the issues that confront technology diffusion today.

  9. Danish surgeons' views on minimally invasive surgery

    DEFF Research Database (Denmark)

    Edwards, Hellen; Jørgensen, Lars Nannestad

    2014-01-01

    BACKGROUND AND AIM: Advancements in minimally invasive surgery have led to increases in popularity of single-incision laparoscopic surgery (SILS) and natural orifice translumenal surgery (NOTES(®); American Society for Gastrointestinal Endoscopy [Oak Brook, IL] and Society of American...... Gastrointestinal and Endoscopic Surgeons [Los Angeles, CA]) due to their postulated benefits of better cosmesis, less pain, and quicker recovery. This questionnaire-based study investigated Danish surgeons' attitudes toward these new procedures. SUBJECTS AND METHODS: A 26-item questionnaire was developed...... and distributed electronically via e-mail to a total of 1253 members of The Danish Society of Surgeons and The Danish Society of Young Surgeons. RESULTS: In total, 352 (approximately 30%) surgeons completed the questionnaire, 54.4% were over 50 years of age, and 76.6% were men. When choosing surgery, the most...

  10. Experimental study of the core grid by-pass orifices inlet pressure drop of the new core of the R A 6 reactor

    International Nuclear Information System (INIS)

    Masson, V. P; Garcia, J. C; Delmastro, D. F

    2006-01-01

    In this work the core grid by-pass orifices inlet pressure drop of the new core of the R A6 reactor are experimentally studied.The experiments are performed using a 1:1 scale mock-up of an external fuel element cell.Different gaps between fuel elements are considered in order to take into account the design allowances. Different flows are considered to take into account the normal operation flow range.Measurement uncertainties are included.The results will be used to calculate the core flow distribution [es

  11. Pemodelan Dan Analisis Pengaruh Variasi Oli dan Diameter Orifice terhadap Gaya Redam Shock Absorber Dan Respon Dinamis Sepeda Motor Yamaha Jupiter Z 2008

    Directory of Open Access Journals (Sweden)

    Newanda Asa Wahid

    2017-03-01

    Full Text Available Sepeda motor merupakan moda transportasi yang paling banyak diminati oleh masyarakat Indonesia. Dalam hal kenyamanan, maka komponen sepeda motor yang berperan penting adalah sistem suspensi. Sistem suspensi berfungsi menyerap getaran berlebih akibat profil permukaan jalan, sehingga meningkatkan kenyamanan dan keamanan. Oleh karena itu, perlu dilakukan penelitian untuk mendapatkan sistem suspensi yang terbaik. Dalam tugas akhir ini dilakukan pemodelan dan analisis pengaruh perubahan parameter sistem suspensi sepeda motor Yamaha Jupiter Z 2008 khususnya pada komponen monotube hydraulic shock absorber yang didasarkan pada pemodelan setengah kendaraan. Parameter yang divariasikan adalah tipe oli dan diameter orifice, dimana terdapat 5 macam tipe oli dengan rentang nilai massa jenis (ρ sebesar 845 – 874 kg/m3, dan viskositas (ν sebesar 11,3 – 46 mm2/s, sementara untuk diameter orifice yaitu saat kompresi (Docomp sebesar 1,2 – 1,5 mm, saat ekspansi (Doexp sebesar 0,8 – 1 mm. Input yang digunakan pada simulasi adalah input sinusoidal dan input bump modified. Dari penelitian ini didapatkan hasil bahwa sistem suspensi modifikasi monotube hydraulic shock absorber yang menghasilkan gaya redam optimal memiliki nilai parameter viskositas kinematis oli 46 mm2/s, massa jenis oli 845 kg/m3, diameter orifice kompresi 0,00135 m, dan diameter orifice ekspansi 0,0009 m. Nilai gaya redam optimal yang dihasilkan sistem suspensi modifikasi adalah sebesar 1171,3 N, lebih tinggi hingga 546,44 N dibandingkan dengan gaya redam sistem supensi asli yang bernilai 624,86 N pada frekuensi 2 Hz. Pada sistem setengah kendaraan motor dengan penggunaan sistem suspensi asli maupun modifikasi, untuk input bump, respon kendaraan dan penumpang mencapai steady state kurang dari 2 detik dan 5 detik, sedangkan untuk input sinusoidal responnya mencapai steady state kurang dari 2 detik dan 3 detik. Penggunaan suspensi asli maupun modifikasi menghasilkan nilai perpindahan RMS yang

  12. A study on the root cause identification of local wall thinning caused by deflected turbulent flow inside orifice of carbon steel components

    International Nuclear Information System (INIS)

    Park, S. H.; Kim, K. H.; Hwang, K. M.

    2010-01-01

    When components made of carbon steel in nuclear, fossil, and industry plants are exposed to flowing fluid, wall thinning caused by FAC (flow accelerated corrosion) can be generated and eventually ruptured at the portion of pressure boundary. A study to identify the locations generating local wall thinning and to disclose turbulence coefficients related to the local wall thinning was performed. Experiments and numerical analyses for orifice of down-scaled piping components were performed and the results were compared. Based on the results that the flow behaviors inside piping components can be simulated by numerical analysis, numerical analyses for magnified models to actual size of plants were performed. To disclose the relationship between turbulence coefficients and local thinning rate, numerical analyses were preformed for orifice components included in the main feedwater systems. The turbulence coefficients based on the numerical analyses were compared with the local wear rate based on the measured data. From the comparison of the results, the vertical flow velocity component (Vr) flowing to the wall after separating in the wall due to the geometrical configuration and colliding with the wall directly at an angle of some degree was analogous to the configuration of local wall thinning. (authors)

  13. FORMULATION DEVELOPMENT OF MUCOADHESIVE MICROCAPSULES OF METFORMIN HYDROCHLORIDE USING NATURAL AND SYNTHETIC POLYMERS AND IN VITRO CHARACTERIZATION

    OpenAIRE

    Yellanki Shiva Kumar; Deb Sambit kumar; Goranti Sharada; Nerella Naveen kumar

    2010-01-01

    The objective of this work was to develop optimized and systematically evaluate performances of mucoadhesive microcapsules of antihyperglycemic agent drug Metformin. Alginate microcapsules coated with mucoadhesive natural or synthetic polymers were prepared by Orifice-Ionic Gelation technique utilizing calcium chloride as a cross linking agent. The effect of type (natural or synthetic) and concentration of coating polymers and concentration of alginate on formulation was investigated. Prepare...

  14. Injection and spray characteristics of a variable orifice nozzle applied the jerk type fuel injection pump for DI diesel engine; Jerk shiki nenryo funsha pump wo mochiita kahen funko nozzle no funsha funmu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T; Matsui, K; Iwasaki, T; Kobayashi, T [Zexel Corp., Tokyo (Japan); Matsumoto, Y [The University of Tokyo, Tokyo (Japan)

    1997-10-01

    A Variable Orifice Nozzle (VON) by changing a cross-sectional area of the nozzle injection hole, for improving a rate of injection and injection duration, has been developed to study its injection and spray characteristics. The nozzle geometry was optimized to analyze a nozzle internal flow by computational method. Results show that, injection and spray pattern responded to the nozzle orifice cross-sectional area which is changing larger to smaller in the part load range. This results suggest to contribute a combustion improvement which decreasing NOx and soot. 14 refs., 10 figs.

  15. Transjejunal Extraction of Gallbladder After Mini-Laparoscopic Cholecystectomy in Patients with Previous Roux-en-Y Gastric Bypass: A Small Case Series.

    Science.gov (United States)

    Kayaalp, Cuneyt; Tardu, Ali; Yagci, Mehmet Ali; Sumer, Fatih

    2015-07-01

    The length of incisions on the abdominal wall directly correlates with wound-related morbidities and patient comfort. Both mini-laparoscopy (only ≤5-mm trocars) and natural orifice specimen extraction avoid larger abdominal incisions. This study described a new natural orifice translumenal endoscopic surgery (NOTES(®); American Society for Gastrointestinal Endoscopy [Oak Brook, IL] and Society of American Gastrointestinal and Endoscopic Surgeons [Los Angeles, CA]) cholecystectomy technique by combination of these two advanced laparoscopic techniques for cholelithiasis in patients who had prior laparoscopic Roux-en-Y gastric bypass (LRYGB) for obesity. Three patients (two males, one female; 39, 62, and 34 years old, respectively) were admitted with symptomatic cholelithiasis (multiple millimeter-sized gallstones), and all had previously had LRYGB. They were treated by mini-laparoscopic cholecystectomy using three 5-mm trocars. The gallbladder was removed through the dilated efferent limb of the jejunum, 5 cm distal from the gastrojejunostomy. Transjejunal extraction was performed under endoscopic guidance. The gallbladder in the jejenum was passed through the anastomosis and extracted with an endoscopic snare by the transoral way. The enterotomy was closed intracorporeally. There was no conversion or additional trocar requirement. All the procedures were completed successfully without problems. Respective operating times were 95, 75, and 120 minutes. Only 1 patient required postoperative analgesic; the others did not. The patients started to get a liquid diet on the night of surgery and were discharged on Days 1, 1, and 2, respectively, with normal diet recommendations. There were no morbidities. Mini-laparoscopic cholecystectomy is technically feasible in patients with previous LRYGB. Prior LRYGB was not an obstacle for transoral specimen extraction. The dilated efferent jejunal limb is a good alternative route for natural orifice specimen extraction. This

  16. Triple-orifice valve repair in severe Barlow disease with multiple-jet mitral regurgitation: report of mid-term experience.

    Science.gov (United States)

    Fucci, Carlo; Faggiano, Pompilio; Nardi, Matilde; D'Aloia, Antonio; Coletti, Giuseppe; De Cicco, Giuseppe; Latini, Leonardo; Vizzardi, Enrico; Lorusso, Roberto

    2013-09-10

    Barlow disease represents a surgical challenge for mitral valve repair (MR) in the presence of mitral insufficiency (MI) with multiple regurgitant jets. We hereby present our mid-term experience using a modified edge-to-edge technique to address this peculiar MI. From March 2003 till December 2010, 25 consecutive patients (mean age 54 ± 7 years, 14 males) affected by severe Barlow disease with multiple regurgitant jets were submitted to MR. Preoperative transesophageal echo (TEE) in all the cases showed at least 2 regurgitant jets, involving one or both leaflets in more than one segment. In all the patients, a triple orifice valve (TOV) repair with annuloplasty was performed. Intra-operative TEE and postoperative transthoracic echocardiography (TTE) were carried out to evaluate results of the TOV repair. There was no in-hospital death and one late death (non-cardiac related). At intra-operative TEE, the three orifices showed a mean total valve area of 2.9 ± 0.1cm(2) (range 2.5-3.3 cm(2)) with no residual regurgitation (2 cases of trivial MI) and no sign of valve stenosis (mean transvalvular gradient 4.6 ± 1.5 mmHg). At follow up (mean 38 ± 22 months), TTE showed favourable MR and no recurrence of significant MI (6 cases of trivial and 1 of mild MI). Stress TTE was performed in 5 cases showing persistent effective valve function (2 cases of trivial MI at peak exercise). All the patients showed significant NYHA functional class improvement. This report indicates that the TOV technique is effective in correcting complex Barlow mitral valves with multiple jets. Further studies are required to confirm long-term applicability and durability in more numerous clinical cases. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  17. EMR of laterally spreading lesions around or involving the appendiceal orifice: technique, risk factors for failure, and outcomes of a tertiary referral cohort (with video).

    Science.gov (United States)

    Tate, David J; Desomer, Lobke; Awadie, Halim; Goodrick, Kathleen; Hourigan, Luke; Singh, Rajvinder; Williams, Stephen J; Bourke, Michael J

    2018-05-01

    EMR of sessile periappendiceal laterally spreading lesions (PA-LSLs) is technically demanding because of poor endoscopic access to the appendiceal lumen and the thin colonic wall at the base of the cecum. We aimed to assess the feasibility and safety of EMR for PA-LSLs. Consecutive LSLs ≥20 mm and PA-LSLs ≥10 mm detected at 3 academic endoscopy centers from September 2008 until January 2017 were eligible. Prospective patient, procedural, and lesion data were collected. PA-LSLs were compared with LSLs in other colonic locations. Thirty-eight PA-LSLs were compared with 1721 LSLs. Referral for surgery without an attempt at EMR was more likely with PA-LSLs (28.9% vs 5.1%, P < .001), and those that involved a greater percentage of the appendiceal orifice (AO) were less likely to be attempted (P = .038). Most PA-LSLs (10/11) were not attempted because of deep extension into the appendiceal lumen; 2 of 11 of these surgical specimens contained invasive cancer. Once attempted, complete clearance of visible adenoma (92.6% PA-LSLs vs 97.6% LSLs, P = .14), adverse events, and rates of adenoma recurrence did not vary significantly between PA-LSLs and LSLs. All 7 patients with prior appendicectomy achieved complete adenoma clearance. There were no cases of post-EMR appendicitis. Twenty of 22 PA-LSLs (91%) eligible for surveillance avoided surgery to longest follow-up. EMR is a safe, effective, and durable treatment for PA-LSLs when specific criteria are fulfilled. If the distal margin of the PA-LSL within the AO cannot be visualized or if more than 50% of the circumference of the orifice is involved, surgery should be considered. (Clinical trial registration number: NTC01368289.). Copyright © 2018. Published by Elsevier Inc.

  18. NOTES performed using multiple ports of entry: Current experience and potential implications for urologic applications.

    Science.gov (United States)

    Lima, Estevao; Rolanda, Carla; Correia-Pinto, Jorge

    2009-05-01

    An isolated transgastric port raises serious limitations in performing natural orifice translumenal endoscopic surgery (NOTES) complex procedures in the urology field. In an attempt to overcome these limitations, several solutions has been advanced, such as the hybrid approach (adding a single abdominal port access) or the pure NOTES combined approach (joining multiple natural orifice ports). To review the current state of experimental and clinical results of multiple ports in NOTES, a literature search of PubMed was performed, seeking publications from January 2002 to 2008 on NOTES. In addition, we looked at pertinent abstracts of annual meetings of the American Urological Association, the European Association of Urology, and the World Congress of Endourology from 2007. Multiple ports of entry seem to be necessary, mainly for moderately complex procedures. Thus, we could find studies using the hybrid approach (combination of transgastric or transvaginal access with a single transabdominal port), or using the pure NOTES combined approach (transgastric and transvesical, transvaginal and transcolonic, or transgastric and transvaginal). There is still limited experience in humans using these approaches, and no comparative studies exist to date. It is predictable that for moderately complex procedures, we will need multiple ports, so the transvaginal-transabdominal (hybrid) approach is the most appealing, whereas in a pure NOTES perspective, the transgastric-transvesical approach seems to be the preferred approach. We are waiting for new equipment and instruments that are more appropriate for these novel techniques.

  19. Decolorization of Acid Orange 7 by an electric field-assisted modified orifice plate hydrodynamic cavitation system: Optimization of operational parameters.

    Science.gov (United States)

    Jung, Kyung-Won; Park, Dae-Seon; Hwang, Min-Jin; Ahn, Kyu-Hong

    2015-09-01

    In this study, the decolorization of Acid Orange 7 (AO-7) with intensified performance was obtained using hydrodynamic cavitation (HC) combined with an electric field (graphite electrodes). As a preliminary step, various HC systems were compared in terms of decolorization, and, among them, the electric field-assisted modified orifice plate HC (EFM-HC) system exhibited perfect decolorization performance within 40 min of reaction time. Interestingly, when H2O2 was injected into the EFM-HC system as an additional oxidant, the reactor performance gradually decreased as the dosing ratio increased; thus, the remaining experiments were performed without H2O2. Subsequently, an optimization process was conducted using response surface methodology with a Box-Behnken design. The inlet pressure, initial pH, applied voltage, and reaction time were chosen as operational key factors, while decolorization was selected as the response variable. The overall performance revealed that the selected parameters were either slightly interdependent, or had significant interactive effects on the decolorization. In the verification test, complete decolorization was observed under statistically optimized conditions. This study suggests that EFM-HC is a useful method for pretreatment of dye wastewater with positive economic and commercial benefits. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Analysis of Simultaneous Gas-Liquid Flow Through an Orifice and Its Application to Flow Metering Etude de l'écoulement simultané d'un mélange gaz-liquide à travers un orifice et son application à la mesure du débit

    Directory of Open Access Journals (Sweden)

    Pascal H.

    2006-11-01

    Full Text Available The purpose of this article is to show a more accurate orifice equation for a two-phase flow, such a compressible mixture of gas and liquid. The orifice equation given here con be used for the measurement of a gas-liquid mixture of fine emulsions by the orificemeter method. From the thermodynamic point of view, an equation of state has been formulated which provides the relationship between the specific mass of the mixture and pressure, under conditions of adiabatic expansion. The results obtained enable the mass flow rates of gas and liquid ta be determined without separation of the phases, provided thot the gas liquid mass ratio is known. The critical pressure ratio corresponding ta sonic velocity is also determined. Cet article présente une relation plus précise pour l'écoulement d'un système à deux phases, tel qu'un mélange compressible gaz-liquide, à travers un diaphragme. Cette relation peut être utilisée pour des mesures de mélanges gaz-liquide très finement divisés, c'est-à-dire des émulsions ou brouillards, par la méthode du diaphragme en paroi mince. Du point de vue thermodynamique, on a formulé une équation d'état donnant la relation entre la masse spécifique du mélange et la pression dans des conditions d'expansion adiabatique. Les résultats obtenus per-mettent de déterminer le débit massique du gaz et du liquide, sans séparation des deux phases, à condition que le rapport de masse gaz-liquide soit connu. On détermine également le rapport de pression critique correspondantà la vitesse du son.

  1. Modelling of fluid flow through short tube orifices under metastable conditions: A new numerical validation approach for evaluating the mass flow rate with refrigerant mixtures (HFC-407C and HFC-410A)

    International Nuclear Information System (INIS)

    García-Valladares, O.; Santoyo, E.

    2014-01-01

    In a previous work, one-dimensional numerical modelling of fluid-flow inside short tube orifices was performed, and successfully validated against a wide range of mass flow rate measurements reported for the refrigerant HFC-134a. Governing equations of continuity, momentum, energy and entropy were solved for describing the fluid flow under a wide variety of thermodynamic transitions (e.g., subcooled liquid region, metastable liquid region, metastable two-phase region and equilibrium two-phase region), including sudden contraction and enlargement. In this new study, a comprehensive comparison analysis between numerical simulation data and experimental measurements obtained for HFC-407C and HFC-410A refrigerants (N o  = 241) to extend the applicability of the same mathematical model was carried out. Using a widespread statistical analysis, based on weighted linear regressions with an outlier detection/rejection module at 95% of confidence level, the prediction performance of the mathematical model was again assessed. Linear regressions between predicted mass flow rate data and experimental measurements were computed, and used them as a statistical comparison criterion. A statistical comparison between predicted simulation results and mass flow rate experimental data are reported. Average deviation errors of ±11.1% (for the refrigerant HFC-407C) and ±7.3% (for refrigerant HFC-410A) were found between numerical model and experimental data. These results demonstrate a new and robust application of the model to predict reliably the mass flow rate through short tube orifices under metastable conditions, which enable this tool to be reliably used for the design of short tube orifices. - Highlights: •A modelling for evaluating short tube orifice was developed for refrigerant mixtures. •The numerical model applied considered metastable regions and choke flow. •The model was validated against experimental data for HFC-407C and HFC-410A. •Statistical analysis based

  2. Needs analysis for developing a virtual-reality NOTES simulator.

    Science.gov (United States)

    Sankaranarayanan, Ganesh; Matthes, Kai; Nemani, Arun; Ahn, Woojin; Kato, Masayuki; Jones, Daniel B; Schwaitzberg, Steven; De, Suvranu

    2013-05-01

    INTRODUCTION AND STUDY AIM: Natural orifice translumenal endoscopic surgery (NOTES) is an emerging surgical technique that requires a cautious adoption approach to ensure patient safety. High-fidelity virtual-reality-based simulators allow development of new surgical procedures and tools and train medical personnel without risk to human patients. As part of a project funded by the National Institutes of Health, we are developing the virtual transluminal endoscopic surgery trainer (VTEST) for this purpose. The objective of this study is to conduct a structured needs analysis to identify the design parameters for such a virtual-reality-based simulator for NOTES. A 30-point questionnaire was distributed at the 2011 National Orifice Surgery Consortium for Assessment and Research meeting to obtain responses from experts. Ordinal logistic regression and the Wilcoxon rank-sum test were used for analysis. A total of 22 NOTES experts participated in the study. Cholecystectomy (CE, 68 %) followed by appendectomy (AE, 63 %) (CE vs AE, p = 0.0521) was selected as the first choice for simulation. Flexible (FL, 47 %) and hybrid (HY, 47 %) approaches were equally favorable compared with rigid (RI, 6 %) with p virtual NOTES simulator in training and testing new tools for NOTES were rated very high by the participants. Our study reinforces the importance of developing a virtual NOTES simulator and clearly presents expert preferences. The results of this analysis will direct our initial development of the VTEST platform.

  3. Left ventricular mass regression is independent of gradient drop and effective orifice area after aortic valve replacement with a porcine bioprosthesis.

    Science.gov (United States)

    Sádaba, Justo Rafael; Herregods, Marie-Christine; Bogaert, Jan; Harringer, Wolfgang; Gerosa, Gino

    2012-11-01

    The question of whether left ventricular mass (LVM) regression following aortic valve replacement (AVR) is affected by the prosthesis indexed effective orifice area (IEOA) and transprosthetic gradient has not been fully elucidated. Data from a prospective, core-laboratory-reviewed echocardiography and magnetic resonance imaging (MRI) study was used to determine if the degree of LVM regression following AVR with two types of porcine bioprosthesis in patients suffering from predominant aortic valve stenosis (AS) was related to the prosthesis IEOA and transprosthetic gradient. Over a two-year period, 149 patients enrolled at eight centers received either an Epic or an Epic Supra aortic bioprosthesis (St. Jude Medical, MN, USA). Preoperative valve dysfunction was pure AS in 54 patients (36%) and mixed valve disease (primarily stenosis) in 95 patients (64%). LVM was determined preoperatively and at six months postoperatively, using MRI. The prosthesis IEOA and transprosthetic gradient were calculated at six months by means of echocardiography. Data were available for 111 patients at both enrolment and six months postoperatively. The LVM at enrolment and at follow up was 154.96 +/- 42.50 g and 114.83 +/- 29.20 g, respectively (p regression methods, showed LVM regression to be independent of the mean systolic pressure gradient, peak systolic pressure and prosthesis IEOA at six months (p = 0.53, 0.43, and 0.15, respectively). At six months after AVR with a porcine bioprosthesis to treat AS, there was a significant LVM regression that was independent of the prosthesis IEOA and the mean systolic pressure gradient and peak systolic pressure.

  4. Morphometry of the Myopectineal Orifice

    African Journals Online (AJOL)

    Hp 630 Dual Core

    ГЕНЙФСЧРЖ ОО ЙФСЛР КЗФРЛГХ СЕЕЧФ ЦКФСЧЙК Г ЩЗГНРЗХХ ГЦ ЦКЗ ОСЩЗФ ЗЪЦФЗПЛЦЫ СИ ЦКЗ. ГДЖСПЗР ЦКЗ ПЫСТЗЕЦЛРЗГО СФЛИЛЕЗ ...

  5. Indexed effective orifice area is a significant predictor of higher mid- and long-term mortality rates following aortic valve replacement in patients with prosthesis-patient mismatch.

    Science.gov (United States)

    Chen, Jian; Lin, Yiyun; Kang, Bo; Wang, Zhinong

    2014-02-01

    Prosthesis-patient mismatch (PPM) is defined as a too-small effective orifice area (EOA) of an inserted prosthetic relative to body size, resulting in an abnormally high postoperative gradient. It is unclear, however, whether residual stenosis after aortic valve replacement (AVR) has a negative impact on mid- and long-term survivals. We searched electronic databases, including PubMed, Embase, Medline and the Cochrane controlled trials register, through October 2012, to identify published full-text English studies on the association between PPM and mortality rates. A significant PPM was defined as an indexed EOA (iEOA)<0.85 cm2/m2, and severe PPM as an iEOA<0.65 cm2/m2. Two reviewers independently assessed the studies for inclusion and extracted data. Fourteen observational studies, involving 14 874 patients, met our final inclusion criteria. Meta-analysis demonstrated that PPM significantly increased mid-term (odds ratio [OR] 1.42, 95% confidence interval [CI] 1.19-1.69) and long-term (OR 1.52, 95% CI 1.26-1.84) all-cause mortalities. Subgroup analysis showed that PPM was associated with higher mid- and long-term mortality rates only in younger and predominantly female populations. Risk-adjusted sensitivity analysis showed that severe PPM was associated with reduced survival (adjusted hazard ratio [HR] 1.50, 95% CI 1.24-1.80), whereas moderate PPM was not (adjusted HR 0.96, 95% CI 0.86-1.07). Regardless of severity, however, PPM had a negative effect on survival in patients with impaired ejection fraction (adjusted HR 1.26, 95% CI 1.09-1.47). PPM (iEOA<0.85 cm2/m2) after AVR tended to be associated with increased long-term all-cause mortality in younger patients, females and patients with preoperative left ventricular dysfunction. Severe PPM (iEOA<0.65 cm2/m2) was a significant predictor of reduced long-term survival in all populations undergoing AVR.

  6. Natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, J W

    1967-08-01

    This report on the natural gas industry of Canada includes: composition and uses of natural gas, production statistics, exploration and development, reserve estimates, natural gas processing, transportation, and marketing. For the Canadian natural gas industry, 1966 was a year of moderate expansion in all phases, with a strong demand continuing for sulfur and liquid hydrocarbons produced as by-products of gas processing. Value of natural gas production increased to $199 million and ranked sixth in terms of value of mineral ouput in Canada. Currently, natural gas provides over 70% of Canada's energy requirements. Proved remaining marketable reserves are estimated to be in excess of a 29-yr supply.

  7. Natural Gas

    OpenAIRE

    Bakar, Wan Azelee Wan Abu; Ali, Rusmidah

    2010-01-01

    Natural gas fuel is a green fuel and becoming very demanding because it is environmental safe and clean. Furthermore, this fuel emits lower levels of potentially harmful by-products into the atmosphere. Most of the explored crude natural gas is of sour gas and yet, very viable and cost effective technology is still need to be developed. Above all, methanation technology is considered a future potential treatment method for converting the sour natural gas to sweet natural gas.

  8. PLURALIZING NATURE

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    Denmark is widely recognised for its democratic approach to planning and the idea of planning for the common good. This interest in the common good and common values seems also to be reflected in the way which nature restoration is planned and managed – one common nature directed by the public...... authorities. But nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site......-specificity. As exemplified by the Skjern River Restoration Project (1999-2003), one interpretation of the landscape sometimes suppresses other valid interpretations neglecting its diverse history. However, evidence from Switzerland suggests that planning for the common good, in the case of nature restoration, does...

  9. Natural Philosophy

    OpenAIRE

    Blair, Ann M.

    2006-01-01

    Natural philosophy” is often used by European historians as an umbrella term to designate the study of nature before it can easily be identified with what we call “science” today, to avoid the modern and potentially anachronistic connotations of that term. But “natural philosophy” (and its equivalents in different languages) was also an actor's category, a term commonly used throughout the early modern period and typically defined quite broadly as the study of natural bodies. As the central ...

  10. Dissonant Nature

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2013-01-01

    Nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site-specificity. As exempl...... and allows for multiple interpretations to coexist. Evidence can be found in the Re-naturalization of River Aire (2002-2015), a restoration project, which reveals approaches that could be labelled landscape architecture specific....

  11. Temporal naturalism

    Science.gov (United States)

    Smolin, Lee

    2015-11-01

    Two people may claim both to be naturalists, but have divergent conceptions of basic elements of the natural world which lead them to mean different things when they talk about laws of nature, or states, or the role of mathematics in physics. These disagreements do not much affect the ordinary practice of science which is about small subsystems of the universe, described or explained against a background, idealized to be fixed. But these issues become crucial when we consider including the whole universe within our system, for then there is no fixed background to reference observables to. I argue here that the key issue responsible for divergent versions of naturalism and divergent approaches to cosmology is the conception of time. One version, which I call temporal naturalism, holds that time, in the sense of the succession of present moments, is real, and that laws of nature evolve in that time. This is contrasted with timeless naturalism, which holds that laws are immutable and the present moment and its passage are illusions. I argue that temporal naturalism is empirically more adequate than the alternatives, because it offers testable explanations for puzzles its rivals cannot address, and is likely a better basis for solving major puzzles that presently face cosmology and physics. This essay also addresses the problem of qualia and experience within naturalism and argues that only temporal naturalism can make a place for qualia as intrinsic qualities of matter.

  12. Matematica Natural.

    Science.gov (United States)

    Lozano, Patricia; Medearis, Linda

    Matematica Natural (Natural Mathematics) is a mathematics curriculum for young children based on the assumption that they learn mathematics through concrete, real life, relevant experiences and that educational differences rather than cultural differences influence math achievement. The curriculum uses hands-on materials and activities to teach…

  13. Natural radiation

    International Nuclear Information System (INIS)

    Feliciano, Vanusa Maria Delage

    2016-01-01

    Cosmic radiation, as well as cosmogenic radiation, terrestrial radiation, radon and thorium are introduced in this chapter 3. The distribution of natural radiation sources is treated, where the percentage distribution of the contribution relative to exposure to radiation from natural and artificial sources is also included

  14. Framing nature

    NARCIS (Netherlands)

    Jansen, Peter

    2017-01-01

    This PhD thesis is about communication concerning nature in the Netherlands. The purpose of this exploratory study is to take both a theoretical and an empirical look at whether (implicit) religious elements play a role in this communication about nature in the Netherlands.

    In this PhD

  15. Natur formet

    DEFF Research Database (Denmark)

    Søberg, Martin

    2011-01-01

    Anmeldelse af Malene Hauxner, "Fra naturlig natur til SUPERNATUR – Europæisk landskabsarkitektur 1967-2007 set fra Danmark", Risskov: Ikaros Press, 2011.......Anmeldelse af Malene Hauxner, "Fra naturlig natur til SUPERNATUR – Europæisk landskabsarkitektur 1967-2007 set fra Danmark", Risskov: Ikaros Press, 2011....

  16. Natural radiation; A radiacao natural

    Energy Technology Data Exchange (ETDEWEB)

    Feliciano, Vanusa Maria Delage

    2016-07-01

    Cosmic radiation, as well as cosmogenic radiation, terrestrial radiation, radon and thorium are introduced in this chapter 3. The distribution of natural radiation sources is treated, where the percentage distribution of the contribution relative to exposure to radiation from natural and artificial sources is also included.

  17. Natural Communities

    Data.gov (United States)

    Kansas Data Access and Support Center — This dataset shows the locations of known tracts of high quality natural communities in Kansas, generalized to the PLSS section. It is not a compehensive dataset of...

  18. Sciences & Nature

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING AJOL ... Sciences & Nature, the Scientific Journal edited by the University of ... Subjects covered include agronomy, sciences of the earth, environment, biological, ...

  19. Pluralising Nature

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2017-01-01

    suppress other valid perceptions, in conflict with the need for different groups of people to be able to identify with the same territory. However, planning for the common good, in the case of nature restoration, does not necessarily mean planning for one common nature. Understanding and working......Denmark is recognised for its democratic approach to planning, and for the idea of planning for the common good. This interest in the common good and in common values also seems to be reflected in the way that the restoration of nature is planned and managed, suggesting that there is one common...... “nature” that everyone can agree on. But nature restoration is far from being an unproblematic undertaking. As with any other type of heritage production, it can be the source of dissonance. As exemplified by the Skjern River Restoration Project, one perception of a landscape and its value as “nature” can...

  20. Writing Nature

    Directory of Open Access Journals (Sweden)

    Kristin Asdal

    2014-06-01

    Full Text Available This special issue of the Nordic Journal of Science and Technology Studies is interested in how nature, in different versions and forms, is invited into our studies, analyses, and stories. How is it that we “write nature”? How is it that we provide space for, and actually describe the actors, agents, or surroundings, in our stories and analyses? The articles in the issue each deal with different understandings of both the practices of writing and the introduction of various natures into these. In this introduction to the issue the editors engage with actor-network theory as a material semiotic resource for writing nature. We propose to foreground actor-network theory as a writing tool, at the expense of actor-network theory as a distinct vocabulary. In doing this and pointing out the semiotic origins to material-semiotics we also want to problematize a clear-cut material approach to writing nature.

  1. Natural aphrodisiacs.

    Science.gov (United States)

    Shamloul, Rany

    2010-01-01

    The search for a remedy or a prescription that can enhance sexual function and/or treat male erectile dysfunction has been an obsession throughout known history. Whether it was an Eastern civilization or a Western one, religious or atheist, man's aspiration for a better or best "manhood" has been a history-time goal. This review will discuss the current research done on the most popular natural aphrodisiacs and examine the weight of evidence to support or discourage the use of any of these substances to enhance sexual desire and/or function. Review of the current evidence on the use of natural substances as aphrodisiacs. Efficacy of natural aphrodisiacs in enhancing sexual function in men and women. There is little evidence from literature to recommend the usage of natural aphrodisiacs for the enhancement of sexual desire and/or performance. Data on yohimbine's efficacy does not support the wide use of the drug, which has only mild effects in the treatment of psychogenic ED. Although there's a positive trend towards recommending ginseng as an effective aphrodisiac, however, more in depth studies involving large number of subjects and its mechanism of action are needed before definite conclusions could be reached. Data on the use of natural aphrodisiacs in women is limited. The current body of objective evidence does not support the use of any natural aphrodisiac as an effective treatment for male or female sexual dysfunctions. Potent men and men with ED will continue the search for natural aphrodisiacs despite the current disappointing data on their effectiveness. Care should be taken regarding the fraud addition of sildenafil analogues to natural aphrodisiacs.

  2. Emancipating Nature

    DEFF Research Database (Denmark)

    Munk, Anders Kristian

    2012-01-01

    The issue of riverine flooding in the UK is closely tied up with computer simulations. Arguably, these modelling practices are ripe with the anticipation of nature. They aspire to pre-empt it, hence expect it to be ‘out there’, and ultimately work through formalized distillations of it – hydrodyn......The issue of riverine flooding in the UK is closely tied up with computer simulations. Arguably, these modelling practices are ripe with the anticipation of nature. They aspire to pre-empt it, hence expect it to be ‘out there’, and ultimately work through formalized distillations...... of it – hydrodynamic equations – which have their own anticipations and place their own demands on their modellers. Through the experience of a flood modelling apprenticeship I argue that the taking-place of such anticipations paradoxically relies on the birth of a hybrid, the model-modeller, and thus on a nature...

  3. Natural aerodynamics

    CERN Document Server

    Scorer, R S

    1958-01-01

    Natural Aerodynamics focuses on the mathematics of any problem in air motion.This book discusses the general form of the law of fluid motion, relationship between pressure and wind, production of vortex filaments, and conduction of vorticity by viscosity. The flow at moderate Reynolds numbers, turbulence in a stably stratified fluid, natural exploitation of atmospheric thermals, and plumes in turbulent crosswinds are also elaborated. This text likewise considers the waves produced by thermals, transformation of thin layer clouds, method of small perturbations, and dangers of extra-polation.Thi

  4. Provincialising Nature

    DEFF Research Database (Denmark)

    Provincialising Nature: Multidisciplinary Approaches to the Politics of the Environment in Latin America offers a timely analysis of some of the crucial challenges, contradictions and promises within current environmental discourses and practices in the region. This book shows both challenging...... scenarios and original perspectives that have emerged in Latin America in relation to the globally urgent issues of climate change and the environmental crisis. Two interconnected analytical frameworks guide the discussions in the book: the relationship between nature, knowledge and identity and their role...

  5. Peroral endoscopic myotomy

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Peroral endoscopic myotomy (POEM) incorporatesconcepts of natural orifice translumenal endoscopicsurgery and achieves endoscopic myotomy by utilizinga submucosal tunnel as an operating space.Although intended for the palliation of symptoms ofachalasia, there is mounting data to suggest it is alsoefficacious in the management of spastic esophagealdisorders. The technique requires an understanding ofthe pathophysiology of esophageal motility disorders aswell as knowledge of surgical anatomy of the foregut.POEM achieves short term response in 82% to 100% ofpatients with minimal risk of adverse events. In addition,it appears to be effective and safe even at the extremesof age and regardless of prior therapy undertaken.Although infrequent, the ability of the endoscopist tomanage an intraprocedural adverse event is critical asfailure to do so could result in significant morbidity. Themajor late adverse event is gastroesophageal refluxwhich appears to occur in 20% to 46% of patients.Research is being conducted to clarify the optimaltechnique for POEM and a personalized approach bymeasuring intraprocedural esophagogastric junctiondistensibility appears promising. In addition toesophageal disorders,POEM is being studied in themanagement of gastroparesis (gastric pyloromyotomy)with initial reports demonstrating technical feasibility.Although POEM represents a paradigm shift themanagement of esophageal motility disorders, theresults of prospective randomized controlled trials withlong-term follow up are eagerly awaited.

  6. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 3. Nature Watch Diversity of Bats. G Marimuthu. Feature Article Volume 1 Issue 3 March 1996 pp 103-110. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/03/0103-0110. Author Affiliations.

  7. Nature's Palette

    Science.gov (United States)

    McBride, Brooke B.; Brewer, Carol A.

    2010-01-01

    Flower petals, acorn hats, exoskeletons of beetles, and lichens are just a few of the objects students may find in a surprising array of vivid colors. These tiny examples from nature's palette can be discovered in a school yard, a park, or even along the edges of a paved sidewalk...it simply takes careful observation! This article describes a…

  8. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 9. Nature Watch - Coral Reefs and their Fauna: An Underwater Fantasyland. Anuradha Bhat. Feature Article Volume 9 Issue 9 September 2004 pp 62-73. Fulltext. Click here to view fulltext PDF. Permanent link:

  9. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 3. Nature Watch: Symbiosis in Coastal Marine Communities. Neelam Pereira. Feature Article Volume 20 Issue 3 March 2015 pp 245-253. Fulltext. Click here to view fulltext PDF. Permanent link:

  10. Nature Watch

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 5. Nature Watch - Thinking Like a Tahr: When Males and Females go their Separate Ways. M D Madhusudan. Feature Article Volume 3 Issue 5 May 1998 pp 43-47 ...

  11. Natural Propositions

    DEFF Research Database (Denmark)

    Stjernfelt, Frederik

    Preface -- Introduction -- The generality of signs -- Dicisigns -- Some consequences of the dicisign doctrine -- Dicisigns and cognition -- Natural propositions--the evolution of semiotic self-control -- Dicisigns beyond language -- Operational and optimal iconicity in Peirce's diagrammatology...... -- Cows, red cows, and red herrings -- Corollarial and theorematic experiments with diagrams -- Strategies of research: Peirce's enlightenment maxims -- Perspective -- References -- Index....

  12. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Nature Watch - Singapore's Jurong BirdPark: A Study Model. Abraham Verghese. Feature Article Volume 6 Issue 7 July 2001 pp 74-88. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Kritikkens natur

    DEFF Research Database (Denmark)

    Schatz-Jakobsen, Claus

    1999-01-01

    Artiklen introducerer det nye forskningsfelt inden for samtænkning af litteratur, kultur og natur, den såkaldt økologiske kritik, og kaster et kritisk blik på  dens brug af romantisk litteratur som proto-økologisk kanon....

  14. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 7. Nature Watch - The Odyssey of the Olive Ridley. Kartik Shanker. Feature Article Volume 4 Issue 7 July 1999 pp 68-78. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/004/07/0068-0078 ...

  15. Nature Watch

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 8. Nature Watch - Secrets of the Shieldtails. Kartik Shanker. Feature Article Volume 1 Issue 8 August 1996 pp 64-70. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/08/0064-0070 ...

  16. Nature Watch

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... ... 20; Issue 1. Nature Watch: A Tale of Two Turtles. V Deepak. Feature Article Volume 20 Issue 1 January 2015 pp 47-54. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/020/01/0047-0054. Keywords. Ecology; endemic; India; turtles; tortoises; Western Ghats.

  17. Provincialising Nature

    DEFF Research Database (Denmark)

    Provincialising Nature: Multidisciplinary Approaches to the Politics of the Environment in Latin America offers a timely analysis of some of the crucial challenges, contradictions and promises within current environmental discourses and practices in the region. This book shows both challenging...... scenarios and original perspectives that have emerged in Latin America in relation to the globally urgent issues of climate change and the environmental crisis. Two interconnected analytical frameworks guide the discussions in the book: the relationship between nature, knowledge and identity and their role...... in understanding recent and current practices of climate change and environmental policy. The different chapters in this volume contribute to this debate by offering multidisciplinary perspectives on particular aspects of these two frameworks and through a multidirectional outlook that links the local, national...

  18. Unbounded Naturalism

    Directory of Open Access Journals (Sweden)

    Andrew Taggart

    2008-10-01

    Full Text Available nbsp;font face="Times, serif"font size="3"In the Anglo-American reception of John McDowellrsquo;s /font/fontfont face="Times, serif"font size="3"emMind and World/em/font/fontfont face="Times, serif"font size="3", there has been little attention paid to the developmental aspect of his lsquo;partially re-enchantedrsquo; naturalism. In lsquo;Naturalism Unboundedrsquo;, I argue that McDowellrsquo;s story of our normal upbringing (/font/fontfont face="Times, serif"font size="3"emBildung/em/font/fontfont face="Times, serif"font size="3" presents problems for his claim that we have a lsquo;standing obligationrsquo; to reflect on our perceptual experiences. I follow this critique up with a Hegelian-inspired attempt to retain and revise the vital points he makes about experience./font/font

  19. Natural games

    International Nuclear Information System (INIS)

    Anttila, Jani; Annila, Arto

    2011-01-01

    A course of a game is formulated as a physical process that will consume free energy in the least time. Accordingly, the rate of entropy increase is the payoff function that will subsume all forms of free energy that motivate diverse decisions. Also other concepts of game theory are related to their profound physical counterparts. When the physical portrayal of behavior is mathematically analyzed, the course of a game is found to be inherently unpredictable because each move affects motives in the future. Despite the non-holonomic character of the natural process, the objective of consuming free energy in the least time will direct an extensive-form game toward a Lyapunov-stable point that satisfies the minimax theorem. -- Highlights: → Behavior in the context of game theory is described as a natural process. → The rate of entropy increase, derived from statistical physics of open systems, is identified as the payoff function. → Entropy as the payoff function also clarifies motives of collaboration and subjective nature of decision making. → Evolutionary equation of motion that accounts for the course of a game is inherently unpredictable.

  20. Comparison of peak flow velocity through the left ventricular outflow tract and effective orifice area indexed to body surface area in Golden Retriever puppies to predict development of subaortic stenosis in adult dogs.

    Science.gov (United States)

    Javard, Romain; Bélanger, Marie-Claude; Côté, Etienne; Beauchamp, Guy; Pibarot, Philippe

    2014-12-15

    To evaluate the usefulness of Doppler-derived peak flow velocity through the left ventricular outflow tract (LVOT Vmax) and effective orifice area indexed to body surface area (EOAi) in puppies to predict development of subaortic stenosis (SAS) in the same dogs as adults. Prospective, longitudinal, observational study. 38 Golden Retrievers. Cardiac auscultation and echocardiography were performed on 2- to 6-month-old puppies, then repeated at 12 to 18 months. Subaortic stenosis was diagnosed when LVOT Vmax was ≥ 2.3 m/s in adult dogs with left basilar systolic murmurs. All puppies with EOAi 2.3 m/s in puppyhood was 63% sensitive and 100% specific for SAS in adulthood. In puppies, LVOT Vmax was more strongly associated with a future diagnosis of SAS (area under the curve [AUC], 0.89) than was EOAi (AUC, 0.80). In puppies, the combination of LVOT Vmax and EOAi yielded slightly higher sensitivity (69%) and specificity (100%) for adult SAS than did LVOT Vmax alone. In unaffected and affected dogs, LVOT Vmax increased significantly from puppyhood to adulthood but EOAi did not. In Golden Retriever puppies, LVOT Vmax > 2.3 m/s and EOAi < 1.46 cm(2)/m(2) were both associated with a diagnosis of SAS at adulthood. The combination of these 2 criteria may result in higher sensitivity for SAS screening. Unlike LVOT Vmax, EOAi did not change during growth in either unaffected Golden Retrievers or those with SAS.

  1. Natural games

    Science.gov (United States)

    Anttila, Jani; Annila, Arto

    2011-10-01

    A course of a game is formulated as a physical process that will consume free energy in the least time. Accordingly, the rate of entropy increase is the payoff function that will subsume all forms of free energy that motivate diverse decisions. Also other concepts of game theory are related to their profound physical counterparts. When the physical portrayal of behavior is mathematically analyzed, the course of a game is found to be inherently unpredictable because each move affects motives in the future. Despite the non-holonomic character of the natural process, the objective of consuming free energy in the least time will direct an extensive-form game toward a Lyapunov-stable point that satisfies the minimax theorem.

  2. Natural uranium

    International Nuclear Information System (INIS)

    Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain

    2014-08-01

    This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with natural uranium

  3. Next nature : nature changes along with us

    NARCIS (Netherlands)

    Mensvoort, van K.M.; Grievink, H.J.

    2011-01-01

    We debate saving nature, we dream about escaping to nature, but rarely do we ask "What is nature?". The Next Nature book radically shifts your notion of nature. Where technology and nature are traditionally seen as opposed, they now appear to merge or even trade places. With our urge to design our

  4. Natural isotopes

    International Nuclear Information System (INIS)

    Vogel, J.C.

    1986-01-01

    14 C dates between 600 and 900 AD were obtained for early Iron Age sites in Natal, and from 1300 to 1450 AD for rock engraving sites in Bushmanland. Palaeoenvironmental data derived from the dating of samples related to sedimentary and geomorphic features in the central and northern Namib Desert enabled the production of a tentative graph for the changes in humidity in the region over the past 40000 years. These results suggest that relatively humid conditions came to an end in the Namib at ±25000 BP (before present). The increased precision of the SIRA mass spectrometer enabled the remeasurement of 13 C and 18 O in the Cango stalagmite. This data confirmed that the environmental temperatures in the Southern Cape remained constant to within ±1 o C during the past 5500 years. Techniques and applications for environmental isotopes in hydrology were developed to determine the origin and movement of ground water. Isotopic fractionation effects in light elements in nature were investigated. The 15 N/ 14 N ratio in bones of animals and humans increases in proportion to the aridity of the environment. This suggests that 15 N in bone from dated archaeological sites could be used to detect changes in past climatic conditions as naturally formed nitrate minerals are higly soluble and are only preserved in special, very dry environments. The sources and sinks of CO 2 on the South African subcontinent were also determined. The 13 C/ 12 C ratios of air CO 2 obtained suggest that the vegetation provides the major proportion of respired CO 2 . 9 refs., 1 fig

  5. Nature and nature values in organic agriculture

    DEFF Research Database (Denmark)

    Hansen, Lene; Noe, Egon; Højring, Katrine

    2006-01-01

    The relationship between agriculture and nature is a centra issue in the current agricultural debate. Organic farming has ambitions and a special potential in relation to nature. Consideration for nature is part of the guiding principals of organic farming and many organic farmers are committed...... to protecting natural qualities. However, the issue of nature, landscape, and land use is not straightforward. Nature is an ambiguous concept that involves multiple interests and actors reaching far beyond farmers. The Danish research project ......

  6. Liquid entrainment through orifices by sparging gas

    International Nuclear Information System (INIS)

    Bonnet, J.M.; Malara, M.; Amblard, M.; Seiler, J.M.

    2001-01-01

    Corium Coolability by water flood during an MCCI (Molten Corium Concrete Interaction) is still an open problem. Several physical mechanisms have been identified which may reduce significantly and finally stop the ablation of concrete. Among these mechanisms, corium ejection by sparging gas into the overlying water may represent an important contribution. This mechanism was at the origin of a large and coolable debris bed and volcano formation in the MACE M3B test. This mechanism has also been observed in simulant material tests performed at UCSB and at FZK. The objective of the work, which is described in the present paper, is to model this mechanism and to quantify the liquid entrainment rate by sparging gas. (author)

  7. Complication related to colostomy orifice: intestinal evisceration

    Directory of Open Access Journals (Sweden)

    Valdemir José Alegre Salles

    2011-12-01

    Full Text Available Intestinal evisceration at the site of a stoma is a rare event, with high morbimortality. Its clinical manifestation often occurs between the sixth and seventh days after surgery. The risk factors most frequently related to evisceration are: increased intra-abdominal pressure, digestive tract cancer surgery, emergency surgery and stomas in the surgical incision. The authors report the case of a male patient, aged 62, suffering from adenocarcinoma of the rectum with obstructive acute abdomen, who underwent loop transversotomy for decompression. On the fourth day after surgery, he had a bronchospasm crisis, with evisceration of ileum and colon through the colostomic hole. The association of some triggering factors, such as emergency surgery, colorectal malignant neoplasm, increased intra-abdominal pressure and technical failure of colostomy were decisive in the development of this rare peri-colostomy complication.A evisceração intestinal desenvolvida no sítio de um estoma é um evento raro, tendo elevada morbimortalidade. Sua manifestação clínica ocorre frequentemente entre o sexto e o sétimo dias de pós-operatório. Os fatores de risco mais frequentemente relacionados à evisceração são: aumento da pressão intra-abdominal, câncer do aparelho digestório, cirurgia de urgência e estomias na incisão cirúrgica. Os autores relatam o caso de um paciente do sexo masculino, com 62 anos, portador de adenocarcinoma do reto médio com abdômen agudo obstrutivo, sendo submetido à transversostomia em alça, com finalidade descompressiva. No quarto dia de pós-operatório com crise de broncoespasmo, apresentou evisceração do cólon e íleo pelo orifício abdominal colostômico. A associação de alguns fatores desencadeantes, como a cirurgia de urgência, a doença neoplásica colorretal maligna, o aumento da pressão intra-abdominal e a falha técnica na confecção da colostomia, foram determinantes para o desenvolvimento desta rara complicação pericolostômica.

  8. Nature and nature values in organic agriculture

    DEFF Research Database (Denmark)

    Hansen, Lene; Noe, Egon; Højring, Katrine

    2006-01-01

    The relationship between agriculture and nature is a centra issue in the current agricultural debate. Organic farming has ambitions and a special potential in relation to nature. Consideration for nature is part of the guiding principals of organic farming and many organic farmers are committed...

  9. Three Sorts of Naturalism

    DEFF Research Database (Denmark)

    Fink, Hans

    2006-01-01

    In "Two sorts of Naturalism" John McDowell is sketching his own sort of naturalism in ethics as an alternative to "bald naturalism". In this paper I distinguish materialist, idealist and absolute conceptions of nature and of naturalism in order to provide a framework for a clearer understanding...

  10. Natural gas trends

    International Nuclear Information System (INIS)

    Anderson, A.

    1991-01-01

    This book provides data on many facets of the natural gas industry. Topics include: Canadian, Mexican; US natural gas reserves and production; Mexican and US natural gas consumption; market conditions for natural gas in the US; and Canadian natural gas exports

  11. A Natural Language Architecture

    OpenAIRE

    Sodiya, Adesina Simon

    2007-01-01

    Natural languages are the latest generation of programming languages, which require processing real human natural expressions. Over the years, several groups or researchers have trying to develop widely accepted natural language languages based on artificial intelligence (AI). But no true natural language has been developed. The goal of this work is to design a natural language preprocessing architecture that identifies and accepts programming instructions or sentences in their natural forms ...

  12. Virginia Natural Heritage Program

    Science.gov (United States)

    Heritage About Natural Heritage Overview, Mission Natural Heritage Inventory Community Ecology Program ) | Strategic Plan (PDF) | Executive Progress Report (PDF) | Code of Ethics (PDF) Your browser does not support

  13. Natural Colorants: Food Colorants from Natural Sources.

    Science.gov (United States)

    Sigurdson, Gregory T; Tang, Peipei; Giusti, M Mónica

    2017-02-28

    The color of food is often associated with the flavor, safety, and nutritional value of the product. Synthetic food colorants have been used because of their high stability and low cost. However, consumer perception and demand have driven the replacement of synthetic colorants with naturally derived alternatives. Natural pigment applications can be limited by lower stability, weaker tinctorial strength, interactions with food ingredients, and inability to match desired hues. Therefore, no single naturally derived colorant can serve as a universal alternative for a specified synthetic colorant in all applications. This review summarizes major environmental and biological sources for natural colorants as well as nature-identical counterparts. Chemical characteristics of prevalent pigments, including anthocyanins, carotenoids, betalains, and chlorophylls, are described. The possible applications and hues (warm, cool, and achromatic) of currently used natural pigments, such as anthocyanins as red and blue colorants, and possible future alternatives, such as purple violacein and red pyranoanthocyanins, are also discussed.

  14. Regularities, Natural Patterns and Laws of Nature

    Directory of Open Access Journals (Sweden)

    Stathis Psillos

    2014-02-01

    Full Text Available  The goal of this paper is to sketch an empiricist metaphysics of laws of nature. The key idea is that there are regularities without regularity-enforcers. Differently put, there are natural laws without law-makers of a distinct metaphysical kind. This sketch will rely on the concept of a natural pattern and more significantly on the existence of a network of natural patterns in nature. The relation between a regularity and a pattern will be analysed in terms of mereology.  Here is the road map. In section 2, I will briefly discuss the relation between empiricism and metaphysics, aiming to show that an empiricist metaphysics is possible. In section 3, I will offer arguments against stronger metaphysical views of laws. Then, in section 4 I will motivate nomic objectivism. In section 5, I will address the question ‘what is a regularity?’ and will develop a novel answer to it, based on the notion of a natural pattern. In section 6, I will raise the question: ‘what is a law of nature?’, the answer to which will be: a law of nature is a regularity that is characterised by the unity of a natural pattern.

  15. Verification procedures of ultrasonic flow meters for natural gas applications; Procedimento de verificacao de medidores ultra-sonicos para gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Lourenco, Tulio C. [TRANSPETRO, Rio de Janeiro, RJ (Brazil)

    2009-12-19

    In recent years, the use of ultrasonic flow meters for natural gas applications has grown significantly, especially after the issuance of AGA Report 9 and AGA Report 10. The reasons this technology has stood out from the others, such as orifice-plates or turbines, are: accuracy, wide range ability, it is bi-directional, robustness, low maintenance and, mainly, integrated diagnostic parameters, such as sound velocity, signal quality and profile velocity analysis. TRANSPETRO currently operates 56 ultrasonic natural gas flow-meter systems. For operational control applications, 90% of the meters are ultrasonic, of which 85% are provided with internal diagnostic tools through the manufacturer's software. Within this perspective, it is essential and unquestionable that there are procedures and routines for ultrasonic flow-meter verification and analysis, in order to monitor their performance and integrity, in addition to the early identification of potential problems. This paper discusses the practical application of several tools and diagnostic parameters inherent in ultrasonic flow meters in periodical verifications using TRANSPETRO's procedure. (author)

  16. Natural and near natural tropical forest values

    Science.gov (United States)

    Daniel H. Henning

    2011-01-01

    This paper identifies and describes some of the values associated with tropical rain forests in their natural and near-natural conditions. Tropical rain forests are moist forests in the humid tropics where temperature and rainfall are high and the dry season is short. These closed (non-logged) and broad-leaved forests are a global resource. Located almost entirely in...

  17. Natural gas in India

    International Nuclear Information System (INIS)

    Lefevre, Thierry; Todoc, Jessie L.

    1999-11-01

    Contains Executive Summary and Chapters on: Country background; Overview of the energy sector; Natural gas supply; Natural gas infrastructure; Natural gas infrastructure; Natural gas demand; Outlook-government policy reform and industry development, and Appendices on Global and regional energy and gas trends; Overview of India's investment policy, incentives and regulation; The ENRON Dabhol power project. (Author)

  18. Three Sorts of Naturalism

    OpenAIRE

    Fink, Hans

    2006-01-01

    In "Two sorts of Naturalism" John McDowell is sketching his own sort of naturalism in ethics as an alternative to "bald naturalism". In this paper I distinguish materialist, idealist and absolute conceptions of nature and of naturalism in order to provide a framework for a clearer understanding of what McDowell's own naturalism amounts to. I argue that nothing short of an absolute naturalism will do for a number of McDowell's own purposes, but that it is far from obvious that this is his posi...

  19. Natural gas monthly

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-01-01

    The Natural Gas Monthly highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the Natural Gas Monthly features articles designed to assist readers in using and interpreting natural gas information.

  20. The Nature of Natural Hazards Communication (Invited)

    Science.gov (United States)

    Kontar, Y. Y.

    2013-12-01

    Some of the many issues of interest to natural hazards professionals include the analysis of proactive approaches to the governance of risk from natural hazards and approaches to broaden the scope of public policies related to the management of risks from natural hazards, as well as including emergency and environmental management, community development and spatial planning related to natural hazards. During the talk we will present results of scientific review, analysis and synthesis, which emphasize same new trends in communication of the natural hazards theories and practices within an up-to-the-minute context of new environmental and climate change issues, new technologies, and a new focus on resiliency. The presentation is divided into five sections that focus on natural hazards communication in terms of education, risk management, public discourse, engaging the public, theoretical perspectives, and new media. It includes results of case studies and best practices. It delves into natural hazards communication theories, including diffusion, argumentation, and constructivism, to name a few. The presentation will provide information about: (1) A manual of natural hazards communication for scientists, policymakers, and media; (2) An up-to-the-minute context of environmental hazards, new technologies & political landscape; (3) A work by natural hazards scientists for geoscientists working with social scientists and communication principles; (4) A work underpinned by key natural hazards communication theories and interspersed with pragmatic solutions; (5) A work that crosses traditional natural hazards boundaries: international, interdisciplinary, theoretical/applied. We will further explore how spatial planning can contribute to risk governance by influencing the occupation of natural hazard-prone areas, and review the central role of emergency management in risk policy. The goal of this presentation is to contribute to the augmentation of the conceptual framework

  1. Mathematical modeling of cryogenic spills onto quiescent sea waters followed by pool fires of liquefied natural gas (LNG)

    International Nuclear Information System (INIS)

    Esteves, Alan Silva; Reis Parise, José Alberto

    2013-01-01

    Spill and combustion of a pool as a result of a spreading of liquefied natural gas (LNG) at sea from punctures on carrier hulls is presented. Models from literature combined mechanisms of flow thorough an orifice, formation of a semicircular pool, vaporization of a cryogenic fluid by boiling and pool fire heating, ignition, non-premixed turbulent fire with variation with height of the emissive power of the ‘visible’ plume, burning of fuel along the ‘luminous’ zone (fire base) and radiation emitted by gray gases and soot particles from the combustion zone. A review of the experimental data on vaporization velocity and burning rate is presented. Predictions agreed well with existing experimental data and other models. The model simulated fires from 1 to 5 m diameter holes in vessel geometries of 125,000 and 265,000 m 3 . Predictions are plausible, and robust enough to be applied in industrial practice. The construction of an LNG terminal involves, among other parameters, the prediction of thermal radiation fields emitted by pool fires. This is to evaluate safe distances to vulnerable resources around the facility. -- Highlights: • More than 20 orifice models published since 1969 were reviewed. • Flow parameter adjusted with proxy equations for a ∗,max and t * v within 1/3 ≤ ϕ ≤ 30. • Review of experimental of data for vaporization velocities covered since 1978. • The axial emissive power along the fire plume increases with vaporization velocity. • Plume height/diameter ratio of termal plume was nearly insensitive to the scale up of carrier cargo capacity

  2. Transanal total mesorectal excision: a systematic review of the experimental and clinical evidence.

    Science.gov (United States)

    Araujo, S E; Crawshaw, B; Mendes, C R; Delaney, C P

    2015-02-01

    Achieving a clear distal or circumferential resection margins with laparoscopic total mesorectal excision (TME) may be laborious, especially in obese males and when operating on advanced distal rectal tumors with a poor response to neoadjuvant treatment. Transanal (TaTME) is a new natural orifice translumenal endoscopic surgery modality in which the rectum is mobilized transanally using endoscopic techniques with or without laparoscopic assistance. We conducted a comprehensive systematic review of publications on this new technique in PubMed and Embase databases from January, 2008, to July, 2014. Experimental and clinical studies written in English were included. Experimental research with TaTME was done on pigs with and without survival models and on human cadavers. In these studies, laparoscopic or transgastric assistance was frequently used resulting in an easier upper rectal dissection and in a longer rectal specimen. To date, 150 patients in 16 clinical studies have undergone TaTME. In all but 15 cases, transabdominal assistance was used. A rigid transanal endoscopic operations/transanal endoscopic microsurgery (TEO/TEM) platform was used in 37 patients. Rectal adenocarcinoma was the indication in all except for nine cases of benign diseases. Operative times ranged from 90 to 460 min. TME quality was deemed intact, satisfactory, or complete. Involvement in circumferential resection margins was detected in 16 (11.8 %) patients. The mean lymph node harvest was equal or greater than 12 in all studies. Regarding morbidity, pneumoretroperitoneum, damage to the urethra, and air embolism were reported intraoperatively. Mean hospital stay varied from 4 to 14 days. Postoperative complications occurred in 34 (22.7 %) patients. TaTME with TEM is feasible in selected cases. Oncologic safety parameters seem to be adequate although the evidence relies on small retrospective series conducted by highly trained surgeons. Further studies are expected.

  3. A randomized comparison of laparoscopic, flexible endoscopic, and wired and wireless magnetic cameras on ex vivo and in vivo NOTES surgical performance.

    Science.gov (United States)

    Chang, Victoria C; Tang, Shou-Jiang; Swain, C Paul; Bergs, Richard; Paramo, Juan; Hogg, Deborah C; Fernandez, Raul; Cadeddu, Jeffrey A; Scott, Daniel J

    2013-08-01

    The influence of endoscopic video camera (VC) image quality on surgical performance has not been studied. Flexible endoscopes are used as substitutes for laparoscopes in natural orifice translumenal endoscopic surgery (NOTES), but their optics are originally designed for intralumenal use. Manipulable wired or wireless independent VCs might offer advantages for NOTES but are still under development. To measure the optical characteristics of 4 VC systems and to compare their impact on the performance of surgical suturing tasks. VC systems included a laparoscope (Storz 10 mm), a flexible endoscope (Olympus GIF 160), and 2 prototype deployable cameras (magnetic anchoring and guidance system [MAGS] Camera and PillCam). In a randomized fashion, the 4 systems were evaluated regarding standardized optical characteristics and surgical manipulations of previously validated ex vivo (fundamentals of laparoscopic surgery model) and in vivo (live porcine Nissen model) tasks; objective metrics (time and errors/precision) and combined surgeon (n = 2) performance were recorded. Subtle differences were detected for color tests, and field of view was variable (65°-115°). Suitable resolution was detected up to 10 cm for the laparoscope and MAGS camera but only at closer distances for the endoscope and PillCam. Compared with the laparoscope, surgical suturing performances were modestly lower for the MAGS camera and significantly lower for the endoscope (ex vivo) and PillCam (ex vivo and in vivo). This study documented distinct differences in VC systems that may be used for NOTES in terms of both optical characteristics and surgical performance. Additional work is warranted to optimize cameras for NOTES. Deployable systems may be especially well suited for this purpose.

  4. Pure NOTES rectosigmoid resection: transgastric endoscopic IMA dissection and transanal rectal mobilization in animal models.

    Science.gov (United States)

    Park, Sun Jin; Lee, Kil Yeon; Choi, Sung Il; Kang, Byung Mo; Huh, Chang; Choi, Dong Hyun; Lee, Chang Kyun

    2013-07-01

    We report a pure natural orifice translumenal endoscopic surgery (NOTES(®); American Society for Gastrointestinal Endoscopy [Oak Brook, IL] and the Society of American Gastrointestinal and Endoscopic Surgeons [Los Angeles, CA]) rectosigmoidectomy in animal models using transgastric endoscopic inferior mesenteric artery (IMA) dissection and transanal rectal mobilization. Ten live animals (2 pigs weighing 35-40 kg each and 8 dogs weighing 25-30 kg each) were used. A gastrotomy was made using a needle-knife puncture and the balloon dilatation technique or following the creation of a submucosal tunnel. A circular stapler shaft was transanally inserted up to the sigmoid colon for spatial orientation and traction of the mesocolon. The IMA was endoscopically dissected using a Coagrasper™ (Olympus, Tokyo, Japan) and then clipped. Endoscopic division of the sigmoid mesocolon was conducted laterally toward the marginal artery. Transanal full-thickness circumferential rectal and mesorectal dissections were performed, and a colorectal anastomosis was performed using a circular stapler with a single stapling technique. During the transanal approach, the gastrotomy was closed using four endoscopic clips. Endoscopic dissection of the IMA was successful in all cases, but minor bleedings occurred in 3 cases. The mean time from dissection and clipping to division of the IMA was 36.7 minutes (range, 25-45 minutes). The mean operation time was 180.5 minutes (range, 145-210 minutes). There were no intraoperative complications or hemodynamic instability. The mean length of the resected specimen was 11.2 cm (range, 9-17 cm). A pure NOTES approach to rectosigmoid resection using transgastric endoscopic IMA dissection is technically feasible in animal models.

  5. A technical review of flexible endoscopic multitasking platforms.

    Science.gov (United States)

    Yeung, Baldwin Po Man; Gourlay, Terence

    2012-01-01

    Further development of advanced therapeutic endoscopic techniques and natural orifice translumenal endoscopic surgery (NOTES) requires a powerful flexible endoscopic multitasking platform. Medline search was performed to identify literature relating to flexible endoscopic multitasking platform from year 2004-2011 using keywords: Flexible endoscopic multitasking platform, NOTES, Instrumentation, Endoscopic robotic surgery, and specific names of various endoscopic multitasking platforms. Key articles from articles references were reviewed. Flexible multitasking platforms can be classified as either mechanical or robotic. Purely mechanical systems include the dual channel endoscope (DCE) (Olympus), R-Scope (Olympus), the EndoSamurai (Olympus), the ANUBIScope (Karl-Storz), Incisionless Operating Platform (IOP) (USGI), and DDES system (Boston Scientific). Robotic systems include the MASTER system (Nanyang University, Singapore) and the Viacath (Hansen Medical). The DCE, the R-Scope, the EndoSamurai and the ANUBIScope have integrated visual function and instrument manipulation function. The IOP and DDES systems rely on the conventional flexible endoscope for visualization, and instrument manipulation is integrated through the use of a flexible, often lockable, multichannel access device. The advantage of the access device concept is that it allows optics and instrument dissociation. Due to the anatomical constrains of the pharynx, systems are designed to have a diameter of less than 20 mm. All systems are controlled by traction cable system actuated either by hand or by robotic machinery. In a flexible system, this method of actuation inevitably leads to significant hysteresis. This problem will be accentuated with a long endoscope such as that required in performing colonic procedures. Systems often require multiple operators. To date, the DCE, the R-Scope, the IOP, and the Viacath system have data published relating to their application in human. Alternative forms of

  6. New trends in minimally invasive urological surgery: what is beyond the robot?

    Science.gov (United States)

    Micali, Salvatore; Pini, Giovannalberto; Teber, Dogu; Sighinolfi, Maria Chiara; De Stefani, Stefano; Bianchi, Giampaolo; Rassweiler, Jens

    2013-06-01

    To review the minimal-invasive development of surgical technique in urology focusing on nomenclature, history and outcomes of Laparo-Endoscopic Single-site Surgery (LESS), Natural Orifice Translumenal Endoscopic Surgery (NOTES) and Computer-Assisted Surgery (CAS). A comprehensive literature search was conducted in order to find article related to LESS, NOTES and CAS in urology. The most relevant papers over the last 10 years were selected in base to the experience from the panel of experts, journal, authorship and/or content. Seven hundred and fifty manuscripts were found. Papers on LESS describe feasibility/safety in most of the procedures with a clinical experience of more than 300 cases and five compared results to standard laparoscopy without showing significant differences. NOTES accesses have been proved their feasibility/safety in experimental study. In human, the only procedures performed are on kidney and through a hybrid-Transvaginal route. New robots overcome the main drawbacks of the DaVinci® platform. The use of CAS is increasing its popularity in urology. LESS has been applied in clinical practice, but only ongoing technical and instrumental refinement will define its future role and overall benefit. The transition to a clinical application of NOTES seems at present only possible with multiple NOTES access and transvaginal access. Robot and Soft Tissue Navigation appear to be important to improve surgical skills. We are already witness to the advantages offered by the former even if costs need to be redefined based on pending long-term results. The latter will probably upgrade the quality of surgery in a near future.

  7. Cautionary considerations regarding N.O.T.E.S. in oncology.

    LENUS (Irish Health Repository)

    O'Riordain, M G

    2012-01-31

    Over the last number of years, the emphasis in abdominal surgery has been to reduce invasiveness and to minimise trauma to the patient. This has led to the rapid development of laparoscopic techniques initially for the surgical management of benign disease and later for the successful management of malignant disease. Laparoscopy has now been shown to provide significant benefits to the cancer patient, in particular the reduction of wound infection, herniation and pain. More recently, benefits have been demonstrated in earlier discharge from hospital and return to normal activity. Laparoscopy has therefore been accepted as at least a valid alternative to open surgery for most types of abdominal cancer. With the objective of reducing invasiveness even more, the last few years has seen a rapid expansion in the development of Natural Orifice Translumenal Endoscopic Surgery (NOTES). Currently, NOTES is still in the early stages of evolution but its potential uses in the field of cancer surgery are already being proposed. To develop NOTES to the stage that it will be safe, effective and widely available for the management of cancer patients represents a huge challenge ranging from the development of equipment and techniques to the demonstration of safety and efficacy in clinical trials as well as training and competence issues. It is still not clear whether these challenges will be surmounted so that NOTES becomes mainstream therapy. A period of \\'watchful waiting\\' seems appropriate therefore for the uncommitted general surgeon in order that NOTES may be given time to prove compelling and convincing before its general uptake into routine practice.

  8. Perception of preference and risk-taking in laparoscopy, transgastric, and rigid-hybrid transvaginal NOTES for cholecystectomy.

    Science.gov (United States)

    Sulz, Michael C; Zerz, Andreas; Sagmeister, Markus; Roll, Thomas; Meyenberger, Christa

    2013-12-03

    Few data are available regarding patients' perceptions of new cholecystectomy (CC) techniques, in the context of the patients' risk behaviours. We investigated patients' preferences for transgastric pure natural orifice translumenal endoscopic surgery (NOTES; transgastric NCC) and rigid-hybrid transvaginal NOTES CC (tvNCC) compared with the standard laparoscopic CC (SL-CC), and patients' risk behaviours. A total of 140 inpatients scheduled for elective laparoscopic CC were enrolled in this prospective single-centre study, from January 2009 to January 2010. Patients judged the potential advantages and disadvantages of transgastric NCC and tvNCC compared with SL-CC. The individual's risk behaviour was analysed by means of the validated 40-item Domain-Specific Risk Attitude Scale (DOSPERT). Of the 140 recruited patients, 57 (65% females; mean age 51.5 years) were analysed. Twenty-five percent of males opted for transgastric NCC and 75% opted for SL-CC. Among females, 10.8%, 37.8% and 51.4% opted for transgastric NCC, tvNCC and SL-CC, respectively. Faster convalescence was graded as the primary potential advantage of transgastric NCC, whereas the potential risk of long-term stomach injuries was considered a primary disadvantage. Females graded the reduction of hospital-acquired morbidity as the primary advantage of tvNCC. The risk assessment showed significantly more risk-taking behaviour in the recreational domain of life among patients who opted for innovative surgical techniques than among those opting for conventional surgery. Transgastric NCC is rarely accepted by females but accepted by a quarter of males. Females consider rigid-hybrid tvNCC and SL-CC similarly attractive. Despite promising new techniques, three-quarters of male and one half of female patients still prefer the standard laparoscopic CC.

  9. Development of urologic laparoscopy in Germany, Austria, and Switzerland: a survey among urologists.

    Science.gov (United States)

    Imkamp, Florian; Herrmann, Thomas R W; Stolzenburg, Jens U; Rassweiler, Jens; Sulser, Tullio; Zimmermann, Uwe; Dziuba, Sebastian; Kuczyk, Markus A; Burchardt, Martin

    2014-12-01

    Laparoscopy introduction has dramatically changed urology. Novel techniques, such as laparoendoscopic single-site surgery (LESS) and natural orifice translumenal endoscopic surgery (NOTES), might also have substantial influence. This 2012 survey evaluated present laparoscopy use, its appraisal among urologic surgeons, laparoscopy training, and use of new techniques. Results were compared to the previous surveys, demonstrating the 10-year development of laparoscopy. A detailed questionnaire regarding demographic data, laparoscopy use, attitudes concerning laparoscopy, and novel techniques was send to 424 departments in Germany, Austria, and Switzerland. Procedures performed in 25 indications were quantitatively evaluated. The response rate was 63 % (269). Eighty-six percent of the respondents reported performing laparoscopy, compared to 54 % in 2002. Only 16 % expected economic advantages with laparoscopy, whereas 67 % expected shorter hospitalization. Seventy percent of responders anticipated comparable functional and oncological results between laparoscopic procedures and open surgery. Slow learning curves (81 %) and insufficient training facilities (32 %) were reported to impair laparoscopic surgery. On average, laparoscopic and non-laparoscopic surgical teams consisted of 2.5 and 3.5 members, respectively. LESS procedures were performed at 15 % of institutions. Twenty-two percent of respondents considered NOTES techniques valuable for future urology. Few indications (laparoscopic prostatectomies or nephrectomies) were performed frequently in specialized centers, and the rapidly increasing procedure numbers observed between 2002 and 2007 had dropped to a mild accretion. The results demonstrate broad acceptance of laparoscopy in German urologic surgery, depict the need for structured training facilities, and indicate limited impact of novel techniques (LESS and NOTES). The survey demonstrates the 10-year development of urologic laparoscopy and the broad acceptance

  10. Breast reconstruction - natural tissue

    Science.gov (United States)

    ... flap; TRAM; Latissimus muscle flap with a breast implant; DIEP flap; DIEAP flap; Gluteal free flap; Transverse upper gracilis flap; TUG; Mastectomy - breast reconstruction with natural tissue; Breast cancer - breast reconstruction with natural tissue

  11. Natural short sleeper

    Science.gov (United States)

    Sleep - natural short sleeper ... 7 to 9 hours of sleep each night. Short sleepers sleep less than 75% of what is normal for their age. Natural short sleepers are different from people who chronically do ...

  12. Vermont Natural Resources Atlas

    Data.gov (United States)

    Vermont Center for Geographic Information — The purpose of the�Natural Resources Atlas�is to provide geographic information about environmental features and sites that the Vermont Agency of Natural Resources...

  13. Natural Weathering Exposure Station

    Data.gov (United States)

    Federal Laboratory Consortium — The Corps of Engineers' Treat Island Natural Weathering Exposure Station is a long-term natural weathering facility used to study concrete durability. Located on the...

  14. Natural gas annual 1995

    International Nuclear Information System (INIS)

    1996-11-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1995 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1991 to 1995 for each Census Division and each State. Annual historical data are shown at the national level

  15. Natural gas annual 1993

    International Nuclear Information System (INIS)

    1994-01-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1993 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. Tables summarizing natural gas supply and disposition from 1989 to 1993 are given for each Census Division and each State. Annual historical data are shown at the national level

  16. Natural gas annual 1991

    International Nuclear Information System (INIS)

    1992-01-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1991 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. Tables summarizing natural gas supply and disposition form 1987 to 1991 are given for each Census Division and each State. Annual historical data are shown at the national level

  17. Natural gas for vehicles

    International Nuclear Information System (INIS)

    Prieur, A.

    2006-01-01

    Following a decade-long upsurge in the use of natural gas in the energy sector (heating and especially electricity), new outlets for natural gas are being developed in the transport sector. For countries endowed with substantial local resources, development in this sector can help reduce oil dependence. In addition, natural gas is often used to reduce pollution, particularly in cities

  18. Natural gas annual 1991

    International Nuclear Information System (INIS)

    1993-01-01

    The Natural Gas Annual 1991 provides information on the supply and disposition of natural gas to a wide audience including industry, consumers Federal and State agencies, and education institutions. This report, the Natural Gas Annual 1991 Supplement: Company Profiles, presents a detailed profile of selected companies

  19. Naturalisms and religion

    NARCIS (Netherlands)

    Drees, Willem

    1997-01-01

    Such terms as materialism, naturalism, and near synonyms evoke strong negative reactions among many believers. However, the notion of naturalism has various meanings; implications for religion differ for the several varieties of naturalism. In this paper I analyze epistemological and ontological

  20. NATURAL GAS TRANSPORTATION

    OpenAIRE

    Stanis³aw Brzeziñski

    2007-01-01

    In the paper, Author presents chosen aspects of natural gas transportation within global market. Natural gas transportation is a technicaly complicated and economicly expensive process; in infrastructure construction and activities costs. The paper also considers last and proposed initiatives in natural gas transportation.

  1. Natural gas marketing II

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This book covers all aspects of gas marketing, from the basic regulatory structure to the latest developments in negotiating agreements and locating markets. Topics include: Federal regulation of the gas industry; Fundamentals of gas marketing contracts; FERC actions encouraging competitive markets; Marketing conditions from the pipelines' perspective; State non-utility regulation of natural gas production, transportation, and marketing; Natural gas wellhead agreements and tariffs; Natural gas processing agreements; Effective management of producer's natural gas contracts; Producer-pipeline litigation; Natural gas purchasing from the perspective of industrial gas users; Gas marketing by co-owners: problems of disproportionate sales, gas balancing, and accounting to royalty owners; Alternatives and new directions in marketing

  2. Nature in Preschool

    DEFF Research Database (Denmark)

    Husted, Mia; Frøkjær, Thorleif

    Nature and nature phenomena’ has formed a specific curriculum theme in Danish preschool since early childhood curriculum was prescribed by law in 2004. However, recent evaluations show that the implementation of an early childhood curriculum has not produced an increased pedagogical focus...... on ‘nature and nature phenomena’ in preschools (EVA 2012). This finding, along with an increased political interest in goals and measurable outcome of early childhood curriculum (Broström 2012), will be the starting point in our ambition to carry out a more thorough qualitative investigation into links...... between preschool teachers’ understanding and interest in teaching nature and the rather poor evaluation....

  3. Learning from nature: Nature-inspired algorithms

    DEFF Research Database (Denmark)

    Albeanu, Grigore; Madsen, Henrik; Popentiu-Vladicescu, Florin

    2016-01-01

    .), genetic and evolutionary strategies, artificial immune systems etc. Well-known examples of applications include: aircraft wing design, wind turbine design, bionic car, bullet train, optimal decisions related to traffic, appropriate strategies to survive under a well-adapted immune system etc. Based......During last decade, the nature has inspired researchers to develop new algorithms. The largest collection of nature-inspired algorithms is biology-inspired: swarm intelligence (particle swarm optimization, ant colony optimization, cuckoo search, bees' algorithm, bat algorithm, firefly algorithm etc...... on collective social behaviour of organisms, researchers have developed optimization strategies taking into account not only the individuals, but also groups and environment. However, learning from nature, new classes of approaches can be identified, tested and compared against already available algorithms...

  4. Novel natural food antimicrobials.

    Science.gov (United States)

    Juneja, Vijay K; Dwivedi, Hari P; Yan, Xianghe

    2012-01-01

    Naturally occurring antimicrobial compounds could be applied as food preservatives to protect food quality and extend the shelf life of foods and beverages. These compounds are naturally produced and isolated from various sources, including plants, animals and microorganisms, in which they constitute part of host defense systems. Many naturally occurring compounds, such as nisin, plant essential oils, and natamycin, have been widely studied and are reported to be effective in their potential role as antimicrobial agents against spoilage and pathogenic microorganisms. Although some of these natural antimicrobials are commercially available and applied in food processing, their efficacy, consumer acceptance and regulation are not well defined. This manuscript reviews natural antimicrobial compounds with reference to their applications in food when applied individually or in combination with other hurdles. It also reviews the mechanism of action of selected natural antimicrobials, factors affecting their antimicrobial activities, and future prospects for use of natural antimicrobials in the food industry.

  5. On nature and bioethics.

    Science.gov (United States)

    Peterson, Paul Silas

    2010-01-01

    The account of nature and humanity's relationship to nature are of central importance for bioethics. The Scientific Revolution was a critical development in the history of this question and many contemporary accounts of nature find their beginnings here. While the innovative approach to nature going out of the seventeenth century was reliant upon accounts of nature from the early modern period, the Middle Ages, late-antiquity and antiquity, it also parted ways with some of the understandings of nature from these epochs. Here I analyze this development and suggests that some of the insights from older understandings of nature may be helpful for bioethics today, even if there can be no simple return to them.

  6. A Natural Love of Natural Products

    OpenAIRE

    Kingston, David G. I.

    2008-01-01

    Recent research on the chemistry of natural products from the author?s group that led to the receipt of the ACS Ernest Guenther Award in the Chemistry of Natural Products is reviewed. REDOR NMR and synthetic studies established the T-taxol conformation as the bioactive tubulin-binding conformation, and these results were confirmed by the synthesis of compounds which clearly owed their activity or lack of activity to whether or not they could adopt the T-taxol conformation. Similar studies wit...

  7. Natural Information Processing Systems

    OpenAIRE

    John Sweller; Susan Sweller

    2006-01-01

    Natural information processing systems such as biological evolution and human cognition organize information used to govern the activities of natural entities. When dealing with biologically secondary information, these systems can be specified by five common principles that we propose underlie natural information processing systems. The principles equate: (1) human long-term memory with a genome; (2) learning from other humans with biological reproduction; (3) problem solving through random ...

  8. Natural gas annual 1997

    International Nuclear Information System (INIS)

    1998-10-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1997 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1993 to 1997 for each Census Division and each State. Annual historical data are shown at the national level. 27 figs., 109 tabs

  9. Natural Ventilation in Atria

    DEFF Research Database (Denmark)

    Svidt, Kjeld; Heiselberg, Per; Hendriksen, Ole Juhl

    This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions.......This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions....

  10. Nature-based integration

    DEFF Research Database (Denmark)

    Pitkänen, Kati; Oratuomi, Joose; Hellgren, Daniela

    Increased attention to, and careful planning of the integration of migrants into Nordic societies is ever more important. Nature based integration is a new solution to respond to this need. This report presents the results of a Nordic survey and workshop and illustrates current practices of nature...... based integration by case study descriptions from Denmark, Sweden Norway and Finland. Across Nordic countries several practical projects and initiatives have been launched to promote the benefits of nature in integration and there is also growing academic interest in the topic. Nordic countries have...... the potential of becoming real forerunners in nature based integration even at the global scale....

  11. Natural gas annual 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-10-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1997 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1993 to 1997 for each Census Division and each State. Annual historical data are shown at the national level. 27 figs., 109 tabs.

  12. Natural gas outlook

    International Nuclear Information System (INIS)

    Molyneaux, M.P.

    1998-01-01

    An overview of natural gas markets in Canada and in the United States was provided. The major factors that determine the direction of natural gas prices were depicted graphically. Price volatility has decreased in recent months. As expected, April through November total energy consumption reached historically high levels. Demand for natural gas during the summer of 1997 was not as strong as anticipated. Nuclear energy appears to be on the slippery slope, with natural gas-driven electricity projects to fill the void. Hydroelectricity had a strong showing in 1997. Prospects are less bright for 1998 due to above average temperatures. Canadian natural gas export capacity has increased 5.5 times between 1986 and estimated 1999 levels. Despite this, in 1997, deliveries to the United States were marginally behind expectations. Natural gas consumption, comparative fuel prices, natural gas drilling activity, natural gas storage capacity, actual storage by region, and average weekly spot natural gas prices, for both the U. S. and Canada, were also provided. With regard to Canada, it was suggested that Canadian producers are well positioned for a significant increase in their price realization mostly because of the increase in Canada's export capacity in 1997 (+175 Mmcf/d), 1998 (1,060 Mmcf/d) and potentially in 1999 or 2000, via the Alliance Pipeline project. Nevertheless, with current production projections it appears next to impossible to fill the 10.9 Bcf/d of export capacity that will be potentially in place by the end of 1999. tabs., figs

  13. Nephrotoxicity of Natural Products.

    Science.gov (United States)

    Nauffal, Mary; Gabardi, Steven

    2016-01-01

    The manufacture and sale of natural products constitute a multi-billion dollar industry. Nearly a third of the American population admit to using some form of complementary or alternative medicine, with many using them in addition to prescription medications. Most patients fail to inform their healthcare providers of their natural product use and physicians rarely inquire. Annually, thousands of natural product-induced adverse events are reported to Poison Control Centers nationwide. Natural product manufacturers are not responsible for proving safety and efficacy, as the FDA does not regulate them. However, concerns exist surrounding the safety of natural products. This review provides details on natural products that have been associated with renal dysfunction. We have focused on products that have been associated with direct renal injury, immune-mediated nephrotoxicity, nephrolithiasis, rhabdomyolysis with acute renal injury, hepatorenal syndrome, and common adulterants or contaminants that are associated with renal dysfunction. The potential for natural products to cause renal dysfunction is justifiable. It is imperative that natural product use be monitored closely in all patients. Healthcare practitioners must play an active role in identifying patients using natural products and provide appropriate patient education. © 2016 S. Karger AG, Basel.

  14. Nature as Dissonant Heritage

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    accepts that nature it not existing outside culture as something that be restored to its original state, but a contemporary product created and managed with certain objectives in mind, nature restoration like heritage production are prone to same kind of dissonance – our nature is not necessary...... their nature. According to Ashworth cultural dissonance can be managed in a number of different way depending on which type of plural society is preferred. Many of these management strategies consciously or unconsciously involve some form of denial, neglect, destruction, reinterpretation or marginalizing...

  15. Oklo natural reactor

    International Nuclear Information System (INIS)

    Fujii, Isao

    1985-01-01

    In 1954, Professor Kazuo, Kuroda of Arkansas University in USA published the possibility that spontaneously generated natural nuclear reactors existed in prehistoric age. In 1972, 18 years after that, Commissariat a l'Energie Atomique published that in the Oklo uranium deposit in Gabon, Africa, a natural nuclear reactor was found. This fact was immediately informed to the whole world, but in Japan, its details have not necessarily been well known. The chance of investigating into this fact and visiting the Oklo deposit by the favor of COMUF, the owner of the Oklo deposit, was given, therefore, the state of the natural reactors, which has been known so far, is reported. At present, 12 natural reactors have been found in the vicinity of the Oklo deposit. The natural reactors were generated spontaneously in uranium deposits about 1.7 billion years ago when the isotopic abundance of U-235 was 3 %, and the chain reaction started naturally. When the concentration of U-235 lowered, the reaction stopped naturally. The abnormality in the U-235 abundance in natural uranium was found, and the cause was pursued. The evidence of the existence of natural reactors was shown. (Kako, I.)

  16. A mathematical nature walk

    CERN Document Server

    Adam, John A

    2009-01-01

    How heavy is that cloud? Why can you see farther in rain than in fog? Why are the droplets on that spider web spaced apart so evenly? If you have ever asked questions like these while outdoors, and wondered how you might figure out the answers, this is a book for you. An entertaining and informative collection of fascinating puzzles from the natural world around us, A Mathematical Nature Walk will delight anyone who loves nature or math or both. John Adam presents ninety-six questions about many common natural phenomena--and a few uncommon ones--and then shows how to answer them using mostly b

  17. A method for simulating the release of natural gas from the rupture of high-pressure pipelines in any terrain.

    Science.gov (United States)

    Deng, Yajun; Hu, Hongbing; Yu, Bo; Sun, Dongliang; Hou, Lei; Liang, Yongtu

    2018-01-15

    The rupture of a high-pressure natural gas pipeline can pose a serious threat to human life and environment. In this research, a method has been proposed to simulate the release of natural gas from the rupture of high-pressure pipelines in any terrain. The process of gas releases from the rupture of a high-pressure pipeline is divided into three stages, namely the discharge, jet, and dispersion stages. Firstly, a discharge model is established to calculate the release rate of the orifice. Secondly, an improved jet model is proposed to obtain the parameters of the pseudo source. Thirdly, a fast-modeling method applicable to any terrain is introduced. Finally, based upon these three steps, a dispersion model, which can take any terrain into account, is established. Then, the dispersion scenarios of released gas in four different terrains are studied. Moreover, the effects of pipeline pressure, pipeline diameter, wind speed and concentration of hydrogen sulfide on the dispersion scenario in real terrain are systematically analyzed. The results provide significant guidance for risk assessment and contingency planning of a ruptured natural gas pipeline. Copyright © 2017. Published by Elsevier B.V.

  18. Development and in vitro evaluation of diclofenac sodium loaded mucoadhesive microsphere with natural gum for sustained delivery.

    Science.gov (United States)

    Amin, Md Lutful; Jesmeen, Tasbira; Sutradhar, Kumar Bishwajit; Mannan, Md Abdul

    2013-12-01

    The objective of this study was to develop and evaluate mucoadhesive microsphere of diclofenac sodium with natural gums for sustained delivery. Guar gum and tragacanth were used along with sodium alginate as mucoadhesive polymers. Microspheres were formulated using orifice-ionic gelation method. Particle size, surface morphology, swelling study and drug entrapment efficiency of the prepared microspheres were determined. In vitro evaluation was carried out comprising of mucoadhesion and drug release study. The prepared microspheres were discrete and free flowing. Sodium alginate and natural gum, at a ratio of 1:0.25, showed good mucoadhesive property and they had high drug entrapment efficiencies. They also exhibited the best rate retarding effect among all the formulations. Drug entrapment efficiency of all the microspheres ranged from 80.42% to 91.67%. An inverse relationship was found between extent of crosslinking and drug release rate. Release rate was slow and extended in case of the formulations of 1:0.25 ratio (F1 and F3), releasing 68.36% and 70.56% drug respectively after 8 hours. Tragacanth-containing microspheres of F1 showed superiority over other formulations, with best mucoadhesive and rate retarding profile. The correlation value (r(2)) indicated that the drug release of all the formulations followed Higuchi's model. Overall, the results indicated that mucoadhesive microspheres containing natural gum can be promising in terms of prolonged delivery with good mucoadhesive action, targeting the absorption site to thrive oral drug delivery.

  19. Nature as Measure

    DEFF Research Database (Denmark)

    Peters, Terri

    2011-01-01

    The potential for biomimicry lies far beyond the direct imitation of natural forms. Guest-editor Terri Peters describes how Janine Benyus, the biologist and innovation consultant, is using biomimicry to create performance metrics from natural technologies and processes for assessing aspects...

  20. Modeling Natural Selection

    Science.gov (United States)

    Bogiages, Christopher A.; Lotter, Christine

    2011-01-01

    In their research, scientists generate, test, and modify scientific models. These models can be shared with others and demonstrate a scientist's understanding of how the natural world works. Similarly, students can generate and modify models to gain a better understanding of the content, process, and nature of science (Kenyon, Schwarz, and Hug…

  1. Greenland and Natural Resources

    DEFF Research Database (Denmark)

    Lyck, Lise

    Greenland policy can delay and maybe change the future of the forecasted development of the use of natural resources. This book is relevant for anyone interested in Greenland in general and the development of Greenland both politically and economically and in relation natural resources....

  2. Natural - synthetic - artificial!

    DEFF Research Database (Denmark)

    Nielsen, Peter E

    2010-01-01

    The terms "natural," "synthetic" and "artificial" are discussed in relation to synthetic and artificial chromosomes and genomes, synthetic and artificial cells and artificial life.......The terms "natural," "synthetic" and "artificial" are discussed in relation to synthetic and artificial chromosomes and genomes, synthetic and artificial cells and artificial life....

  3. European natural gas

    International Nuclear Information System (INIS)

    Thackeray, Fred

    1999-11-01

    Contains Executive Summary and Chapters on: Main issues; Natural gas consumption and supply: statistics and key features of individual countries; Sectoral natural gas consumption; Indigenous production; Imports; Prices and taxes; The spot market: The interconnector; Forecasts of production and consumption and contracted imports; Progress of markets liberalisation; Effects of environmentalist developments; Transmission networks and storage; Some principal players. (Author)

  4. Nature Foil Reliefs

    Science.gov (United States)

    Lane, Shaw J.

    2012-01-01

    Nature has always been a source of inspiration for artists across the centuries. Artists such as Leonardo da Vinci, Georgia O'Keeffe, Ansel Adams, and Andy Goldsworthy all drew inspiration for their work from nature. Seeds come from the dried pods, which when planted and cared for, bear fruit. In this article, the author describes how her…

  5. Plutonium in nature

    International Nuclear Information System (INIS)

    Madic, C.

    1994-01-01

    Plutonium in nature comes from natural sources and anthropogenic ones. Plutonium at the earth surface comes principally from anthropogenic sources. It is easily detectable in environment. The plutonium behaviour in environment is complex. It seems necessary for the future to reduce releases in environment, to improve predictive models of plutonium behaviour in geosphere, to precise biological impact of anthropogenic plutonium releases

  6. Exposure to natural radiation

    International Nuclear Information System (INIS)

    Green, B.M.R.

    1985-01-01

    A brief report is given of a seminar on the exposure to enhanced natural radiation and its regulatory implications held in 1985 at Maastricht, the Netherlands. The themes of the working sessions included sources of enhanced natural radiation, parameters influencing human exposure, measurement and survey programmes, technical countermeasures, risk and assessment studies, philosophies of dose limitations and national and international policies. (U.K.)

  7. Nature and landscape protection

    International Nuclear Information System (INIS)

    Klinda, J.; Lieskovska, Z.

    1998-01-01

    In accordance with National Council of the Slovak Republic Act N. 287/1994 Coll. on Nature and Landscape Protection, the system of complex nature landscape protection has been designed based on five levels of protection. Categories of protected areas as well as cultural monuments in the Slovak Republic are reviewed.Slovak contribution to the world heritage is included

  8. Growing natural gas usage

    International Nuclear Information System (INIS)

    Saarni, T.

    1996-01-01

    Finnish natural gas usage topped the 3.3 billion cubic metre mark last year, up 3.6 % on the 1994 figure. Growth has increased now for 12 years in a row. Thanks to offtake by large individual users, the pipeline network has been expanded from South-East Finland to the Greater Helsinki area and central southern Finland. Natural gas plays a much larger role in this region than the 10 % accounted for by natural gas nationally would indicate. The growth in the share of Finland's energy use accounted for by natural gas has served to broaden the country's energy supply base. Natural gas has replaced coal and oil, which has considerably reduced the level of emissions resulting form energy generation

  9. Unnaturalised racial naturalism.

    Science.gov (United States)

    Hochman, Adam

    2014-06-01

    Quayshawn Spencer (2014) misunderstands my treatment of racial naturalism. I argued that racial naturalism must entail a strong claim, such as "races are subspecies", if it is to be a substantive position that contrasts with anti-realism about biological race. My recognition that not all race naturalists make such a strong claim is evident throughout the article Spencer reviews (Hochman, 2013a). Spencer seems to agree with me that there are no human subspecies, and he endorses a weaker form of racial naturalism. However, he supports his preferred version of 'racial naturalism' with arguments that are not well described as 'naturalistic'. I argue that Spencer offers us an unnaturalised racial naturalism. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. "Diseases and natural kinds".

    Science.gov (United States)

    Sulmasy, Daniel P

    2005-01-01

    David Thomasma called for the development of a medical ethics based squarely on the philosophy of medicine. He recognized, however, that widespread anti-essentialism presented a significant barrier to such an approach. The aim of this article is to introduce a theory that challenges these anti-essentialist objections. The notion of natural kinds presents a modest form of essentialism that can serve as the basis for a foundationalist philosophy of medicine. The notion of a natural kind is neither static nor reductionistic. Disease can be understood as making necessary reference to living natural kinds without invoking the claim that diseases themselves are natural kinds. The idea that natural kinds have a natural disposition to flourish as the kinds of things that they are provides a telos to which to tether the notion of disease - an objective telos that is broader than mere survival and narrower than subjective choice. It is argued that while nosology is descriptive and may have therapeutic implications, disease classification is fundamentally explanatory. Sickness and illness, while referring to the same state of affairs, can be distinguished from disease phenomenologically. Scientific and diagnostic fallibility in making judgments about diseases do not diminish the objectivity of this notion of disease. Diseases are things, not kinds. Injury is a concept parallel to disease that also makes necessary reference to living natural kinds. These ideas provide a new possibility for the development of a philosophy of medicine with implications for medical ethics.

  11. Almacenamiento de gas natural

    Directory of Open Access Journals (Sweden)

    Tomás Correa

    2008-12-01

    Full Text Available The largest reserves of natural gas worldwide are found in regions far of main cities, being necessary different alternatives to transport the fluid to the consumption cities, such as pipelines, CNG or ships, LNG, depending on distances between producing regions and demanding regions and the producing volumes. Consumption regions have three different markets to naturalgas; residential and commercial, industrial and power generation sector. The residential and commercial is highly seasonal and power generation sector is quite variable depending on increases of temperature during summer time. There are also external issuesthat affect the normal gas flow such as fails on the national system or unexpected interruptions on it, what imply that companies which distribute natural gas should design plans that allow supplying the requirements above mentioned. One plan is using underground natural gas storage with capacities and deliverability rates enough to supply demands. In Colombia there are no laws in this sense but it could be an exploration to discuss different ways to store gas either way as underground natural gas storage or above superficies. Existing basically three different types of underground natural gas storage; depleted reservoirs, salt caverns and aquifers. All ofthem are adequate according to geological characteristics and the needs of the distributors companies of natural gas. This paper is anexploration of technical and economical characteristics of different kind of storages used to store natural gas worldwide.

  12. Natural convection in closed vertical cylinders with particular reference to gas cooled reactor standpipes

    International Nuclear Information System (INIS)

    Spence, I.D.

    1975-09-01

    The access to the core for fuel assemblies and control rods of the Advanced Gas Cooled Reactor is through the top cap by means of standpipes. The standpipe is essentially a cylindrical, vertical tube with cooled side wall, closed upper end and an orifice at the lower end which is exposed to the hot core fluid. This creates confined natural convection flow in the empty standpipe and this is the subject of this thesis. The investigation is carried out using analytical and experimental methods. For the analytical work, solution of laminar and turbulent flow is attempted using finite-difference computer techniques. The laminar flow performance is evaluated using two different finite-difference procedures, and the results are compared to each other and to existing analytical and experimental results for the open thermosyphon with cool inflow and hot sidewall, i.e. the complementary problem to the present one. For turbulent flow a two equation turbulence model is employed which provides transport equations for the kinetic energy of turbulence and its dissipation rate. The experimental rig is a full scale replica of the Advanced Gas Cooled Reactor control rod mechanism standpipe. Carbon dioxide and helium are used as the working fluids for the series of tests. (author)

  13. Natural gas in Mexico

    International Nuclear Information System (INIS)

    Ramirez, M.

    1999-01-01

    A series of overhead viewgraphs accompanied this presentation which focused on various aspects of the natural gas industry in Mexico. Some of the viewgraphs depicted statistics from 1998 regarding natural gas throughput from various companies in North America, natural gas reserves around the world, and natural gas reserves in Mexico. Other viewgraphs depicted associated and non-associated natural gas production from 1988 to 1998 in million cubic feet per day. The Burgos Basin and the Cantarell Basin gas production from 1997 to 2004 was also depicted. Other viewgraphs were entitled: (1) gas processing infrastructure for 1999, (2) cryogenic plant at Cd. PEMEX, (3) average annual growth of dry natural gas production for 1997-2004 is estimated at 5.2 per cent, (4) gas flows for December 1998, (5) PGPB- interconnect points, (6) U.S. Mexico gas trade for 1994-1998, (7) PGPB's interconnect projects with U.S., and (8) natural gas storage areas. Technological innovations in the industry include more efficient gas turbines which allow for cogeneration, heat recovery steam generators which reduce pollutant emissions by 21 per cent, cold boxes which increase heat transfer efficiency, and lateral reboilers which reduce energy consumption and total costs. A pie chart depicting natural gas demand by sector shows that natural gas for power generation will increase from 16 per cent in 1997 to 31 per cent in 2004. The opportunities for cogeneration projects were also reviewed. The Comision Federal de Electricidad and independent power producers represent the largest opportunity. The 1997-2001 investment program proposes an 85 per cent sulphur dioxide emission reduction compared to 1997 levels. This presentation also noted that during the 1998-2001 period, total ethane production will grow by 58 tbd. 31 figs

  14. Closer to Nature?

    DEFF Research Database (Denmark)

    Borkfelt, Sune; Kondrup, Sara; Röcklinsberg, Helena

    2015-01-01

    discourses in order to sell one image of animal welfare in intensive animal production while the actual production at the same time presupposes a quite different paradigm of animal welfare. Specifically, product advertising utilizes representations tied to concepts of naturalness in depictions of both animal...... lives and product processes as “natural”. Product marketing suggests a coherence between nature, production process (farm, animal), and end product, thereby creating associations that the lives of production animals are lived in nature and that their products bring a wholesome and sustainable...

  15. Natural radiation environment

    International Nuclear Information System (INIS)

    Vohra, K.G.; Mishra, U.C.; Pillai, K.C.; Sadasivan, S.

    1982-01-01

    The volume presented contains papers presented at the Second Special Symposium on Natural Radiation Environment held at Bombay, India, during January 1981. The papers deal with such topics as : 1)high natural radiation background areas; 2)environmental natural radioactivity; 3)measurement techniques; 4)technologically enhanced radioactivity; 5)indoor radiation environment; 6)radon and daughters in ambient air, and 7)applications in Geosciences. Each of the 87 papers presented has been abstracted and indexed for the U.S. Department of Energy Technical Information Center's Energy Data Base

  16. EEC's: natural uramium supplies

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The demand for nuclear fuel to supply the nuclear plants within the ECC (31,200 MW at the end of last year) totalled nearly 9,600 tons of natural uranium and 4,900 of separation work units (SWU). Once reactors currently under construction come into service, the demand for natural uranium will reach 13,200 tons by 1985 and that for SWUs to 8,600. If one takes the years 1981 to 1985, total natural uranium needs during this period will be 56,300 tons and those for SWUs 35.100 [fr

  17. Living in cities, naturally.

    Science.gov (United States)

    Hartig, Terry; Kahn, Peter H

    2016-05-20

    Natural features, settings, and processes in urban areas can help to reduce stress associated with urban life. In this and other ways, public health benefits from, street trees, green roofs, community gardens, parks and open spaces, and extensive connective pathways for walking and biking. Such urban design provisions can also yield ecological benefits, not only directly but also through the role they play in shaping attitudes toward the environment and environmental protection. Knowledge of the psychological benefits of nature experience supports efforts to better integrate nature into the architecture, infrastructure, and public spaces of urban areas. Copyright © 2016, American Association for the Advancement of Science.

  18. The unnatural racial naturalism.

    Science.gov (United States)

    Spencer, Quayshawn

    2014-06-01

    In the recent article, "Against the New Racial Naturalism", Adam Hochman (2013, p. 332) argues that new racial naturalists have been too hasty in their racial interpretation of genetic clustering results of human populations. While Hochman makes a number of good points, the purpose of this paper is to show that Hochman's attack on new racial naturalists is misguided due to his definition of 'racial naturalism'. Thus, I will show that Hochman's critique is merely a consequence of an unnatural interpretation of racial naturalism. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Diagrams of natural deductions

    Energy Technology Data Exchange (ETDEWEB)

    Popov, S V

    1982-01-01

    The concept of natural deductions was investigated by the author in his analysis of the complexity of deductions in propositional computations (1975). Here some natural deduction systems are considered, and an analytical procedure proposed which results in a deduction diagram for each system. Each diagram takes the form of an orientated, charge graph, features of which can be used to establish the equivalence of classes of deductions. For each of the natural deduction systems considered, a system of equivalent transformation schemes is derived, which is complete with respect to the given definition of equivalence. 2 references.

  20. Web life: Ask Nature

    Science.gov (United States)

    2012-11-01

    Ask Nature is a site devoted to biomimicry, an interdisciplinary field in which practitioners study how animals and plants solve problems, and then use those solutions to develop better human technologies.

  1. Natural Gas Acquisition Program

    Data.gov (United States)

    General Services Administration — The "NGAP" system is a web based application which serves NGAP GSA users for tracking information details for various natural gas supply chain elements like Agency,...

  2. Sciences & Nature: Submissions

    African Journals Online (AJOL)

    Sciences & nature publish original works in French or in English that have not been ... This page should provide a summary (200 words maximum) in French and English .... one copy of the journal where his article is published, and 10 offprints.

  3. Natural Hazards Image Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Photographs and other visual media provide valuable pre- and post-event data for natural hazards. Research, mitigation, and forecasting rely on visual data for...

  4. The Nature of Grammar

    Institute of Scientific and Technical Information of China (English)

    王楠

    2012-01-01

    This paper describes the nature of grammar as "universalness". The universal grammar indicates that all the languages in the world have identical grammar. This is discussed from three aspects, which gives insight into grammar acquisition.

  5. Art, Technology and Nature

    DEFF Research Database (Denmark)

    Camilla Skovbjerg Paldam and Jacob Wamberg trace the Kantian heritage of radically separating art and technology, and inserting both at a distance to nature, suggesting this was a transient chapter in history. Thus, they argue, the present renegotiation between art, technology and nature is reminiscent......Since 1900, the connections between art and technology with nature have become increasingly inextricable. Through a selection of innovative readings by international scholars, this book presents the first investigation of the intersections between art, technology and nature in post-medieval times....... Transdisciplinary in approach, this volume’s 14 essays explore art, technology and nature’s shifting constellations that are discernible at the micro level and as part of a larger chronological pattern. Included are subjects ranging from Renaissance wooden dolls, science in the Italian art academies, and artisanal...

  6. Historic Natural Vegetation

    Data.gov (United States)

    California Natural Resource Agency — In 2001, the US Fish and Wildlife Service (USFWS) and the U.S. Bureau of Reclamation (BOR) contracted with the California State University, Chico Research Foundation...

  7. Vermont Designated Natural Areas

    Data.gov (United States)

    Vermont Center for Geographic Information — Under Natural Areas Law (10 Vermont Statutes Annotated, Chapter 83 � 2607) the FPR commissioner, with the approval of the governor, may designate and set aside areas...

  8. Radon - natural health threat

    International Nuclear Information System (INIS)

    Wrixon, Anthony

    1985-01-01

    Natural sources of radiation attract little attention, yet a survey has found radon gas in buildings at levels which put the occupants at some risk. The author wants safety standards set without undue delay. (author)

  9. Natural gas pricing

    International Nuclear Information System (INIS)

    Freedenthal, C.

    1993-01-01

    Natural gas pricing is the heart and soul of the gas business. Price specifically affects every phase of the industry. Too low a price will result in short supplies as seen in the mid-1970s when natural gas was scarce and in tight supply. To fully understand the pricing of this energy commodity, it is important to understand the total energy picture. In addition, the effect and impact of world and US economies, and economics in general are crucial to understanding natural gas pricing. The purpose of this presentation will be to show the parameters going into US natural gas pricing including the influence of the many outside industry factors like crude oil and coal pricing, market drivers pushing the gas industry, supply/demand parameters, risk management for buyers and sellers, and other elements involved in pricing analysis

  10. Natural Gas STAR Program

    Science.gov (United States)

    EPA’s Voluntary Methane Programs encourage oil and natural gas companies to adopt cost-effective technologies and practices that improve operational efficiency and reduce emissions of methane, a potent greenhouse gas.

  11. Natural gas for vehicles

    International Nuclear Information System (INIS)

    Chauveron, S. de

    1996-01-01

    This article presents compressed natural gas for vehicles (CNG), which can provide considerable advantages both as an alternative fuel and as a clean fuel. These assets are not only economic but also technical. The first part deals with what is at stake in developing natural gas as a motor fuel. The first countries to use CNG were those with natural gas resources in their subsoil. Today, with a large number of countries having to cope with growing concern about increasing urban pollution, natural gas is also seen as a clean fuel that can help cut vehicle pollutant emissions dramatically. In the second part a brief technical descriptions is given of CNG stations and vehicles, with the aim of acquainting the reader with some of CNG's specific technical features as compared to gasoline and diesel oil. Here CNG technologies are seen to be very close to the more conventional ones. (author)

  12. Natural polymers: an overview

    CSIR Research Space (South Africa)

    John, MJ

    2012-08-01

    Full Text Available The scarcity of natural polymers during the world war years led to the development of synthetic polymers like nylon, acrylic, neoprene, styrene-butadiene rubber (SBR) and polyethylene. The increasing popularity of synthetic polymers is partly due...

  13. Solitonic natural orbitals

    Science.gov (United States)

    Cioslowski, Jerzy

    2018-04-01

    The dependence of the natural amplitudes of the harmonium atom in its ground state on the confinement strength ω is thoroughly investigated. A combination of rigorous analysis and extensive, highly accurate numerical calculations reveals the presence of only one positive-valued natural amplitude ("the normal sign pattern") for all ω ≥1/2 . More importantly, it is shown that unusual, weakly occupied natural orbitals (NOs) corresponding to additional positive-valued natural amplitudes emerge upon sufficient weakening of the confinement. These solitonic NOs, whose shapes remain almost invariant as their radial positions drift toward infinity upon the critical values of ω being approached from below, exhibit strong radial localization. Their asymptotic properties are extracted from the numerical data and their relevance to calculations on fully Coulombic systems is discussed.

  14. Biomimetics: nature based innovation

    National Research Council Canada - National Science Library

    Bar-Cohen, Yoseph

    2012-01-01

    "Based on the concept that nature offers numerous sources of inspiration for inventions related to mechanisms, materials, processes, and algorithms, this book covers the topic of biomimetics and the inspired innovation...

  15. Natural gas benefits

    International Nuclear Information System (INIS)

    1999-01-01

    The General Auditor in the Netherlands studied the natural gas policy in the Netherlands, as has been executed in the past decades, in the period 1997-1999. The purpose of the study is to inform the Dutch parliament on the planning and the backgrounds of the natural gas policy and on the policy risks with respect to the benefits for the Dutch State, taking into account the developments in the policy environment. The final conclusion is that the proposed liberalization of the national natural gas market will result in a considerable deprivation of income for the State in case the benefit policy is not adjusted. This report includes a reaction of the Dutch Minister of Economic Affairs and an afterword of the General Auditor. In the appendix an outline is given of the natural gas policy

  16. Natural Gas Market Hubs

    Data.gov (United States)

    Department of Homeland Security — A hub is a physical transfer point for natural gas where several pipelines are connected. A market center is a hub where the operator offers services that facilitate...

  17. Managing soil natural capital

    DEFF Research Database (Denmark)

    Cong, Ronggang; Termansen, Mette; Brady, Mark

    2017-01-01

    Farmers are exposed to substantial weather and market related risks. Rational farmers seek to avoid large losses. Future climate change and energy price fluctuations therefore make adaptating to increased risks particularly important for them. Managing soil natural capital—the capacity of the soil...... to generate ecosystem services of benefit to farmers—has been proven to generate the double dividend: increasing farm profit and reducing associated risk. In this paper we explore whether managing soil natural capital has a third dividend: reducing the downside risk (increasing the positive skewness of profit......). This we refer to as the prudence effect which can be viewed as an adaptation strategy for dealing with future uncertainties through more prudent management of soil natural capital. We do this by developing a dynamic stochastic portfolio model to optimize the stock of soil natural capital—as indicated...

  18. Lesson "Balance in Nature

    Science.gov (United States)

    Chapanova, V.

    2012-04-01

    Lesson "Balance in Nature" This simulation game-lesson (Balance in Nature) gives an opportunity for the students to show creativity, work independently, and to create models and ideas. It creates future-oriented thought connected to their experience, allowing them to propose solutions for global problems and personal responsibility for their activities. The class is divided in two teams. Each team chooses questions. 1. Question: Pollution in the environment. 2. Question: Care for nature and climate. The teams work on the chosen tasks. They make drafts, notes and formulate their solutions on small pieces of paper, explaining the impact on nature and society. They express their points of view using many different opinions. This generates alternative thoughts and results in creative solutions. With the new knowledge and positive behaviour defined, everybody realizes that they can do something positive towards nature and climate problems and the importance of individuals for solving global problems is evident. Our main goal is to recover the ecological balance, and everybody explains his or her own well-grounded opinions. In this work process the students obtain knowledge, skills and more responsible behaviour. This process, based on his or her own experience, dialogue and teamwork, helps the participant's self-development. Making the model "human↔ nature" expresses how human activities impact the natural Earth and how these impacts in turn affect society. Taking personal responsibility, we can reduce global warming and help the Earth. By helping nature we help ourselves. Teacher: Veselina Boycheva-Chapanova " Saint Patriarch Evtimii" Scholl Str. "Ivan Vazov"-19 Plovdiv Bulgaria

  19. More natural gas

    International Nuclear Information System (INIS)

    Leprince, P.; Valais, M.

    1993-01-01

    This paper reports that large resources and growing markets are the salient prospects of natural gas for the coming decades. The greater impact of natural gas on the worldwide energy market can become a reality if several scientific disciplines can be mobilized in order to succeed in cutting production costs. Modeling, mechanics of complex fluids, and physical chemistry of interfaces are basic disciplines for understanding and mastering the gas processing technologies

  20. Natural rubber: leather composites

    OpenAIRE

    Ravichandran,K.; Natchimuthu,N.

    2005-01-01

    Leather is a fibrous protein consisting of collagen in a three dimensionally crosslinked network. Chrome tanning of leather improves the appearance of leather but at the same time emits both solid and liquid chrome leather wastes. Scrap rubber recycling using untreated and neutralized leather fibrous particles in natural rubber has been studied. Vulcanization, mechanical, morphological and swelling properties of the natural rubber - scrap rubber composites containing neutralized leather have ...

  1. Natural Hazards, Second Edition

    Science.gov (United States)

    Rouhban, Badaoui

    Natural disaster loss is on the rise, and the vulnerability of the human and physical environment to the violent forces of nature is increasing. In many parts of the world, disasters caused by natural hazards such as earthquakes, floods, landslides, drought, wildfires, intense windstorms, tsunami, and volcanic eruptions have caused the loss of human lives, injury, homelessness, and the destruction of economic and social infrastructure. Over the last few years, there has been an increase in the occurrence, severity, and intensity of disasters, culminating with the devastating tsunami of 26 December 2004 in South East Asia.Natural hazards are often unexpected or uncontrollable natural events of varying magnitude. Understanding their mechanisms and assessing their distribution in time and space are necessary for refining risk mitigation measures. This second edition of Natural Hazards, (following a first edition published in 1991 by Cambridge University Press), written by Edward Bryant, associate dean of science at Wollongong University, Australia, grapples with this crucial issue, aspects of hazard prediction, and other issues. The book presents a comprehensive analysis of different categories of hazards of climatic and geological origin.

  2. Natural Resource Management Plan

    Energy Technology Data Exchange (ETDEWEB)

    Green, T. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Schwager, K. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2016-10-01

    This comprehensive Natural Resource Management Plan (NRMP) for Brookhaven National Laboratory (BNL) was built on the successful foundation of the Wildlife Management Plan for BNL, which it replaces. This update to the 2003 plan continues to build on successes and efforts to better understand the ecosystems and natural resources found on the BNL site. The plan establishes the basis for managing the varied natural resources located on the 5,265-acre BNL site, setting goals and actions to achieve those goals. The planning of this document is based on the knowledge and expertise gained over the past 15 years by the Natural Resources management staff at BNL in concert with local natural resource agencies including the New York State Department of Environmental Conservation, Long Island Pine Barrens Joint Planning and Policy Commission, The Nature Conservancy, and others. The development of this plan works toward sound ecological management that not only benefits BNL’s ecosystems but also benefits the greater Pine Barrens habitats in which BNL is situated. This plan applies equally to the Upton Ecological and Research Reserve (Upton Reserve). Any difference in management between the larger BNL area and the Upton Reserve are noted in the text.

  3. The system of nature

    CERN Document Server

    D'Holbac, Baron

    1999-01-01

    "The source of Man's unhappiness is his ignorance of Nature."D'Holbach believed that the misery he saw in mankind around him was caused by religion and its superstitious beliefs - that there was a God who controlled destiny and would reward or punish individuals. The System of Nature was written to replace these delusions with a schema of understanding based solely on the physical workings of nature. "Let Man study this nature, let him learn her laws, contemplate her energies." For d'Holbach the soul is only the physical body, understood from a certain point of view, which dies when the body dies. All the events and the nature of the world can be understood in terms of the motion and properties of matter; even the tiniest causes contribute to huge events - a simple change in the diet of an Emperor (or some other such insignificant cause), he suggests might have been capable of "saving kingdoms." For him, nature's laws are fixed and necessary, and if Man wants to find happiness it is best to accept this - if g...

  4. Natural gas prices

    International Nuclear Information System (INIS)

    Johnson, W.A.

    1990-01-01

    Since the 1970s, many electric utilities and industrial boiler fuel users have invested in dual fuel use capability which has allowed them to choose between natural gas, residual fuel oil, and in some instances, coal as boiler fuels. The immediate reason for this investment was the need for security of supply. Wellhead regulation of natural gas prices had resulted in shortages during the 1970s. Because many industrial users were given lowest priority in pipeline curtailments, these shortages affected most severely boiler fuel consumption of natural gas. In addition, foreign supply disruptions during the 1970s called into question the ready availability of oil. Many boiler fuel users of oil responded by increasing their ability to diversify to other sources of energy. Even though widespread investment in dual fuel use capability by boiler fuel users was initially motivated by a need for security of supply, perhaps the most important consequence of this investment was greater substitutability between natural gas and resid and a more competitive boiler fuel market. By the early 1980s, most boiler fuel users were able to switch from one fuel to another and often did for savings measured in pennies per MMBtu. Boiler fuel consumption became the marginal use of both natural gas and resid, with coal a looming threat on the horizon to both fuels

  5. Natural Dietary Phytosterols.

    Science.gov (United States)

    Racette, Susan B; Lin, Xiaobo; Ma, Lina; Ostlund, Richard E

    2015-01-01

    Most clinical phytosterol studies are performed by adding purified supplements to smaller phytosterol amounts present in the natural diet. However, natural dietary phytosterols themselves may also have important effects on cholesterol metabolism. Epidemiological work using food frequency questionnaires to estimate dietary intake suggest that extremes of normal consumption may be associated with 3-14% changes in LDL cholesterol. Standardized food databases do not have enough phytosterol values to allow calculation of phytosterol intake for individuals outside of specialized studies. Natural diets contain phytosterol amounts ranging from less than 60 mg/2000 kcal to over 500 mg/2000 kcal. Physiological studies in which whole body cholesterol metabolism is investigated show large effects of natural dietary phytosterols on cholesterol absorption efficiency, cholesterol biosynthesis and cholesterol excretion which exceed the magnitude of changes in LDL cholesterol. The dual effects of natural phytosterols on both LDL-C and whole body cholesterol metabolism need to be considered in relating them to potential protection from coronary heart disease risk.

  6. Symmetries in nature

    International Nuclear Information System (INIS)

    Mainzer, K.

    1988-01-01

    Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs

  7. Symmetries in nature

    Energy Technology Data Exchange (ETDEWEB)

    Mainzer, K

    1988-05-01

    Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs.

  8. Natural gas purchasing

    International Nuclear Information System (INIS)

    Freedenthal, C.

    1993-01-01

    In recent years, natural gas has gained new momentum because of changes in marketing and regulations. The gas industry has always received an inordinate amount of regulatory control starting at the well head where the gas is produced to the consuming burner tip. Regulations have drastically impacted the availability of gas. Changes in the marketing and regulations have made the natural gas market sensitive at the point of production, the well head. Now, with plentiful supply and ease of transportation to bring the gas from the producing fields to the consumer, natural gas markets are taking advantage of the changed conditions. At the same time, new markets are developing to take advantage of the changes. This section shows consumers, especially the energy planners for large buyers of fuel, the advantages, sources and new methods of securing natural gas supplies. Background on how natural gas is produced and marketed are given. This section lists marketing sources, regulatory agencies and information groups available to help buyers and consumers of this important fuel for US industries and residences. 7 figs., 8 tabs

  9. Naturalness and Animal Welfare.

    Science.gov (United States)

    Yeates, James

    2018-04-05

    Naturalness is considered important for animals, and is one criterion for assessing how we care for them. However, it is a vague and ambiguous term, which needs definition and assessments suitable for scientific and ethical questions. This paper makes a start on that aim. This paper differentiates the term from other related concepts, such as species-typical behaviour and wellbeing. It identifies contingent ways in which naturalness might be used, as: (i) prompts for further welfare assessment; (ii) a plausible hypothesis for what safeguards wellbeing; (iii) a threshold for what is acceptable; (iv) constraints on what improvements are unacceptable; and (v) demarcating what is not morally wrong, because of a lack of human agency. It then suggests an approach to evaluating animals' behaviour that is quantitative, is based on reality, and which assesses naturalness by degrees. It proposes classing unaffected wild populations as natural by definition. Where animals might have been affected by humans, they should be compared to the closest population(s) of unaffected animals. This approach could allow us both to assess naturalness scientifically, and to make practical decisions about the behaviour of domestic animals.

  10. Natural gas deregulation

    International Nuclear Information System (INIS)

    Ronchi, M.

    1993-01-01

    With the aim of establishing realistic options for deregulation in the natural gas industry, this paper first considers the structural evolution of this industry and evidences how it differs from the petroleum industry with which it exhibits some essential characteristics in common. This comparison is made in order to stress that, contrary to popular belief, that which is without doubt good for the petroleum industry is not necessarily so also for the natural gas industry. The paper concludes with separate analyses of the natural gas markets in the principal industrialized countries. Arguments are provided to show that the 'soft' deregulation option for the natural gas industry is not feasible, and that 'total' deregulation instead, backed by the passing of a suitable package of anti-trust laws 'unbundling' the industry's four major activities, i.e., production, storage, primary and secondary distribution, is the preferable option. The old concept of guaranteed supplies for minor users of natural gas should give way to the laws of supply and demand governing inter-fuel competition ensured through the strict supervision of vigilance committees

  11. Okulo natural reactors

    International Nuclear Information System (INIS)

    Yamakawa, Minoru

    1993-01-01

    French CEA has reported in 1972 that natural nuclear reactors existed in Okulo uranium deposit in Gabon in Africa, that caused nuclear fission chain reaction (Okulo phenomena) spontaneously two billion years ago. The fission products and transuranic elements produced by the natural reactors have been preserved in strata without movement while subjected to geological phenomena for such very long years. 16 zones of the natural reactors have been discovered so far. The geological features of the Okulo uranium deposit are explained. The total amount of 235 U lost by the chain reaction was estimated to be about 6t, and the fission products were about 6t. The Okulo phenomena offered the valuable results of the synthetic formation disposal test that the nature has carried out for such long years. The significance of the study on natural analog is discussed. Organic substances and the mechanism of holding and movement of uranium and fission nuclides, the stability of uraninite and the age measurement of the deposit by Nd-Sm process are reported as the main results. (K.I.)

  12. Hauntings of Human Nature

    DEFF Research Database (Denmark)

    Clasen, Mathias

    2017-01-01

    The central conflicts of Stephen King’s horror novel The Shining are rooted in human nature and reflect evolutionarily recurrent adaptive problems—the problem of balancing conflicting evolved motives, such as motives for selfish status striving versus motives for affiliative nurturing behavior......, and the problem of surviving the hostile forces of nature. Moreover, the supernatural elements of the novel resonate with evolved intuitions about non-material, moral forces at work in the world. That is why the novel continues to engage readers worldwide. Most critics, however, have overlooked or distorted...... the psychological underpinnings of the novel and the crucial function of the supernatural elements in the meaning structure of the novel. Hence we need an evolutionary psychological perspective which builds on recent findings in the sciences of human nature to account for the novel’s meaning, effects, and continued...

  13. Nature/culture/seawater.

    Science.gov (United States)

    Helmreich, Stefan

    2011-01-01

    Seawater has occupied an ambiguous place in anthropological categories of "nature" and "culture." Seawater as nature appears as potentiality of form and uncontainable flux; it moves faster than culture - with culture frequently figured through land-based metaphors - even as culture seeks to channel water's (nature's) flow. Seawater as culture manifests as a medium of pleasure, sustenance, travel, disaster. I argue that, although seawater's qualities in early anthropology were portrayed impressionistically, today technical, scientific descriptions of water's form prevail. For example, processes of globalization - which may also be called "oceanization" - are often described as "currents," "flows," and "circulations." Examining sea-set ethnography, maritime anthropologies, and contemporary social theory, I propose that seawater has operated as a “theory machine” for generating insights about human cultural organization. I develop this argument with ethnography from the Sargasso Sea and in the Sea Islands. I conclude with a critique of appeals to water's form in social theory.

  14. nature in the city

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2016-08-01

    The object of the issue is a wonderful museum on the Kulikovo Field designed by Sergey Gnedovsky. The unusual architecture of the new museum makes it akin to the earth’s tectonic fault caused by an intolerable tension in expectation of the battle (pp. 113-123. Oleg Yavein and Ilya Lezhava bring us back to the classic of the 20th century Mies van der Rohe and his unique dialogue with nature (pp. 162-175. Relationship between architecture and nature is a rich and limitless theme, like both of these substances. That is why the new Project Baikal issue contains, as usual, more questions than answers. Such is the nature of our journal.

  15. Natural Gas Regulation

    International Nuclear Information System (INIS)

    1995-01-01

    The regulation of Natural Gas. Natural gas Regulation clarifies and consolidates the legal and institutional framework for development of the industry through six principal elements: 1) Establishment of a vision of the industry. 2) Development of regulatory objectives. 3) Determination of relationships among industry participants. 4) Clear specification of the role of PEMEX in the industry. 5) Definition of the functions of the Regulatory authority. 6) Creation of a transition regime. In parallel with the development of the substantive legal framework, the law of the Comision Reguladora de Energia (CRE) was also enacted by Congress in October 1995 to strength the institutional framework and implement the legal changes. This law defines the CRE as an agency of the Energy Ministry with technical, operational, and budgetary autonomy, and responsibility for implementing natural gas industry regulation. (Author)

  16. Natural resource damage assessment

    International Nuclear Information System (INIS)

    Seddelmeyer, J.

    1991-01-01

    The assessment and collection of natural resource damages from petroleum and chemical companies unfortunate enough to have injured publicly owned natural resources is perhaps the most rapidly expanding area of environmental liability. The idea of recovering for injury to publicly owned natural resources is an extension of traditional common law tort concepts under which a person who negligently injures another or his property is called upon to compensate the injured party. Normally, once liability has been established, it is a fairly straightforward matter to calculate the various elements of loss, such as the cost to repair or replace damaged property, or medical expenses, and lost income. More difficult questions, such as the amount to be awarded for pain and suffering or emotional distress, are left to the jury, although courts limit the circumstances in which the jury is permitted to award such damages

  17. Livelihoods and natural resources

    DEFF Research Database (Denmark)

    Cotta, Jamie Nicole

    generation and shock coping. In addition, a multi-method approach (utilizing income, transect inventory and free-list data) demonstrates the significant economic importance of agroforestry environments, particularly managed fallows, when compared with natural forests. Interventions aimed at sustaining...... by both high vulnerability (e.g., residents with flood-vulnerable cultivation) and limited availability/diversity of environmentally-sourced coping products. Finally, future research and development initiatives should take into account not just natural forests or agricultural systems, but also......This dissertation research contributes to the emerging body of knowledge on the economic contributions of natural resources to rural livelihoods, including their role in household shock coping, in the humid tropics. Data from one of the first comprehensive household income quantifications...

  18. Natural photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Vigneron, Jean Pol, E-mail: jean-pol.vigneron@fundp.ac.be [Research Center in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), rue de Bruxelles, 61, B-5000 Namur (Belgium); Simonis, Priscilla [Research Center in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), rue de Bruxelles, 61, B-5000 Namur (Belgium)

    2012-10-15

    Photonic structures appeared in nature several hundred millions years ago. In the living world, color is used for communication and this important function strongly impacts the individual chances of survival as well as the chances to reproduce. This has a statistical influence on species populations. Therefore, because they are involved in evolution, natural color-generating structures are - from some point of view - highly optimized. In this short review, a survey is presented of the development of natural photonic crystal-type structures occurring in insects, spiders, birds, fishes and other marine animals, in plants and more, from the standpoint of light-waves propagation. One-, two-, and three-dimensional structures will be reviewed with selected examples.

  19. Antiplasmodial Natural Products

    Directory of Open Access Journals (Sweden)

    Cláudio R. Nogueira

    2011-03-01

    Full Text Available Malaria is a human infectious disease that is caused by four species of Plasmodium. It is responsible for more than 1 million deaths per year. Natural products contain a great variety of chemical structures and have been screened for antiplasmodial activity as potential sources of new antimalarial drugs. This review highlights studies on natural products with antimalarial and antiplasmodial activity reported in the literature from January 2009 to November 2010. A total of 360 antiplasmodial natural products comprised of terpenes, including iridoids, sesquiterpenes, diterpenes, terpenoid benzoquinones, steroids, quassinoids, limonoids, curcubitacins, and lanostanes; flavonoids; alkaloids; peptides; phenylalkanoids; xanthones; naphthopyrones; polyketides, including halenaquinones, peroxides, polyacetylenes, and resorcylic acids; depsidones; benzophenones; macrolides; and miscellaneous compounds, including halogenated compounds and chromenes are listed in this review.

  20. Natural rubber: leather composites

    Directory of Open Access Journals (Sweden)

    K. Ravichandran

    2005-06-01

    Full Text Available Leather is a fibrous protein consisting of collagen in a three dimensionally crosslinked network. Chrome tanning of leather improves the appearance of leather but at the same time emits both solid and liquid chrome leather wastes. Scrap rubber recycling using untreated and neutralized leather fibrous particles in natural rubber has been studied. Vulcanization, mechanical, morphological and swelling properties of the natural rubber - scrap rubber composites containing neutralized leather have been discussed. Use of chrome leather particles has been found to improve the consumption of scrap rubber powder in natural rubber formulations. Polymer composites based on leather wastes as fillers are reported to be useful for many applications such as in construction materials, automobile interior moldings, heat and sound insulating boards, shoe soles, flooring materials and moldings with good anti-static properties, air permeability and good appearances.

  1. Canadian natural gas

    International Nuclear Information System (INIS)

    Lucas, D.A.

    1991-01-01

    Canada's natural gas industry enjoys a quiet confidence as it looks ahead to the 1990s. In this paper, the author explains why, despite some critical uncertainties, the optimism endures. Reviewing the current conditions of supply, production, consumption, pipelines, and pipeline expansion plans, the author contends that the New World of the 1990s will belong to natural gas. The author's assessment of natural gas markets proceeds far beyond the borders of Canada. The author examines the determinants of gas prices throughout North America and he identifies the one force that promises to seize almost complete control of gas prices throughout the continent. While the analysis points out the attributes of this new pricing regime, it also names the obstacles that could prevent this emerging mechanism from assuming its anticipated position

  2. Natural photonic crystals

    International Nuclear Information System (INIS)

    Vigneron, Jean Pol; Simonis, Priscilla

    2012-01-01

    Photonic structures appeared in nature several hundred millions years ago. In the living world, color is used for communication and this important function strongly impacts the individual chances of survival as well as the chances to reproduce. This has a statistical influence on species populations. Therefore, because they are involved in evolution, natural color-generating structures are - from some point of view - highly optimized. In this short review, a survey is presented of the development of natural photonic crystal-type structures occurring in insects, spiders, birds, fishes and other marine animals, in plants and more, from the standpoint of light-waves propagation. One-, two-, and three-dimensional structures will be reviewed with selected examples.

  3. Natural gas's hottest spot

    International Nuclear Information System (INIS)

    Peterson, T.

    1993-01-01

    This paper reviews the growing power and economic strength of Enron Corp., a natural gas distributor and exploration company. The paper reviews the policy of the company to exploit deregulation at home and privatization of all sorts of energy companies abroad. Enron is actively building its own power plants in the US and has successfully boosted their profits by 20 percent in what was considered a flat natural gas market. The paper goes on to discuss the company's view of the new energy tax and how it should benefit natural gas companies as a whole. Finally the paper reviews the contracting procedures of the company to secure long-term fixed price contracts in a volatile market which precludes most companies from taking the risk

  4. Anthropologie de la nature

    OpenAIRE

    Descola, Philippe

    2010-01-01

    En apparence, l’anthropologie de la nature est une sorte d’oxymore puisque, depuis plusieurs siècles en Occident, la nature se caractérise par l’absence de l’homme, et l’homme par ce qu’il a su surmonter de naturel en lui. Mais la nature n’existe pas comme une sphère de réalités autonomes pour tous les peuples. En postulant une distribution universelle des humains et des non-humains dans deux domaines ontologiques séparés, nous sommes bien mal armés pour analyser tous ces systèmes d’objectiva...

  5. The natural radiation background

    International Nuclear Information System (INIS)

    Duggleby, J.C.

    1982-01-01

    The components of the natural background radiation and their variations are described. Cosmic radiation is a major contributor to the external dose to the human body whilst naturally-occurring radionuclides of primordial and cosmogenic origin contribute to both the external and internal doses, with the primordial radionuclides being the major contributor in both cases. Man has continually modified the radiation dose to which he has been subjected. The two traditional methods of measuring background radiation, ionisation chamber measurements and scintillation counting, are looked at and the prospect of using thermoluminescent dosimetry is considered

  6. Natural User Interfaces

    OpenAIRE

    Câmara , António

    2011-01-01

    Dissertação de Mestrado em Engenharia Informática apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra This project’s main subject are Natural User Interfaces. These interfaces’ main purpose is to allow the user to interact with computer systems in a more direct and natural way. The popularization of touch and gesture devices in the last few years has allowed for them to become increasingly common and today we are experiencing a transition of interface p...

  7. Atmospheric natural radioactivity outdoors

    International Nuclear Information System (INIS)

    Renoux, A.

    1985-01-01

    Following a short account of natural atmospheric radioactivity, radon concentrations are given as well as their variations with time obtained by means of a original apparatus developped in Brest. The radioactive equilibrium of radon and its daughters is then considered, many experiments demonstrating that equilibrium is seldom reached even for 218 Po (RaA). Finally, some characteristics of natural radioactive aerosols are studied: charge, particle size distribution (demonstrating they are fine aerosols since only 30 per cent are made of particles with radii exceeding 0,1 μm) [fr

  8. Natural atmospheric radioactivity

    International Nuclear Information System (INIS)

    Renoux, A.

    1986-01-01

    After having summed up the different old or new units, used in radioactivity and radioprotection, the origins of atmospheric radioactivity are reported. Next the authors deal with the air content in radon, thoron and their radioactive descendants, insisting on the variations of the radon air content and on the radioactive balance between radon and its descendants. Then a few notions concerning the natural radioactive aerosol are developed: electric charge state, granulometric distribution. The possible effects of natural atmospheric radioactivity on man are studied with a distinction between inner irradiation and outer irradiation, an average assessment is shown. Finally the important problem of radon in inhabitations is approached [fr

  9. Monitoring natural phytoplankton communities

    DEFF Research Database (Denmark)

    Haraguchi, L.; Jakobsen, H. H.; Lundholm, Nina

    2017-01-01

    -consuming and/or expensive, limiting sampling frequency. The use of faster methods, such as flow cytometry, has become more frequent in phytoplankton studies, although comparisons between this technique and traditional ones are still scarce. This study aimed to assess if natural phytoplankton communities...... carbon biomass with PFCM, applying the same conversion factors as for microscopy. Biomasses obtained with PFCM, estimated from live cells, were higher than microscopy for natural samples. We conclude that PFCM results are comparable to classical techniques, yet the data from PFCM had poor taxonomic...

  10. Training and natural immunity

    DEFF Research Database (Denmark)

    Pedersen, Bente Klarlund; Helge, Jørn Wulff; Richter, Erik

    2000-01-01

    these subjects were used to eliminate day-to-day variation in the immunological tests. Independently of diet, training increased the percentage of CD3-CD16+ CD56+ natural killer (NK) cells from [mean (SEM)] 14 (1) % to 20 (3) % (P = 0.05), whereas the NK-cell activity, either unstimulated or stimulated...... influence natural immunity, and suggest that ingestion of a fat-rich diet during training is detrimental to the immune system compared to the effect of a carbohydrate-rich diet....

  11. Natural Heavy Supersymmetry

    CERN Document Server

    Batell, Brian; McCullough, Matthew

    2015-01-01

    We study how, as a result of the scanning of supersymmetry breaking during the cosmological evolution, a relaxation mechanism can naturally determine a hierarchy between the weak scale and the masses of supersymmetric particles. Supersymmetry breaking is determined by QCD instanton effects, in an extremely minimal setup in which a single field drives the relaxation and breaks supersymmetry. Since gauginos are lighter than the other supersymmetric particles by a one-loop factor, the theory is a realisation of Split Supersymmetry free from the naturalness problem.

  12. The natural gas market

    International Nuclear Information System (INIS)

    Lagrasta, F.; Kaminski, V.; Prevatt, R.

    1999-01-01

    This chapter presents a brief history of the natural gas market highlighting the changes in the gas market and examining risk management in practice detailing the types of price risks, and the use of hedging using forwards and swaps. Options to manage risk are identified, and the role of risk management in financing, the role of the intermediary, and the market outlook are discussed. Panels describing the market structure, storage and natural gas risk management, the art of risk management, the winter 1995-96 basis blowout, spark spreads, the UK gas market and Europe, and weather derivatives are presented

  13. Natural Selection and Morality

    Directory of Open Access Journals (Sweden)

    Alejandro Rosas

    2006-12-01

    Full Text Available Resumen:En este ensayo abordo los intentos, relativamente recientes, de dar una explicación de la moralidad como adaptación por selección natural. Mi exposición tiene una introducción y cuatro partes: en la primera explico en qué consiste la paradoja del altruismo biológico. En la segunda expongo la solución que apela a la selección de grupos, recientemente resurgida; la solución que presuntamente aplicó Charles Darwin cuando formuló sus reflexiones biológicas sobre la moralidad humana. En la tercera expongo la solución sociobiológica, que opta por negar que la selección natural pueda explicar directamente la moralidad humana. La moralidad se presenta más bien como opuesta a la naturaleza diseñada por selección natural. En la cuarta parte desarrollo brevemente una explicación de la moralidad como adaptación que beneficia a los individuos. No opone la moralidad a la naturaleza, ni apela a la selección de grupos. Se sirve de un mecanismo de selección que opera a través de preferencias en la interacción social.Abstract:In this essay, I address recent attempts to account for morality as an adaptation due to natural selection. After a brief introduction, my exposition has four sections. I first explain the paradox of biological altruism. Second, I explain the solution to the paradox in terms of group selection. This solution was presumably applied by Darwin himself as he discussed human morality, and it has experienced a recent revival, though it remains suspicious to most biologists. In the third section I offer a socio-biological solution that opts for denying that morality can be explained by any form of natural selection. Morality is opposed to human nature as designed by natural selection. In the fourth, I argue for an explanation in terms of individual selection. It does not oppose morality to nature, and does not need the workings of group selection; rather, it operates through the agents’ psychological preferences

  14. MENOPAUSE AND NATURAL HEALING

    Directory of Open Access Journals (Sweden)

    Lucija Vrabič Dežman

    2008-12-01

    The studies could not decisively confirm the effectiveness of various phytoestrogens inamelioration of climacteric symptoms. Most studies have proven the effectiveness of thenatural medication made of Cimicifuga racemosa and its safe short-term use. Gynecologists should be familiar with the basics of phytotherapy and the results of clinical studiesin this field in order to confidently advise women to use the natural medications in caseswhere despite the climacteric symptoms they cannot or will not use HRT, consequentlygreatly reducing the quality of their lives. In cases where climacteric symptoms are mild tomoderate, some menopausal societies around the globe suggest trying natural medicationfirst, and only later implementing HRT

  15. Battles Fought in Nature

    DEFF Research Database (Denmark)

    Poulsen, Dorthe Varning; Stigsdottir, Ulrika S.

    2015-01-01

    Using horticultural activities and nature experiences to aid the recovery of returning soldiers has a long history. An increasing number of practical experiences and a few research studies confirm the fact that it may well be beneficial. A review by Varning Poulsen et al. (Under review) describes......, based on evidence and practical experience, to develop a transparent nature-based treatment program for war veterans suffering from PTSD. The treatment took place at the University of Copenhagen’s forest therapy garden. A qualitative research study documented and investigated the project. The lessons...

  16. Natural language modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, J.K. [Sandia National Labs., Albuquerque, NM (United States)

    1997-11-01

    This seminar describes a process and methodology that uses structured natural language to enable the construction of precise information requirements directly from users, experts, and managers. The main focus of this natural language approach is to create the precise information requirements and to do it in such a way that the business and technical experts are fully accountable for the results. These requirements can then be implemented using appropriate tools and technology. This requirement set is also a universal learning tool because it has all of the knowledge that is needed to understand a particular process (e.g., expense vouchers, project management, budget reviews, tax, laws, machine function).

  17. Nature of Human Rights

    Directory of Open Access Journals (Sweden)

    Carlos López Dawson

    2016-07-01

    Full Text Available In the formation of a new Constitution the constituents will require to know or reach an agreement on the nature of human rights; then, to determine how the State will enforce the respect to those rights. To do so, it is necessary to resort to the history and evolution of these rights, and the present work aims to contribute to an efficient productive debate about the nature of human rights, so that citizens can decide on the understanding that this is a thoughtful democratic and humanistic founded decision. The analysis is in the actual technical-ideological republican system which correspond to the current state of international law

  18. Natural gas for vehicles

    International Nuclear Information System (INIS)

    Tissot-Favre, V.; Sudour, D.; Binutti, M.; Zanetta, P.; Rieussec, J.L.

    2005-01-01

    As a true alternative to oil products, and environment friendly fuel, Natural Gas for Vehicles complies with requirements for sustainable development. In addition, it is part of the European Union policy which underlines the importance of energy diversification through alternative fuels. This workshop will look into the current offer to the public transport segment, waste collection vehicles, and commercial vehicle fleets. Actions taken to spread the use of natural gas to all types of cars will also be covered. This article gathers 5 presentations about this topic given at the gas conference

  19. Enhance Nature Exploration with Technology

    Science.gov (United States)

    Holloway, Patricia; Mahan, Carol

    2012-01-01

    Kids and nature seem like a natural combination, but what was natural a generation ago is different today. Children are spending less time outdoors but continue to need nature for their physical, emotional, and mental development. This fact has led author Richard Louv to suggest that today's children are suffering from "nature-deficit disorder"…

  20. Patterns in natural systems

    NARCIS (Netherlands)

    Sewalt, L.

    2016-01-01

    In the thesis, `Patterns in natural systems’ the formation and evolution of patterns as solutions of several partial differential systems are studied. These mathematical systems model three different biological and ecological processes. First, the way that plankton concentrates in the water column,

  1. Natural history of COPD

    DEFF Research Database (Denmark)

    Vestbo, Jørgen; Lange, Peter

    2016-01-01

    The natural history of chronic obstructive pulmonary disease (COPD) is usually described with a focus on change in forced expiratory volume in 1 s (FEV1 ) over time as this allows for exploration of risk factors for an accelerated decline-and thus of developing COPD. From epidemiological studies we...

  2. THE NATURE OF COMPREHENSION.

    Science.gov (United States)

    CLELAND, DONALD L.

    THE NATURE OF COMPREHENSION IS DEFINED AND CLARIFIED. THE LITERATURE IS SURVEYED TO SHOW THAT THE DEVELOPMENT OF CONCEPTS IS IMPORTANT IN INTELLECTUAL ACTIVITIES. IT IS POINTED OUT THAT CONCEPTS ARE BUILT FROM PERCEPTS, IMAGES, SENSATION, AND MEMORIES, AND THAT THE STEPS WHICH ARE EMPLOYED AS CONCEPTS ARE BUILT AND REFINED AND INCLUDE PERCEIVING,…

  3. Cultivating human nature

    NARCIS (Netherlands)

    Derksen, Maarten

    2007-01-01

    Evolutionary psychology claims to offer a unified perspective on human nature and culture, which can serve to further the integration of psychology and the social sciences. I describe four approaches to evolutionary psychology, and note increasing attention to the agency of the individual in

  4. Reinventing Natural Selection

    Science.gov (United States)

    Geraedts, Caspar L.; Boersma, Kerst Th.

    2006-01-01

    Although many research studies report students' Lamarckian misconceptions, only a few studies present learning and teaching strategies that focus on the successful development of the concept of natural selection. The learning and teaching strategy for upper secondary students (aged 15-16) presented in this study conducted in The Netherlands is…

  5. Surfaces with Natural Ridges

    DEFF Research Database (Denmark)

    Brander, David; Markvorsen, Steen

    2015-01-01

    We discuss surfaces with singularities, both in mathematics and in the real world. For many types of mathematical surface, singularities are natural and can be regarded as part of the surface. The most emblematic example is that of surfaces of constant negative Gauss curvature, all of which...

  6. Natural attenuation of herbicides

    DEFF Research Database (Denmark)

    Tuxen, Nina; Højberg, Anker Lajer; Broholm, Mette Martina

    2002-01-01

    A field injection experiment in a sandy, aerobic aquifer showed that two phenoxy acids MCPP (mecoprop) and dichlorprop were degraded within I in downgradient of the injection wells after an apparent lag period. The plume development and microbial measurements indicated that microbial growth gover....... The observations may be important for application of natural attenuation as a remedy in field scale systems....

  7. Wasserpflanzen in der Natur

    DEFF Research Database (Denmark)

    Pedersen, Ole; Christensen, Claus

    2011-01-01

    Unsere Aquarienpflanzen kommen in der Natur vor oder sind Zuchtformen natürlicher Arten. Dennoch konnten erst sehr wenige Aquarianer diese Pflanzen in ihrer natürlichen Umgebung beobachten. Oft stellten sie fest, dass die Pflanzen meist ganz anders aussehen als im Aquarium. Neben einem ständigen...

  8. Patagonia: nature and territories

    Directory of Open Access Journals (Sweden)

    Alejandro Fabián Schweitzer

    2014-12-01

    This paper analyzes the place occupied by Patagonia in today’s fin de siècle scenario of commodities, hegemony crisis and multi-polar world emergence concurring with the convergence of consumerist guidelines, all of which would apparently lead to an in-depth socio-ecological crisis as well as to an accelerated dispute over nature and territory sense.

  9. Nature teaching structures

    DEFF Research Database (Denmark)

    Wester, Ture

    2002-01-01

    -living nature a number of striking statical and kinematical peculiarities have been observed. The paper will try to isolate and describe some of these observations and their relation to our engineered structures based on human thinking. The paper will deal with basic aspects as geometry, topology, redundancy...

  10. Demystifying Nature of Science

    Science.gov (United States)

    Lederman, Judith; Bartels, Selina; Lederman, Norman; Gnanakkan, Dionysius

    2014-01-01

    With the emergence of the "Next Generation Science Standards" ("NGSS"; NGSS Lead States 2013), it is apparent that teaching and learning about nature of science (NOS) continues to be an important goal of science education for all K-12 students. With this emphasis on NOS, early childhood teachers are asking how to design…

  11. Radioactivity: A Natural Phenomenon.

    Science.gov (United States)

    Ronneau, C.

    1990-01-01

    Discussed is misinformation people have on the subject of radiation. The importance of comparing artificial source levels of radiation to natural levels is emphasized. Measurements of radioactivity, its consequences, and comparisons between the risks induced by radiation in the environment and from artificial sources are included. (KR)

  12. Natural gas industry regulations

    International Nuclear Information System (INIS)

    Clo, A.

    1999-01-01

    In the reception of the EU Directive on the internal gas market, it is quite necessary to avoid the mistakes already made in the case of electricity. A possible cause is there suggested which may help rearrange the natural gas industry and market in Italy. It's four points are: general interests, national peculiarities, public policies, regulatory framework [it

  13. How Is Nature Asymmetric?

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 6. How Is Nature Asymmetric? - Discrete Symmetries in Particle Physics and their Violation ... Indian Institute of Technology, Chennai. Aligarh Muslim University. University of Rajasthan, Jaipur. Indian Institute of Science, Bangalore 560012, India.

  14. Natural radiation environment III

    International Nuclear Information System (INIS)

    Gesell, T.F.; Lowder, W.M.

    1980-01-01

    Separate abstracts were prepared for the 52 research papers presented at this symposium in April 1978. The major topics in this volume deal with penetrating radiation measurements, radiation surveys and population exposure, radioactivity in the indoor environment, and technologically enhanced natural radioactivity

  15. Natural radiation environment III

    International Nuclear Information System (INIS)

    Gesell, T.F.; Lowder, W.M.

    1980-01-01

    Separate abstracts were prepared for the 57 research papers presented at this symposium in April 1978 at Houston, Texas. This symposium provided a common forum for scientists in several disciplines that deal with natural radiation because there is an increasing interest in the environment as it pertains to human health and the competition for scarce energy and material resources

  16. SUIKERBOSRAND NATURE RESERVE

    African Journals Online (AJOL)

    reserve, the total length being 66 km with six overnight huts. There are also the BokmakiePie. Nature Troil. and the Cheetah Interpretive Troil. which can be used by day visitors. The former has two loops, one of 10 km and another of 17 km. The. Cheetah Troil. is much shorter and various points of interest are interpreted en ...

  17. Rehabilitating Afghanistan's natural resources

    Science.gov (United States)

    George Hernandez

    2011-01-01

    The Soviet Union invaded Afghanistan in late 1979. During the next 23 years, the war between the Mujahideen Resistance and the Soviet forces, the ensuing civil war, and eventual take over by the Taliban caused enormous harm to the natural resources of Afghanistan. In 2003, the USDA Forest Service (USFS) was asked by the USDA Foreign Agricultural Service to provide...

  18. Sciences & Nature: Site Map

    African Journals Online (AJOL)

    Journal Home · Journals · Sciences & Nature · About · Log In · Register · Advanced Search · By Author · By Title. Issues. Current Issue · Archives · Open Journal Systems · Help. ISSN: 1812-0741. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  19. Nature remedies human damage

    International Nuclear Information System (INIS)

    Heikkonen, H.

    1994-01-01

    Ecolution Ltd puts its emphasis on technologies which use nature's own methods. This technology is best suited to the bioremediation of old industrial sites, saw mills or oil- contaminated areas. The results of biopurification are consistently good and, in comparison with burning, the costs are low

  20. Shooting mechanisms in nature

    NARCIS (Netherlands)

    Sakes, Aimée; Wiel, van der Marleen; Henselmans, Paul W.J.; Leeuwen, van Johan L.; Dodou, Dimitra; Breedveld, Paul

    2016-01-01

    Background In nature, shooting mechanisms are used for a variety of purposes, including prey capture, defense, and reproduction. This review offers insight into the working principles of shooting mechanisms in fungi, plants, and animals in the light of the specific functional demands that these

  1. Venezuela natural gas outlook

    International Nuclear Information System (INIS)

    Silva, P.

    1991-01-01

    This paper reports on the natural gas outlook for Venezuela. First of all, it is very important to remember that in the last few years we have had frequent and unforeseen changes in the energy, ecological, geopolitical and economical fields which explain why all the projections of demand and prices for hydrocarbons and their products have failed to predict what later would happen in the market. Natural gas, with its recognized advantages over other traditional competitors such as oil, coal and nuclear energy, is identified as the component that is acquiring more weight in the energy equation, with a strengthening projection, not only as a resource that covers demand but as a key element in the international energy business. In fact, natural gas satisfies 21% of overall worldwide energy consumption, with an annual increase of 2.7% over the last few years, which is higher than the global energy growth of other fossil fuels. This tendency, which dates from the beginning of the 1980's, will continue with a possibility of increasing over the coming years. Under a foreseeable scenario, it is estimated that worldwide use of natural gas will increase 40% over the next 10 years and 75% on a longer term. Specifically for liquid methane (LNG), use should increase 60% during this last decade. The LPG increase should be moderate due to the limited demand until 1995 and to the stable trends that will continue its use until the end of this century

  2. Knowledge and Natural Resources

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Justinussen, Jens Christian Svabo

    2016-01-01

    Arctic economies are generally natural resource based economies, whether they are indigenous economies largely dependent on living on the land or industrialized economies depending on marine resources, mineral resources or fossil or renewable energy resources. However, the central role of knowledge...

  3. Natural gas annual 1992

    International Nuclear Information System (INIS)

    1993-01-01

    This document provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. This report, Volume 2, presents historical data for the Nation from 1930 to 1992, and by State from 1967 to 1992. The Supplement of this report presents profiles of selected companies

  4. Nature in the City.

    Science.gov (United States)

    Melber, Leah W.

    2000-01-01

    Presents three science activities targeted to help urban students learn about nature: (1) observing coloration patterns of pigeons; (2) measuring local rainfall and comparing it to other areas; and (3) conducting a biodiversity study by observing a patch of lawn. (YDS)

  5. A new nature

    DEFF Research Database (Denmark)

    Abraham, Anders

    ”A New Nature - 9 ARCHITECTURAL CONDITIONS BETWEEN LIQUID AND SOLID” opbygger en tankegang om arkitektur som tilstande i modsætning til arkitektur som form og type.  Ved at se på verden som tilstande og organiseringer mellem ”flydende” og ”fast”, homogent og heterogent m.v., er det muligt...

  6. Nature Identical Prosody

    DEFF Research Database (Denmark)

    Juel Henrichsen, Peter

    2012-01-01

    ; such as low naturalness (DiSyn) and dependence on huge amounts of background data (UnitSyn). We present a hybrid model based on high-level speech data. As preliminary tests show, prosodic models combining DiSyn style at the phone level with UnitSyn style at the supra-segmental levels may approach Unit...

  7. Nature as Inspiration

    Science.gov (United States)

    Tank, Kristina; Moore, Tamara; Strnat, Meg

    2015-01-01

    This article describes the final lesson within a seven-day STEM and literacy unit that is part of the Picture STEM curriculum (pictureSTEM. org) and uses engineering to integrate science and mathematics learning in a meaningful way (Tank and Moore 2013). For this engineering challenge, students used nature as a source of inspiration for designs to…

  8. Nature, Education and Things

    Science.gov (United States)

    Rømer, Thomas Aastrup

    2013-01-01

    In this essay it is argued that the educational philosophy of John Dewey gains in depth and importance by being related to his philosophy of nature, his metaphysics. The result is that any experiental process is situated inside an event, an existence, a thing, and I try to interpret this "thing" as schools or major cultural events such…

  9. Logic and Natural selection

    Czech Academy of Sciences Publication Activity Database

    Peregrin, Jaroslav

    2010-01-01

    Roč. 4, č. 2 (2010), s. 207-223 ISSN 1661-8297 R&D Projects: GA ČR(CZ) GAP401/10/1279 Institutional research plan: CEZ:AV0Z9009908 Keywords : logic * natural selection * modus potens * inferentialism Subject RIV: AA - Philosophy ; Religion

  10. New force in nature?

    International Nuclear Information System (INIS)

    Fischbach, E.; Sudarsky, D.; Szafer, A.; Talmadge, C.; Aronson, S.H.

    1986-01-01

    We review recent experimental and theoretical work dealing with the proposed fifth force. Further analysis of the original Eoetvoes experiments has uncovered no challenges to our original assertion that these data evidence a correlation characteristic of the presence of a new coupling to baryon number or hypercharge. Various models suggest that the proposed fifth force could be accomodated naturally into the existing theoretical framework

  11. Natural hazards science strategy

    Science.gov (United States)

    Holmes, Robert R.; Jones, Lucile M.; Eidenshink, Jeffery C.; Godt, Jonathan W.; Kirby, Stephen H.; Love, Jeffrey J.; Neal, Christina A.; Plant, Nathaniel G.; Plunkett, Michael L.; Weaver, Craig S.; Wein, Anne; Perry, Suzanne C.

    2012-01-01

    The mission of the U.S. Geological Survey (USGS) in natural hazards is to develop and apply hazard science to help protect the safety, security, and economic well-being of the Nation. The costs and consequences of natural hazards can be enormous, and each year more people and infrastructure are at risk. USGS scientific research—founded on detailed observations and improved understanding of the responsible physical processes—can help to understand and reduce natural hazard risks and to make and effectively communicate reliable statements about hazard characteristics, such as frequency, magnitude, extent, onset, consequences, and where possible, the time of future events.To accomplish its broad hazard mission, the USGS maintains an expert workforce of scientists and technicians in the earth sciences, hydrology, biology, geography, social and behavioral sciences, and other fields, and engages cooperatively with numerous agencies, research institutions, and organizations in the public and private sectors, across the Nation and around the world. The scientific expertise required to accomplish the USGS mission in natural hazards includes a wide range of disciplines that this report refers to, in aggregate, as hazard science.In October 2010, the Natural Hazards Science Strategy Planning Team (H–SSPT) was charged with developing a long-term (10-year) Science Strategy for the USGS mission in natural hazards. This report fulfills that charge, with a document hereinafter referred to as the Strategy, to provide scientific observations, analyses, and research that are critical for the Nation to become more resilient to natural hazards. Science provides the information that decisionmakers need to determine whether risk management activities are worthwhile. Moreover, as the agency with the perspective of geologic time, the USGS is uniquely positioned to extend the collective experience of society to prepare for events outside current memory. The USGS has critical statutory

  12. Natural products as photoprotection.

    Science.gov (United States)

    Saewan, Nisakorn; Jimtaisong, Ampa

    2015-03-01

    The rise in solar ultraviolet radiation on the earth's surface has led to a depletion of stratospheric ozone over recent decades, thus accelerating the need to protect human skin against the harmful effects of UV radiation such as erythema, edema, hyperpigmentation, photoaging, and skin cancer. There are many different ways to protect skin against UV radiation's harmful effects. The most popular way to reduce the amount of UV radiation penetrating the skin is topical application of sunscreen products that contain UV absorbing or reflecting active molecules. Based on their protection mechanism, the active molecules in sunscreens are broadly divided into inorganic and organic agents. Inorganic sunscreens reflect and scatter UV and visible radiation, while organic sunscreens absorb UV radiation and then re-emit energy as heat or light. These synthetic molecules have limited concentration according to regulation concern. Several natural compounds with UV absorption property have been used to substitute for or to reduce the quantity of synthetic sunscreen agents. In addition to UV absorption property, most natural compounds were found to act as antioxidants, anti-inflammatory, and immunomodulatory agents, which provide further protection against the damaging effects of UV radiation exposure. Compounds derived from natural sources have gained considerable attention for use in sunscreen products and have bolstered the market trend toward natural cosmetics. This adds to the importance of there being a wide selection of active molecules in sunscreen formulations. This paper summarizes a number of natural products derived from propolis, plants, algae, and lichens that have shown potential photoprotection properties against UV radiation exposure-induced skin damage. © 2015 Wiley Periodicals, Inc.

  13. Immigration, social cohesion, and naturalization

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2010-01-01

    social trust do not connect with issues of naturalization at all. Other conceptions of social cohesion are either politically controversial, problematic as part of the justification of stricter naturalization requirements, or in fact justify less demanding naturalization requirements....

  14. Design, science and naturalism

    Science.gov (United States)

    Deming, David

    2008-09-01

    The Design Argument is the proposition that the presence of order in the universe is evidence for the existence of God. The Argument dates at least to the presocratic Greek philosophers, and is largely based on analogical reasoning. Following the appearance of Aquinas' Summa Theologica in the 13th century, the Christian Church in Europe embraced a Natural Theology based on observation and reason that allowed it to dominate the entire world of knowledge. Science in turn advanced itself by demonstrating that it could be of service to theology, the recognized queen of the sciences. During the heyday of British Natural Theology in the 17th and 18th centuries, the watchmaker, shipbuilder, and architect analogies were invoked reflexively by philosophers, theologians, and scientists. The Design Argument was not systematically and analytically criticized until David Hume wrote Dialogues on Natural Religion in the 1750s. After Darwin published Origin of Species in 1859, Design withered on the vine. But in recent years, the Argument has been resurrected under the appellation "intelligent design," and been the subject of political and legal controversy in the United States. Design advocates have argued that intelligent design can be formulated as a scientific hypothesis, that new scientific discoveries validate a design inference, and that naturalism must be removed as a methodological requirement in science. If science is defined by a model of concentric epistemological zonation, design cannot be construed as a scientific hypothesis because it is inconsistent with the core aspects of scientific methodology: naturalism, uniformity, induction, and efficient causation. An analytical examination of claims by design advocates finds no evidence of any type to support either scientific or philosophical claims that design can be unambiguously inferred from nature. The apparent irreducible complexity of biological mechanisms may be explained by exaptation or scaffolding. The argument

  15. Natural light illumination system.

    Science.gov (United States)

    Whang, Allen Jong-Woei; Chen, Yi-Yung; Yang, Shu-Hua; Pan, Po-Hsuan; Chou, Kao-Hsu; Lee, Yu-Chi; Lee, Zong-Yi; Chen, Chi-An; Chen, Cheng-Nan

    2010-12-10

    In recent years, green energy has undergone a lot of development and has been the subject of many applications. Many research studies have focused on illumination with sunlight as a means of saving energy and creating healthy lighting. Natural light illumination systems have collecting, transmitting, and lighting elements. Today, most daylight collectors use dynamic concentrators; these include Sun tracking systems. However, this design is too expensive to be cost effective. To create a low-cost collector that can be easily installed on a large building, we have designed a static concentrator, which is prismatic and cascadable, to collect sunlight for indoor illumination. The transmission component uses a large number of optical fibers. Because optical fibers are expensive, this means that most of the cost for the system will be related to transmission. In this paper, we also use a prismatic structure to design an optical coupler for coupling n to 1. With the n-to-1 coupler, the number of optical fibers necessary can be greatly reduced. Although this new natural light illumination system can effectively guide collected sunlight and send it to the basement or to other indoor places for healthy lighting, previously there has been no way to manage the collected sunlight when lighting was not desired. To solve this problem, we have designed an optical switch and a beam splitter to control and separate the transmitted light. When replacing traditional sources, the lighting should have similar characteristics, such as intensity distribution and geometric parameters, to those of traditional artificial sources. We have designed, simulated, and optimized an illumination lightpipe with a dot pattern to redistribute the collected sunlight from the natural light illumination system such that it equals the qualities of a traditional lighting system. We also provide an active lighting module that provides lighting from the natural light illumination system or LED auxiliary

  16. Querying Natural Logic Knowledge Bases

    DEFF Research Database (Denmark)

    Andreasen, Troels; Bulskov, Henrik; Jensen, Per Anker

    2017-01-01

    This paper describes the principles of a system applying natural logic as a knowledge base language. Natural logics are regimented fragments of natural language employing high level inference rules. We advocate the use of natural logic for knowledge bases dealing with querying of classes...... in ontologies and class-relationships such as are common in life-science descriptions. The paper adopts a version of natural logic with recursive restrictive clauses such as relative clauses and adnominal prepositional phrases. It includes passive as well as active voice sentences. We outline a prototype...... for partial translation of natural language into natural logic, featuring further querying and conceptual path finding in natural logic knowledge bases....

  17. Hybrid Natural Inflation

    Science.gov (United States)

    Ross, Graham G.; Germán, Gabriel; Vázquez, J. Alberto

    2016-05-01

    We construct two simple effective field theory versions of Hybrid Natural Inflation (HNI) that illustrate the range of its phenomenological implications. The resulting inflationary sector potential, V = Δ4(1 + acos( ϕ/f)), arises naturally, with the inflaton field a pseudo-Nambu-Goldstone boson. The end of inflation is triggered by a waterfall field and the conditions for this to happen are determined. Also of interest is the fact that the slow-roll parameter ɛ (and hence the tensor r) is a non-monotonic function of the field with a maximum where observables take universal values that determines the maximum possible tensor to scalar ratio r. In one of the models the inflationary scale can be as low as the electroweak scale. We explore in detail the associated HNI phenomenology, taking account of the constraints from Black Hole production, and perform a detailed fit to the Planck 2015 temperature and polarisation data.

  18. Hybrid Natural Inflation

    International Nuclear Information System (INIS)

    Ross, Graham G.; Germán, Gabriel; Vázquez, J. Alberto

    2016-01-01

    We construct two simple effective field theory versions of Hybrid Natural Inflation (HNI) that illustrate the range of its phenomenological implications. The resulting inflationary sector potential, V=Δ"4(1+acos (ϕ/f)), arises naturally, with the inflaton field a pseudo-Nambu-Goldstone boson. The end of inflation is triggered by a waterfall field and the conditions for this to happen are determined. Also of interest is the fact that the slow-roll parameter ϵ (and hence the tensor r) is a non-monotonic function of the field with a maximum where observables take universal values that determines the maximum possible tensor to scalar ratio r. In one of the models the inflationary scale can be as low as the electroweak scale. We explore in detail the associated HNI phenomenology, taking account of the constraints from Black Hole production, and perform a detailed fit to the Planck 2015 temperature and polarisation data.

  19. Natural analogue working group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.

    1986-01-01

    A Natural Analogue Working Group was established by the Commission of the European Communities in 1985. The purpose of this group is to bring together modellers with earth scientists and others, so that maximum benefit can be obtained from natural analogue studies with a view to safe geological disposal of radioactive waste. The first meeting of this group was held in Brussels from November 5 to 7, 1985. The discussions mainly concerned the identification of the modellers' needs and of the earth scientists' capacity to provide for them. Following the debates, a written statement was produced by the Group; this document forms the core of the present Report. Notes and outlines of many of the presentations made are grouped in four appendixes. The valuable contribution of all those involved in the meeting is gratefully acknowledged

  20. Natural Blue Food Colour

    DEFF Research Database (Denmark)

    Roda-Serrat, Maria Cinta

    In recent years, there has been a growing tendency to avoid the use of artificial colorants and additives in food products, especially after some studies linked their consumption with behavioural changes in children. However, the incorporation of colorants from natural origin remains a challenge...... for food technologists, as these are typically less vivid and less stable than their synthetic alternatives. Regarding blue colorants, phycocyanins from cyanobacteria are currently in the spotlight as promising new natural blue colorants. Phycocyanins are proteins which blue colour results from...... the presence of the chromophore phycocyanobilin (PCB), a covalently attached linear tetrapyrrole. The applications of phycocyanins as food colorants are however limited, as they show poor stability in certain conditions of pH, light and temperature. Cleavage of PCB from the protein followed by careful product...

  1. Epidemics after Natural Disasters

    Science.gov (United States)

    Gayer, Michelle; Connolly, Maire A.

    2007-01-01

    The relationship between natural disasters and communicable diseases is frequently misconstrued. The risk for outbreaks is often presumed to be very high in the chaos that follows natural disasters, a fear likely derived from a perceived association between dead bodies and epidemics. However, the risk factors for outbreaks after disasters are associated primarily with population displacement. The availability of safe water and sanitation facilities, the degree of crowding, the underlying health status of the population, and the availability of healthcare services all interact within the context of the local disease ecology to influence the risk for communicable diseases and death in the affected population. We outline the risk factors for outbreaks after a disaster, review the communicable diseases likely to be important, and establish priorities to address communicable diseases in disaster settings. PMID:17370508

  2. Challenging Exclusionary Naturalism

    Directory of Open Access Journals (Sweden)

    Nathan Robert Cockram

    2014-03-01

    Full Text Available The purpose of this paper is to reconstruct Hilary Kornblith’s (2002 argument for excluding conceptual analysis from epistemological inquiry, and then provide three objections to it. More specifically, Kornblith argues that epistemological properties such as ‘knowledge’ reduce to natural kinds (with a constitutive essence which can only be discovered and investigated using the a posteriori methods of the natural sciences. Thus, he continues, conceptual analysis can’t properly illuminate the target domain. The three objections to Kornblith’s argument which I present are as follows: (i Multiple Realizeability, (ii Psychological Explanation, (iii Starting Points. On strength of these objections, I conclude that Kornblith’s brand of a posteriori epistemology both eliminates our ability to make epistemic evaluations in general, and also implies a strong form of scepticism.

  3. Oil and natural gas

    International Nuclear Information System (INIS)

    Riddell, C.H.

    1993-01-01

    The natural gas industry and market prospects in Canada are reviewed from a producer's point of view. In the first eight months of 1993, $2.3 billion in new equity was raised for natural gas exploration and production, compared to $900 million in 1991 and $1.2 billion in 1992. The number of wells drilled in the western Canada basin is expected to reach 8,000-9,000 in 1993, up from 5,600 in 1992, and Canadian producers' share of the North American natural gas market will probably reach 20% in 1993, up from 13% in 1986. Potential and proved gas supply in North America is ca 750 trillion ft 3 , of which ca 30% is in Canada. Factors affecting gas producers in Canada are the deregulated nature of the market, low costs for finding gas (finding costs in the western Canada basin are the lowest of any basin in North America), and the coming into balance of gas supply and demand. The former gas surplus has been reduced by expanding markets and by low prices which reduced the incentive to find new reserves. This surplus is largely gone, and prices have started rising although they are still lower than the pre-deregulation prices. Progress is continuing toward an integrated North American gas market in which a number of market hubs allow easy gas trading between producers and consumers. Commodity exchanges for hedging gas prices are beginning operation and electronic trading of gas contracts and pipeline capacity will also become a reality. 4 figs

  4. Natural SUSY endures

    Energy Technology Data Exchange (ETDEWEB)

    Papucci, Michele; Ruderman, Joshua T. [Lawrence Berkeley National Laboratory, CA (United States). Theoretical Physics Group; California Univ., Berkeley, CA (United States). Dept. of Physics; Weiler, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); European Organization for Nuclear Research, Geneva (Switzerland). Theoretical Physics Div.

    2011-10-31

    The first 1 fb{sup -1} of LHC searches have set impressive limits on new colored particles decaying to missing energy. We address the implication of these searches for naturalness in supersymmetry (SUSY). General bottom-up considerations of natural electroweak symmetry breaking show that higgsinos, stops, and the gluino should not be too far above the weak scale. The rest of the spectrum, including the squarks of the first two generations, can be heavier and beyond the current LHC reach. We have used collider simulations to determine the limits that all of the 1 fb{sup -1} searches pose on higgsinos, stops, and the gluino. We find that stops and the left-handed sbottom are starting to be constrained and must be heavier than about 200-300 GeV when decaying to higgsinos. The gluino must be heavier than about 600-800 GeV when it decays to stops and sbottoms. While these findings point toward scenarios with a lighter third generation split from the other squarks, we do find that moderately-tuned regions remain, where the gluino is just above 1 TeV and all the squarks are degenerate and light. Among all the searches, jets plus missing energy and same-sign dileptons often provide the most powerful probes of natural SUSY. Overall, our results indicate that natural SUSY has survived the first 1 fb{sup -1} of data. The LHC is now on the brink of exploring the most interesting region of SUSY parameter space. (orig.)

  5. Harnessing natural ventilation benefits.

    Science.gov (United States)

    O'Leary, John

    2013-04-01

    Making sure that a healthcare establishment has a good supply of clean fresh air is an important factor in keeping patients, staff, and visitors, free from the negative effects of CO2 and other contaminants. John O'Leary of Trend Controls, a major international supplier of building energy management solutions (BEMS), examines the growing use of natural ventilation, and the health, energy-saving, and financial benefits, that it offers.

  6. Symbolic Natural Language Processing

    OpenAIRE

    Laporte , Eric

    2005-01-01

    The connection between language processing and combinatorics on words is natural. Historically, linguists actually played a part in the beginning of the construction of theoretical combinatorics on words. Some of the terms in current use originate from linguistics: word, prefix, suffix, grammar, syntactic monoid... However, interpenetration between the formal world of computer theory and the intuitive world of linguistics is still a love story with ups and downs. We will encounter in this cha...

  7. Nature's Greatest Puzzles

    International Nuclear Information System (INIS)

    Quigg, Chris

    2005-01-01

    It is a pleasure to be part of the SLAC Summer Institute again, not simply because it is one of the great traditions in our field, but because this is a moment of great promise for particle physics. I look forward to exploring many opportunities with you over the course of our two weeks together. My first task in talking about Nature's Greatest Puzzles, the title of this year's Summer Institute, is to deconstruct the premise a little bit

  8. Natural matrix standards

    International Nuclear Information System (INIS)

    Bowen, V.T.

    1976-01-01

    Environmental radiochemistry needs, for use in analytical intercomparision and as standard reference materials, very large homogeneous samples of a variety of matrices, each naturally contaminated by a variety of longer-lived radionuclides, at several different ranges of concentrations. The reasons for this need are discussed, and the minimum assortment of matrices of radionuclides, and of concentrations is established. Sources of suitable materials are suggested, and the international approach to meeting this need is emphasized

  9. Extremes in nature

    CERN Document Server

    Salvadori, Gianfausto; Kottegoda, Nathabandu T

    2007-01-01

    This book is about the theoretical and practical aspects of the statistics of Extreme Events in Nature. Most importantly, this is the first text in which Copulas are introduced and used in Geophysics. Several topics are fully original, and show how standard models and calculations can be improved by exploiting the opportunities offered by Copulas. In addition, new quantities useful for design and risk assessment are introduced.

  10. Intoxication with natural sources

    International Nuclear Information System (INIS)

    Toropilova, D.; Toropila, M.; Tomko, M.; Takac, L.; Fric, M.

    2015-01-01

    The authors of this article deal with intoxication of the organism with natural resources. As objects of our interest we chose some interchangeable types of fungi which cause severe intoxication of gastrointestinal tract: Scleroderma citrinum, Boletus luridus var. rubriceps (Maire) Dermek, Boletus satanas, Agaricus xanthodermus and poisonous plants affect mainly digestive tract such as Sambucus nigra L. (elderberry). Sambucus ebulus L. (European dwarf elder), Viburnum lantana L. (wayfaring tree), Viburnum opulus (guelder-rose), Rhamnus cathartica (purging buckthorn).

  11. Natural radiation exposure indoors

    International Nuclear Information System (INIS)

    Brown, L.; Cliff, K.D.; Wrixon, A.D.

    1981-01-01

    A brief review is presented of the state of knowledge of indoor natural radiation exposure in the U.K. and the current survey work the N.R.P.B. is carrying out in this field. Discussion is limited in this instance to the improvement in estimation of population exposure and the identification of areas and circumstances in which high exposure occur, rather than the study of properties of a building and methods of building affecting exposure to radiation. (U.K.)

  12. The nature of leadership

    OpenAIRE

    2012-01-01

    With contributions from leading authors in the most important areas of current research, this book provides insight into the streams that are driving leadership theory and practice today. The Nature of Leadership, Second Edition provides students with an updated and complete yet concise handbook that solidifies and integrates the vast and disparate leadership literature.Key Features of the Second Edition· Provides contributions from twenty-three subject-matter experts-ranging from the eminent...

  13. Microflyers: inspiration from nature

    Science.gov (United States)

    Sirohi, Jayant

    2013-04-01

    Over the past decade, there has been considerable interest in miniaturizing aircraft to create a class of extremely small, robotic vehicles with a gross mass on the order of tens of grams and a dimension on the order of tens of centimeters. These are collectively refered to as micro aerial vehicles (MAVs) or microflyers. Because the size of microflyers is on the same order as that of small birds and large insects, engineers are turning to nature for inspiration. Bioinspired concepts make use of structural or aerodynamic mechanisms that are observed in insects and birds, such as elastic energy storage and unsteady aerodynamics. Biomimetic concepts attempt to replicate the form and function of natural flyers, such as flapping-wing propulsion and external appearance. This paper reviews recent developments in the area of man-made microflyers. The design space for microflyers will be described, along with fundamental physical limits to miniaturization. Key aerodynamic phenomena at the scale of microflyers will be highlighted. Because the focus is on bioinspiration and biomimetics, scaled-down versions of conventional aircraft, such as fixed wing micro air vehicles and microhelicopters will not be addressed. A few representative bioinspired and biomimetic microflyer concepts developed by researchers will be described in detail. Finally, some of the sensing mechanisms used by natural flyers that are being implemented in man-made microflyers will be discussed.

  14. Petroleum and natural gas

    Energy Technology Data Exchange (ETDEWEB)

    060,

    1965-02-01

    Substantial increases in demand for Canadian petroleum and natural gas in both domestic and export markets resulted in another good year throughout the main sectors of the industry. In February, production averaged 850,000 bpd, or about 8% more than 1963 output of crude oil and natural gas liquids. Construction began on the first full scale plant for the extraction of oil from the Athabasca bituminous sands. In 1964, exploratory and development drilling in western Canada increased 10% from the previous year. A total of 15.5 million ft was drilled, the largest since the record drilling year of 1956. The main oil field development areas in Alberta were the House Mountain, Deer Mountain and Goose River Fields, and the Bantry-Taber heavy oil region in southeastern Alberta. Oil reserves were increased substantially by waterflood pressure maintenance projects in many of the older oil fields. The largest oil accumulation discovered in 1964 was the Syvia-Honda Field in the Devonian Gilwood sandstone in N.-central Alberta. Two graphs illustrate the crude petroleum in Canada in millions of barrels from 1940 to 1964, and natural gas in Canada in billions of cu ft from 1950 to 1964. The outlook for the industry in 1965 is good.

  15. NATURAL RESOURCES ASSESSMENT

    International Nuclear Information System (INIS)

    D.F. Fenster

    2000-01-01

    The purpose of this report is to summarize the scientific work that was performed to evaluate and assess the occurrence and economic potential of natural resources within the geologic setting of the Yucca Mountain area. The extent of the regional areas of investigation for each commodity differs and those areas are described in more detail in the major subsections of this report. Natural resource assessments have focused on an area defined as the ''conceptual controlled area'' because of the requirements contained in the U.S. Nuclear Regulatory Commission Regulation, 10 CFR Part 60, to define long-term boundaries for potential radionuclide releases. New requirements (proposed 10 CFR Part 63 [Dyer 1999]) have obviated the need for defining such an area. However, for the purposes of this report, the area being discussed, in most cases, is the previously defined ''conceptual controlled area'', now renamed the ''natural resources site study area'' for this report (shown on Figure 1). Resource potential can be difficult to assess because it is dependent upon many factors, including economics (demand, supply, cost), the potential discovery of new uses for resources, or the potential discovery of synthetics to replace natural resource use. The evaluations summarized are based on present-day use and economic potential of the resources. The objective of this report is to summarize the existing reports and information for the Yucca Mountain area on: (1) Metallic mineral and mined energy resources (such as gold, silver, etc., including uranium); (2) Industrial rocks and minerals (such as sand, gravel, building stone, etc.); (3) Hydrocarbons (including oil, natural gas, tar sands, oil shales, and coal); and (4) Geothermal resources. Groundwater is present at the Yucca Mountain site at depths ranging from 500 to 750 m (about 1,600 to 2,500 ft) below the ground surface. Groundwater resources are not discussed in this report, but are planned to be included in the hydrology

  16. NATURAL RESOURCES ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    D.F. Fenster

    2000-12-11

    The purpose of this report is to summarize the scientific work that was performed to evaluate and assess the occurrence and economic potential of natural resources within the geologic setting of the Yucca Mountain area. The extent of the regional areas of investigation for each commodity differs and those areas are described in more detail in the major subsections of this report. Natural resource assessments have focused on an area defined as the ''conceptual controlled area'' because of the requirements contained in the U.S. Nuclear Regulatory Commission Regulation, 10 CFR Part 60, to define long-term boundaries for potential radionuclide releases. New requirements (proposed 10 CFR Part 63 [Dyer 1999]) have obviated the need for defining such an area. However, for the purposes of this report, the area being discussed, in most cases, is the previously defined ''conceptual controlled area'', now renamed the ''natural resources site study area'' for this report (shown on Figure 1). Resource potential can be difficult to assess because it is dependent upon many factors, including economics (demand, supply, cost), the potential discovery of new uses for resources, or the potential discovery of synthetics to replace natural resource use. The evaluations summarized are based on present-day use and economic potential of the resources. The objective of this report is to summarize the existing reports and information for the Yucca Mountain area on: (1) Metallic mineral and mined energy resources (such as gold, silver, etc., including uranium); (2) Industrial rocks and minerals (such as sand, gravel, building stone, etc.); (3) Hydrocarbons (including oil, natural gas, tar sands, oil shales, and coal); and (4) Geothermal resources. Groundwater is present at the Yucca Mountain site at depths ranging from 500 to 750 m (about 1,600 to 2,500 ft) below the ground surface. Groundwater resources are not discussed in this

  17. Defining Nature-Based Preschools

    Science.gov (United States)

    Larimore, Rachel

    2016-01-01

    Nature-based early childhood education. Nature-based preschool. Nature preschool. Forest kindergarten. Nature kindergarten. Waldkindergarten. Forest school. These are a few of the program terms currently being discussed among early childhood environmental education professionals in the United States. Why is there so much discussion about the names…

  18. Orifice diseases project - experience of the "Hospital das Clínicas" University of São Paulo Medical Center in day-hospital of anorectal disease Projeto doenças orificiais experiência do HCFMUSP em hospital-dia e doenças anorretais

    Directory of Open Access Journals (Sweden)

    Sergio Carlos Nahas

    1999-06-01

    Full Text Available The treatment of malignant or benign colorectal pathologies that require more complex management are priorities in tertiary hospitals such as "Hospital das Clínicas" University of São Paulo Medical Center (HCFMUSP. Therefore, benign, uncomplicated orifice conditions are relegated to second place. The number of patients with hemorrhoids, perianal fistulas, fissures, condylomas and pilonidal cysts who seek treatment at the HFMUSP is very great, resulting in over-crowding in the outpatient clinics and a long waiting list for recommended surgical treatment (at times over 18 months. The authors describe the experience of the HCFMUSP over an eight-day period with day-hospital surgery in which 140 patients underwent surgery. Data was prospectively taken on the patients undergoing surgery for benign orifice pathologies including age, sex, diagnosis, surgery performed, immediate and late postoperative complications, and follow-up. 140 patients operated on over eight days were studied. 68 were males (48.75% with ages ranging from 25 to 62 (mean 35.2 yrs.. Hemorrhoids was the most frequent condition encountered (82 hemorrhoidectomies, 58.6%, followed by perineal fistula (28 fistula repairs, 20.0%. The most common complication was headache secondary to rachianesthesia occurring in 9 patients (6.4%. One patient (0.7% developed bleeding immediately PO that required reoperation. Mean follow-up was 104 days. Day-surgery characterized by quality care and low morbidity is feasible in tertiary public hospitals, permitting surgery for benign orifice pathologies on many patients within a short period of time.O tratamento das patologias colorretais malignas ou benignas, que necessitam tratamento com maior grau de complexidade são prioridades em hospitais terciários, como é o Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP, permanecendo assim as patologias orificiais benignas em um segundo plano. Todavia devido à sua

  19. Nature, Nurture and Epigenetics

    Science.gov (United States)

    Crews, David; Gillette, Ross; Miller-Crews, Isaac; Gore, Andrea C.; Skinner, Michael K.

    2015-01-01

    Real life by definition combines heritability (e.g., the legacy of exposures) and experience (e.g. stress during sensitive or ‘critical’ periods), but how to study or even model this interaction has proven difficult. The hoary concept of evaluating traits according to nature vs. nurture continues to persist despite repeated demonstrations that it retards, rather than advances, our understanding of biological processes. Behavioral genetics has proven the obvious, that genes influences behavior and, vice versa, that behavior influences genes. The concept of Genes X Environment (G X E) and its modern variants was viewed as an improvement on nature-nurture but has proven that, except in rare instances, it is not possible to fractionate phenotypes into these constituent elements. The entanglement inherent in terms such as nature-nurture or GXE is a Gordian knot that cannot be dissected or even split. Given that the world today is not what it was less than a century ago, yet the arbitrator (differential survival and reproduction) has stayed constant, de novo principles and practices are needed to better predict what the future holds. Put simply, the transformation that is now occurring within and between individuals as a product of global endocrine disruption is quite independent of what has been regarded as evolution by selection. This new perspective should focus on how epigenetic modifications might revise approaches to understand how the phenotype and, in particular its components, is shaped. In this review we summarize the literature in this developing area, focusing on our research on the fungicide vinclozolin. PMID:25102229

  20. Nature, nurture and epigenetics.

    Science.gov (United States)

    Crews, David; Gillette, Ross; Miller-Crews, Isaac; Gore, Andrea C; Skinner, Michael K

    2014-12-01

    Real life by definition combines heritability (e.g., the legacy of exposures) and experience (e.g. stress during sensitive or 'critical' periods), but how to study or even model this interaction has proven difficult. The hoary concept of evaluating traits according to nature versus nurture continues to persist despite repeated demonstrations that it retards, rather than advances, our understanding of biological processes. Behavioral genetics has proven the obvious, that genes influence behavior and, vice versa, that behavior influences genes. The concept of Genes X Environment (G X E) and its modern variants was viewed as an improvement on nature-nurture but has proven that, except in rare instances, it is not possible to fractionate phenotypes into these constituent elements. The entanglement inherent in terms such as nature-nurture or G X E is a Gordian knot that cannot be dissected or even split. Given that the world today is not what it was less than a century ago, yet the arbitrator (differential survival and reproduction) has stayed constant, de novo principles and practices are needed to better predict what the future holds. Put simply, the transformation that is now occurring within and between individuals as a product of global endocrine disruption is quite independent of what has been regarded as evolution by selection. This new perspective should focus on how epigenetic modifications might revise approaches to understand how the phenotype and, in particular its components, is shaped. In this review we summarize the literature in this developing area, focusing on our research on the fungicide vinclozolin. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Why Nature Chose Selenium.

    Science.gov (United States)

    Reich, Hans J; Hondal, Robert J

    2016-04-15

    The authors were asked by the Editors of ACS Chemical Biology to write an article titled "Why Nature Chose Selenium" for the occasion of the upcoming bicentennial of the discovery of selenium by the Swedish chemist Jöns Jacob Berzelius in 1817 and styled after the famous work of Frank Westheimer on the biological chemistry of phosphate [Westheimer, F. H. (1987) Why Nature Chose Phosphates, Science 235, 1173-1178]. This work gives a history of the important discoveries of the biological processes that selenium participates in, and a point-by-point comparison of the chemistry of selenium with the atom it replaces in biology, sulfur. This analysis shows that redox chemistry is the largest chemical difference between the two chalcogens. This difference is very large for both one-electron and two-electron redox reactions. Much of this difference is due to the inability of selenium to form π bonds of all types. The outer valence electrons of selenium are also more loosely held than those of sulfur. As a result, selenium is a better nucleophile and will react with reactive oxygen species faster than sulfur, but the resulting lack of π-bond character in the Se-O bond means that the Se-oxide can be much more readily reduced in comparison to S-oxides. The combination of these properties means that replacement of sulfur with selenium in nature results in a selenium-containing biomolecule that resists permanent oxidation. Multiple examples of this gain of function behavior from the literature are discussed.

  2. NATURAL ANALOGUE SYNTHESIS REPORT

    International Nuclear Information System (INIS)

    Simmons, A.M.

    2004-01-01

    The purpose of this report is to present analogue studies and literature reviews designed to provide qualitative and quantitative information to test and provide added confidence in process models abstracted for performance assessment (PA) and model predictions pertinent to PA. This report provides updates to studies presented in the Yucca Mountain Site Description (CRWMS M and O 2000 [151945], Section 13) and new examples gleaned from the literature along with results of quantitative studies conducted specifically for the Yucca Mountain Project (YMP). The intent of the natural analogue studies was to collect corroborative evidence from analogues to demonstrate additional understanding of processes expected to occur during postclosure at a potential Yucca Mountain repository. The report focuses on key processes by providing observations and analyses of natural and anthropogenic (human-induced) systems to improve understanding and confidence in the operation of these processes under conditions similar to those that could occur in a nuclear waste repository. The process models include those that represent both engineered and natural barrier processes. A second purpose of this report is to document the various applications of natural analogues to geologic repository programs, focusing primarily on the way analogues have been used by the YMP. This report is limited to providing support for PA in a confirmatory manner and to providing corroborative inputs for process modeling activities. Section 1.7 discusses additional limitations of this report. Key topics for this report are analogues to emplacement-drift degradation, waste-form degradation, waste-package degradation, degradation of other materials proposed for the engineered barrier, seepage into drifts, radionuclide flow and transport in the unsaturated zone (UZ), analogues to coupled thermal-hydrologic-mechanical-chemical processes, saturated-zone (SZ) transport, impact of radionuclide release on the biosphere

  3. Liquid Natural Gas

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    After a brief introduction on the origins of the Liquid Natural Gas (LNG) industry the production and transportation of LNG are discussed. Special attention is paid to the importance of the safety aspect during every activity or handling of LNG. Next the most important trade flows for LNG are dealt with. Two zones can be distinguished: the western part of the Pacific and the Atlantic basin. Subsequently the main aspects of a LNG-project are mentioned, as well as the success factors. Finally the prospects for the LNG-industry are reviewed. 11 figs

  4. Natural Analogue Synthesis Report

    Energy Technology Data Exchange (ETDEWEB)

    A. M. Simmons

    2002-05-01

    The purpose of this report is to present analogue studies and literature reviews designed to provide qualitative and quantitative information to test and provide added confidence in process models abstracted for performance assessment (PA) and model predictions pertinent to PA. This report provides updates to studies presented in the ''Yucca Mountain Site Description'' (CRWMS M and O 2000 [151945], Section 13) and new examples gleaned from the literature, along with results of quantitative studies conducted specifically for the Yucca Mountain Site Characterization Project (YMP). The intent of the natural analogue studies was to collect corroborative evidence from analogues to demonstrate additional understanding of processes expected to occur during postclosure at a potential Yucca Mountain repository. The report focuses on key processes by providing observations and analyses of natural and anthropogenic (human-induced) systems to improve understanding and confidence in the operation of these processes under conditions similar to those that could occur in a nuclear waste repository. The process models include those that represent both engineered and natural barrier processes. A second purpose of this report is to document the various applications of natural analogues to geologic repository programs, focusing primarily on the way analogues have been used by the YMP. This report is limited to providing support for PA in a confirmatory manner and to providing corroborative inputs for process modeling activities. Section 1.7 discusses additional limitations of this report. Key topics for this report are analogues to emplacement drift degradation, waste form degradation, waste package degradation, degradation of other materials proposed for the engineered barrier, seepage into drifts, radionuclide flow and transport in the unsaturated zone (UZ), analogues to coupled thermal-hydrologic-mechanical-chemical processes, saturated zone (SZ) transport

  5. The nature of mathematics

    CERN Document Server

    Jourdain, Philip E B

    2007-01-01

    Anyone with an interest in mathematics will welcome the republication of this little volume by a remarkable mathematician who was also a logician, a philosopher, and an occasional writer of fiction and poetry. Originally published in 1913, and later included in the acclaimed anthology The World of Mathematics, Jourdain's survey shows how and why the methods of mathematics were developed, traces the development of mathematical science from the earliest to modern times, and chronicles the application of mathematics to natural science.Starting with the ancient Egyptians and Greeks, the author p

  6. Thermoluminescence from natural calcites

    International Nuclear Information System (INIS)

    Calderon, T.; Jaque, F.; Coy-yll, R.

    1984-01-01

    Thermoluminescence (TL) as well as absorption and EPR spectra of x-irradiated natural calcites have been obtained. Irradiation produces UV absorption bands and a decrease of the Mn 2+ EPR spectrum. A correlation of each TL peak with the bleaching steps of UV absorption bands and the recovering in intensity of the Mn 2+ EPR spectrum has been found. These experimental results support a new model for the radiation damage and thermoluminescence process in calcites. The main point in this model is that holes become trapped at impurities, and the electrons are trapped at dislocations in the form of CO 3 3- . (author)

  7. Eksistens og natur

    DEFF Research Database (Denmark)

    Pahuus, Mogens

    Eksistens og Natur er et centralt stykke livsfilosofi skrevet af en af dansk filosofis grand old men. Professor emeritus fra Aalborg Universitet Mogens Pahuus præsenterer her den grundidé om mennesket, at ethvert individ er formet i en dobbelthed mellem det givne i os - naturen - og det, at vi fo...... forholder os til det givne - eksistensen. Mogens Pahuus sammenfatter i denne bog sin livsfilosofiske tænkning, og han tør give sig i kast med en stor og systematisk fremstilling af menneskets væsen. Bogen er et modent værk med overskud og overblik....

  8. Western Australian natural gas

    International Nuclear Information System (INIS)

    Harman, Frank

    1994-01-01

    Western Australia has 80% of Australia's natural gas resources. These are currently exploited to supply the Western Australian market and LNG to Japan. Growth in the market is dependent on limited prospects for power generation and mineral resource processing. Future exploitation of gas resources will require new export LNG markets and/or the installations of a transcontinental pipeline to eastern Australia. The transcontinental option should only be considered after other options for energy supply in eastern Australia are eliminated. Competition to meet market growth in North-east Asia will be considerable and Australia lacks the policies to underpin future LNG capacity. (author)

  9. Natural radio-exposure

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    Although the amounts are small, man is exposed on a daily basis to alpha, beta, and gamma radiation emitted by radioactive elements present in the earth's crust. The natural radioactive elements are measurable, either by physicochemical means or by radiometric methods and can be the cause of external or internal exposure in man. Also of importance is cosmic radiation. Of galactic or solar origin, primary cosmic rays cause external radiation exposure. The majority of these particles disintegrate rapidly. They reach the ground at a mean rate of the order of one particle per square centimeter per minute

  10. Natural gas technology

    International Nuclear Information System (INIS)

    Todaro, J.M.; Herbert, J.H.

    1997-01-01

    This presentation is devoted to a discussion regarding current and planned US fossil energy research and development for fiscal years 1996, 1997 and 1998. The principal focus of research in the immediate future will be: clean coal fuels, natural gas and oil exploration and production, especially reservoir life extension, advanced drilling completion and stimulation systems, advanced diagnostics and imaging systems, environmental compliance in technology development, regulatory streamlining and risk assessment. Program goals to 2010 were summarized as: increasing domestic oil and gas recovery; increasing recoverable reserves; decreasing cumulative industry environmental compliance costs; increasing revenues to the federal government; saving jobs in the U.S

  11. Natural gas; Erdgas

    Energy Technology Data Exchange (ETDEWEB)

    Graf, Frank [DVGW-Forschungsstelle am KIT, Karlsruhe (Germany); Groeschl, Frank; Wetzel, Uwe [DVGW, Bonn (Germany); Heikrodt, Klaus [Hochschule Ostwestfalen-Lippe, Lemgo (Germany); Krause, Hartmut [DBI Gastechnologisches Institut, An-Institut der TU Bergakademie, Freiberg (Germany); Beestermoeller, Christina; Witschen, Bernhard [Team Consult G.P.E. GmbH, Berlin (Germany); Albus, Rolf; Burmeister, Frank [Gas- und Waerme-Institut Essen e.V., Essen (Germany)

    2015-07-01

    The reform of the EEG in Germany, a positive global development in natural gas, the decline in oil prices, questions about the security of supply in Europe, and not least the effect of the decision by E.on at the end of 2014 have moved the gas industry. Gas has the lowest CO{sub 2} emissions of fossil fuels. Flexibility, storability, useful for networks and the diversity in the application make it an ideal partner for renewable energy. However, these complementary properties are valued at wind and photovoltaics internationally and nationally different. The situation in the gas power plants remains tense. LNG - liquefied natural gas - is on the rise. [German] Die Reform des EEG in Deutschland, eine positive Entwicklung beim Gas weltweit, der Verfall der Oelpreises, Fragen zur Versorgungssicherheit in Europa und nicht zuletzt die Auswirkung der Entscheidung von E.on Ende 2014 haben die Gaswirtschaft bewegt. Gas weist die geringsten CO{sub 2}-Emissioen der fossilen Energietraeger auf. Flexibilitaet, Speicherbarkeit, Netzdienlichkeit sowie die Vielfalt in der Anwendung machen es zum idealen Partner der erneuerbaren Energien. Allerdings werden diese komplementaeren Eigenschaften zu Wind und Photovoltaik international und national unterschiedlich bewertet. Die Lage bei den Gaskraftwerken bleibt weiter angespannt. LNG - verfluessigtes Erdgas - ist auf dem Vormarsch.

  12. CERN in "Nature"

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    CERN is nestled within a verdant natural environment which, thanks to a conservation-oriented policy, is characterized by a remarkable biodiversity. The continued protection of that diversity calls for thoughtful, carefully planned measures.   CERN’s site is an extensive one: its 650 hectares include 210 hectares of buildings, roadways and parking lots, 100 hectares of fenced-off green area, and 340 hectares of non-fenced land, a patchwork of fields, woods and pasture. This land teems with a great variety of plants and animals, including some rare and unexpected species. In 2009 CERN received a certificate from the Swiss foundation Nature & économie for the Meyrin site, and the award was renewed in 2012 for three more years. “The green spaces inside the fenced area are tended by six ISS gardeners, whose duties also include keeping the sidewalks and footpaths clear of snow in winter. The Meyrin site also includes orchid sanctuaries, meadows and sheep pasture...

  13. Natural Circulation with Boiling

    Energy Technology Data Exchange (ETDEWEB)

    Mathisen, R P

    1967-09-15

    A number of parameters with dominant influence on the power level at hydrodynamic instability in natural circulation, two-phase flow, have been studied experimentally. The geometrical dependent quantities were: the system driving head, the boiling channel and riser dimensions, the single-phase as well as the two phase flow restrictions. The parameters influencing the liquid properties were the system pressure and the test section inlet subcooling. The threshold of instability was determined by plotting the noise characteristics in the mass flow records against power. The flow responses to artificially obtained power disturbances at instability conditions were also measured in order to study the nature of hydrodynamic instability. The results presented give a review over relatively wide ranges of the main parameters, mainly concerning the coolant performance in both single and parallel boiling channel flow. With regard to the power limits the experimental results verified that the single boiling channel performance was intimately related to that of the parallel channels. In the latter case the additional inter-channel factors with attenuating effects were studied. Some optimum values of the parameters were observed.

  14. Natural and artificial photoprotection

    International Nuclear Information System (INIS)

    Cripps, D.J.

    1981-01-01

    A solar simulator is described with collimated filtered radiation incorporating an optical integrator to more evenly diffuse the xenon 2.5 KW light source. Populations can be catogorized into skin types I-VI and the minimal erythema dose (MED) in each skin type measured in Joules/cm2 was compared to give a relative suntan photoprotection factor or SPF compared with type I (1.0) so that type II had an SPF of 1.67, type III SPF of 2.5, type IV V had an SPF of nearly 4, whereas the darker Negroid skin (type VI) had an SPF of 9.68, or nearly 10 times that of type I. In addition, various studies were performed to determine the natural protection factor after natural sunlight (3 1/2 mo of summer sun). In 21 subjects the mean SPF was 2.33 when compared to the MED on unexposed skin on the buttocks. Five subjects who had received a mean total dose of 3.49 J/cm2 of UVB within a 4-week period had a mean SPF of 8.01 and 5 subjects who had received a mean total dose of 20 J/cm2 of UVA with PUVA therapy within 2 weeks had a mean SPF of 2.7. These studies were compared with the photoprotection ability of topical chemical protective agents with a range of 4-15

  15. En-gauging naturalness

    Energy Technology Data Exchange (ETDEWEB)

    Bharucha, Aoife [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Technische Univ. Muenchen, Garching (Germany). Physik-Dept. T31; Goudelis, Andreas [Savoie Univ., CNRS, Annecy-le-Vieux (France). LAPTh; McGarrie, Moritz [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-10-15

    The discovery of a 125.5 GeV Higgs with standard model-like couplings and naturalness considerations motivate gauge extensions of the MSSM. We analyse two variants of such an extension and carry out a phenomenological study of regions of the parameter space statisfying current direct and indirect constraints, employing state-of-the-art two-loop RGE evolution and GMSB boundary conditions. We find that due to the appearance of non-decoupled D-terms it is possible to obtain a 125.5 GeV Higgs with stops below 2 TeV, while the uncolored sparticles could still lie within reach of the LHC. We compare the contributions of the stop sector and the non-decoupled D-terms to the Higgs mass, and study their effect on the Higgs couplings. We further investigate the nature of the next-to lightest supersymmetric particle, in light of the GMSB motivated searches currently being pursued by ATLAS and CMS.

  16. En-gauging naturalness

    International Nuclear Information System (INIS)

    Bharucha, Aoife; Goudelis, Andreas; McGarrie, Moritz

    2014-01-01

    The discovery of a 125.5 GeV Higgs with standard model-like couplings and naturalness considerations motivate gauge extensions of the MSSM. We analyse two variants of such an extension and carry out a phenomenological study of regions of the parameter space satisfying current direct and indirect constraints, employing state-of-the-art two-loop RGE evolution and GMSB boundary conditions. We find that due to the appearance of non-decoupled D-terms it is possible to obtain a 125.5 GeV Higgs with stops below 2 TeV, while the uncoloured sparticles could still lie within reach of the LHC. We compare the contributions of the stop sector and the non-decoupled D-terms to the Higgs mass, and study their effect on the Higgs couplings. We further investigate the nature of the next-to lightest supersymmetric particle, in light of the GMSB motivated searches currently being pursued by ATLAS and CMS. (orig.)

  17. Natural antioxidants in chemoprevention

    Energy Technology Data Exchange (ETDEWEB)

    Dragsted, L.O. [Danish Veterinary and Food Administration, Soeberg (Denmark). Inst. of Toxicology

    1998-12-31

    It is well documented that diets rich in fruits and vegetables can reduce the risk of most common cancers, and that some food items from this class may be protective against heart disease. Several explanations have been offered, one of which relates to the natural presence of potent antioxidants in plant products. Destructive oxidation of lipids, proteins, DNA, and other important biomolecules, often involving radical chain reactions, affect vital cellular structures and their normal functions. Such processes are involved in the development of cancer as well as heart disease, and it seems logical to assume that antioxidants might be preventive. Large human trials with natural antioxidants have not provided a uniform support, however, for the hypothesis that antioxidation per se may prevent cancer or coronary heart disease (CHD). One reason is that other effects, unrelated to antioxidation, may compromise their preventive effects. Another reason may be that many potent antioxidants can also act as pro-oxidants under certain conditions. The interpretation of animal trials is likewise often compromised by the fact that most antioxidants have other physiological effects which might very well explain their protective action or lead to toxic side-effects. (orig.)

  18. One for all? : connectedness to nature, inclusion of nature, environmental identity, and implicit association with nature

    NARCIS (Netherlands)

    Brügger, A; Kaiser, F.G.; Roczen, N.

    2011-01-01

    Pleasurable experiences in nature are suspected to promote a personal connection with nature, and subsequently, nature conservation in individuals. Using an Internet-based survey employing a convenience sample of the general population (N = 1,309), we developed a connection-with-nature instrument

  19. Constructing nature behind the glass

    Directory of Open Access Journals (Sweden)

    Samuel J.M.M. Alberti

    2008-07-01

    Full Text Available By way of introducing this special issue of Museum and Society, ‘Constructing nature behind glass’, this paper first surveys the literature devoted to analyses of natural history objects and collections. Such work is to be found in interesting places – not only in museum studies, history of science, and professional museum literature, but also in visual studies, anthropology and cultural geography. After exploiting this writing for different perspectives on the cultural and practical construction of museum nature, this paper moves on to consider one popular topic, taxidermy. The ambiguous nature of taxidermic mounts, or ‘remnant models’, leads to a discussion of the relative status of specimen and artefact. I identify four configurations of their relationship: museum nature as opposed to material culture; museum nature as material culture; museum nature and material culture sharing parallel processes; and finally, museum nature and material culture entangled. All offer perspectives on the construction of nature and culture behind glass.

  20. Nature's loss, Immunologists gain?

    Science.gov (United States)

    Aluvihare

    2000-01-01

    Nature Reviews Molecular Cell Biology Nature Publishing Group (2000). ISSN 1471-0072. Monthly First there was Annual Reviews, then came the monthly Elsevier Trends Journals, both of which try to identify hot topics in their chosen fields. The Current Opinion journals followed several years later, and Current Opinion in Cell Biology is presently one of the highest 'impact factor' review journals, with a distinguished board of editors and advisors and a systematic approach to regular coverage of the major fields of cell biology. Important topics are visited once a year, whether or not something specially exciting happened in the last 12 months. Add to this list Seminars in Cell and Developmental Biology, the FASEB journal and the countless minireviews in 'real' journals, and you begin to wonder how anyone finds any time for doing experiments, or indeed reading the primary literature. So, into this already crowded field arrive three important newcomers: Nature Reviews in Molecular Cell Biology, Genetics, and Neurosciences, of which the first two will probably interest readers of Journal of Cell Science the most. Backed by the name and money of Nature and edited by experienced Nature staff, it is hard to see how these publications can possibly do other than succeed with writers and readers alike. What's inside the first issue? The cover of Nature Reviews in Molecular Cell Biology presents a 3-colour montage of a blue cell nucleus surrounded by splotches of green GPI-anchored GFP overlaid by orange actin stress fibres that seem to come from somewhere else. This image trails a comprehensive review from Kai Simons and Derek Toomre about Lipid Rafts. There are another five major review articles: calcium puffs and sparks, rings around DNA, HIV inhibitors, kinesin and the circadian clock provide a rich and varied mix of topics from authors who know what they're talking about. Surrounding this core is an entertaining mixture of 'highlights' at the front: news and views about

  1. Natural gas : nirvana

    International Nuclear Information System (INIS)

    Stonehouse, D.

    2001-01-01

    Despite completing 8,900 gas wells in year 2000, the deliverability of natural gas out of the Western Canadian Sedimentary Basin (WCSB) was stagnant which has left many analysts wondering whether the basin has reached its limit. It also leaves many wondering if gas producers will be able to meet the strong demand for natural gas in the future. Nearly all new electrical generation being built in the U.S. is gas-based due to strict new environmental standards limiting the growth in hydro and coal-powered generation. Any future coal plants will use gasification technology and combined cycle turbines. Combined cycle turbines developed by Boeing and Lockheed are more efficient than combustion turbines, making gas more competitive with fuel alternatives. The lack of growth in natural gas supply has left storage levels near record lows. Demand is expected to increase in 2001 by 3.2 per cent to 23 trillion cubic feet in the U.S. Longer term, major new reserves must be brought on stream to meet this demand. It was noted that the easy discoveries within the WCSB have been made. The new plays are smaller, more technically complex and expensive which suggests that more investment is needed in training geologists, geophysicists and petroleum engineers to find new reserves. The Canadian Energy Research Institute agrees that there is enough gas in Alberta and British Columbia to meet current demands but efforts must shift towards drilling in the foothills front and northwest regions of Alberta to increase deliverability. Brief notes on several gas finds by various oil and gas companies in the area were presented. The article also discussed the huge untapped potential of northern reserves. Analysts have noted 44 Tcf of proven reserve, with a potential of 165 Tcf. In addition, new pipelines from the Alaskan North Slope and the Mackenzie Delta could transport nearly 2 Tcf annually to market. Wells drilled by Chevron and Paramount at Fort Liard in 1999 initially flowed at rates up to

  2. natural or artificial diets

    Directory of Open Access Journals (Sweden)

    A. O. Meyer-Willerer

    2005-01-01

    Full Text Available Se probaron alimentos artificiales y naturales con larva de camarón (Litopenaeus vannamei cultivados en diferentes recipientes. Estos fueron ocho frascos cónicos con 15L, ocho acuarios con 50L y como grupo control, seis tanques de fibra de vidrio con 1500L; todos con agua marina fresca y filtrada. La densidad inicial en todos los recipientes fue de 70 nauplios/L. Aquellos en frascos y acuarios recibieron ya sea dieta natural o artificial. El grupo control fue cultivado con dieta natural en los tanques grandes que utilizan los laboratorios para la producción masiva de postlarvas. El principal producto de excreción de larva de camarón es el ión amonio, que es tóxico cuando está presente en concentraciones elevadas. Se determinó diariamente con el método colorimétrico del indofenol. Los resultados muestran diferencias en la concentración del ión amonio y en la sobrevivencia de larvas entre las diferentes dietas y también entre los diferentes recipientes. En aquellos con volúmenes pequeños comparados con los grandes, se presentó mayor concentración de amonio (500 a 750µg/L, en aquellos con dietas naturales, debido a que este ión sirve de fertilizante a las algas adicionadas, necesitando efectuar recambios diarios de agua posteriores al noveno día de cultivo para mantener este ión a una concentración subletal. Se obtuvo una baja cosecha de postlarvas (menor a 15% con el alimento artificial larvario, debido a la presencia de protozoarios, alimentándose con el producto comercial precipitado en el fondo de los frascos o acuarios. Los acuarios con larvas alimentadas con dieta natural también mostraron concentraciones subletales de amonio al noveno día; sin embargo, la sobrevivencia fue cuatro veces mayor que con dietas artificiales. Los tanques control con dietas naturales presentaron tasas de sobrevivencia (70 ± 5% similares a la reportada por otros laboratorios.

  3. Natural gas monthly, April 1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-06

    The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. There are two feature articles in this issue: Natural gas 1998: Issues and trends, Executive summary; and Special report: Natural gas 1998: A preliminary summary. 6 figs., 28 tabs.

  4. Is disease a natural kind?

    Science.gov (United States)

    D'Amico, R

    1995-10-01

    In The Nature of Disease, Lawrie Reznek argues that disease is not a natural kind term. I raise objections to Reznek's two central arguments for establishing that disease is not a natural kind. In criticizing his a priori, conceptual argument against naturalism, I argue that his conclusion rests on a weaker argument that appeals to the empirical diversity in the symptoms and manifestations of disease. I also raise questions about the account of natural kinds which Reznek utilizes and his point that conventions for classification are excluded by there being natural kinds.

  5. Liquefied Natural Gas Transfer

    Science.gov (United States)

    1980-01-01

    Chicago Bridge & Iron Company's tanks and associated piping are parts of system for transferring liquefied natural gas from ship to shore and storing it. LNG is a "cryogenic" fluid meaning that it must be contained and transferred at very low temperatures, about 260 degrees below Fahrenheit. Before the LNG can be pumped from the ship to the storage tanks, the two foot diameter transfer pipes must be cooled in order to avoid difficulties associated with sharp differences of temperature between the supercold fluid and relatively warm pipes. Cooldown is accomplished by sending small steady flow of the cryogenic substance through the pipeline; the rate of flow must be precisely controlled or the transfer line will be subjected to undesirable thermal stress.

  6. Natural gas powered bus

    International Nuclear Information System (INIS)

    Ambuehl, D.; Fernandez, J.

    2003-01-01

    This report for the Swiss Federal Office of Energy presents the results of a project carried out by the Swiss Federal Institute of Technology in Zurich to evaluate the performance of a natural-gas-powered bus in comparison with two diesel buses. The report provides details on the vehicles, their routes and the results of interviews made with both passengers and drivers. Details of measurements made on fuel consumption and pollutant emissions are presented in tabular and graphical form, as are those made on noise emissions inside and outside the vehicles. The conclusions of the project are presented including economic aspects of using gas as a motor fuel. Also, the views of passengers, who were more concerned with comfort aspects, and drivers, who were more interested in technical aspects, are quoted

  7. Gas hydrate in nature

    Science.gov (United States)

    Ruppel, Carolyn D.

    2018-01-17

    Gas hydrate is a naturally occurring, ice-like substance that forms when water and gas combine under high pressure and at moderate temperatures. Methane is the most common gas present in gas hydrate, although other gases may also be included in hydrate structures, particularly in areas close to conventional oil and gas reservoirs. Gas hydrate is widespread in ocean-bottom sediments at water depths greater than 300–500 meters (m; 984–1,640 feet [ft]) and is also present in areas with permanently frozen ground (permafrost). Several countries are evaluating gas hydrate as a possible energy resource in deepwater or permafrost settings. Gas hydrate is also under investigation to determine how environmental change may affect these deposits.

  8. OPEC and natural gas

    International Nuclear Information System (INIS)

    Samsam Bakhtiari, A.M.; Shahbudaghlou, F.

    1998-01-01

    This paper reviews the involvement of OPEC Member Countries in the natural gas industry in the past, present and future. It notes a tenfold increase in marketed production and a fourfold rise in re-injection since 1970. Collectively, Members now hold 41 per cent of the world's proven gas reserves and account for 20 per cent of exports. Individually, four of these countries hold position 2-5 in the world gas reserve rankings. Within OPEC, however, there remains an emphasis of oil over gas, not least because of oil's favourable position with regard to revenue-generation and profitability. As global demand continues on its upward growth curve in a more environmentally aware world, OPEC's gas horizons will widen. OPEC's strong reserve base will give its Members an undeniable role to play on the future global gas stage. However, these countries will give priority to domestic usage, particularly re-injection schemes

  9. Predicting natural catastrophes tsunamis

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    1. Tsunamis - Introduction - Definition of phenomenon - basic properties of the waves Propagation and dispersion Interaction with coasts - Geological and societal effects Origin of tsunamis - natural sources Scientific activities in connection with tsunamis. Ideas about simulations 2. Tsunami generation - The earthquake source - conventional theory The earthquake source - normal mode theory The landslide source Near-field observation - The Plafker index Far-field observation - Directivity 3. Tsunami warning - General ideas - History of efforts Mantle magnitudes and TREMOR algorithms The challenge of "tsunami earthquakes" Energy-moment ratios and slow earthquakes Implementation and the components of warning centers 4. Tsunami surveys - Principles and methodologies Fifteen years of field surveys and related milestones. Reconstructing historical tsunamis: eyewitnesses and geological evidence 5. Lessons from the 2004 Indonesian tsunami - Lessons in seismology Lessons in Geology The new technologies Lessons in civ...

  10. Nordic urban nature recreation

    DEFF Research Database (Denmark)

    Cole, Scott; Lindhjem, Henrik; Zandersen, Marianne

    the associated nonmarket welfare benefits. The study stresses the need to collect user data to better understand visitation patterns, which can be combined with valuation methods to provide evidence of economic benefits associated with e.g., hiking, cycling, skiing, paddling and other recreation activities. Once......The Nordic countries continue to experience growth of urban areas, which provides benefits like economic growth, but also imposes economic costs in terms of reduced ecosystem services. This report focuses on urban nature recreation and highlights economic methods and data that can help capture...... these benefits are visible, decision-makers will have a better basis to balance economic growth with the environmental costs it imposes on urban ecosystem services....

  11. Natural Radioactivity in Bananas

    Science.gov (United States)

    Zagatto, V. A. B.; Medina, N. H.; Okuno, E.; Umisedo, N. K.

    2008-08-01

    The content of 40K natural radionuclide in bananas (Musa sapientum) from the Vale do Ribeira region, São Paulo, Brazil, has been measured. We have collected several samples of bananas prata and nanica, its peels, leaves, and also different soils where the banana tree was planted, such as soil with a standard amount of fertilizer, the fertilizer itself and also soil without fertilizer for comparison. We have used the gamma-ray spectroscopy technique with a NaI(T1) crystal inside a 12 cm thick lead shield to detect the gamma-radiation. The results indicate that only part of the available potassium is absorbed by the plant, which is mainly concentrated in the banana peel.

  12. Art and human nature

    Directory of Open Access Journals (Sweden)

    Mirta Toledo

    2008-06-01

    Full Text Available This article presents a visual artist’s point of view about art. This view confronts the Eurocentric traditional cannon with some ignored, but valuable traditions, thus proposing a contra-canon. These ideas are examined on the light of a variety of sources, including prehistoric, pre-Columbian, and 20th century art expressions, in a variety of media, from sculpture to literature. Recent art expressions are characterized by their incorporation of minority values and perspectives that challenge “universal” views. Using samples of works from Latino and African American artists, the author shows that, even today, art is a means to know the world and its people, to exhibit personal life, to create personal symbolism, and to show one’s identity or the search for it. Like the human nature it represents, art has multiple faces.

  13. Natural Radioactivity in Bananas

    International Nuclear Information System (INIS)

    Zagatto, V. A. B.; Medina, N. H.; Okuno, E.; Umisedo, N. K.

    2008-01-01

    The content of 40 K natural radionuclide in bananas (Musa sapientum) from the Vale do Ribeira region, Sao Paulo, Brazil, has been measured. We have collected several samples of bananas prata and nanica, its peels, leaves, and also different soils where the banana tree was planted, such as soil with a standard amount of fertilizer, the fertilizer itself and also soil without fertilizer for comparison. We have used the gamma-ray spectroscopy technique with a NaI(T1) crystal inside a 12 cm thick lead shield to detect the gamma-radiation. The results indicate that only part of the available potassium is absorbed by the plant, which is mainly concentrated in the banana peel

  14. Virtual-World Naturalism

    Directory of Open Access Journals (Sweden)

    Daniel Reynolds

    2010-07-01

    Full Text Available Sometimes a player will stray from the path described by a game, moving into new spaces, developing new possible modes of interaction, and often discovering the rougher edges of the game world, where physics models break down, textures become incongruous, and the pieces don’t quite fit together. Gameplay that seeks out these spaces and these phenomena, that searches for such clues to the underlying construction of the virtual environment, is a kind of virtual-world naturalism, at once a return to an investigative urge that has been subsumed to the exhaustive mapping and description of the real world and a form of resistance to the very idea of pre-defined paths of action, of externally imposed limits, in virtual worlds as well as in our own.

  15. Natural flexible dermal armor.

    Science.gov (United States)

    Yang, Wen; Chen, Irene H; Gludovatz, Bernd; Zimmermann, Elizabeth A; Ritchie, Robert O; Meyers, Marc A

    2013-01-04

    Fish, reptiles, and mammals can possess flexible dermal armor for protection. Here we seek to find the means by which Nature derives its protection by examining the scales from several fish (Atractosteus spatula, Arapaima gigas, Polypterus senegalus, Morone saxatilis, Cyprinius carpio), and osteoderms from armadillos, alligators, and leatherback turtles. Dermal armor has clearly been developed by convergent evolution in these different species. In general, it has a hierarchical structure with collagen fibers joining more rigid units (scales or osteoderms), thereby increasing flexibility without significantly sacrificing strength, in contrast to rigid monolithic mineral composites. These dermal structures are also multifunctional, with hydrodynamic drag (in fish), coloration for camouflage or intraspecies recognition, temperature and fluid regulation being other important functions. The understanding of such flexible dermal armor is important as it may provide a basis for new synthetic, yet bioinspired, armor materials. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Natural convection type reactor

    International Nuclear Information System (INIS)

    Nakayama, Takafumi; Horiuchi, Tetsuo; Moriya, Kimiaki; Matsumoto, Masayoshi; Akita, Minoru.

    1988-01-01

    Purpose: To improve the reliability by decreasing the number of dynamic equipments and safely shutdown the reactor core upon occurrence of accidents. Constitution: A pressure relief valve and a pressurizing tank or gravitational water falling tank disposed to the main steam pipe of a reactor are installed in combination. Upon loss-of-coolant accident, the pressure relief valve is opened to reduce the pressure in the reactor pressure vessel to the operation pressure for each of the tanks, thereby enabling to inject water in the pressurizing tank at first and, thereafter, water in the gravitational water falling tank successively to the inside of the pressure vessel. By utilizing the natural force in this way, the reliability can be improved as compared with the case of pumped water injection. Further, by injecting an aqueous boric acid to a portion of a plurality of tanks, if the control rod insertion becomes impossible, aqueous boric acid can be injected. (Takahashi, M.)

  17. Natural climate solutions

    Science.gov (United States)

    Griscom, Bronson W.; Adams, Justin; Ellis, Peter W.; Houghton, Richard A.; Lomax, Guy; Miteva, Daniela A.; Schlesinger, William H.; Shoch, David; Siikamäki, Juha V.; Smith, Pete; Woodbury, Peter; Zganjar, Chris; Blackman, Allen; Campari, João; Conant, Richard T.; Delgado, Christopher; Elias, Patricia; Gopalakrishna, Trisha; Hamsik, Marisa R.; Herrero, Mario; Kiesecker, Joseph; Landis, Emily; Laestadius, Lars; Leavitt, Sara M.; Minnemeyer, Susan; Polasky, Stephen; Potapov, Peter; Putz, Francis E.; Sanderman, Jonathan; Silvius, Marcel; Wollenberg, Eva; Fargione, Joseph

    2017-10-01

    Better stewardship of land is needed to achieve the Paris Climate Agreement goal of holding warming to below 2 °C; however, confusion persists about the specific set of land stewardship options available and their mitigation potential. To address this, we identify and quantify “natural climate solutions” (NCS): 20 conservation, restoration, and improved land management actions that increase carbon storage and/or avoid greenhouse gas emissions across global forests, wetlands, grasslands, and agricultural lands. We find that the maximum potential of NCS—when constrained by food security, fiber security, and biodiversity conservation—is 23.8 petagrams of CO2 equivalent (PgCO2e) y‑1 (95% CI 20.3–37.4). This is ≥30% higher than prior estimates, which did not include the full range of options and safeguards considered here. About half of this maximum (11.3 PgCO2e y‑1) represents cost-effective climate mitigation, assuming the social cost of CO2 pollution is ≥100 USD MgCO2e‑1 by 2030. Natural climate solutions can provide 37% of cost-effective CO2 mitigation needed through 2030 for a >66% chance of holding warming to below 2 °C. One-third of this cost-effective NCS mitigation can be delivered at or below 10 USD MgCO2‑1. Most NCS actions—if effectively implemented—also offer water filtration, flood buffering, soil health, biodiversity habitat, and enhanced climate resilience. Work remains to better constrain uncertainty of NCS mitigation estimates. Nevertheless, existing knowledge reported here provides a robust basis for immediate global action to improve ecosystem stewardship as a major solution to climate change.

  18. A Natural Logic for Natural-Language Knowledge Bases

    DEFF Research Database (Denmark)

    Andreasen, Troels; Styltsvig, Henrik Bulskov; Jensen, Per Anker

    2017-01-01

    We describe a natural logic for computational reasoning with a regimented fragment of natural language. The natural logic comes with intuitive inference rules enabling deductions and with an internal graph representation facilitating conceptual path finding between pairs of terms as an approach t...

  19. A Natural Logic for Natural-language Knowledge Bases

    DEFF Research Database (Denmark)

    Andreasen, Troels; Bulskov, Henrik; Jensen, Per Anker

    2017-01-01

    We describe a natural logic for computational reasoning with a regimented fragment of natural language. The natural logic comes with intuitive inference rules enabling deductions and with an internal graph representation facilitating conceptual path finding between pairs of terms as an approach t...

  20. Which naturalism for bioethics? A defense of moderate (pragmatic) naturalism.

    Science.gov (United States)

    Racine, Eric

    2008-02-01

    There is a growing interest in various forms of naturalism in bioethics, but there is a clear need for further clarification. In an effort to address this situation, I present three epistemological stances: anti-naturalism, strong naturalism, and moderate pragmatic naturalism. I argue that the dominant paradigm within philosophical ethics has been a form of anti-naturalism mainly supported by a strong 'is' and 'ought' distinction. This fundamental epistemological commitment has contributed to the estrangement of academic philosophical ethics from major social problems and explains partially why, in the early 1980s, 'medicine saved the life of ethics'. Rejection of anti-naturalism, however, is often associated with strong forms of naturalism that commit the naturalistic fallacy and threaten to reduce the normative dimensions of ethics to biological imperatives. This move is rightly dismissed as a pitfall since ethics is, in part, a struggle against the course of nature. Rejection of naturalism has drawbacks, however, such as deterring bioethicists from acknowledging the implicit naturalistic epistemological commitments of bioethics. I argue that a moderate pragmatic form of naturalism represents an epistemological position that best embraces the tension of anti-naturalism and strong naturalism: bioethics is neither disconnected from empirical knowledge nor subjugated to it. The discussion is based upon historical writings in philosophy and bioethics.

  1. Morphometry of the Myopectineal Orifice: Relevance in Prosthesis ...

    African Journals Online (AJOL)

    Hp 630 Dual Core

    ГЕНЙФСЧРЖ ОО ЙФСЛР КЗФРЛГХ СЕЕЧФ ЦКФСЧЙК Г ЩЗГНРЗХХ ГЦ ЦКЗ ОСЩЗФ ЗЪЦФЗПЛЦЫ СИ ЦКЗ. ГДЖСПЗР ЦКЗ ПЫСТЗЕЦЛРЗГО СФЛИЛЕЗ ...

  2. Usefulness of radionuclide angiocardiography in predicting stenotic mitral orifice area

    International Nuclear Information System (INIS)

    Burns, R.J.; Armitage, D.L.; Fountas, P.N.; Tremblay, P.C.; Druck, M.N.

    1986-01-01

    Fifteen patients with pure mitral stenosis (MS) underwent high-temporal-resolution radionuclide angiocardiography for calculation of the ratio of peak left ventricular (LV) filling rate divided by mean LV filling rate (filling ratio). Whereas LV filling normally occurs in 3 phases, in MS it is more uniform. Thus, in 13 patients the filling ratio was below the normal range of 2.21 to 2.88 (p less than 0.001). In 11 patients in atrial fibrillation, filling ratio divided by mean cardiac cycle length and by LV ejection fraction provided good correlation (r = 0.85) with modified Gorlin formula derived mitral area and excellent correlation with echocardiographic mitral area (r = 0.95). Significant MS can be detected using radionuclide angiocardiography to calculate filling ratio. In the absence of the confounding influence of atrial systole calculation of 0.14 (filling ratio divided by cardiac cycle length divided by LV ejection fraction) + 0.40 cm2 enables accurate prediction of mitral area (+/- 4%). Our data support the contention that the modified Gorlin formula, based on steady-state hemodynamics, provides less certain estimates of mitral area for patients with MS and atrial fibrillation, in whom echocardiography and radionuclide angiocardiography may be more accurate

  3. Multi-orifice deposition nozzle for additive manufacturing

    Science.gov (United States)

    Lind, Randall F.; Post, Brian K.; Cini, Colin L.

    2017-11-21

    An additive manufacturing extrusion head includes a nozzle for accepting and depositing a heated material onto a work surface and/or part. The nozzle includes a valve body and an internal poppet body moveable between positions to permit deposition of at least two bead sizes of heated material onto a work surface and/or part.

  4. An acoustic criterion for the whistling of orifices in pipes

    NARCIS (Netherlands)

    Moussou, P.; Testud, Ph.; Auregan, Y.; Hirschberg, A.; Hasegawa, K.; Scarth, D.A.

    2008-01-01

    Whistling due to vortex shedding has been extensively studied in the case of cylinders in cross-flows, of flow separation above cavities and of shear layers with flow impingement feedback. Less attention has been given to pressure drop devices in piping systems, which are known to generate high

  5. The developing dorsal ganglion of the salp Thalia democratica, and the nature of the ancestral chordate brain

    Science.gov (United States)

    C.Lacalli, T.

    1998-01-01

    The development of the dorsal ganglion of the salp, Thalia democratica, is described from electron microscope reconstructions up to the stage of central neuropile formation. The central nervous system (CNS) rudiment is initially tubular with an open central canal. Early developmental events include: (i) the formation of a thick dorsal mantle of neuroblasts from which paired dorsal paraxial neuropiles arise; (ii) the differentiation of clusters of primary motor neurons along the ventral margin of the mantle; and (iii) the development from the latter of a series of peripheral nerves. The dorsal paraxial neuropiles ultimately connect to the large central neuropile, which develops later. Direct contact between neuroblasts and muscle appears to be involved in the development of some anterior nerves. The caudal nerves responsible for innervating more distant targets in the posterior part of the body develop without such contacts, which suggests that a different patterning mechanism may be employed in this part of the neuromuscular system. The results are compared with patterns of brain organization in other chordates. Because the salp CNS is symmetrical and generally less reduced than that of ascidian larvae, it is more easily compared with the CNS of amphioxus and vertebrates. The dorsal paraxial centres in the salp resemble the dorsolateral tectal centres in amphioxus in both position and organization; the central neuropile in salps likewise resembles the translumenal system in amphioxus. The neurons themselves are similar in that many of their neurites appear to be derived from the apical surface instead of the basal surface of the cell. Such neurons, with extensively developed apical neurites, may represent a new cell type that evolved in the earliest chordates in conjunction with the formation of translumenal or intralumenal integrative centres. In comparing the salp ganglion with vertebrates, we suggest that the main core of the ganglion is most like the mes

  6. Comparative evaluation of a two stroke compressed natural gas mixer design using simulation and experimental techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ramasamy, D.; Bakar, R.A.; Rahim, M.F.; Noor, M.M. [Malaysia Pahang Univ., Pahang (Malaysia). Automotive Focus Group

    2008-07-01

    A study was conducted in which a two-stroke engine was converted for use with bi-fuel, notably compressed natural gas and gasoline. The excessive by-products generated by two-stroke engine combustion can be attributed to the inefficient combustion process. This prototype uniflow-type single-cylinder engine was equipped with a bi-fuel conversion system. A dedicated mixer was also developed to meter the gaseous fuel through the engine intake system. It was designed to meet air and fuel requirement similar to its gasoline counterpart. The mixer was modeled to obtain optimum orifice diameter using three different sizes of 14, 16 and 18 mm respectively. A standard computational fluid dynamics (CFD) software package was used to simulate the flow. A pressure reading was obtained during the prototype test. The drop in pressure across the venturi was shown to be an important parameter as it determined the actual fuel-air ratio in the actual engine. A good agreement of CFD outputs with that of the experimental outputs was recorded. The experimental technique validated the pressure distribution predicted by CFD means on the effects of the three insert rings in the CNG mixer. The simulation exercise can be used to predict the amount of CNG consumed by the engine. It was concluded that the 14 mm throat ring was best suited for the CNG mixer because it provided the best suction. Once the mixer is tested on a real engine, it will clear any doubts as to whether the throat can function at high engine speeds. 5 refs., 3 tabs., 8 figs.

  7. Natural gas monthly, October 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-10-01

    The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. 6 figs., 27 tabs.

  8. Natural gas monthly, May 1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time the NGM features articles designed to assist readers in using and interpreting natural gas information. 6 figs., 27 tabs.

  9. Natural gas monthly, June 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-06-01

    The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. 6 figs., 27 tabs.

  10. Natural gas monthly, August 1994

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-24

    The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information.

  11. Natural gas monthly, November 1993

    International Nuclear Information System (INIS)

    1993-01-01

    The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground state data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information

  12. Legal nature of affatomia

    Directory of Open Access Journals (Sweden)

    Stanković Miloš

    2015-01-01

    Full Text Available In Salian and Ripuarian Code affatomia represented a bilateral legal transaction that was aimed at changing of the scoped of heirs determined by the customs, at least insofar being applied in the absence of biological descendants only. However, almost all further similarities in the field cease at this point. The form for using affatomia with Ripuarian Franks was much simpler than the one with the Salian Franks. Unlike the Salian Franks, affatomia could by all odds be used by Ripuarian Franks spouses in determining each other for a heir. Legal nature of the Salian Franks affatomia is most similar to the mancipatio familiae type of will in the Roman law (which does not mean it emerged from this law, while its form in the Ripuarian Code is much closer to testamentary adoption. As with Ripuarian Franks, affatomia seems to have definitely produced legal effects only after the death of the disposant, while its legal effects with the Salian Code performed inter vivos. Contemporary authors are trying to designate the legal nature of legal affairs from the early development of human and legal civilization through modern institutes that represent the completion of their evolutionary path. Taking the inheritance contract of the German or Swiss law, or the future assets donation of the French law, for example, and then comparing them to affatomia and thinx is an anachronism. This is evident by the fact that the legal nature of these ancient Germanic institutes can not be viewed unilaterally, but always through a combination of those institutes which we know today as adoption, gift or mixed donation with retention of different modalities for the transferor or the testator (usually usufruct. In this sense, if we are looking for a inheritance agreement in the Middle Ages, the contract in which a person determines other person for his/her universal or singular successor in the modern sense, we will certainly not find one. However, if within this institute we

  13. Mother natural: Motivations and associations for consuming natural foods.

    Science.gov (United States)

    Moscato, Emily M; Machin, Jane E

    2018-02-01

    Natural is perceived as innately positive and is a widely sought-after attribute in food products. The natural food industry continues to grow in response to rising consumer demand. This qualitative study explored mothers' motivations for purchasing and consuming natural food products for themselves and their families. Mothers are an important population because of their disproportionate influence on household food consumption. We employed participant photography and a series of three weekly focus groups to derive a rich understanding of the activities surrounding and motivations behind seeking natural in everyday buying decisions. Five major themes were identified. First, natural nurtures well-being: physical, psychological, social, and emotional health. Second, natural behaves "supernaturally," allowing positive attributes to be transmitted from the source to the recipient. Third, natural is associated with authenticity, providing a sense of trust, transparency, and control. Fourth, consuming natural reinforces the socially constructed idea of a good mother. Lastly, the preference for natural does not always translate into purchase; mothers face compromises because of conflicting priorities and resources. Understanding mothers' multiple motivations provides deeper insight into the attraction for natural products. The findings have application in positioning interventions for more nutritional eating and revising regulations on the food label natural. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. US crude oil, natural gas, and natural gas liquids reserves

    International Nuclear Information System (INIS)

    1992-01-01

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1991, as well as production volumes for the United States, and selected States and State subdivisions for the year 1991. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), its two major components (nonassociated and associated-dissolved gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, two components of natural gas liquids, lease condensate and natural gas plant liquids, have their reserves and production data presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1991 is also presented

  15. Naturalness as an educational value

    DEFF Research Database (Denmark)

    Frølund, Sune

    2016-01-01

    Existentialism and postmodernism have both abandoned the idea of a human nature. Also, the idea of naturalness as a value for education has been targeted as a blind for conservative ideology. There are, however, good reasons to re-establish a sound concept of human naturalness. First of all...

  16. Natural radioactivity in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Petr, I [Ceske Vysoke Uceni Technicke, Prague (Czechoslovakia). Fakulta Jaderna a Fysikalne Inzenyrska

    1980-01-01

    The effects were analyzed of natural radionuclides and cosmic radiation on radiation burden in man. The contents are shown of natural radionuclides in the earth crust, water, atmosphere, food chain and human organism. Using the data, the annual doses from natural sources to the gonads (1025 ..mu..Sv/yr) and to the bone marrow (986 ..mu..Sv) are estimated.

  17. Natural gas for vehicles (NGV)

    International Nuclear Information System (INIS)

    Prieur, A.

    2006-01-01

    Following a decade-long upsurge in the use of natural gas in the energy sector (heating and especially electricity), new outlets for natural gas are being developed in the transport sector. For countries endowed with substantial local resources, development in this sector can help reduce oil dependence. In addition, natural gas is often used to reduce pollution, particularly in cities. (author)

  18. Natural family planning.

    Science.gov (United States)

    Brown, J B; Blackwell, L F; Billings, J J; Conway, B; Cox, R I; Garrett, G; Holmes, J; Smith, M A

    1987-10-01

    It is now well accepted that a woman can conceive from an act of intercourse for a maximum of only about 7 days of her menstrual cycle. The reliability of natural family planning depends on identifying this window of fertility without ambiguity. Several symptomatic markers, cervical mucus and basal body temperature, have been used extensively and with considerable success in most women but failures occur. Ovarian and pituitary hormone production show characteristic patterns during the cycle. Urinary estrogen and pregnanediol measurements yield reliable information concerning the beginning, peak, and end of the fertile period, provided that the assays are accurate and performed on timed specimens of urine. We have developed such enzyme immunoassays for urinary estrogen and pregnanediol glucuronides that can be performed at home. In the early versions of the assays, enzyme reaction rates were measured by eye, but more recently, a simple photoelectronic rate meter has been used. The final problem to be solved is not technologic but whether women are sufficiently motivated to expend the same time and effort each day for 10 days a month, with less cost, on fertility awareness as they spend on making a cup of tea.

  19. A natural ice boom

    Energy Technology Data Exchange (ETDEWEB)

    Hopper, H.R. [Manitoba Hydro, Winnipeg, MB (Canada)

    1998-10-01

    Planning for ice jams and ice movements are critical on the Nelson River in northern Manitoba in designing cofferdams. Experience on the St. Lawrence River demonstrated the possibility of exercising some control over ice action by judicious placement of log booms or ice control structures. The success of experiments with man-made controls led to field tests in which an ice sheet of sufficient magnitude and competence was introduced into the open water stream of the Nelson River. The ice sheet was subsequently jammed in a narrow channel, thereby creating a natural ice bridge or boom upstream of a proposed hydro development. Under favourable conditions, this boom would initiate the progression of the ice cover from its location upstream, cutting off the downstream reach from the ice producing potential of the upstream reach. Although ice would still be generated downstream, the length of the reach between the ice boom and the development site would be short enough that ice jamming at the development site would never occur. Although problems in blasting prevented the introduction of a competent ice sheet into the main stream of the river at the location chosen, sufficient confidence in the theory was gained to warrant further consideration. 4 refs., 1 tab., 10 figs.

  20. Management of natural resources

    International Nuclear Information System (INIS)

    Danielo, Olivier; Loubens, Audrey

    2016-08-01

    As a sustainable exploitation of fossil natural resources has become an ecological opportunity, this publication proposes a set of articles focused on the cases of gas, oils (conventional or not) and coal. A first article outlines the unavoidable environmental issue associated with the exploitation of fossil energies. The second one comments the meaning of fossil fuel availability, and more particularly the distinction between resources and reserves, and the transformation of resources into reserves for saving purposes. This last issue of transformation of resources into reserves is addressed by next articles which respectively focus on conventional gases and oils, on non conventional gases and oils, and on coal. Two articles then comment perspectives by 2040 by discussing the high tension between fossil resources and geopolitical situation, and by discussing whether a world energy transition is possible. The three last articles notice that the abundance of fossil energies is hiding the potential of renewable energies, discuss whether chemical industry could do without oil, and comment the fact that Russia strengthens its claims on Arctic territories