On the existence of Jones birefringence and Jones dichroism.
Arteaga, Oriol
2010-05-01
We claim that the so-called Jones birefringence and Jones dichroism effects, understood as new optical phenomena of difficult experimental observation, cannot be deduced from Jones publications and were proposed due to a misinterpretation of his original work.
Lam, Lewis Y W; Weatherhead, Robert G
2015-01-01
We report a case of tympanic membrane rupture during snorkeling in a 17-year-old young man who had previously undergone bilateral Jones tubes placed for epiphora. To our knowledge, this phenomenon has not been previously reported.
Lam, Lewis Y. W.; Weatherhead, Robert G.
2015-01-01
Summary We report a case of tympanic membrane rupture during snorkeling in a 17-year-old young man who had previously undergone bilateral Jones tubes placed for epiphora. To our knowledge, this phenomenon has not been previously reported. PMID:27330470
ERIC Educational Resources Information Center
Briscoe, Lori; Collins, Erica S.; Deal, Amanda; Hancock, Ron; McGraw, Kristyn
2000-01-01
Loyal Jones talks about his role in the Council of the Southern Mountains, the controversy that led to its demise, founding the Appalachian Center at Berea College (Kentucky), and elitist attitudes of liberal arts colleges that hinder sincere efforts to help Appalachian people. He discusses humor as a way of simultaneously putting people on and…
Rishworth, Susan K
2012-01-01
The purpose of this historical article is to demonstrate, as the biography of Verina Morton Jones, MD, is uncovered, the difficulties inherent in researching original source material on the lives of 19th- and early 20th-century African American physicians as well as the great benefits derived from doing this research. The procedures used include basic archival research and close examination of published materials about her in the past, in conjunction with oral history. Original correspondence from Dr Morton Jones to her niece and nephew is used to illustrate events in her life and the thoughts and attitudes she expressed. Some of these thoughts and attitudes reflect those current situations in which African Americans found themselves, and others are quite unique, no doubt owing to her privileged position in the African American community. The principle conclusions reached include the great benefits derived from doing this kind of research, as difficult and time-consuming as that may be, with the enhanced knowledge and appreciation of the heritage of African American physicians, and insights into American social history during this period.
Bence-Jones protein - quantitative
... this page: //medlineplus.gov/ency/article/003597.htm Quantitative Bence-Jones protein test To use the sharing ... Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare ...
Setzer, S.W.; Rubin, D.K.
1992-07-06
This article is a review of the recent award of the engineering contract at Hanford to a joint venture of Duke Power and J. A. Jones Construction Services. The contract, worth an estimated $500M, is for a three-year period running through September 1995. Impact on the incumbent (ICF Kaiser) work force is expected to be minimal, with the majority of the personnel being retained by Duke/Jones.
No More Indiana Jones Warehouses
ERIC Educational Resources Information Center
Pannapacker, William
2012-01-01
In "Raiders of the Lost Ark," Indiana Jones--perhaps the last heroic professor to appear in a major Hollywood film--survives a series of adventures involving spiders, snakes, treacherous colleagues, and countless Nazis who are determined to recover the ark of the covenant for their "Fuhrer." Apparently the ark has mystical powers. Ultimately,…
ERIC Educational Resources Information Center
Rist, Marilee C.
1992-01-01
Describes lifelong commitment of middle-school principal and major W.J. Jones to Coahoma, a small town in Mississippi Delta. Thanks to his efforts, town recently acquired a sewage system, blacktopped roads, and new housing (through Habitat for Humanity and World Vision). Although town elementary school fell victim to consolidation and children are…
The Jones Family's Culture of Literacy
ERIC Educational Resources Information Center
Johnson, Amy Suzanne
2010-01-01
This article considers the uses of literacy within the Jones family (all names are pseudonyms), an African American family who lives in the rural South of the United States. Drawing on life history data with three women in the Jones family--Harriet Jones (grandmother), Sally Harris (mother), and Lola Harris (granddaughter)--the author traces how…
Doug Jones Home Improvement Information Sheet
Doug Jones Home Improvement (the Company) is located in Louisville, Kentucky. The settlement involves renovation activities conducted at property constructed prior to 1978, located in Louisville, Kentucky.
Gallagher, Timothy
2014-07-01
When I began my medical student clinical rotations, I quickly became overwhelmed by feelings of inadequacy. While the doctors around me conjured appropriate diagnoses and treatment approaches, I fumbled with the only tools I possessed: my time and a smile. It was only when I met the patient Ms Jones that I came to understand the potential impact of these simple tools. My encouragement became part of her recovery process. She gave me the confidence to construct this ability of comforting patients into a small platform of confidence from which I could safely venture to educate patients or suggest treatments to residents. It could be something that I could reliably fall back on in times of doubt and something I could pass along to other people I met.
Gallagher, Timothy
2014-01-01
When I began my medical student clinical rotations, I quickly became overwhelmed by feelings of inadequacy. While the doctors around me conjured appropriate diagnoses and treatment approaches, I fumbled with the only tools I possessed: my time and a smile. It was only when I met the patient Ms Jones that I came to understand the potential impact of these simple tools. My encouragement became part of her recovery process. She gave me the confidence to construct this ability of comforting patients into a small platform of confidence from which I could safely venture to educate patients or suggest treatments to residents. It could be something that I could reliably fall back on in times of doubt and something I could pass along to other people I met. PMID:25024247
Federal Register 2010, 2011, 2012, 2013, 2014
2012-07-16
... determination was published in the Federal Register on February 8, 2012 (77 FR 6590). At the request of a... Employment and Training Administration Dow Jones & Company, Inc., Dow Jones Content Services Division... January 26, 2011, applicable to workers of Dow Jones & Company, Inc., Dow Jones Content...
Federal Register 2010, 2011, 2012, 2013, 2014
2012-04-02
... Federal Register on February 8, 2012 (77 FR 6590). At the request of the New Jersey State agency, the... Employment and Training Administration Dow Jones & Company, Inc., Dow Jones Content Services Including On... at Dow Jones Corporation, Dow Jones Content Services Princeton, New Jersey. The workers are...
Jones Center Vocational/Academic Program (JCVA).
ERIC Educational Resources Information Center
Rydalch, Jeff
This document provides information on the Jones Center Vocational/Academic Program of the Granite School District (Utah), the purpose of which is to maintain or reintegrate students who are potential high school dropouts or dropouts into appropriate educational alternatives. Its mission statement is followed by a list of program components,…
Federal Register 2010, 2011, 2012, 2013, 2014
2010-04-21
... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; New York Air Show at Jones Beach State Park, Atlantic Ocean off of Jones Beach, Wantagh, NY AGENCY: Coast Guard, DHS. ACTION: Notice of proposed... Air Show at Jones Beach State Park in Wantagh, New York. This proposed safety zone is necessary...
Hydrophobicity in Lennard-Jones solutions.
Ishizaki, Mario; Tanaka, Hideki; Koga, Kenichiro
2011-02-14
The analogue of the hydrophobic hydration is explored for Lennard-Jones solutions. The free energy of solvation and its temperature derivatives, both in the constant-pressure process and in the constant-volume process, are obtained numerically for a variety of the size and energy parameters for the solute-solvent Lennard-Jones potential. We identify in the parameter space a region in which the solvation is of hydrophobic character, with an understanding that hydrophobicity is characterized by both the solvation free energy being positive and the solvation process being exothermic. Such a region is found in each case of the isobaric and isochoric conditions and the region is seen to be much wider in the isochoric process than in the isobaric one. Its origin and implication are discussed.
Lennnard Jones Potential for Mesoscopic System
NASA Astrophysics Data System (ADS)
Taruna, Jutri
2005-11-01
The liquid-gas phase transition of a Lennard Jones system of N=500 particles is studied via Molecular Dynamics simulations. Rather than displaying a positive isothermal compressibility --- as is demanded of stable systems in the thermodynamic limit --- the system develops a ``Van der Waals loop'', namely, a region with negative isothermal compressibility. We use various observables as well as state-of-the-art computer renderings to elucidate the nature of this behavior.
Test pilots 1952 - Walker, Butchart, and Jones
NASA Technical Reports Server (NTRS)
1952-01-01
This photo shows test pilots, (Left-Right) Joseph A. Walker, Stanley P. Butchart and Walter P. Jones, standing in front of the Douglas D-558-II Skystreak, in 1952. These three test pilots at the National Advisory Committee for Aeronautics' High-Speed Flight Research Station probably were discussing their flights in the aircraft. Joe flew research flights on the D-558-I #3 (14 flights, first on June 29, 1951) investigating buffeting, tail loads, and longitudinal stability. He flew the D-558-II #2 (3 flights, first on April 29, 1955) and recorded data on lateral stability and control. He also made pilot check-out flights in the D-558-II #3 (2 flights, first on May 7, 1954). For fifteen years Walker served as a pilot at the Edwards flight research facility (today known as the National Aeronautics and Space Administration's Dryden Flight Research Center) on research flights as well as chase missions for other pilots on NASA and Air Force research programs. On June 8, 1966, he was flying chase in NASA's F-104N for the Air Force's experimental bomber, North American XB-70A, when he was fatally injured in a mid-air collision between the planes. Stan flew the D-558-I #3 (12 flights, first on October 19, 1951) to determine the dynamic longitudinal stability characteristics and investigations of the lateral stability and control. He made one flight in the D-558-II #3 on June 26, 1953, as a pilot check-out flight. Butchart retired from the NASA Dryden Flight Research Center at Edwards, California, on February 27, 1976, after a 25-year career in research aviation. Stan served as a research pilot, chief pilot, and director of flight operations. Walter P. Jones was a research pilot for NACA from the fall of 1950 to July 1952. He had been in the U.S. Air Force as a pilot before joining the Station. Jones flew the D-558-I #3 (5 flights, first on February 13, 1951) to study buffeting, tail loads and longitudinal stability. Jones made research flights on the D-558-II #3 ( 7 flights
3. Historic American Buildings Survey Lester Jones, Photographer. July 31, ...
3. Historic American Buildings Survey Lester Jones, Photographer. July 31, 1940 INTERIOR OF CHESTNUT STREET ENTRANCE - Wainwright Building, Seventh & Chestnut Streets, Saint Louis, Independent City, MO
6. Historic American Buildings Survey Lester Jones, Photographer May 30, ...
6. Historic American Buildings Survey Lester Jones, Photographer May 30, 1940. BRICKWORK DETAIL - NORTHWEST ELEVATION - Colonel William Whitley House, Stanford-Crab Orchard Pike, Stanford, Lincoln County, KY
1. Historic American Buildings Survey Russell Jones, Photographer June 1963 ...
1. Historic American Buildings Survey Russell Jones, Photographer June 1963 SOUTHWEST VIEW - Abner Cloud House, Intersection of Canal Road & Reservoir Road Northwest, Washington, District of Columbia, DC
2. Historic American Buildings Survey Russell Jones, Photographer June 1963 ...
2. Historic American Buildings Survey Russell Jones, Photographer June 1963 SOUTHEAST VIEW - Abner Cloud House, Intersection of Canal Road & Reservoir Road Northwest, Washington, District of Columbia, DC
2. Historic American Buildings Survey Lester Jones, Photographer March 2, ...
2. Historic American Buildings Survey Lester Jones, Photographer March 2, 1940 GENERAL VIEW FROM SOUTHWEST - Fort Smith, Commissary Building, 100 South Garrison Avenue, Fort Smith, Sebastian County, AR
Freezing of Lennard-Jones-type fluids
Khrapak, Sergey A.; Chaudhuri, Manis; Morfill, Gregor E.
2011-02-07
We put forward an approximate method to locate the fluid-solid (freezing) phase transition in systems of classical particles interacting via a wide range of Lennard-Jones-type potentials. This method is based on the constancy of the properly normalized second derivative of the interaction potential (freezing indicator) along the freezing curve. As demonstrated recently it yields remarkably good agreement with previous numerical simulation studies of the conventional 12-6 Lennard-Jones (LJ) fluid [S.A.Khrapak, M.Chaudhuri, G.E.Morfill, Phys. Rev. B 134, 052101 (2010)]. In this paper, we test this approach using a wide range of the LJ-type potentials, including LJ n-6 and exp-6 models, and find that it remains sufficiently accurate and reliable in reproducing the corresponding freezing curves, down to the triple-point temperatures. One of the possible application of the method--estimation of the freezing conditions in complex (dusty) plasmas with ''tunable'' interactions--is briefly discussed.
Jones precoder for polarization mode dispersion compensation
NASA Astrophysics Data System (ADS)
Zhu, Zhenyu; Sadjadpour, Hamid R.; Blum, Rick S.; Andrekson, Peter A.; Li, Tiffany Jing
2008-04-01
A new electrical-domain precoder is proposed to mitigate polarization mode dispersion (PMD) in optical communications by modeling a PMD-dominant fiber optical channel using a single input multiple output (SIMO) channel. Employing a bank of finite impulse response filters and a polarization modulator, and using parameters derived from the Jones matrix representation of PMD, the proposed precoder efficiently adapts to the time-varying nature of PMD and simultaneously pre-equalizes both polarization modes at the transmitter. The transmitter-only structure avoids losing phase and polarization information due to the nonlinearity of the commonly used square law direct-detection receiver. Analysis is performed to evaluate the impact of channel mismatch due to feedback delay, channel estimation errors, and the impact of the finite length of the precoder filters. The analytical results are used to guide selection of the appropriate feedback rate for the adaptive system. Extensive simulation results confirm the efficiency of the proposed Jones precoder, and present it as an effective, low-cost replacement to the complicated, expensive optical-domain counter-parts.
Chemical Potential of a Lennard Jones Fluid
NASA Astrophysics Data System (ADS)
Celebonovic, V.
2010-12-01
The aim of this paper is to present results of analytical calculation of chemical potential of a Lennard Jones (LJ) fluid performed in two ways: by using the thermodynamical formalism and the formalism of statistical mechanics. The integration range is divided into two regions. In the small distance region, which is r≤σ in the usual notation, the integration range had to be cut off in order to avoid the occurence of divergences. In the large distance region, the calculation is technically simpler. The calculation reported here will be useful in all kinds of studies concerning phase equilibrium in a LJ fluid. Interesting kinds of such systems are the giant planets and the icy satellites in various planetary systems, but also the (so far) hypothetical quark stars.
Robert T. Jones, One of a Kind
NASA Astrophysics Data System (ADS)
Vincenti, Walter G.
2005-01-01
His contemporaries saw R.T. Jones as one of the notably creative aerodynamicists of the twentieth century. This essay reviews his remarkable life and career, including his years as a farm-country boy, college dropout, and fledgling airplane designer in Missouri, his time as an elevator operator and self-directed student in Washington, D.C., and his long professional career as an aerodynamicist at the Langley and Ames Aeronautical Laboratories and Stanford University. The focus in his career is on his fundamental discovery of the benefits of sweepback for the wings of high-speed airplanes. This includes speculation about his highly intuitive thought processes in arriving at his creative ideas. I also give an account of his work on blood flow and the mechanical heart, his avocational accomplishments as a maker of telescopes and violins, and his philosophical interest in human affairs.
Longer term rest from grazing: a response to Jones & Carter
Technology Transfer Automated Retrieval System (TEKTRAN)
Jones and Carter (this issue) in a response to Davies et al. (2014) misrepresent the original article and other articles, develop arguments not supported by scientific literature, and ignore literature counter to their opinion. Most peculiar, Jones and Carter incorrectly state that Davies et al. co...
CATABOLIC ORIGIN OF A BENCE JONES PROTEIN FRAGMENT
Cioli, D.; Baglioni, C.
1968-01-01
Gel filtration analysis of the urinary proteins of some patients with myeloma has shown the presence of "fragments" of Bence Jones proteins which correspond to the variable half of these proteins. Experiments have been carried out to establish the origin of a "fragment" observed in a patient who excreted a large amount of this protein. Labeled homologous Bence Jones protein has been injected into this and other control patients. Excretion of labeled "fragment" has been observed in all. Analysis by peptide mapping and radio-autography of this labeled "fragment" isolated from the urine showed that the invariable half of the Bence Jones protein was not excreted; it seemed thus likely that the invariable half was metabolized to small peptides and free amino acids. A labeled Bence Jones protein which was excreted without any accompanying "fragment" was injected into the patient who excreted large amounts of "fragment." No excretion of labeled "fragment" was observed. It was thus concluded that the property of being degraded to "fragment" is characteristic of some "fragile" Bence Jones proteins and is not determined by the patient. Incubation with serum or urine of the "fragile" Bence Jones protein failed to produce any "fragment." "Fragments" of Bence Jones proteins are thus most likely formed during excretion of these proteins through the kidney and are products of the catabolism of Bence Jones proteins. PMID:5666962
Obituary: Frank Culver Jones, 1932-2007
NASA Astrophysics Data System (ADS)
Ormes, Johnathan F.; Streitmatter, Robert E.
2007-12-01
Frank C. Jones, an emeritus theoretical physicist at NASA, died May 2, 2007 at age 74 after a struggle with a rare form of cancer. He died at his home in Silver Spring, Maryland, surrounded by his family. Frank was born July 30, 1932 in Fort Worth, Texas, the oldest of three boys. His parents were Kenneth Hugh and Nancy Culver Jones. Frank's father was a lawyer, and his grandfather was a Methodist minister. Frank graduated from Rice University in 1954 and earned a master's degree in 1955 and a doctorate in 1961, both in physics, from the University of Chicago. He did his graduate work with Prof. John Simpson. Dr. Jones began his professional career as an instructor in physics at Princeton University before joining NASA's Goddard Space Flight Center in 1963 as a National Research Council associate. He subsequently became a member of the Theory Division and the Laboratory for High Energy Astrophysics. His area of expertise was the origin, transport, and electromagnetic interactions of cosmic rays. His particular focus was the stochastic physics related to the diffusion of particles in random fields, plasma turbulence, and the shock acceleration of charged particles in collisionless plasmas. From 1993 to 1995, Frank was head of Goddard's Theoretical High Energy Astrophysics Office and continued to serve as Head of the Theory group. In 2003 he served as Acting Chief of the Laboratory for High Energy Astrophysics. He retired in 2005 and continued his affiliation with NASA as an emeritus scientist at Goddard until his death. As a youngster, Frank showed the signs of curiosity and initiative that indicated he might become an experimentalist. At the memorial service for Frank, his brother related the stories of how Frank had rigged a hidden microphone to play through the family television as his brother courted a young woman on the front porch swing, and how one of Frank's early chemistry experiments caused all the family silverware to turn black. Although Frank started
Solomon, A; McLaughlin, C L; Capra, J D
1975-01-01
Urine specimens from patients with multiple myeloma and Bence Jones proteinuria frequently contain low molecular weight proteins which correspond either to the amino-terminal, variant half (VL) or to the carboxyl-terminal, constant half (CL) of the Bence Jones protein. Analyses of urine specimens from such patients who had received high doses of corticosteroids as part of their treatment regimen revealed that concomitantly with a decrease in Bence Jones protein excretion was the appearance of a low molecular weight protein related to the Bence Jones protein but not identical to the VL or to the CL. Analyses of daily urine specimens obtained from one such patient over an extended time period revealed that a reproducible chain of events occurred during a treatment regimen which included oral administration of 75 mg of prednisone daily for 7 consecutive days. The amount of Bence Jones protein excreted decreased progressively, and by the 5th day was usually less than 10% of the pretreatment value. The urine specimen obtained on the 6th day of treatment was virtually devoid of Bence Jones protein but contained a newly appearing protein whose electrophoretic mobility was distinct from that of the Bence Jones protein or its VL or CL. Cessation of corticosteroid therapy resulted in a prompt disappearance of the new protein and in a progressive increase in the amount of Bence Jones protein excreted. The new protein was isolated from the urine of this patient and was purified for comparative studies with Bence Jones protein and with the VL and CL prepared by specific enzymatic cleavage of the Bence Jones protein. These studies revealed that the new protein was most related antigenically to the CL, but could be distinguished immunochemically from the CL. This new protein, a component found in vivo related to the constant half of the light polypeptide chain, was designated CL, and was structurally 25 amino acid residues longer than the CL, that is, the amino-terminus of the
12. Historic American Buildings Survey, Stanley Jones, Photographer July 6, ...
12. Historic American Buildings Survey, Stanley Jones, Photographer July 6, 1936, copied from portrait, PORTRAIT OF WILLIAM HENRY 3RD, OWNER OF HENRY GUN FACTORY. - Henry Gun Factory, Belfast, Northampton County, PA
11. Historic American Buildings Survey, Stanley Jones, Photographer July 6, ...
11. Historic American Buildings Survey, Stanley Jones, Photographer July 6, 1936, copied from portrait, PORTRAIT OF WILLIAM HENRY, INVENTOR OF HENRY GUN. - Henry Gun Factory, Belfast, Northampton County, PA
1. Historic American Buildings Survey Lester Jones, Photographer October 1, ...
1. Historic American Buildings Survey Lester Jones, Photographer October 1, 1940. VIEW FROM SOUTHEAST - Fort de Chartres, East Barracks (Foundations), Fort de Chartres State Park, Prairie du Rocher, Randolph County, IL
1. Historic American Buildings Survey, Lester Jones, Photographer. October 1, ...
1. Historic American Buildings Survey, Lester Jones, Photographer. October 1, 1940. VIEW FROM NORTHWEST - Fort de Chartres, Officers' Quarters (Foundations), Fort de Chartres State Park, Prairie du Rocher, Randolph County, IL
1. Historic American Buildings Survey Lester Jones, Photographer October 1, ...
1. Historic American Buildings Survey Lester Jones, Photographer October 1, 1940. VIEW FROM NORTHWEST - Fort de Chartres, West Barracks (Foundations), Fort de Chartres State Park, Prairie du Rocher, Randolph County, IL
1. Historic American Buildings Survey Lester Jones, Photographer. October 1, ...
1. Historic American Buildings Survey Lester Jones, Photographer. October 1, 1940. VIEW FROM NORTHEAST - Fort de Chartres, Commandant's Quarters (Foundations), Fort de Chartres State Park, Prairie du Rocher, Randolph County, IL
ISS Update: Status of Space Act Agreement with Brad Jones
NASA Public Affairs Officer Kyle Herring interviews Brad Jones, Deputy Manager, Partner Integration Office â Commercial Crew Program, about the Space Act Agreement. Questions? Ask us on Twitter ...
STS-80 Mission Specialist Thomas Jones in White Room
NASA Technical Reports Server (NTRS)
1996-01-01
STS-80 Mission Specialist Thomas D. Jones prepares to enter the Space Shuttle Columbia at Launch Pad 39B, with assistance from white room closeout crew members (from left) Rick Welty and Bob Saulnier.
15. Historic American Buildings Survey Russell Jones, Photographer June 1963 ...
15. Historic American Buildings Survey Russell Jones, Photographer June 1963 WINDOW DETAIL Rear Main House, First Floor - Timothy Caldwell House, 2017 "Eye" Street Northwest, Washington, District of Columbia, DC
14. Historic American Buildings Survey Russell Jones, Photographer June 1963 ...
14. Historic American Buildings Survey Russell Jones, Photographer June 1963 DOOR DETAIL From Dining Room to Garden - Timothy Caldwell House, 2017 "Eye" Street Northwest, Washington, District of Columbia, DC
1. Historic American Buildings Survey Russell Jones, Photographer March 1959 ...
1. Historic American Buildings Survey Russell Jones, Photographer March 1959 FRONT (SOUTH) ELEVATION FROM THE SOUTH EAST. - Justice Horace Gray House, 1601 Eye Street Northwest, Washington, District of Columbia, DC
6. Historic American Buildings Survey Russell Jones, Photographer January 1959 ...
6. Historic American Buildings Survey Russell Jones, Photographer January 1959 WINDOW DETAIL - REAR FACADE (S. W. CORNER), 2nd FLOOR - Forrest-Marbury House, 3350 M Street Northwest, Washington, District of Columbia, DC
5. Historic American Buildings Survey Russell Jones, Photographer January 1959 ...
5. Historic American Buildings Survey Russell Jones, Photographer January 1959 CHIMNEY DETAIL, SHOWING CAST_IRON CAP. - Forrest-Marbury House, 3350 M Street Northwest, Washington, District of Columbia, DC
1. Historic American Buildings Survey Lester Jones, Photographer. October 1, ...
1. Historic American Buildings Survey Lester Jones, Photographer. October 1, 1940. VIEW FROM NORTHEAST - Fort de Chartres, Powder Magazine, Fort de Chartres State Park, Prairie du Rocher, Randolph County, IL
2. Historic American Buildings Survey Lester Jones, Photographer. October 1, ...
2. Historic American Buildings Survey Lester Jones, Photographer. October 1, 1940. VIEW FROM SOUTHWEST - Fort de Chartres, Powder Magazine, Fort de Chartres State Park, Prairie du Rocher, Randolph County, IL
6. Watchman Robert 'Jerry' Jones at Camp Dyer. Photographer James ...
6. Watchman Robert 'Jerry' Jones at Camp Dyer. Photographer James Dix Schuyler, 1903. Source: Schuyler report. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ
6. Historic American Buildings Survey Lester Jones, Photographer July 7, ...
6. Historic American Buildings Survey Lester Jones, Photographer July 7, 1940 SERVANT'S STAIRWAY - Colonel William Oliver Anderson House, Civil War Battle of Lexington State Park, Lexington, Lafayette County, MO
7. Historic American Buildings Survey Lester Jones, Photographer May 29, ...
7. Historic American Buildings Survey Lester Jones, Photographer May 29, 1940. SUNDIAL With motto: 'Look to your laws rather than progenitors for inheritance.' - Samuel Taylor House, Chatham Pike, Harrodsburg, Mercer County, KY
1. Historic American Buildings Survey Lester Jones, Photographer June 1, ...
1. Historic American Buildings Survey Lester Jones, Photographer June 1, 1940 VIEW FROM SOUTHWEST - Morrison College, Transylvania University, West Third Street, between Upper Street & Broadway, Lexington, Fayette County, KY
2. Historic American Buildings Survey Lester Jones, Photographer June 1, ...
2. Historic American Buildings Survey Lester Jones, Photographer June 1, 1940 VIEW FROM NORTH - Morrison College, Transylvania University, West Third Street, between Upper Street & Broadway, Lexington, Fayette County, KY
HOT METAL BRIDGE (NOTE: BUILDERS: JONES AND LAUGHLIN STEEL CA. ...
HOT METAL BRIDGE (NOTE: BUILDERS: JONES AND LAUGHLIN STEEL CA. 1890), SOUTH PORTAL. THREE PIN CONNECTED CAMELBACK TRUSS SPANS, ONE SKEWED THROUGH TRUSS SPAN ON NORTH SIDE TRUSS BRIDGE, EAST OF HOT METAL BRIDGE BUILT BY AMERICAN BRIDGE COMPANY CA. 1910. (RIVETED MULTI-SPAN TRUSS). - Jones & Laughlin Steel Corporation, Pittsburgh Works, Morgan Billet Mill Engine, 550 feet north of East Carson Street, opposite South Twenty-seventh Street, Pittsburgh, Allegheny County, PA
NEWS: John Goronwy Jones (1920-1999)
NASA Astrophysics Data System (ADS)
Jennison, Brenda M.
2000-05-01
John Goronwy Jones Gron Jones, as he was known to all, was a champion of Physics Education and his death, shortly before his eightieth birthday, robbed physics teachers of a colleague who fought many battles on their behalf. He was not shy of taking issue with anyone in authority who might be putting forward policies which would harm his great love: Physics Education and Physics Teaching. His photograph shows a man with an impish grin, looking friend and foe alike straight in the eye, before delivering the death blow to an argument which was founded on less than common sense. At other times he would listen patiently to the woes of colleagues before offering them fatherly/grandfatherly advice so that whoever was on the receiving end would go away feeling better for the encounter. Gron was born in Swansea and educated at Lewis Boys Grammar School in Glamorgan before entering University College Cardiff first of all as a mathematician before graduating in Physics in 1941. After his war service in the RAF, working on signals and radar development, he returned to do an MSc in X-ray crystallography before completing a PGCE in Bristol. What then passed for teacher training in all institutions left him wary of returning to train teachers himself but after 14 years spent teaching physics in three schools he returned to Cardiff and began a 25 year career in teacher training. He and his two colleagues, Clifford Othen (chemistry) and Douglas Hillier (biology) built up the Cardiff Science Centre as a focus for initial and in-service science teacher training in South Wales. The triumvirate was well known and a power to be reckoned with. They created links between the University Science Departments and the Schools. Gron knew the local schools and their physics teachers intimately. Cardiff became a focus for science education both nationally and internationally. He was a frequent attender at both ICPE (International Commission for Physics Education) and GIREP (International Physics
The Lester-Jones tube and scuba diving.
Mani, Navin; de Carpentier, John
2009-01-01
Insertion of a Lester-Jones tube remains the standard treatment for epiphora secondary to canalicular obstruction. We report on a patient requiring removal of his correctly working Lester-Jones tube to allow him to continue his hobby of scuba diving. This particular complication of the Lester-Jones tube has never previously been reported in the literature. Patients with Lester-Jones tubes are unable to perform the valsalva manoeuvre. The valsalva manoeuvre involves blowing the nose against occluded nostrils resulting in a raised pressure in the nose and post-nasal space which is transmitted via the eustachian tubes to the middle ear. The ability to perform a successful valsalva manoeuvre is a prerequisite of scuba diving to equalise middle ear pressure. Inability to equalise middle ear pressure can lead to barotrauma, including pain, rupture of the tympanic membrane and labyrinthine fistula. We recommend that when planning the insertion of a Lester-Jones tube it is wise to enquire whether the patient undertakes scuba diving. If the patient prefers to scuba dive raher than have control of their epiphora, the surgery should be deferred until the patient gives up diving.
Flight into sanity. Jones's allegation of Ferenczi's mental deterioration reconsidered.
Bonomi, C
1999-06-01
In 'The Life and Work of Sigmund Freud', Volume III, Ernest Jones explained Ferenczi's final contributions as the product of a mental deterioration based on a progressive psychosis. Erich Fromm collected various testimonies by witnesses of Ferenczi's last years, all contrasting with Jones's assertions, and challenged Jones's manner of writing history. However, since Fromm was himself a dissident, and his witnesses were pupils, relatives or friends of Ferenczi's, they were discarded as 'partisans'. The present study aims at reconsidering the question of Ferenczi's insanity on the basis of many unpublished documents. The consulted documents do not support Jones's allegation of Ferenczi's insanity. At the same time, they show that Jones's allegation was not a one-man fabrication, but reflected a shared belief, eliciting many questions about the nature of this belief, the lack of scrutiny that characterised its spreading, and its possible function within the psychoanalytic community. It is suggested that Ferenczi's personality and teaching, especially his emphasis on the need to accept the patient's criticism, contrasted with the dominant conception of psychoanalysis, based on the analyst's infallibility.
Dr. Howard Jones, Jr. (1910-2015): In Memoriam
Oehninger, S.; Kruger, T.F.
2015-01-01
We honor the life of Howard W. Jones, Jr., MD, 104, a pioneer and visionary in reproductive medicine, a dedicated mentor, internationally renowned gynecological surgeon, and the father of in vitro fertilization IVF) in the United States. Dr. Jones founded the Jones Institute for Reproductive Medicine, in Norfolk, Virginia, at Eastern Virginia Medical School, in 1983. Today, IVF has grown exponentially not only in its direct application but also in the development of newer techniques would have been unimaginable a couple of decades ago. Throughout the years Dr. Howard has been a teacher and a mentor to many around the world. To us he also was a friend, a supporter at the time of difficult decisions, someone who would inspire hope, ignite the imagination, and instill a love of learning and untangling some of the complexities of the field, even of the human condition. His leadership, vision, knowledge, enthusiasm and inquisitive mind will be missed.
11. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
11. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (7th STREET) ELEVATION FRON THE SOUTH EAST - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
7. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
7. Historic American Buildings Survey Russell Jones, Photographer April 1959 ENTRANCE, 316 - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
8. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
8. Historic American Buildings Survey Russell Jones, Photographer April 1959 ENTRANCE, 318 - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
16. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
16. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (WEST) ELEVATION (132 ON THE LEFT) - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
7. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
7. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT ELEVATION - 122 (LEFT) 124 (RIGHT) - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
2. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
2. Historic American Buildings Survey Russell Jones, Photographer April 1959 EAST CENTER SECTION OF GROUP FROM THE NORTH - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
17. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
17. Historic American Buildings Survey Russell Jones, Photographer April 1959 UNIT AT 132 - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
18. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
18. Historic American Buildings Survey Russell Jones, Photographer April 1959 ENTRANCE, 132 (LEFT) 134 (RIGHT) - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
6. Historic American Buildings Survey Russell Jones, Photographer March 1959 ...
6. Historic American Buildings Survey Russell Jones, Photographer March 1959 SOUTH ELEVATION FROM THE SOUTH EAST - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
2. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
2. Historic American Buildings Survey Russell Jones, Photographer April 1959 REAR (NORTH) ELEVATION FROM THE N. W. - Southeast Area Survey, 600-602 & 1100 G Street (House), 1002,1006 Eye Street (House), 808-810,812-814, & 1016 K Street (House), 817-819 L Street (House), Washington, District of Columbia, DC
3. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
3. Historic American Buildings Survey Russell Jones, Photographer April 1959 WEST CENTER SECTION OF GROUP FROM THE NORTH - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
5. Historic American Buildings Survey Russell Jones, Photographer March 1959 ...
5. Historic American Buildings Survey Russell Jones, Photographer March 1959 DETAIL - PLAQUE - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
8. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
8. Historic American Buildings Survey Russell Jones, Photographer April 1959 DETAIL - 124 - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
20. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
20. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (WEST) ELEVATION FROM THE N. W. - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
22. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
22. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (EAST) ELEVATION FROM THE S. E. - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
6. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
6. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (WEST) ELEVATION (316 AT THE LEFT) - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
12. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
12. Historic American Buildings Survey Russell Jones, Photographer April 1959 ENTRANCE DETAIL - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
8. Historic American Buildings Survey Russell Jones, Photographer March 1959 ...
8. Historic American Buildings Survey Russell Jones, Photographer March 1959 DETAIL - 2nd AND 3rd FLOOR WINDOWS, SOUTH ELEVATION - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
5. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
5. Historic American Buildings Survey Russell Jones, Photographer April 1959 WEST END OF GROUP FROM THE NORTH - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
9. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
9. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (SOUTH) ELEVATION FROM THE SOUTH EAST 706 (LEFT) 708 (RIGHT) - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
4. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
4. Historic American Buildings Survey Russell Jones, Photographer April 1959 ENTRY, #324 - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
1. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
1. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (WEST) ELEVATION - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
15. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
15. Historic American Buildings Survey Russell Jones, Photographer April 1959 REAR (EAST) AND LEFT (NORTH) ELEVATIONS - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
1. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
1. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (SOUTH) ELEVATION. 600 (LEFT) 602 (RIGHT) - Southeast Area Survey, 600-602 & 1100 G Street (House), 1002,1006 Eye Street (House), 808-810,812-814, & 1016 K Street (House), 817-819 L Street (House), Washington, District of Columbia, DC
7. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
7. Historic American Buildings Survey Russell Jones, Photographer April 1959 EAST ELEVATION FROM THE N. E. - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
1. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
1. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT ELEVATION, 156 (LEFT) 158 (RIGHT) - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
3. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
3. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (SOUTH) ELEVATION. 324 (LEFT) 326 (RIGHT) - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
13. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
13. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (EAST) ELEVATION. 1105 (LEFT) 1103 (RIGHT) - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
5. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
5. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (SOUTH) ELEVATION - Southeast Area Survey, 600-602 & 1100 G Street (House), 1002,1006 Eye Street (House), 808-810,812-814, & 1016 K Street (House), 817-819 L Street (House), Washington, District of Columbia, DC
10. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
10. Historic American Buildings Survey Russell Jones, Photographer April 1959 GENERAL VIEW FROM THE SOUTH - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
2. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
2. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (EAST) ELEVATION - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
21. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
21. Historic American Buildings Survey Russell Jones, Photographer April 1959 REAR (EAST) ELEVATION FROM THE N. E. - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
14. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
14. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (WEST) ELEVATION - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
4. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
4. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (SOUTH) ELEVATION - Southeast Area Survey, 600-602 & 1100 G Street (House), 1002,1006 Eye Street (House), 808-810,812-814, & 1016 K Street (House), 817-819 L Street (House), Washington, District of Columbia, DC
1. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
1. Historic American Buildings Survey Russell Jones, Photographer April 1959 EAST END OF GROUP FROM THE NORTH - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
9. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
9. Historic American Buildings Survey Russell Jones, Photographer April 1959 GENERAL VIEW FROM THE EAST - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
6. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
6. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (SOUTH) ELEVATION 808 (LEFT) 810 (RIGHT) - Southeast Area Survey, 600-602 & 1100 G Street (House), 1002,1006 Eye Street (House), 808-810,812-814, & 1016 K Street (House), 817-819 L Street (House), Washington, District of Columbia, DC
3. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
3. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (EAST) ELEVATION - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
19. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
19. Historic American Buildings Survey Russell Jones, Photographer April 1959 WINDOW DETAIL - 132 - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
6. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
6. Historic American Buildings Survey Russell Jones, Photographer April 1959 ENTRY - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
4. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
4. Historic American Buildings Survey Russell Jones, Photographer April 1959 DETAIL - ONE UNIT OF GROUP - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
11. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
11. Historic American Buildings Survey Russell Jones, Photographer April 1959 GENERAL VIEW FROM THE EAST. 1016 and 1018. - Southeast Area Survey, 101 & 122-124 Carroll Street (House), 1008 Potomac Street (House), Canal Street at Independence Avenue (Row House), 1016-1018 Potomac Street (House), Washington, District of Columbia, DC
4. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
4. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (WEST) ELEVATION - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
3. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
3. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (NORTH) ELEVATION - Southeast Area Survey, 600-602 & 1100 G Street (House), 1002,1006 Eye Street (House), 808-810,812-814, & 1016 K Street (House), 817-819 L Street (House), Washington, District of Columbia, DC
2. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
2. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT ELEVATION. 306 (LEFT), 308 (RIGHT) - Southeast Area Survey, 330 & 706-708 Virginia Avenue (Houses), 306-308,324-326 Virginia Avenue (Houses), 156-158 North Carolina Avenue (Houses), Washington, District of Columbia, DC
9. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
9. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (WEST) ELEVATION FROM THE N.W. - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
10. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
10. Historic American Buildings Survey Russell Jones, Photographer April 1959 REAR(EAST) & LEFT ELEVATIONS FROM THE N. E. - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
5. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
5. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (EAST) ELEVATION - Southeast Area Survey, Sixth & G Streets (Synagogue), 132-144 & 900-905 Eleventh Street (Row Houses), 215 Second Street (House), Seventh & G Streets (School), 214 First Street (House), Washington, District of Columbia, DC
10. Historic American Buildings Survey Russell Jones, Photographer April 1959 ...
10. Historic American Buildings Survey Russell Jones, Photographer April 1959 FRONT (NORTH) ELEVATION. 819 (LEFT) 817 (RIGHT) - Southeast Area Survey, 600-602 & 1100 G Street (House), 1002,1006 Eye Street (House), 808-810,812-814, & 1016 K Street (House), 817-819 L Street (House), Washington, District of Columbia, DC
Birefringence of Cellotape: Jones Representation and Experimental Analysis
ERIC Educational Resources Information Center
Belendez, Augusto; Fernandez, Elena; Frances, Jorge; Neipp, Cristian
2010-01-01
In this paper, we analyse a simple experiment to study the effects of polarized light. A simple optical system composed of a polarizer, a retarder (cellotape) and an analyser is used to study the effect on the polarization state of the light which impinges on the setup. The optical system is characterized by means of a Jones matrix, and a simple…
Thermal conductivity of the Lennard-Jones chain fluid model
NASA Astrophysics Data System (ADS)
Galliero, Guillaume; Boned, Christian
2009-12-01
Nonequilibrium molecular dynamics simulations have been performed to estimate, analyze, and correlate the thermal conductivity of a fluid composed of short Lennard-Jones chains (up to 16 segments) over a large range of thermodynamic conditions. It is shown that the dilute gas contribution to the thermal conductivity decreases when the chain length increases for a given temperature. In dense states, simulation results indicate that the residual thermal conductivity of the monomer increases strongly with density, but is weakly dependent on the temperature. Compared to the monomer value, it has been noted that the residual thermal conductivity of the chain was slightly decreasing with its length. Using these results, an empirical relation, including a contribution due to the critical enhancement, is proposed to provide an accurate estimation of the thermal conductivity of the Lennard-Jones chain fluid model (up to 16 segments) over the domain 0.8≤T∗≤6 and 0≤ρ∗≤1 . Additionally, it has been noted that all reduced thermal conductivity values of the Lennard-Jones chain fluid model merge on the same “universal” curve when plotted as a function of the excess entropy. Furthermore, it is shown that the reduced configurational thermal conductivity of the Lennard-Jones chain fluid model is approximately proportional to the reduced excess entropy for all fluid states and all chain lengths.
'Jones Hybrid' hickory: A case study in Carya curation
Technology Transfer Automated Retrieval System (TEKTRAN)
'Jones Hybrid' hickory is an accession in the National Collection of Genetic Resources for Pecans and Hickories that was inherited with little information concerning its origination, its identity or its characteristics. It has been phenotypically and genetically profiled and is described here. Tha...
Edward Burne-Jones' Heavenly Conception: A Biblical Cosmos
NASA Astrophysics Data System (ADS)
Cheney, L. D. G.
2016-01-01
Edward Burne-Jones was a Pre-Raphaelite artist and designer, who collaborated with William Morris on many decorative arts (stained glass windows, book illustrations, ceramic and tapestry designs). He was a founding partner in the firm Morris, Marshall, Faulkner & Company. Burne-Jones composed The Days of Creation between 1870 and 1876 for the Morris firm. These paintings were executed in gouache and gold paint, and cartoons were made for tile and in stained glass, for the Church of St. Editha at Tamworth in Staffordshire. Burne-Jones' creation was highly praised and elegantly described by Oscar Wilde: “The picture is divided into six compartments, each representing a day in the Creation of the World, under the symbol of an angel holding a crystal globe, within which is shown the work of a day.” This paper will examine how Burne-Jones visualized an unusual celestial creation where angels holding magical spheres unveil the divine manifestation for the creation of a terrestrial realm. He created a cosmic utopia of the natural world.
Contextual view of Fyffe Avenue between Jones and Boone Drives. ...
Contextual view of Fyffe Avenue between Jones and Boone Drives. ASA office (U.S. Border Control Environmental Office Building no. 317) is shown at center. Camera facing east. - Naval Supply Annex Stockton, Rough & Ready Island, Stockton, San Joaquin County, CA
A tribute to Robert Edwards and Howard Jones Jr
Ombelet, W.
2011-01-01
“2010 was a fascinating year. Robert Edwards finally received the Nobel prize for Medicine and his friend in the United States, Howard W. Jones Jr. was honored in Denver by the American Society of Reproductive Medicine (ASRM) upon his Centennial Birthday. He turned 100 on December 30th” PMID:24753845
DREDGED MATERIAL RECLAMATION AT THE JONES ISLAND CONFINED DISPOSAL FACILITY SITE CAPSULE
In this SITE demonstration, phytoremediation technology was applied to contaminated dredged materials from the Jones Island Confined Disposal Facility (CDF) located in Milwaukee Harbor, Wisconsin. The Jones Island CDF receives dredged materials from normal maintenance of Milwauke...
DREDGED MATERIAL RECLAMATION AT THE JONES ISLAND CONFINED DISPOSAL FACILITY - ITER
In this SITE demonstration, phytoremediation technology was applied to contaminated dredged materials from the Jones Island Confined Disposal Facility (CDF) located in Milwaukee Harbor, Wisconsin. The Jones Island CDF receives dredged materials from normal maintenance of Milwauke...
21 CFR 866.5150 - Bence-Jones proteins immunological test system.
Code of Federal Regulations, 2010 CFR
2010-04-01
... the Bence-Jones proteins in urine and plasma. Immunoglobulin molecules normally consist of pairs of... disulfide bridges. In some cancerous conditions, there is a proliferation of one plasma cell (antibody... plasma, and have been called Bence-Jones proteins. Measurement of Bence-Jones proteins and...
21 CFR 866.5150 - Bence-Jones proteins immunological test system.
Code of Federal Regulations, 2011 CFR
2011-04-01
... the Bence-Jones proteins in urine and plasma. Immunoglobulin molecules normally consist of pairs of... disulfide bridges. In some cancerous conditions, there is a proliferation of one plasma cell (antibody... plasma, and have been called Bence-Jones proteins. Measurement of Bence-Jones proteins and...
21 CFR 866.5150 - Bence-Jones proteins immunological test system.
Code of Federal Regulations, 2012 CFR
2012-04-01
... the Bence-Jones proteins in urine and plasma. Immunoglobulin molecules normally consist of pairs of... disulfide bridges. In some cancerous conditions, there is a proliferation of one plasma cell (antibody... plasma, and have been called Bence-Jones proteins. Measurement of Bence-Jones proteins and...
21 CFR 866.5150 - Bence-Jones proteins immunological test system.
Code of Federal Regulations, 2013 CFR
2013-04-01
... the Bence-Jones proteins in urine and plasma. Immunoglobulin molecules normally consist of pairs of... disulfide bridges. In some cancerous conditions, there is a proliferation of one plasma cell (antibody... plasma, and have been called Bence-Jones proteins. Measurement of Bence-Jones proteins and...
21 CFR 866.5150 - Bence-Jones proteins immunological test system.
Code of Federal Regulations, 2014 CFR
2014-04-01
... the Bence-Jones proteins in urine and plasma. Immunoglobulin molecules normally consist of pairs of... disulfide bridges. In some cancerous conditions, there is a proliferation of one plasma cell (antibody... plasma, and have been called Bence-Jones proteins. Measurement of Bence-Jones proteins and...
Second virial coefficient of a generalized Lennard-Jones potential.
González-Calderón, Alfredo; Rocha-Ichante, Adrián
2015-01-21
We present an exact analytical solution for the second virial coefficient of a generalized Lennard-Jones type of pair potential model. The potential can be reduced to the Lennard-Jones, hard-sphere, and sticky hard-sphere models by tuning the potential parameters corresponding to the width and depth of the well. Thus, the second virial solution can also regain the aforementioned cases. Moreover, the obtained expression strongly resembles the one corresponding to the Kihara potential. In fact, the Fk functions are the same. Furthermore, for these functions, the complete expansions at low and high temperature are given. Additionally, we propose an alternative stickiness parameter based on the obtained second virial coefficient.
Second virial coefficient of a generalized Lennard-Jones potential
NASA Astrophysics Data System (ADS)
González-Calderón, Alfredo; Rocha-Ichante, Adrián
2015-01-01
We present an exact analytical solution for the second virial coefficient of a generalized Lennard-Jones type of pair potential model. The potential can be reduced to the Lennard-Jones, hard-sphere, and sticky hard-sphere models by tuning the potential parameters corresponding to the width and depth of the well. Thus, the second virial solution can also regain the aforementioned cases. Moreover, the obtained expression strongly resembles the one corresponding to the Kihara potential. In fact, the Fk functions are the same. Furthermore, for these functions, the complete expansions at low and high temperature are given. Additionally, we propose an alternative stickiness parameter based on the obtained second virial coefficient.
'Jones hybrid' hickory: a case study in Carya curation.
Grauke, L J; Mendoza-Herrera, M Azucena; Stelly, David M; Klein, Patricia E
2016-01-01
'Jones Hybrid' hickory is an accession in the National Collection of Genetic Resources for Pecans and Hickories for which information about origin, identity and characteristics is very incomplete. Phenotypic and genetic profiles, when examined in the context of historic literature, provide evidence that the accession in question is 'Siers' a cultivar of Carya × laneyi (an interspecific hybrid between C. ovata and C. cordiformis). The accession has traits that make it interesting in the pecan breeding program, with potential for both rootstock and scion development. The tall, slender tree form of 'Jones Hybrid' is a trait that could be valuable in commercial pecan cultivars, allowing increased tree densities and reducing the need for expensive hedging operations. Tree size reduction is a goal to be pursued in scion selection and rootstock development, with each goal requiring assessment of reproductive potential of the accession.
Gauge-origin independent calculations of Jones birefringence
NASA Astrophysics Data System (ADS)
Shcherbin, Dmitry; Thorvaldsen, Andreas J.; Jonsson, Dan; Ruud, Kenneth
2011-10-01
We present the first gauge-origin independent formulation of Jones birefringence at the Hartree-Fock level of theory. Gauge-origin independence is achieved through the use of London atomic orbitals. The implementation is based on a recently proposed atomic orbital-based response theory formulation that allows for the use of both time- and perturbation-dependent basis sets [Thorvaldsen, Ruud, Kristensen, Jørgensen, and Coriani, J. Chem. Phys. 129, 214108 (2008)]. We present the detailed expressions for the response functions entering the Jones birefringence when London atomic orbitals are used. The implementation is tested on a set of polar and dipolar molecules at the Hartree-Fock level of theory. It is demonstrated that London orbitals lead to much improved basis-set convergence, and that the use of small, conventional basis sets may lead to the wrong sign for the calculated birefringence. For large basis sets, London orbitals and conventional basis sets converge to the same results.
Jones matrix treatment for optical Fourier processors with structured polarization.
Moreno, Ignacio; Iemmi, Claudio; Campos, Juan; Yzuel, Maria J
2011-02-28
We present a Jones matrix method useful to analyze coherent optical Fourier processors employing structured polarization. The proposed method is a generalization of the standard classical optical Fourier transform processor, but considering vectorial spatial functions with two complex components corresponding to two orthogonal linear polarizations. As a result we derive a Jones matrix that describes the polarization output in terms of two vectorial functions defining respectively the structured polarization input and the generalized polarization impulse response. We apply the method to show and analyze an experiment in which a regular scalar diffraction grating is converted into equivalent polarization diffraction gratings by means of an appropriate polarization filtering. The technique is further demonstrated to generate arbitrary structured polarizations. Excellent experimental results are presented.
A Viola-Jones based hybrid face detection framework
NASA Astrophysics Data System (ADS)
Murphy, Thomas M.; Broussard, Randy; Schultz, Robert; Rakvic, Ryan; Ngo, Hau
2013-12-01
Improvements in face detection performance would benefit many applications. The OpenCV library implements a standard solution, the Viola-Jones detector, with a statistically boosted rejection cascade of binary classifiers. Empirical evidence has shown that Viola-Jones underdetects in some instances. This research shows that a truncated cascade augmented by a neural network could recover these undetected faces. A hybrid framework is constructed, with a truncated Viola-Jones cascade followed by an artificial neural network, used to refine the face decision. Optimally, a truncation stage that captured all faces and allowed the neural network to remove the false alarms is selected. A feedforward backpropagation network with one hidden layer is trained to discriminate faces based upon the thresholding (detection) values of intermediate stages of the full rejection cascade. A clustering algorithm is used as a precursor to the neural network, to group significant overlappings. Evaluated on the CMU/VASC Image Database, comparison with an unmodified OpenCV approach shows: (1) a 37% increase in detection rates if constrained by the requirement of no increase in false alarms, (2) a 48% increase in detection rates if some additional false alarms are tolerated, and (3) an 82% reduction in false alarms with no reduction in detection rates. These results demonstrate improved face detection and could address the need for such improvement in various applications.
Partitioned density functional approach for a Lennard-Jones fluid.
Zhou, Shiqi
2003-12-01
The existing classical density functional approach for nonuniform Lennard-Jones fluid, which is based on dividing the Lennard-Jones interaction potential into a short-range, repulsive part, and a smoothly varying, long-range, attractive tail, was improved by dividing the bulk second-order direct correlation function into strongly density-depending short-range part and weakly density-depending long-range part. The latter is treated by functional perturbation expansion truncated at the lowest order whose accuracy depends on how weakly the long-range part depends on the bulk density. The former is treated by the truncated functional perturbation expansion which is rewritten in the form of the simple weighted density approximation and incorporates the omitted higher-order terms by applying Lagrangian theorem of differential calculus to the reformulated form. The two approximations are put into the density profile equation of the density functional theory formalism to predict the density distribution for Lennard-Jones fluid in contact with a hard wall or between two hard walls within the whole density range for reduced temperature T(*)=1.35 and a density point for reduced temperature T(*)=1. The present partitioned density functional theory performs much better than several previous density functional perturbation theory approaches and a recently proposed bridge density functional approximation.
Mueller-Jones Matrix measurement in material identification
NASA Astrophysics Data System (ADS)
Xu, Jiang; Qian, Weixian; Wang, Xiao
2016-09-01
The uniformity of lattice arrangement plays an important role in industrial processing, science and technology studies and environmental pollution detection. However, there are very little papers to study surface structure by depolarization characteristics. In order to improve the efficiency and accuracy of material identification system by polarization technology, we developed a new method to decompose the Mueller matrix, we studied the mechanism of the scattering of electromagnetic wave, and analyzed the relationship between the characteristics of depolarization and mechanism of scattering. We used the Jones Matrix and Mueller Matrix to set up the physical model, and decomposed the Mueller-Jones Matrix by the characteristics of polarization, then got the depolarization coefficients (ωd) of the surfaces of the samples. By using this theory, we deduced the relation formula of Mueller matrix, Mueller-Jones matrix and Isotropic-Depolarizer matrix. Based on the polarized characteristics of the samples, we analyzed design method of material identification system and gave the results of the experimental test. Finally, we applied the theory of Fresnel formulas to verify the theoretical model. From the results, we found that the depolarization coefficients of the samples' surfaces were related to the scattering, and in the whole measurement process, the depolarization coefficients of the samples were far different; the method could easily to distinguish the metal and nonmetal, and more quickly to analyze the surface roughness of the samples. Therefore, the depolarization technology had a great application value, and the paper had very important significance on the development of surface structure study.
Ushcats, M V
2014-09-14
The regularity of the existing data on the virial coefficients for the Lennard-Jones and modified Lennard-Jones models has allowed a rough extrapolation to the coefficients of higher orders. The corresponding approximation of the infinite virial series has been proposed for the limited temperature interval: 0.4-0.8 of the critical temperature. The loci of zero points of isothermal bulk modulus obtained on the basis of this approximation are close to the vapor-liquid branch of the experimental binodal rather than spinodal. In addition, those points ((dP/dV)T = 0) almost coincide with the divergence points of the approximated virial series that may eliminate some disputable questions about the boundaries of adequacy for the virial equation of state and makes the theoretical isotherms qualitatively similar to the real in the condensation region.
Structure diagram of binary Lennard-Jones clusters.
Mravlak, Marko; Kister, Thomas; Kraus, Tobias; Schilling, Tanja
2016-07-14
We analyze the structure diagram for binary clusters of Lennard-Jones particles by means of a global optimization approach for a large range of cluster sizes, compositions, and interaction energies and present a publicly accessible database of 180 000 minimal energy structures (http://softmattertheory.lu/clusters.html). We identify a variety of structures such as core-shell clusters, Janus clusters, and clusters in which the minority species is located at the vertices of icosahedra. Such clusters can be synthesized from nanoparticles in agglomeration experiments and used as building blocks in colloidal molecules or crystals. We discuss the factors that determine the formation of clusters with specific structures.
Bubble nucleation in a Lennard-Jones binary liquid mixture
NASA Astrophysics Data System (ADS)
Baidakov, Vladimir G.; Protsenko, Sergey P.; Bryukhanov, Vasiliy M.
2016-10-01
We report a molecular dynamics (MD) study of homogeneous bubble nucleation in a stretched Lennard-Jones binary mixture at a temperature close to the solvent triple point. The pressure of the limiting stretching pn corresponding to a fixed value of the nucleation rate has been determined. The values of pn achieved in MD simulation are lower than those calculated from classical nucleation theory (CNT). The discrepancy between the data of MD simulation and CNT may be connected with the neglect in the latter of the size dependence of the surface tension of critical bubbles.
Enhanced Crystal Growth in Binary Lennard-Jones Mixtures.
Radu, M; Kremer, K
2017-02-03
We study the crystal growth in binary Lennard-Jones mixtures by molecular dynamics simulations. Growth dynamics, the structure of the liquid-solid interfaces as well as droplet incorporation into the crystal vary with solution properties. For demixed systems we observe a strongly enhanced crystal growth at the cost of enclosed impurities. Furthermore, we find different interface morphologies depending on solubility. We relate our observations to growth mechanisms based on the Gibbs-Thomson effect as well as to predictions of the Kardar-Parisi-Zhang theory in 2+1 dimensions.
Structure diagram of binary Lennard-Jones clusters
NASA Astrophysics Data System (ADS)
Mravlak, Marko; Kister, Thomas; Kraus, Tobias; Schilling, Tanja
2016-07-01
We analyze the structure diagram for binary clusters of Lennard-Jones particles by means of a global optimization approach for a large range of cluster sizes, compositions, and interaction energies and present a publicly accessible database of 180 000 minimal energy structures (http://softmattertheory.lu/clusters.html). We identify a variety of structures such as core-shell clusters, Janus clusters, and clusters in which the minority species is located at the vertices of icosahedra. Such clusters can be synthesized from nanoparticles in agglomeration experiments and used as building blocks in colloidal molecules or crystals. We discuss the factors that determine the formation of clusters with specific structures.
Lennard-Jones and lattice models of driven fluids.
Díez-Minguito, M; Garrido, P L; Marro, J
2005-08-01
We introduce a nonequilibrium off-lattice model for anisotropic phenomena in fluids. This is a Lennard-Jones generalization of the driven lattice-gas model in which the particles' spatial coordinates vary continuously. A comparison between the two models allows us to discuss some exceptional, hardly realistic features of the original discrete system--which has been considered a prototype for nonequilibrium anisotropic phase transitions. We thus help to clarify open issues, and discuss on the implications of our observations for future investigation of anisotropic phase transitions.
Origin of line tension for a Lennard-Jones nanodroplet
NASA Astrophysics Data System (ADS)
Weijs, Joost H.; Marchand, Antonin; Andreotti, Bruno; Lohse, Detlef; Snoeijer, Jacco H.
2011-02-01
The existence and origin of line tension has remained controversial in literature. To address this issue, we compute the shape of Lennard-Jones nanodrops using molecular dynamics and compare them to density functional theory in the approximation of the sharp kink interface. We show that the deviation from Young's law is very small and would correspond to a typical line tension length scale (defined as line tension divided by surface tension) similar to the molecular size and decreasing with Young's angle. We propose an alternative interpretation based on the geometry of the interface at the molecular scale.
Transpose symmetry of the Jones matrix and topological phases.
Bhandari, Rajendra
2008-04-15
The transmission Jones matrix of an arbitrary stack of reciprocal plane-parallel plates that has been turned through 180 degrees about an axis in the plane of the stack is, in an appropriate basis, the transpose of the transmission matrix of the unturned slab with a change in the sign of the off-diagonal elements. We prove this convention-free result for the case where reflection at the interfaces can be ignored and use it to devise an experimental scheme to separate isotropic and topological phase changes in a reciprocal optical medium.
Advanced Jones calculus for the classification of periodic metamaterials
Menzel, Christoph; Rockstuhl, Carsten; Lederer, Falk
2010-11-15
By relying on an advanced Jones calculus, we analyze the polarization properties of light upon propagation through metamaterial slabs in a comprehensive manner. Based on symmetry considerations, we show that all periodic metamaterials may be divided into five different classes only. It is shown that each class differently affects the polarization of the transmitted light and sustains different eigenmodes. We show how to deduce these five classes from symmetry considerations and provide a simple algorithm that can be applied to decide to which class a given metamaterial belongs by measuring only the transmitted intensities.
Accurate Critical Parameters for the Modified Lennard-Jones Model
NASA Astrophysics Data System (ADS)
Okamoto, Kazuma; Fuchizaki, Kazuhiro
2017-03-01
The critical parameters of the modified Lennard-Jones system were examined. The isothermal-isochoric ensemble was generated by conducting a molecular dynamics simulation for the system consisting of 6912, 8788, 10976, and 13500 particles. The equilibrium between the liquid and vapor phases was judged from the chemical potential of both phases upon establishing the coexistence envelope, from which the critical temperature and density were obtained invoking the renormalization group theory. The finite-size scaling enabled us to finally determine the critical temperature, pressure, and density as Tc = 1.0762(2), pc = 0.09394(17), and ρc = 0.331(3), respectively.
Enhanced Crystal Growth in Binary Lennard-Jones Mixtures
NASA Astrophysics Data System (ADS)
Radu, M.; Kremer, K.
2017-02-01
We study the crystal growth in binary Lennard-Jones mixtures by molecular dynamics simulations. Growth dynamics, the structure of the liquid-solid interfaces as well as droplet incorporation into the crystal vary with solution properties. For demixed systems we observe a strongly enhanced crystal growth at the cost of enclosed impurities. Furthermore, we find different interface morphologies depending on solubility. We relate our observations to growth mechanisms based on the Gibbs-Thomson effect as well as to predictions of the Kardar-Parisi-Zhang theory in 2 +1 dimensions.
[Thermodynamic and hydrodynamic study of Bence-Jones proteins].
Tishchenko, V M; Khristoforov, V S; Blizniukov, O P
2009-01-01
Four Bence-Jones proteins were investigated by CD, fluorescence and analytical ultracentrifugation methods at physiological conditions (10 mM phosphate buffer, pH 7.0, 100 mM NaCl). A joint analysis of optical melting curves for proteins and their fragments were demonstrated that protein VAD has reduced stability of its constant half, which correlates with the ability of both intact protein and its constant, rather than variable part to form amyloid fibrils. Data are reported which support the viewpoint that the detected decrease in the stability is caused by abnormal interaction between a pair of constant domains C(L).
The genus Unixenus Jones, 1944 (Diplopoda, Penicillata, Polyxenida) in Australia
Short, Megan; Huynh, Cuong
2011-01-01
Abstract The penicillate genus Unixenus Jones, 1944 is widespread, with species found in Africa, Madagascar, India and Australia. Each of the two Australian species was originally described from single samples from Western Australia. In this study, collections of Penicillata from museums in all states of Australia were examined to provide further details of the two described species, to revise the diagnoses for both the genus and the species, and to better understand the distribution of the two species in Australia. In addition, two new species Unixenus karajinensis sp. n. and Unixenus corticolus sp. n. are described. PMID:22303098
3. Historic American Buildings Survey Russell Jones, Photographer June 1963NORTHWEST ...
3. Historic American Buildings Survey Russell Jones, Photographer June 1963NORTHWEST VIEW - Abner Cloud House, Intersection of Canal Road & Reservoir Road Northwest, Washington, District of Columbia, DC
Phase diagram of the modified Lennard-Jones system.
Asano, Yuta; Fuchizaki, Kazuhiro
2012-11-07
An investigation of the precise determination of melting temperature in the modified Lennard-Jones system under pressure-free conditions [Y. Asano and K. Fuchizaki, J. Phys. Soc. Jpn. 78, 055002 (2009)] was extended under finite-pressure conditions to obtain the phase diagram. The temperature and pressure of the triple point were estimated to be 0.61 ε∕k(B) and 0.0018(5) ε∕σ(3), and those of the critical point were 1.0709(19) ε∕k(B) and 0.1228(20) ε∕σ(3), where ε and σ are the Lennard-Jones parameters for energy and length scales, respectively, and k(B) is the Boltzmann constant. The potential used here has a finite attractive tail and does not suffer from cutoff problems. The potential can thus be a useful standard in examining statistical-mechanical problems in which different treatments for the tail would lead to different conclusions. The present phase diagram will then be a useful guide not only for equilibrium calculations but also for nonequilibrium problems such as discussions of the limits of phase (in)stability.
The BQP-hardness of approximating the Jones polynomial
NASA Astrophysics Data System (ADS)
Aharonov, Dorit; Arad, Itai
2011-03-01
A celebrated important result due to Freedman et al (2002 Commun. Math. Phys. 227 605-22) states that providing additive approximations of the Jones polynomial at the kth root of unity, for constant k=5 and k>=7, is BQP-hard. Together with the algorithmic results of Aharonov et al (2005) and Freedman et al (2002 Commun. Math. Phys. 227 587-603), this gives perhaps the most natural BQP-complete problem known today and motivates further study of the topic. In this paper, we focus on the universality proof; we extend the result of Freedman et al (2002) to ks that grow polynomially with the number of strands and crossings in the link, thus extending the BQP-hardness of Jones polynomial approximations to all values to which the AJL algorithm applies (Aharonov et al 2005), proving that for all those values, the problems are BQP-complete. As a side benefit, we derive a fairly elementary proof of the Freedman et al density result, without referring to advanced results from Lie algebra representation theory, making this important result accessible to a wider audience in the computer science research community. We make use of two general lemmas we prove, the bridge lemma and the decoupling lemma, which provide tools for establishing the density of subgroups in SU(n). Those tools seem to be of independent interest in more general contexts of proving the quantum universality. Our result also implies a completely classical statement, that the multiplicative approximations of the Jones polynomial, at exactly the same values, are #P-hard, via a recent result due to Kuperberg (2009 arXiv:0908.0512). Since the first publication of those results in their preliminary form (Aharonov and Arad 2006 arXiv:quant-ph/0605181), the methods we present here have been used in several other contexts (Aharonov and Arad 2007 arXiv:quant-ph/0702008; Peter and Stephen 2008 Quantum Inf. Comput. 8 681). The present paper is an improved and extended version of the results presented by Aharonov and Arad
The Lennard-Jones melting line and isomorphism.
Heyes, D M; Brańka, A C
2015-12-21
The location of the melting line (ML) of the Lennard-Jones (LJ) system and its associated physical properties are investigated using molecular dynamics computer simulation. The radial distribution function and the behavior of the repulsive and attractive parts of the potential energy indicate that the ML is not a single isomorph, but the isomorphic state evolves gradually with temperature, i.e., it is only "locally isomorphic." The state point dependence of the unitless isomorphic number, X̃, for a range of static and dynamical properties of the LJ system in the solid and fluid states, and for fluid argon, are also reported. The quantity X̃ typically varies most with state point in the vicinity of the triple point and approaches a plateau in the high density (temperature) limit along the ML.
Metastable Lennard-Jones fluids. III. Bulk viscosity.
Baidakov, Vladimir G; Protsenko, Sergey P
2014-09-21
The method of equilibrium molecular-dynamics simulation in combination with the Green-Kubo formula has been used to calculate the bulk viscosity of a Lennard-Jones fluid. Calculations have been made at temperatures 0.4 ≤ k(B)T/ɛ ≤ 2.0 and densities 0.0075 ≤ ρσ(3) ≤ 1.2 at 116 stable and 106 metastable states of liquid and gas. The depth of penetration into the region of metastable states was limited by spontaneous nucleation. In the region of stable states the data obtained are compared with the results of previous investigations. It has been established that the system transition across the lines of liquid-gas and liquid-crystal phase equilibrium and penetration into the metastable regions of liquid and gas are connected with increasing bulk viscosity. The behavior of bulk viscosity close to the spinodal of a superheated liquid and supersaturated vapor is discussed.
Phase behavior of the 38-atom Lennard-Jones cluster.
Sehgal, Ray M; Maroudas, Dimitrios; Ford, David M
2014-03-14
We have developed a coarse-grained description of the phase behavior of the isolated 38-atom Lennard-Jones cluster (LJ38). The model captures both the solid-solid polymorphic transitions at low temperatures and the complex cluster breakup and melting transitions at higher temperatures. For this coarse model development, we employ the manifold learning technique of diffusion mapping. The outcome of the diffusion mapping analysis over a broad temperature range indicates that two order parameters are sufficient to describe the cluster's phase behavior; we have chosen two such appropriate order parameters that are metrics of condensation and overall crystallinity. In this well-justified coarse-variable space, we calculate the cluster's free energy landscape (FEL) as a function of temperature, employing Monte Carlo umbrella sampling. These FELs are used to quantify the phase behavior and onsets of phase transitions of the LJ38 cluster.
Vectorial polarization modes platform realized with Jones vectors in mathematica
NASA Astrophysics Data System (ADS)
Choi, Yong-Dae; Yun, Hee-Joong
2015-09-01
The fundamental concept in physics of polarization propagation of electromagnetic waves is newly understood to be a cardinal keyword in quantum cryptography transport technology and the Standard Model. Interactive visualization of the propagation mechanism of polarized electromagnetism in a medium with its helicity has received attention recently from scientists in the age of information and communication. This study presents a new dynamic polarization platform that presents the polarization modes of a transverse electromagnetic wave by using Jones vectors calculations in the symbolic program Mathematica to convert the state of polarization through the arrangement of the optical elements. The platform simulates a propagation process that satisfies Maxwell's two vector equations precisely with the vectorial nature of the electromagnetic wave.
The Double Jones Birefringence in Magneto-electric Medium
NASA Astrophysics Data System (ADS)
Mahmood, Waqas; Zhao, Qing
2015-09-01
In this paper, the Maxwell’s equations for a tensorial magneto-electric (ME) medium are solved, which is an extension to the work on the uniaxial anisotropic nonmagnetic medium. The coefficients of the dielectric permittivity, magnetic permeability, and of the magneto-electric effect are considered as tensors. The polarization is shown lying in the plane of two perpendicular independent vectors, and the relationship for the transverse polarization is given. The propagation of an electromagnetic wave through a ME medium gives rise to double Jones birefringence. Besides, the condition for an independent phenomenon of D’yakonov surface wave in a magneto-isotropic but with magneto-electric medium is given, which is measurable experimentally when the incident angle is . Lastly, it is shown that the parameter for the magneto-electric effect plays a role in the damping of the wave.
Corresponding states law for a generalized Lennard-Jones potential
NASA Astrophysics Data System (ADS)
Orea, P.; Romero-Martínez, A.; Basurto, E.; Vargas, C. A.; Odriozola, G.
2015-07-01
It was recently shown that vapor-liquid coexistence densities derived from Mie and Yukawa models collapse to define a single master curve when represented against the difference between the reduced second virial coefficient at the corresponding temperature and that at the critical point. In this work, we further test this proposal for another generalization of the Lennard-Jones pair potential. This is carried out for vapor-liquid coexistence densities, surface tension, and vapor pressure, along a temperature window set below the critical point. For this purpose, we perform molecular dynamics simulations by varying the potential softness parameter to produce from very short to intermediate attractive ranges. We observed all properties to collapse and yield master curves. Moreover, the vapor-liquid curve is found to share the exact shape of the Mie and attractive Yukawa. Furthermore, the surface tension and the logarithm of the vapor pressure are linear functions of this difference of reduced second virial coefficients.
Phase behavior of the 38-atom Lennard-Jones cluster
Sehgal, Ray M.; Maroudas, Dimitrios E-mail: ford@ecs.umass.edu; Ford, David M. E-mail: ford@ecs.umass.edu
2014-03-14
We have developed a coarse-grained description of the phase behavior of the isolated 38-atom Lennard-Jones cluster (LJ{sub 38}). The model captures both the solid-solid polymorphic transitions at low temperatures and the complex cluster breakup and melting transitions at higher temperatures. For this coarse model development, we employ the manifold learning technique of diffusion mapping. The outcome of the diffusion mapping analysis over a broad temperature range indicates that two order parameters are sufficient to describe the cluster's phase behavior; we have chosen two such appropriate order parameters that are metrics of condensation and overall crystallinity. In this well-justified coarse-variable space, we calculate the cluster's free energy landscape (FEL) as a function of temperature, employing Monte Carlo umbrella sampling. These FELs are used to quantify the phase behavior and onsets of phase transitions of the LJ{sub 38} cluster.
The Double Jones Birefringence in Magneto-electric Medium
Mahmood, Waqas; Zhao, Qing
2015-01-01
In this paper, the Maxwell’s equations for a tensorial magneto-electric (ME) medium are solved, which is an extension to the work on the uniaxial anisotropic nonmagnetic medium. The coefficients of the dielectric permittivity, magnetic permeability, and of the magneto-electric effect are considered as tensors. The polarization is shown lying in the plane of two perpendicular independent vectors, and the relationship for the transverse polarization is given. The propagation of an electromagnetic wave through a ME medium gives rise to double Jones birefringence. Besides, the condition for an independent phenomenon of D’yakonov surface wave in a magneto-isotropic but with magneto-electric medium is given, which is measurable experimentally when the incident angle is . Lastly, it is shown that the parameter for the magneto-electric effect plays a role in the damping of the wave. PMID:26354609
Corresponding states law for a generalized Lennard-Jones potential.
Orea, P; Romero-Martínez, A; Basurto, E; Vargas, C A; Odriozola, G
2015-07-14
It was recently shown that vapor-liquid coexistence densities derived from Mie and Yukawa models collapse to define a single master curve when represented against the difference between the reduced second virial coefficient at the corresponding temperature and that at the critical point. In this work, we further test this proposal for another generalization of the Lennard-Jones pair potential. This is carried out for vapor-liquid coexistence densities, surface tension, and vapor pressure, along a temperature window set below the critical point. For this purpose, we perform molecular dynamics simulations by varying the potential softness parameter to produce from very short to intermediate attractive ranges. We observed all properties to collapse and yield master curves. Moreover, the vapor-liquid curve is found to share the exact shape of the Mie and attractive Yukawa. Furthermore, the surface tension and the logarithm of the vapor pressure are linear functions of this difference of reduced second virial coefficients.
Freezing point depression in model Lennard-Jones solutions
NASA Astrophysics Data System (ADS)
Koschke, Konstantin; Jörg Limbach, Hans; Kremer, Kurt; Donadio, Davide
2015-09-01
Crystallisation of liquid solutions is of uttermost importance in a wide variety of processes in materials, atmospheric and food science. Depending on the type and concentration of solutes the freezing point shifts, thus allowing control on the thermodynamics of complex fluids. Here we investigate the basic principles of solute-induced freezing point depression by computing the melting temperature of a Lennard-Jones fluid with low concentrations of solutes, by means of equilibrium molecular dynamics simulations. The effect of solvophilic and weakly solvophobic solutes at low concentrations is analysed, scanning systematically the size and the concentration. We identify the range of parameters that produce deviations from the linear dependence of the freezing point on the molal concentration of solutes, expected for ideal solutions. Our simulations allow us also to link the shifts in coexistence temperature to the microscopic structure of the solutions.
A New Large-Scale Global Optimization Method and Its Application to Lennard-Jones Problems
1992-11-01
stochastic methods. Computational results on Lennard - Jones problems show that the new method is considerably more successful than any other method that...our method does not find as good a solution as has been found by the best special purpose methods for Lennard - Jones problems. This illustrates the inherent difficulty of large scale global optimization.
Dow Jones Fund Opens Journalism Programs to White Students after Lawsuit
ERIC Educational Resources Information Center
Scmidt, Peter
2007-01-01
This paper discusses a Lawsuit filed against Dow Jones Newspaper Fund and the legal settlement between the defendant and the plaintiff. The fund, a nonprofit organization affiliated with Dow Jones & Company had been operating more than 20 programs for minority high-school students to pursue careers in newspaper journalism. The organization…
Essential Characteristics of an Highly Resilient Judge: A Case Study of the Honorable Richard Jones
ERIC Educational Resources Information Center
Ericksen, Charles Aaron
2010-01-01
The purpose of this study was to explore judicial resiliency through the personal experiences and perspectives of an experienced trial court judge, the Honorable Richard Jones. This exploratory case study examined the coping skills, traits, and attributes exhibited by Judge Jones over his career and in particular through the experience of…
33 CFR 165.159 - Safety Zone: New York Air Show at Jones Beach State Park, Wantagh, NY.
Code of Federal Regulations, 2011 CFR
2011-07-01
... Jones Beach State Park, Wantagh, NY. 165.159 Section 165.159 Navigation and Navigable Waters COAST GUARD... § 165.159 Safety Zone: New York Air Show at Jones Beach State Park, Wantagh, NY. (a) Location. The following waters of the Atlantic Ocean off of Jones Beach State Park, Wantagh, NY are designated a...
Vere-Jones' self-similar branching model.
Saichev, A; Sornette, D
2005-11-01
Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m' of daughters of first-generation of a mother of magnitude m has two branches m < m' with exponent beta - d and m' > m with exponent beta + d, where beta and d are two positive parameters. We investigate the condition and nature of the subcritical, critical, and supercritical regime in this and in an extended version interpolating smoothly between several models. We predict that the distribution of magnitudes of events triggered by a mother of magnitude m over all generations has also two branches m' < m with exponent and with exponent beta - h, with h=d squareroot of (1-s), where s is the fraction of triggered events. This corresponds to a renormalization of the exponent d into h by the hierarchy of successive generations of triggered events. For a significant part of the parameter space, the distribution of magnitudes over a full catalog summed over an average steady flow of spontaneous sources (immigrants) reproduces the distribution of the spontaneous sources with a single branch and is blind to the exponents beta, d of the distribution of triggered events. Since the distribution of earthquake magnitudes is usually obtained with catalogs including many sequences, we conclude that the two branches of the distribution of aftershocks are not directly observable and the model is compatible with real seismic catalogs. In summary, the exactly self-similar Vere-Jones model provides an attractive new approach to model triggered
Vere-Jones' self-similar branching model
NASA Astrophysics Data System (ADS)
Saichev, A.; Sornette, D.
2005-11-01
Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m' of daughters of first-generation of a mother of magnitude m has two branches m'
Update on diagnosis of acute rheumatic fever: 2015 Jones criteria.
Eroğlu, Ayşe Güler
2016-03-01
In the final Jones criteria, different diagnostic criteria were established for the diagnosis of acute rheumatic fever for low risk and moderate-high risk populations. Turkey was found to be compatible with moderate-high risk populations as a result of regional screenings performed in terms of acute rheumatic fever and rheumatic heart disease. The changes in the diagnostic criteria for low-risk populations include subclinical carditis found on echocardiogram as a major criterion in addition to carditis found clinically and a body temperature of 38.5°C and above as a minor criterion. In moderate-high risk populations including Turkey, subclinical carditis found on echocardiogram in addition to clinical carditis is used as a major criterion as a new amendment. In addition, aseptic monoarthritis and polyarthralgia are used as major criteria in addition to migratory arthritis and monoarhtralgia is used as a minor criterion among joint findings. However, differentiation of subclinical carditis from physiological valve regurgitation found in healthy individuals and exclusion of other diseases involving joints when aseptic monoarthritis and polyarthralgia are used as major criteria are very important. In addition, a body temperature of 38°C and above and an erythrocyte sedimentation rate of 30 mm/h and above have been accepted as minor criteria. The diagnostic criteria for the first attack have not been changed; three minor findings have been accepted in presence of previous sterptococcal infection in addition to the old cirteria for recurrent attacks. In the final Jones criteria, it has been recommended that patients who do not fully meet the diagnostic criteria of acute rheumatic fever should be treated as acute rheumatic fever if another diagnosis is not considered and should be followed up with benzathine penicilin prophylaxis for 12 months. It has been decided that these patients be evaluated 12 months later and a decision for continuation or discontinuation of
Vere-Jones' self-similar branching model
Saichev, A.; Sornette, D.
2005-11-01
Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m{sup '} of daughters of first-generation of a mother of magnitude m has two branches m{sup '}
Update on diagnosis of acute rheumatic fever: 2015 Jones criteria
Eroğlu, Ayşe Güler
2016-01-01
In the final Jones criteria, different diagnostic criteria were established for the diagnosis of acute rheumatic fever for low risk and moderate-high risk populations. Turkey was found to be compatible with moderate-high risk populations as a result of regional screenings performed in terms of acute rheumatic fever and rheumatic heart disease. The changes in the diagnostic criteria for low-risk populations include subclinical carditis found on echocardiogram as a major criterion in addition to carditis found clinically and a body temperature of 38.5°C and above as a minor criterion. In moderate-high risk populations including Turkey, subclinical carditis found on echocardiogram in addition to clinical carditis is used as a major criterion as a new amendment. In addition, aseptic monoarthritis and polyarthralgia are used as major criteria in addition to migratory arthritis and monoarhtralgia is used as a minor criterion among joint findings. However, differentiation of subclinical carditis from physiological valve regurgitation found in healthy individuals and exclusion of other diseases involving joints when aseptic monoarthritis and polyarthralgia are used as major criteria are very important. In addition, a body temperature of 38°C and above and an erythrocyte sedimentation rate of 30 mm/h and above have been accepted as minor criteria. The diagnostic criteria for the first attack have not been changed; three minor findings have been accepted in presence of previous sterptococcal infection in addition to the old cirteria for recurrent attacks. In the final Jones criteria, it has been recommended that patients who do not fully meet the diagnostic criteria of acute rheumatic fever should be treated as acute rheumatic fever if another diagnosis is not considered and should be followed up with benzathine penicilin prophylaxis for 12 months. It has been decided that these patients be evaluated 12 months later and a decision for continuation or discontinuation of
Melting transition of Lennard-Jones fluid in cylindrical pores.
Das, Chandan K; Singh, Jayant K
2014-05-28
Three-stage pseudo-supercritical transformation path and multiple-histogram reweighting technique are employed for the determination of solid-liquid coexistence of the Lennard-Jones (12-6) fluid, in a structureless cylindrical pore of radius, R, ranging from 4 to 20 molecular diameters. The Gibbs free energy difference is evaluated using thermodynamic integration method by connecting solid and liquid phases under confinement via one or more intermediate states without any first order phase transition among them. The thermodynamic melting temperature, Tm, is found to oscillate for pore size, R < 8, which is in agreement with the behavior observed for the melting temperature in slit pores. However, Tm for almost all pore sizes is less than the bulk case, which is contrary to the behavior seen for the slit pore. The oscillation in Tm decays at around pore radius R = 8, and beyond that shift in the melting temperature with respect to the bulk case is in line with the prediction of the Gibbs-Thomson equation.
Metastable Lennard-Jones fluids. II. Thermal conductivity.
Baidakov, Vladimir G; Protsenko, Sergey P
2014-06-07
The method of equilibrium molecular dynamics with the use of the Green-Kubo formalism has been used to calculate the thermal conductivity λ in stable and metastable regions of a Lennard-Jones fluid. Calculations have been made in the range of reduced temperatures 0.4 ≤ T* = k(b)T/ε ≤ 2.0 and densities 0.01 ≤ ρ* = ρσ³ ≤ 1.2 on 15 isotherms for 234 states, 130 of which refer to metastable regions: superheated and supercooled liquids, supersaturated vapor. Equations have been built up which describe the dependence of the regular part of the thermal conductivity on temperature and density, and also on temperature and pressure. It has been found that in (p, T) variables in the region of a liquid-gas phase transition a family of lines of constant value of excess thermal conductivity Δλ = λ - λ0, where λ0 is the thermal conductivity of a dilute gas, has an envelope which coincides with the spinodal. Thus, at the approach to the spinodal of a superheated liquid and supersaturated vapor (∂Δλ/∂p)T → ∞, (∂Δλ/∂T)p → ∞.
Melting transition of Lennard-Jones fluid in cylindrical pores
Das, Chandan K.; Singh, Jayant K.
2014-05-28
Three-stage pseudo-supercritical transformation path and multiple-histogram reweighting technique are employed for the determination of solid-liquid coexistence of the Lennard-Jones (12-6) fluid, in a structureless cylindrical pore of radius, R, ranging from 4 to 20 molecular diameters. The Gibbs free energy difference is evaluated using thermodynamic integration method by connecting solid and liquid phases under confinement via one or more intermediate states without any first order phase transition among them. The thermodynamic melting temperature, T{sub m}, is found to oscillate for pore size, R < 8, which is in agreement with the behavior observed for the melting temperature in slit pores. However, T{sub m} for almost all pore sizes is less than the bulk case, which is contrary to the behavior seen for the slit pore. The oscillation in T{sub m} decays at around pore radius R = 8, and beyond that shift in the melting temperature with respect to the bulk case is in line with the prediction of the Gibbs-Thomson equation.
Freezing of Lennard-Jones fluid on a patterned substrate.
Zhang, Huijun; Peng, Shuming; Mao, Li; Zhou, Xiaosong; Liang, Jianhua; Wan, Chubin; Zheng, Jian; Ju, Xin
2014-06-01
Using molecular dynamics simulations, we study freezing of Lennard-Jones particles at commensurate substrate with triangular pattern. Throughout the box particles freeze onto the substrate and form close-packed layers. For the moderately attractive substrates, an intermediate hexatic phase between liquid and crystal is detected in the first two layers where the hexatic-solid freezing process is continuous while, counterintuitively, the liquid-hexatic process is of first order. Moreover, we observe that liquid-hexatic and hexatic-solid transitions shift towards higher temperatures with the attraction strength increasing. By contrast, the liquid-hexatic transition shifts faster than the hexatic-solid process, significantly widening the temperature range of the hexatic phase. When this phenomenon appears, freezing in the bulk always proceeds through a first-order transition at the same temperature. In addition, changes in the average structural order (three-dimensional) of the layers indicate that freezing processes in layers near substrates seem to cost the structural order of the bulk particles in their vicinity, and an intermediate prestructural cloud of medium-ordered particles is always observed before the layering freezing.
Conformation of a Lennard-Jones polymer in explicit solvent
NASA Astrophysics Data System (ADS)
Ye, Yuting; Taylor, Mark
2012-04-01
The conformation of a polymer chain is solution is coupled to the local structure of the surrounding solvent and can undergo large changes in response to variations in solvent density and temperature. The many-body effects of solvent on the structure of an n-mer chain can be formally mapped to an exact n-body solvation potential. These potentials map the chain-solvent system to a single chain, thereby dramatically reducing the computational complexity of the polymer chain-in-solvent problem. We have recently shown that a pair-decomposition of this n-body potential is valid for short Lennard-Jones (LJ) chains in explicit LJ solvent [1]. Here we use these short chain results to construct solvation potentials for long chains. We present results for the size and intramolecular structure of LJ chains up to length n=400 in LJ solvent at state points spanning the solvent phase diagram (including vapor, liquid, and super-critical regions). In comparison with simulation results for the corresponding full chain-in-solvent system, our solvation potential approach is found to be quantitatively accurate for a wide range of solvent conditions and chain lengths.[4pt] [1] M.P. Taylor and S.R. Adhikari, J. Chem. Phys. 135, 044903 (2011).
Conformation of a Lennard-Jones polymer in explicit solvent
NASA Astrophysics Data System (ADS)
Ye, Yuting; Taylor, Mark
2011-10-01
The conformation of a polymer chain is solution is coupled to the local structure of the surrounding solvent and can undergo large changes in response to variations in solvent density and temperature. The many-body effects of solvent on the structure of an n-mer chain can be formally mapped to an exact n-body solvation potential. These potentials map the chain-solvent system to a single chain, thereby dramatically reducing the computational complexity of the polymer chain-in-solvent problem. We have recently shown that a pair-decomposition of this n-body potential is valid for short Lennard-Jones (LJ) chains in explicit LJ solvent [1]. Here we use these short chain results to construct solvation potentials for long chains. We present results for the size and intramolecular structure of LJ chains up to length n=400 in LJ solvent at state points spanning the solvent phase diagram (including vapor, liquid, and super-critical regions). In comparison with simulation results for the corresponding full chain-in-solvent system, our solvation potential approach is found to be quantitatively accurate for a wide range of solvent conditions and chain lengths.[4pt] [1] M.P. Taylor and S.R. Adhikari, J. Chem. Phys. 135, 044903 (2011).
Vacancy behavior in a compressed fcc Lennard-Jones crystal
Beeler, J.R. Jr.
1981-12-01
This computer experiment study concerns the determination of the stable vacancy configuration in a compressed fcc Lennard-Jones crystal and the migration of this defect in a compressed crystal. Isotropic and uniaxial compression stress conditions were studied. The isotropic and uniaxial compression magnitudes employed were 0.94 less than or equal to eta less than or equal to 1.5, and 1.0 less than or equal to eta less than or equal to 1.5, respectively. The site-centered vacancy (SCV) was the stable vacancy configuration whenever cubic symmetry was present. This includes all of the isotropic compression cases and the particular uniaxial compression case (eta = ..sqrt..2) that give a bcc structure. In addition, the SCV was the stable configuration for uniaxial compression eta < 1.29. The out-of-plane split vacancy (SV-OP) was the stable vacancy configuration for uniaxial compression 1.29 < eta less than or equal to 1.5 and was the saddle-point configuration for SCV migration when the SCV was the stable form. For eta > 1.20, the SV-OP is an extended defect and, therefore, a saddle point for SV-OP migration could not be determined. The mechanism for the transformation from the SCV to the SV-OP as the stable form at eta = 1.29 appears to be an alternating sign (101) and/or (011) shear process.
Contact angle of sessile drops in Lennard-Jones systems.
Becker, Stefan; Urbassek, Herbert M; Horsch, Martin; Hasse, Hans
2014-11-18
Molecular dynamics simulations are used for studying the contact angle of nanoscale sessile drops on a planar solid wall in a system interacting via the truncated and shifted Lennard-Jones potential. The entire range between total wetting and dewetting is investigated by varying the solid-fluid dispersive interaction energy. The temperature is varied between the triple point and the critical temperature. A correlation is obtained for the contact angle in dependence of the temperature and the dispersive interaction energy. Size effects are studied by varying the number of fluid particles at otherwise constant conditions, using up to 150,000 particles. For particle numbers below 10,000, a decrease of the contact angle is found. This is attributed to a dependence of the solid-liquid surface tension on the droplet size. A convergence to a constant contact angle is observed for larger system sizes. The influence of the wall model is studied by varying the density of the wall. The effective solid-fluid dispersive interaction energy at a contact angle of θ = 90° is found to be independent of temperature and to decrease linearly with the solid density. A correlation is developed that describes the contact angle as a function of the dispersive interaction, the temperature, and the solid density. The density profile of the sessile drop and the surrounding vapor phase is described by a correlation combining a sigmoidal function and an oscillation term.
Jones index, secret sharing and total quantum dimension
NASA Astrophysics Data System (ADS)
Fiedler, Leander; Naaijkens, Pieter; Osborne, Tobias J.
2017-02-01
We study the total quantum dimension in the thermodynamic limit of topologically ordered systems. In particular, using the anyons (or superselection sectors) of such models, we define a secret sharing scheme, storing information invisible to a malicious party, and argue that the total quantum dimension quantifies how well we can perform this task. We then argue that this can be made mathematically rigorous using the index theory of subfactors, originally due to Jones and later extended by Kosaki and Longo. This theory provides us with a ‘relative entropy’ of two von Neumann algebras and a quantum channel, and we argue how these can be used to quantify how much classical information two parties can hide form an adversary. We also review the total quantum dimension in finite systems, in particular how it relates to topological entanglement entropy. It is known that the latter also has an interpretation in terms of secret sharing schemes, although this is shown by completely different methods from ours. Our work provides a different and independent take on this, which at the same time is completely mathematically rigorous. This complementary point of view might be beneficial, for example, when studying the stability of the total quantum dimension when the system is perturbed.
The Grande Dame of Afro-American Art: Lois Mailou Jones.
ERIC Educational Resources Information Center
LaDuke, Betty
1987-01-01
Chronicles the personal and professional life of Lois Mailou Jones, a Black woman painter who blends Western and non-Western aesthetic traditions in her art. The influences of Haitian and African native traditions on her work are discussed. (BJV)
Second-order Percus Yevick theory for mixtures of Lennard-Jones fluids
NASA Astrophysics Data System (ADS)
Sokolowski, Douglas Henderson Stefan
The second-order integral equation formalism of Attard, applied recently, with good results, to one-component hard spheres and Lennard-Jones fluids, is applied to some binary mixtures of Lennard-Jones fluids. Comparison with molecular dynamic simulations of the pair correlation functions shows that this method is also quite accurate for mixtures. This is true not only when the Lorentz Berthelot mixing rules are obeyed but also when there are substantial deviations from these rules.
A Sensible Estimate for the Stability Constant of the Lennard-Jones Potential
NASA Astrophysics Data System (ADS)
Yuhjtman, Sergio A.
2015-09-01
We show that the stability constant of the Lennard-Jones potential in , , is smaller than 14.316. This is remarkably smaller than the best previously known bound. Our method is very elementary, and probably applicable to other similar potentials such as the Morse potentials. We also improve slightly, in the Lennard-Jones case, the lower bound for the minimum interparticle distance of an optimal n-particle configuration to 0.684.
Solid-liquid transition in polydisperse Lennard-Jones systems
NASA Astrophysics Data System (ADS)
Sarkar, Sarmistha; Biswas, Rajib; Santra, Mantu; Bagchi, Biman
2013-08-01
We study melting of a face-centered crystalline solid consisting of polydisperse Lennard-Jones spheres with Gaussian polydispersity in size. The phase diagram reproduces the existence of a nearly temperature invariant terminal polydispersity (δt ≃ 0.11), with no signature of reentrant melting. The absence of reentrant melting can be attributed to the influence of the attractive part of the potential upon melting. We find that at terminal polydispersity the fractional density change approaches zero, which seems to arise from vanishingly small compressibility of the disordered phase. At constant temperature and volume fraction the system undergoes a sharp transition from crystalline solid to the disordered amorphous or fluid state with increasing polydispersity. This has been quantified by second- and third-order rotational invariant bond orientational order, as well as by the average inherent structure energy. The translational order parameter also indicates a similar sharp structural change at δ ≃ 0.09 in case of T* = 1.0, ϕ = 0.58. The free energy calculation further supports the sharp nature of the transition. The third-order rotationally invariant bond order shows that with increasing polydispersity, the local cluster favors a more icosahedral arrangement and the system loses its local crystalline symmetry. Interestingly, the value of structure factor S(k) of the amorphous phase at δ ≃ 0.10 (just beyond the solid-liquid transition density at T* = 1) becomes 2.75, which is below the value of 2.85 required for freezing given by the empirical Hansen-Verlet rule of crystallization, well known in the theory of freezing.
Scaling of the dynamics of flexible Lennard-Jones chains.
Veldhorst, Arno A; Dyre, Jeppe C; Schrøder, Thomas B
2014-08-07
The isomorph theory provides an explanation for the so-called power law density scaling which has been observed in many molecular and polymeric glass formers, both experimentally and in simulations. Power law density scaling (relaxation times and transport coefficients being functions of ρ(γ(S)), where ρ is density, T is temperature, and γ(S) is a material specific scaling exponent) is an approximation to a more general scaling predicted by the isomorph theory. Furthermore, the isomorph theory provides an explanation for Rosenfeld scaling (relaxation times and transport coefficients being functions of excess entropy) which has been observed in simulations of both molecular and polymeric systems. Doing molecular dynamics simulations of flexible Lennard-Jones chains (LJC) with rigid bonds, we here provide the first detailed test of the isomorph theory applied to flexible chain molecules. We confirm the existence of isomorphs, which are curves in the phase diagram along which the dynamics is invariant in the appropriate reduced units. This holds not only for the relaxation times but also for the full time dependence of the dynamics, including chain specific dynamics such as the end-to-end vector autocorrelation function and the relaxation of the Rouse modes. As predicted by the isomorph theory, jumps between different state points on the same isomorph happen instantaneously without any slow relaxation. Since the LJC is a simple coarse-grained model for alkanes and polymers, our results provide a possible explanation for why power-law density scaling is observed experimentally in alkanes and many polymeric systems. The theory provides an independent method of determining the scaling exponent, which is usually treated as an empirical scaling parameter.
Solid-liquid transition in polydisperse Lennard-Jones systems.
Sarkar, Sarmistha; Biswas, Rajib; Santra, Mantu; Bagchi, Biman
2013-08-01
We study melting of a face-centered crystalline solid consisting of polydisperse Lennard-Jones spheres with Gaussian polydispersity in size. The phase diagram reproduces the existence of a nearly temperature invariant terminal polydispersity (δ(t) =/~ 0.11), with no signature of reentrant melting. The absence of reentrant melting can be attributed to the influence of the attractive part of the potential upon melting. We find that at terminal polydispersity the fractional density change approaches zero, which seems to arise from vanishingly small compressibility of the disordered phase. At constant temperature and volume fraction the system undergoes a sharp transition from crystalline solid to the disordered amorphous or fluid state with increasing polydispersity. This has been quantified by second- and third-order rotational invariant bond orientational order, as well as by the average inherent structure energy. The translational order parameter also indicates a similar sharp structural change at δ =/~ 0.09 in case of T(*) = 1.0, φ = 0.58. The free energy calculation further supports the sharp nature of the transition. The third-order rotationally invariant bond order shows that with increasing polydispersity, the local cluster favors a more icosahedral arrangement and the system loses its local crystalline symmetry. Interestingly, the value of structure factor S(k) of the amorphous phase at δ =/~ 0.10 (just beyond the solid-liquid transition density at T(*) = 1) becomes 2.75, which is below the value of 2.85 required for freezing given by the empirical Hansen-Verlet rule of crystallization, well known in the theory of freezing.
Liu, Xuan; Yang, Yang; Han, Lu; Guo, Cheng-Shan
2017-04-03
We report a fiber-based lensless holographic imaging system to realize a single-shot measurement of two dimensional (2-D) Jones matrix parameters of polarization-sensitive materials. In this system, a multi-source lensless off-axis Fresnel holographic recording geometry is adopted, and two optical fiber splitters are used to generate the multiple reference and illumination beams required for recording a four-channel angular-multiplexing polarization hologram (AMPH). Using this system and the method described in this paper, spatially resolved Jones matrix parameters of a polarization-sensitive material can be retrieved from one single-shot AMPH. We demonstrate the feasibility of the method by extracting a 2-D Jones matrix of a composite polarizer. Applications of the method to measure the Jones matrix maps of a stressed polymethyl methacrylate sample and a mica fragment are also presented. Benefit from the fiber-based and lensless off-axis holographic design, the system possesses a quite compact configuration, which provides a feasible approach for development of an integrated and portable system to measure Jones matrix parameters of polarization-sensitive materials.
Method of extraction of the Mueller-Jones part out of an experimental Mueller matrix
NASA Astrophysics Data System (ADS)
Savenkov, Sergey N.; Marienko, Valeri V.
1997-05-01
Properly measured experimental Mueller matrix contains complete information on depolarization, anisotropy properties of studied object and on value of isotropic change of probated radiation intensity by studied object as well. They know that Jones matrix contains complete information on value of isotropic change of probated radiation intensity and on anisotropy properties of studied object. Thus, in the case of absent of depolarization and measurement errors reducing to existence of, so called, overpolarization there exist a one-to-one correspondence between Mueller and Jones matrix. Mueller matrix will then be called a Mueller-Jones matrix. The possibility of extraction of Mueller-Jones part out of any experimental Mueller matrix is extremely important because of following. First, it allows us to obtain everything about depolarization properties of studied object directly. Depolarization is very informative 'object' and now, in the majority, one knows little about its nature and methods of its complete description. Second, one gets the possibility to operate with correspondent Jones matrix to analyze of which there exist the powerful methods such as solving of the spectral problem and application of the decomposition theorem formerly proved by the present authors. The distinctive feature of the method proposed here is that it allows us in the best way to take into consideration the important fact that far from all elements of initial Mueller matrix contains information on depolarization.
Phase diagram of power law and Lennard-Jones systems: Crystal phases
Travesset, Alex
2014-10-28
An extensive characterization of the low temperature phase diagram of particles interacting with power law or Lennard-Jones potentials is provided from Lattice Dynamical Theory. For power law systems, only two lattice structures are stable for certain values of the exponent (or softness) (A15, body centered cube (bcc)) and two more (face centered cubic (fcc), hexagonal close packed (hcp)) are always stable. Among them, only the fcc and bcc are equilibrium states. For Lennard-Jones systems, the equilibrium states are either hcp or fcc, with a coexistence curve in pressure and temperature that shows reentrant behavior. The hcp solid never coexists with the liquid. In all cases analyzed, for both power law and Lennard-Jones potentials, the fcc crystal has higher entropy than the hcp. The role of anharmonic terms is thoroughly analyzed and a general thermodynamic integration to account for them is proposed.
Phase diagram of power law and Lennard-Jones systems: crystal phases.
Travesset, Alex
2014-10-28
An extensive characterization of the low temperature phase diagram of particles interacting with power law or Lennard-Jones potentials is provided from Lattice Dynamical Theory. For power law systems, only two lattice structures are stable for certain values of the exponent (or softness) (A15, body centered cube (bcc)) and two more (face centered cubic (fcc), hexagonal close packed (hcp)) are always stable. Among them, only the fcc and bcc are equilibrium states. For Lennard-Jones systems, the equilibrium states are either hcp or fcc, with a coexistence curve in pressure and temperature that shows reentrant behavior. The hcp solid never coexists with the liquid. In all cases analyzed, for both power law and Lennard-Jones potentials, the fcc crystal has higher entropy than the hcp. The role of anharmonic terms is thoroughly analyzed and a general thermodynamic integration to account for them is proposed.
A Look Back in Time: Sir Robert Jones, 'Father of Modern Orthopaedics'.
Tham, Wyw; Sng, Smc; Lum, Y M; Chee, Y H
2014-11-01
This paper describes the life of Sir Robert Jones, from his humble beginnings as an apprentice of Thomas Smith, to his many contributions to the orthopaedic specialty. Robert Jones' passion and interest in the subject led to its advancement from a specialty that dealt mainly with crippling diseases in children, to that of treating and rehabilitating disabled adults. He revolutionized the practice by integrating the use of plain radiography, and by developing many new surgical and procedural techniques. He largely improved the specialty by publishing many textbooks and papers, and trained many orthopaedic surgeons from within England and internationally. The purpose of this paper seeks to provide a platform for readers to learn about the man behind the Jones fracture and bandage. It will help readers understand how one man's passion for orthopaedics helped transform it into a specialty in its own rights.
Phase diagram of power law and Lennard-Jones systems: Crystal phases
NASA Astrophysics Data System (ADS)
Travesset, Alex
2014-10-01
An extensive characterization of the low temperature phase diagram of particles interacting with power law or Lennard-Jones potentials is provided from Lattice Dynamical Theory. For power law systems, only two lattice structures are stable for certain values of the exponent (or softness) (A15, body centered cube (bcc)) and two more (face centered cubic (fcc), hexagonal close packed (hcp)) are always stable. Among them, only the fcc and bcc are equilibrium states. For Lennard-Jones systems, the equilibrium states are either hcp or fcc, with a coexistence curve in pressure and temperature that shows reentrant behavior. The hcp solid never coexists with the liquid. In all cases analyzed, for both power law and Lennard-Jones potentials, the fcc crystal has higher entropy than the hcp. The role of anharmonic terms is thoroughly analyzed and a general thermodynamic integration to account for them is proposed.
Not Available
1988-07-07
The Jones Sanitation Landfill, also known as the Jones Septic Site, is listed on the National Priorities List. From the early 1960s through 1979 the site accepted industrial liquid wastes and sludges. The site now accepts only septic waste collected by commercial firms. Results of environmental sampling indicate that the contaminants of concern at the site include inorganics (e.g., chromium, copper, lead, cadmium, mercury), oil and grease wastes, and several volatile organic chemicals including: 1,1-dichloroethylene; trichloroethylene; trichloroethene, acetone; 1,2,4-trichlorobenzene; chloroform; methylene chloride; and perhaps pentachlorophenol. Based on the available information, the site is considered to be of potential public health concern because of the risk to human health caused by the possibility of exposure to hazardous substances via the above-named human exposure pathways.
Properties of the two-dimensional heterogeneous Lennard-Jones dimers: An integral equation study
NASA Astrophysics Data System (ADS)
Urbic, Tomaz
2016-11-01
Structural and thermodynamic properties of a planar heterogeneous soft dumbbell fluid are examined using Monte Carlo simulations and integral equation theory. Lennard-Jones particles of different sizes are the building blocks of the dimers. The site-site integral equation theory in two dimensions is used to calculate the site-site radial distribution functions and the thermodynamic properties. Obtained results are compared to Monte Carlo simulation data. The critical parameters for selected types of dimers were also estimated and the influence of the Lennard-Jones parameters was studied. We have also tested the correctness of the site-site integral equation theory using different closures.
Closed-form equation of state for Lennard-Jones molecules based on perturbation theory
Bokis, C.P.; Donohue, M.D.
1995-08-17
A comparison of virial theory and perturbation theory for spherical molecules is presented. A new equation of state is derived. This new model has the exact second virial coefficient behavior, converges to the correct mean-field behavior at high densities, and successfully interpolates between these two limits. This new equation of state is applied to molecules that interact via the Lennard-Jones potential. Comparison is made with computer simulation results for the configurational energy, the compressibility factor, and the second virial coefficient of Lennard-Jones molecules. 25 refs., 7 figs.
Gingival Enlargement in a Case of Variant Jones Syndrome: a Case Report
DA, Roopa; Singh, Shinkhala; Gupta, Ira; Gopal, Saumiya
2016-01-01
Gingival enlargement can be caused by a variety of etiological factors like inflammation, drugs, and systemic diseases or can be presented as a part of a syndrome. One such syndrome is Jones Syndrome, which is associated with gingival enlargement and progressive hearing loss. We present here a case of fifteen-year-old boy with gingival enlargement, hearing loss, and generalized alveolar bone loss and diagnosed as Jones syndrome. The diagnosis was made based on history, clinical, radiographic, and histopathological findings. Gingival enlargement was surgically managed using gingivectomy and no recurrence was observed. The patient showed remarkable esthetical and functional improvement. PMID:26966711
A Lennard-Jones-like perspective on first order transitions in biological helices
NASA Astrophysics Data System (ADS)
Oskolkov, Nikolay; Bohr, Jakob
2013-03-01
Helical structures with Lennard-Jones self-interactions are studied for optimal conformations. For this purpose, their self-energy is analyzed for extrema with respect to the geometric parameters of the helices. It is found that Lennard-Jones helices exhibit a first order phase transition from a state with large curvature of the helical backbone to one with a small curvature. I.e. from a dense helix to an extended helix. A transition from one helical structure to another is a phenomenon known to take place in self-assembling helices formed in multicomponent solutions with cholesterol.
The death of John Paul Jones and resurrection as 'father of the US Navy'.
Weir, Matthew R; Bogle, Lori L; Mackowiak, Philip A
2010-01-01
John Paul Jones, 'father of the US Navy', died under mysterious circumstances on July 18, 1792. Although his remains were resurrected and autopsied 113 years later, the cause of his death has yet to be explained fully. In this detailed review of his clinical history and autopsy findings, we conclude, as have others, that Jones died of kidney failure of undermined etiology. Although 'interstitial nephritis' was diagnosed by the prosectors who performed his autopsy, we believe glomerulopathy (possibly IgA nephropathy) was more likely responsible for his kidney failure and that his death was due to a cardiac arrhythmia or some other complication of uremia.
Properties of the two-dimensional heterogeneous Lennard-Jones dimers: An integral equation study.
Urbic, Tomaz
2016-11-21
Structural and thermodynamic properties of a planar heterogeneous soft dumbbell fluid are examined using Monte Carlo simulations and integral equation theory. Lennard-Jones particles of different sizes are the building blocks of the dimers. The site-site integral equation theory in two dimensions is used to calculate the site-site radial distribution functions and the thermodynamic properties. Obtained results are compared to Monte Carlo simulation data. The critical parameters for selected types of dimers were also estimated and the influence of the Lennard-Jones parameters was studied. We have also tested the correctness of the site-site integral equation theory using different closures.
Molecular Simulation of the Vapor-Liquid Phase Behavior of Lennard-Jones Mixtures in Porous Solids
2006-09-01
is used to simulate Lennard - Jones fluid mixtures at several porosities: 0.9, 0.95, and 0.975. Effects based on the size and the energetics of the...to the bulk fluid behavior, dramatic shifts in the phase envelope were found for even highly porous structures. Both the Lennard - Jones size and energy
ERIC Educational Resources Information Center
Marshall, Chloe R.
2012-01-01
The study by Tamburelli, Jones, Gobet, and Pine (2012; henceforth TJGP) is a very welcome addition to the body of work concerning nonword repetition in typical development. TJGP go beyond previous work in considering three syllabic positions--onset, nucleus, and coda--with the aim of investigating how the positional role of phonemes within the…
Creative Imagination and Subjective Agency in Wynne-Jones' "The Maestro"
ERIC Educational Resources Information Center
Cairns, Sue Ann
2009-01-01
The Canadian young adult novel "The Maestro" by Tim Wynne-Jones foregrounds the relationship between imagination and subjective agency. While Burl uses his imagination at the beginning to protect himself from his abusive father, his fantasies become dress rehearsals for small performances that allow him to try on new identities and exercise…
The Game TV Plays: Or, Why an English Teacher Came to Hate Barnaby Jones.
ERIC Educational Resources Information Center
Shaw, Patrick W.
The message of current popular television shows in which the hero is, or appears to be, a dumb clod (e.g., Archie Bunker, Fred Sanford, Columbo, and Barnaby Jones), apparently is that corruption may be equated with articulation, wealth, and education, while virtue may be equated with poverty and, often, illiteracy. Unfortunately, the effect of…
Enhancing Undergraduates' Capabilities through Team-Based Competitions: The Edward Jones Challenge
ERIC Educational Resources Information Center
Umble, Elisabeth J.; Umble, Michael; Artz, Kendall
2008-01-01
The Edward Jones Company recently initiated financial sponsorship of team-based competitions in six undergraduate business core classes at Baylor University. The challenges were chosen to take place in an introductory freshman business class, Managerial Accounting, Principles of Marketing, Corporate Finance, Operations Management, and Strategic…
OXYGEN TRANSFER EFFICIENCY SURVEYS AT THE JONES ISLAND TREATMENT PLANTS - 1985-1988
Ceramic plate diffusers were among the earliest forms of fine pore diffusers used for oxygen transfer in activated sludge treatment. They have been successfully used for over 60 years in the Jones Island West Plant of the Milwaukee Metropolitan Sewerage District and, since initia...
Understanding the interfacial behavior in isopycnic Lennard-Jones mixtures by computer simulations.
Garrido, José Matías; Piñeiro, Manuel M; Mejía, Andrés; Blas, Felipe J
2016-01-14
The physical characterization of the singular interfacial behavior of heterogeneous fluid systems is a very important step in preliminary stages of the design process, and also in the subsequent procedures for the determination of the optimal operating conditions. Molar isopycnicity or molar density inversion is a special case of phase equilibrium behavior that directly affects the relative position of phases in heterogeneous mixtures, without being affected by gravitational fields. This work is dedicated to characterize the impact of molar density inversion on the interfacial properties of Lennard-Jones binary mixtures. The results and specific trends of the molar density inversion phenomena on the peculiar calculated composition profiles across the interface and interfacial tensions are explored by using canonical molecular dynamics simulations of the Lennard-Jones binary mixtures. Our results show that the density inversion causes drastic changes in the density profiles of the mixtures. In particular, symmetrical and equal-sized Lennard-Jones mixtures always exhibit desorption along the interfacial zone, i.e. the interfacial concentration profiles show a relative minimum at the interface of the total density profiles that increases when the dispersive energy parameter (ε(ij)) between unlike species decreases. However, as the asymmetry of the Lennard-Jones mixtures increases (σ(i) ≠ σ(j)), the concentration profiles display a relative maximum at the interface, which implies the adsorption of the total density profiles along the interfacial zone.
ERIC Educational Resources Information Center
Martínez-Roldan, Carmen M.
2013-01-01
This study illustrates the presence of Mock Spanish in some English-based picture books and the ways this usage misrepresents Latino people, language, and culture. The author conducted a critical content analysis of five Skippyjon Jones books. Her guiding question was, How is language used, particularly Spanish, in these English texts, and what…
ERIC Educational Resources Information Center
Baron, Christopher; Hamlin, Christopher
2015-01-01
Between 1906 and 1909 the biologist Ronald Ross and the classicist W.H.S. Jones pioneered interdisciplinary research in biology and history in advancing the claim that malaria had been crucial in the decline of golden-age Greece (fourth century BCE). The idea had originated with Ross, winner of the Nobel Prize for demonstrating the importance of…
Don't Settle: Leslie Monsalve-Jones--New Mexico State Library
ERIC Educational Resources Information Center
Library Journal, 2005
2005-01-01
Leslie Monsalve-Jones is a library technician with the New Mexico State Library, responsible for claiming documents that state agencies don't submit. She also maintains the collection and can immediately track down any requested document. In short, she is the kind of worker whose price is above rubies but whose pay is slightly above pebbles. And…
On the Myth of the Crisis of Representation: A Response to Gilbourne, Jones and Jordan
ERIC Educational Resources Information Center
Gard, Michael
2014-01-01
The author observes that, in "Applied Utility and the Auto-Ethnographic Short Story: Persuasions for, and Illustrations of, Writing Critical Social Science," Gilbourne, Jones and Jordan present claims about why we might choose to represent auto-ethnographic data in a literary form such as short story and for the "potential" or…
Foucault and Colonial Strategy in Douglas C. Jones' "Arrest Sitting Bull"
ERIC Educational Resources Information Center
Murphy, Peter G.
2004-01-01
"Arrest Sitting Bull," a novel written by Douglas C. Jones that relates the personal stories of individuals involved in the military and the political domination of the Sioux Indian during the period leading to the Sitting Bull killing is described. The incessant quest to establish and maintain control and the integral roles played by fear and…
PHYTOREMEDIATION OF DREDGED SEDIMENTS: A CASE STUDY AT THE JONES ISLAND CDF
The Jones Island Confined Disposal Facility (CDF) is a 44 acre in-lake area that receives dredged material from Milwaukee Harbor and the surrounding waterways. Some of those materials are contaminated with industrial waste and urban run-off. The CDF is nearing the end of its desi...
Solid-liquid equilibria and triple points of n-6 Lennard-Jones fluids
NASA Astrophysics Data System (ADS)
Ahmed, Alauddin; Sadus, Richard J.
2009-11-01
Molecular dynamics simulations are reported for the solid-liquid coexistence properties of n-6 Lennard-Jones fluids, where n =12, 11, 10, 9, 8, and 7. The complete phase behavior for these systems has been obtained by combining these data with vapor-liquid simulations. The influence of n on the solid-liquid coexistence region is compared using relative density difference and miscibility gap calculations. Analytical expressions for the coexistence pressure, liquid, and solid densities as a function of temperature have been determined, which accurately reproduce the molecular simulation data. The triple point temperature, pressure, and liquid and solid densities are estimated. The triple point temperature and pressure scale with respect to 1/n, resulting in simple linear relationships that can be used to determine the pressure and temperature for the limiting ∞-6 Lennard-Jones potential. The simulation data are used to obtain parameters for the Raveché, Mountain, and Streett and Lindemann melting rules, which indicate that they are obeyed by the n-6 Lennard Jones potentials. In contrast, it is demonstrated that the Hansen-Verlet freezing rule is not valid for n-6 Lennard-Jones potentials.
Federal Register 2010, 2011, 2012, 2013, 2014
2012-10-01
... Zone Management Act Walter B. Jones and NOAA Excellence Awards AGENCY: National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice. SUMMARY: The Department of Commerce, as part of its continuing... Nedelka, (301) 713-3155 ext. 127 or Patmarie.Nedelka@noaa.gov . SUPPLEMENTARY INFORMATION: I....
Melting line of the Lennard-Jones system, infinite size, and full potential.
Mastny, Ethan A; de Pablo, Juan J
2007-09-14
Literature estimates of the melting curve of the Lennard-Jones system vary by as much as 10%. The origin of such discrepancies remains unclear. We present precise values for the Lennard-Jones melting temperature, and we examine possible sources of systematic errors in the prediction of melting points, including finite-size and interaction-cutoff effects. A hypothetical thermodynamic integration path is used to find the relative free energies of the solid and liquid phases, for various system sizes, at constant cutoff radius. The solid-liquid relative free energy and melting temperature scale linearly as the inverse of the number of particles, and it is shown that finite-size effects can account for deviations in the melting temperature (from the infinite-size limit) of up to 5%. An extended-ensemble density-of-states method is used to determine free energy changes for each phase as a continuous function of the cutoff radius. The resulting melting temperature predictions exhibit an oscillatory behavior as the cutoff radius is increased. Deviations in the melting temperature (from the full potential limit) arising from a finite cutoff radius are shown to be of comparable magnitude as those resulting from finite-size effects. This method is used to identify melting temperatures at five different pressures, for the infinite-size and full potential Lennard-Jones system. We use our simulation results as references to connect the Lennard-Jones solid equation of state of van der Hoef with the Lennard-Jones fluid equation of state of Johnson. Once the references are applied the two equations of state are used to identify a melting curve. An empirical equation that fits this melting curve is provided. We also report a reduced triple point temperature T(tr)=0.694.
ERIC Educational Resources Information Center
Gooden, Mark A.; Green, Terrance L.
2016-01-01
The Honorable Judge Nathaniel Jones litigated the "Milliken v. Bradley I" case before the U.S. District Court and Supreme Court in 1971 and 1974. Nathaniel Jones was born May 12, 1926 in Youngstown, Ohio, and served as the general counsel for the NAACP from 1969-1979. In 1979, President Jimmy Carter nominated Nathaniel Jones to the U.S.…
Phase equilibra in binary Lennard-Jones mixtures: phase diagram simulation
NASA Astrophysics Data System (ADS)
Canongia Lopes, J. N.
A three-box version of the Gibbs ensemble Monte Carlo method was used to determine the phase diagram type of several binary mixtures of one-centre Lennard-Jones particles. The method can be used to establish a direct link between the intermolecular potential modelling the interactions in a given system and its fluid phase diagram, without the knowledge of the corresponding equation of state governing its pV T behaviour. As an example of the application of the method, closed-loop behaviour in an isotropic system could be found using a set of Lennard-Jones parameters exhibiting a cross-interaction diameter with a negative deviation from the Lorentz-Berthelot combination rule.
Density functional theory for crystal-liquid interfaces of Lennard-Jones fluid.
Wang, Xin; Mi, Jianguo; Zhong, Chongli
2013-04-28
A density functional approach is presented to describe the crystal-liquid interfaces and crystal nucleations of Lennard-Jones fluid. Within the theoretical framework, the modified fundamental measure theory is applied to describe the free energy functional of hard sphere repulsion, and the weighted density method based on first order mean spherical approximation is used to describe the free energy contribution arising from the attractive interaction. The liquid-solid equilibria, density profiles within crystal cells and at liquid-solid interfaces, interfacial tensions, nucleation free energy barriers, and critical cluster sizes are calculated for face-centered-cubic and body-centered-cubic nucleus. Some results are in good agreement with available simulation data, indicating that the present model is quantitatively reliable in describing nucleation thermodynamics of Lennard-Jones fluid.
Anisotropy effect on global minimum structures of clusters: two-center Lennard-Jones model.
Feng, Yan; Wu, Jing; Cheng, Longjiu; Liu, Haiyan
2011-12-28
Using a two-center Lennard-Jones (2CLJ) model, the simplest anisotropic case, we investigated how anisotropy affects global minimum structures of clusters and obtained some interesting results. The anisotropy parameter, R, is defined as the ratio of the bond length of 2CLJ dimer to the LJ equilibrium pair separation, where a larger R value means higher anisotropy. For low R values, the structures resemble those of the Lennard-Jones atomic clusters. However, as the pairwise interaction becomes more anisotropic, the "magic numbers" change, and several novel cluster patterns emerge as particularly stable structures, and the global minima change from icosahedral, to polyicosahedral and to novel irregular structures. Moreover, increasing the anisotropy effectively softens the 2CLJ potential. Given the general importance of the LJ cluster as a simple model cluster, 2CLJ model can provide a straightforward and useful analysis of the effect of molecular shape on the structures of clusters.
Low density shear viscosity of Lennard-Jones chains of variable rigidities.
Santacreu, S Delage; Galliero, G; Odunlami, M; Boned, C
2012-11-28
The zero-density shear viscosity of different types of short Lennard-Jones chains, up to the hexa-decamer, has been evaluated using a non-equilibrium molecular dynamics scheme. Simulations have been performed on chains of variable rigidities going from the fully flexible to the fully rigid chains. Very interestingly, it is found that there exists a universal relation (a power law) between the zero-density viscosity of the Lennard-Jones chains and their radius of gyration whatever the rigidity of the chain and for all tested temperatures (ranging from 2.5 to 6 in reduced units). Furthermore, for the studied range of temperature, it is shown that the zero-density viscosity of both fully flexible chains and fully rigid chains models can be obtained with an accuracy of a few percents knowing only the dimer viscosity and the length of the chain.
Hong, Young-Joo; Makita, Shuichi; Sugiyama, Satoshi; Yasuno, Yoshiaki
2014-01-01
Polarization mode dispersion (PMD) degrades the performance of Jones-matrix-based polarization-sensitive multifunctional optical coherence tomography (JM-OCT). The problem is specially acute for optically buffered JM-OCT, because the long fiber in the optical buffering module induces a large amount of PMD. This paper aims at presenting a method to correct the effect of PMD in JM-OCT. We first mathematically model the PMD in JM-OCT and then derive a method to correct the PMD. This method is a combination of simple hardware modification and subsequent software correction. The hardware modification is introduction of two polarizers which transform the PMD into global complex modulation of Jones matrix. Subsequently, the software correction demodulates the global modulation. The method is validated with an experimentally obtained point spread function with a mirror sample, as well as by in vivo measurement of a human retina. PMID:25657888
Baby Boy Jones Interactive Case-Based Learning Activity: A Web-Delivered Teaching Strategy.
Cleveland, Lisa M; Carmona, Elenice Valentim; Paper, Bruce; Solis, Linda; Taylor, Bonnie
2015-01-01
Faced with limited resources, nurse educators are challenged with transforming nursing education while preparing enough qualified nurses to meet future demand; therefore, innovative approaches to teaching are needed. In this article, we describe the development of an innovative teaching activity. Baby Boy Jones is a Web-delivered, case-based learning activity focused on neonatal infection. It was created using e-learning authoring software and delivered through a learning management system.
Pressure-energy correlations in liquids. V. Isomorphs in generalized Lennard-Jones systems.
Schrøder, Thomas B; Gnan, Nicoletta; Pedersen, Ulf R; Bailey, Nicholas P; Dyre, Jeppe C
2011-04-28
This series of papers is devoted to identifying and explaining the properties of strongly correlating liquids, i.e., liquids with more than 90% correlation between their virial W and potential energy U fluctuations in the NVT ensemble. Paper IV [N. Gnan et al., J. Chem. Phys. 131, 234504 (2009)] showed that strongly correlating liquids have "isomorphs," which are curves in the phase diagram along which structure, dynamics, and some thermodynamic properties are invariant in reduced units. In the present paper, using the fact that reduced-unit radial distribution functions are isomorph invariant, we derive an expression for the shapes of isomorphs in the WU phase diagram of generalized Lennard-Jones systems of one or more types of particles. The isomorph shape depends only on the Lennard-Jones exponents; thus all isomorphs of standard Lennard-Jones systems (with exponents 12 and 6) can be scaled onto a single curve. Two applications are given. One tests the prediction that the solid-liquid coexistence curve follows an isomorph by comparing to recent simulations by Ahmed and Sadus [J. Chem. Phys. 131, 174504 (2009)]. Excellent agreement is found on the liquid side of the coexistence curve, whereas the agreement is less convincing on the solid side. A second application is the derivation of an approximate equation of state for generalized Lennard-Jones systems by combining the isomorph theory with the Rosenfeld-Tarazona expression for the temperature dependence of the potential energy on isochores. It is shown that the new equation of state agrees well with simulations.
Modified Jeans instability in Lorentzian dusty self-gravitating plasmas with Lennard-Jones potential
NASA Astrophysics Data System (ADS)
Qian, Y. Z.; Chen, H.; Liu, S. Q.
2014-11-01
The Jeans instability in self-gravitating plasma with Kappa distributed dust grains is investigated basing on assumption that the mutual interaction among dust grains is governed by Lennard-Jones potential. It is shown that the presence of additional suprathermal particles has significant effects on the range of unstable modes and growth rate of Jeans instability. Compared with Maxwellian scenario, suprathermality stabilized the Jeans instability.
Jones matrix formalism for the theory of picosecond shear acoustic pulse detection.
Mounier, Denis; Picart, Pascal; Babilotte, Philippe; Ruello, Pascal; Breteau, Jean-Marc; Pézeril, Thomas; Vaudel, Gwenaëlle; Kouyaté, Mansour; Gusev, Vitalyi
2010-03-29
A theoretical analysis of the transient optical reflectivity of a sample by a normalized Jones matrix is presented. The off-diagonal components of the normalized matrix are identified with the complex rotation of the polarization ellipse. Transient optical polarimetry is a relevant technique to detect shear acoustic strain pulses propagating normally to the surface of an optically isotropic sample. Moreover, polarimetry has a selective sensitivity to shear waves, as this technique cannot detect longitudinal waves that propagate normally to the sample surface.
Finite-size scaling of Lennard-Jones droplet formation at fixed density
NASA Astrophysics Data System (ADS)
Zierenberg, Johannes; Janke, Wolfhard
2016-09-01
We reaccess the droplet condensation-evaporation transition of a three-dimensional Lennard-Jones system upon a temperature change. With the help of parallel multicanonical simulations we obtain precise estimates of the transition temperature and the width of the transition for systems with up to 2048 particles. This allows us to supplement previous observations of finite-size scaling regimes with a clearer picture also for the case of a continuous particle model.
Modified Jeans instability in Lorentzian dusty self-gravitating plasmas with Lennard-Jones potential
Qian, Y. Z. Chen, H. Liu, S. Q.
2014-11-15
The Jeans instability in self-gravitating plasma with Kappa distributed dust grains is investigated basing on assumption that the mutual interaction among dust grains is governed by Lennard-Jones potential. It is shown that the presence of additional suprathermal particles has significant effects on the range of unstable modes and growth rate of Jeans instability. Compared with Maxwellian scenario, suprathermality stabilized the Jeans instability.
Metastability, spectrum, and eigencurrents of the Lennard-Jones-38 network
Cameron, Maria K.
2014-11-14
We develop computational tools for spectral analysis of stochastic networks representing energy landscapes of atomic and molecular clusters. Physical meaning and some properties of eigenvalues, left and right eigenvectors, and eigencurrents are discussed. We propose an approach to compute a collection of eigenpairs and corresponding eigencurrents describing the most important relaxation processes taking place in the system on its way to the equilibrium. It is suitable for large and complex stochastic networks where pairwise transition rates, given by the Arrhenius law, vary by orders of magnitude. The proposed methodology is applied to the network representing the Lennard-Jones-38 cluster created by Wales's group. Its energy landscape has a double funnel structure with a deep and narrow face-centered cubic funnel and a shallower and wider icosahedral funnel. However, the complete spectrum of the generator matrix of the Lennard-Jones-38 network has no appreciable spectral gap separating the eigenvalue corresponding to the escape from the icosahedral funnel. We provide a detailed description of the escape process from the icosahedral funnel using the eigencurrent and demonstrate a superexponential growth of the corresponding eigenvalue. The proposed spectral approach is compared to the methodology of the Transition Path Theory. Finally, we discuss whether the Lennard-Jones-38 cluster is metastable from the points of view of a mathematician and a chemical physicist, and make a connection with experimental works.
Metastability, spectrum, and eigencurrents of the Lennard-Jones-38 network.
Cameron, Maria K
2014-11-14
We develop computational tools for spectral analysis of stochastic networks representing energy landscapes of atomic and molecular clusters. Physical meaning and some properties of eigenvalues, left and right eigenvectors, and eigencurrents are discussed. We propose an approach to compute a collection of eigenpairs and corresponding eigencurrents describing the most important relaxation processes taking place in the system on its way to the equilibrium. It is suitable for large and complex stochastic networks where pairwise transition rates, given by the Arrhenius law, vary by orders of magnitude. The proposed methodology is applied to the network representing the Lennard-Jones-38 cluster created by Wales's group. Its energy landscape has a double funnel structure with a deep and narrow face-centered cubic funnel and a shallower and wider icosahedral funnel. However, the complete spectrum of the generator matrix of the Lennard-Jones-38 network has no appreciable spectral gap separating the eigenvalue corresponding to the escape from the icosahedral funnel. We provide a detailed description of the escape process from the icosahedral funnel using the eigencurrent and demonstrate a superexponential growth of the corresponding eigenvalue. The proposed spectral approach is compared to the methodology of the Transition Path Theory. Finally, we discuss whether the Lennard-Jones-38 cluster is metastable from the points of view of a mathematician and a chemical physicist, and make a connection with experimental works.
Jones matrix treatment of electromagnetic wave propagation in anisotropic stratified media
NASA Astrophysics Data System (ADS)
Allia, P.; Oldano, C.; Trossi, L.
1988-05-01
Light propagation in anisotropic stratified media may be conveniently described, in the quasi-adiabatic limit, by the so-called Jones matrix formalism. In systems like liquid crystals, the quasi adiabatic limit occurs when the director rotates very slightly over distances of the order of the light wavelength. This limit is of relevant interest in many optical devices. As known, the general solution of the Maxwell's equations in anisotropic stratified media may be obtained by using the 4 × 4 Berreman's matrix method. However, as long as the polarization properties of the light transmitted through the medium are concerned, a much simpler approach is possible, which consists in completely neglecting the solutions of the Berreman's equations corresponding to the waves propagating in the backward direction. In this case, the number of differential equations describing light propagation is reduced from 4 to 2. The 2 × 2 matrix introduced in this approximated fromalism is termed the Jones matrix of the problem. In this paper, we show that in general case of oblique incidence of light is possible to properly transform the original Berreman's matrix into a form suitable for reduction to a 2 × 2 Jones matrix.
Crystallization of a human Bence Jones protein in microgravity using vapor diffusion in capillaries
NASA Astrophysics Data System (ADS)
Alvarado, U. R.; DeWitt, C. R.; Shultz, B. B.; Ramsland, P. A.; Edmundson, A. B.
2001-03-01
A simple evaporative method in sealed capillaries was used to produce X-ray diffraction quality crystals of a monoclonal human Bence-Jones protein (Sea) in microgravity and at unit gravity. The λ isotypic Bence-Jones protein was purified from the urine of a multiple myeloma patient using ammonium sulfate precipitation, dialysis and cation exchange, followed by gel filtration. Crystals were produced in glass capillaries where water evaporated from the protein solution was absorbed by one or two suitable absorbents. A crystal grown during the 9-day Space Shuttle STS-95 flight measured 8×1.6×1 mm. It was subjected to X-ray diffraction and was found to be orthorhombic ( P2 12 12 1), with unit-cell dimensions of 48.9, 85.2 and 114.0 Å. X-ray data were collected at room temperature and were 98.3% complete to 2.3 Å resolution. Crystals of the same Bence-Jones protein measuring 1.2-2 mm in length were grown in ground-based controls using a high evaporation rate for the first 12 h, followed by a slower evaporation rate for the remainder of the 19-day growth period.
Scaling of the dynamics of flexible Lennard-Jones chains: Effects of harmonic bonds.
Veldhorst, Arno A; Dyre, Jeppe C; Schrøder, Thomas B
2015-11-21
The previous paper [A. A. Veldhorst et al., J. Chem. Phys. 141, 054904 (2014)] demonstrated that the isomorph theory explains the scaling properties of a liquid of flexible chains consisting of ten Lennard-Jones particles connected by rigid bonds. We here investigate the same model with harmonic bonds. The introduction of harmonic bonds almost completely destroys the correlations in the equilibrium fluctuations of the potential energy and the virial. According to the isomorph theory, if these correlations are strong a system has isomorphs, curves in the phase diagram along which structure, dynamics, and the excess entropy are invariant. The Lennard-Jones chain liquid with harmonic bonds does have curves in the phase diagram along which the structure and dynamics are invariant. The excess entropy is not invariant on these curves, which we refer to as "pseudoisomorphs." In particular, this means that Rosenfeld's excess-entropy scaling (the dynamics being a function of excess entropy only) does not apply for the Lennard-Jones chain with harmonic bonds.
Static and Restricted Rigid Rotor Configurations of Three Classical 12-6-Lennard-Jones Particles
NASA Astrophysics Data System (ADS)
Rupp, Florian
2015-03-01
Motivated by the continuous search for stable geometric configurations of atom and molecule clusters, we analyse the planar evolution of two freely movable point particles around a third immovable one subject to the 12-6-Lennard-Jones potential. This tailors our discussion to systems with one very heavy particle that can be assumed to be permanently at rest in the moving reference frame for the whole ensemble. Relating to Lennard-Jones interactions, we allow all three point particles to take different parameters. This breaks the symmetry conditions that are usually imposed on such systems. Through a classical non-regularized Hamiltonian description of our restricted three particle system, we study the existence of genuine equilibria and rigid rotor solutions around a single axis of rotation. We prove, depending on the choice of the Lennard-Jones parameters, that for these genuine equilibria, collinear alignments and triangular configurations of any shape can occur. Moreover, for the discussed type of relative equilibria a complete classification is provided by proving the existence of rigid rotor configurations in the plane of rotation (collinear cis and trans as well as triangle shaped configurations) and out of the plane of rotation (triangle shaped and flag-like configurations). Furthermore, we show that there are no further rigid rotor solutions of the underlying equations of motion.
Report #09-P-0243, September 23, 2009. In April 2008, the OIG obtained groundwater and surface water samples from the Jones Sanitation Superfund Site and nearby areas, and conducted a site inspection.
NASA Astrophysics Data System (ADS)
Armitage, N. P.
2014-07-01
Optical spectroscopies are most often used to probe dynamical correlations in materials, but they are also a probe of symmetry. Polarization anisotropies are of course sensitive to structural anisotropies, but have been much less used as a probe of more exotic symmetry breakings in ordered states. In this paper, a Jones transfer matrix formalism is discussed to infer the existence of exotic broken symmetry states of matter from their electrodynamic response for a full complement of possible broken symmetries including reflection, rotation, rotation reflection, inversion, and time reversal. A specific condition to distinguish the case of macroscopic time-reversal symmetry breaking is particularly important as in a dynamical experiment like optics, one must distinguish reciprocity from time-reversal symmetry as dissipation violates strict time-reversal symmetry of an experiment. Different forms of reciprocity can be distinguished, but only one is a sufficient (but not necessary) condition for macroscopic time-reversal symmetry breaking. I show the constraints that a Jones matrix develops under the presence or absence of such symmetries. These constraints typically appear in the form of an algebra relating matrix elements or overall constraints (transposition, unitarity, hermiticity, normality, etc.) on the form of the Jones matrix. I work out a number of examples including the trivial case of a ferromagnet and the less trivial cases of magnetoelectrics and vector and scalar spin "chiral" states. I show that the formalism can be used to demonstrate that Kerr rotation must be absent in time-reversal symmetric chiral materials. The formalism here is discussed with an eye towards its use in time-domain terahetrz spectroscopy in transmission, but with small modifications it is more generally applicable.
Precise simulation of the freezing transition of supercritical Lennard-Jones.
Nayhouse, Michael; Amlani, Ankur M; Orkoulas, G
2011-10-21
The fluid-solid transition of the Lennard-Jones model is analyzed along a supercritical isotherm. The analysis is implemented via a simulation method which is based on a modification of the constrained cell model of Hoover and Ree. In the context of hard-sphere freezing, Hoover and Ree simulated the solid phase using a constrained cell model in which each particle is confined within its own Wigner-Seitz cell. Hoover and Ree also proposed a modified cell model by considering the effect of an external field of variable strength. High-field values favor configurations with a single particle per Wigner-Seitz cell and thus stabilize the solid phase. In previous work, a simulation method for freezing transitions, based on constant-pressure simulations of the modified cell model, was developed and tested on a system of hard spheres. In the present work, this method is used to determine the freezing transition of a Lennard-Jones model system on a supercritical isotherm at a reduced temperature of 2. As in the case of hard spheres, constant-pressure simulations of the fully occupied constrained cell model of a system of Lennard-Jones particles indicate a point of mechanical instability at a density which is approximately 70% of the density at close packing. Furthermore, constant-pressure simulations of the modified cell model indicate that as the strength of the field is reduced, the transition from the solid to the fluid is continuous below the mechanical instability point and discontinuous above. The fluid-solid transition of the Lennard-Jones system is obtained by analyzing the field-induced fluid-solid transition of the modified cell model in the high-pressure, zero-field limit. The simulations are implemented under constant pressure using tempering and histogram reweighting techniques. The coexistence pressure and densities are determined through finite-size scaling techniques for first-order phase transitions which are based on analyzing the size-dependent behavior of
Molecular dynamics simulation of graphene on Cu (111) with different Lennard-Jones parameters
NASA Astrophysics Data System (ADS)
Sidorenkov, Alexander V.; Kolesnikov, Sergey V.; Saletsky, Alexander M.
2016-10-01
The interaction between graphene and copper (111) surface have been investigated using the molecular dynamics simulations. The range of Lennard-Jones parameters which correspond to the binding energies and the binding distances calculated via ab initio methods was found. The dependencies of the binding energy, the binding distance and the graphene thickness on the parameters of the potential and the rotational angle are presented. We have found minima of the binding energy which can be related to experimentally observed Moiré superstructures.
Modified Lennard-Jones model: virial coefficients to the 7th order.
Ushcats, M V
2014-06-21
The modified Lennard-Jones potential, which simplifies the numerical simulations and maintains the realistic behavior of its parent, is proposed to a role of the standard interaction model for both the experimental and theoretical studies. The virial coefficients of this model up to the seventh order have been calculated for the range of temperatures kT/ɛ = 0.3-70. In the computations, a technique has been used, that combines the quadrature integration and Mayer Sampling Monte Carlo method (MSMC). Unlike the original MSMC, this technique does not require the reference coefficients of another potential and can be used in a wide range of temperatures for various interaction models.
Relaxation of surface tension in the liquid-solid interfaces of Lennard-Jones liquids.
Lukyanov, Alex V; Likhtman, Alexei E
2013-11-19
We have established the surface tension relaxation time in the liquid-solid interfaces of Lennard-Jones (LJ) liquids by means of direct measurements in molecular dynamics (MD) simulations. The main result is that the relaxation time is found to be almost independent of the molecular structures and viscosity of the liquids (at 70-fold change) used in our study and lies in such a range that in slow hydrodynamic motion the interfaces are expected to be at equilibrium. The implications of our results for the modeling of dynamic wetting processes and interpretation of dynamic contact angle data are discussed.
Vapour-liquid coexistence of an active Lennard-Jones fluid.
Prymidis, Vasileios; Paliwal, Siddharth; Dijkstra, Marjolein; Filion, Laura
2016-09-28
We study a three-dimensional system of self-propelled Lennard-Jones particles using Brownian dynamics simulations. Using recent theoretical results for active matter, we calculate the pressure and report equations of state for the system. Additionally, we chart the vapour-liquid coexistence and show that the coexistence densities can be well described using simple power laws. Lastly, we demonstrate that our out-of-equilibrium system shows deviations from both the law of rectilinear diameters and the law of corresponding states.
Venzal, J; González-Acuña, Daniel; Mangold, A; Guglielmone, A
2012-02-01
Three argasid tick larvae were collected on April 2, 2010, from a common vampire bat, Desmodus rotundus, captured in the Parque Nacional Pan de Azúcar (26°09' S, 70°41' W), Region of Atacama, Chile. The larvae were diagnosed as Ornithodoros, and further comparative analysis showed them to be Ornithodoros peruvianus Kohls, Clifford & Jones or a species close to it. Phylogenetic analysis based on 16S mitochondrial rRNA gene sequences of Ornithodoros species plus four Argas species was carried out to clarify the taxonomic position of the larvae. This is the first finding of ticks parasitizing D. rotundus in Chile.
"Smite this sleeping world awake": Edward Burne-Jones and "The legend of the briar rose".
Rager, Andrea Wolk
2009-01-01
Challenging entrenched preconceptions about the supposed escapism and conservatism of Edward Burne-Jones's art, this paper seeks to establish his monumental painted series, "The Legend of the Briar Rose," as a fundamentally radical and confrontational work. Critics have long viewed it as an endorsement of sleepy stasis, antithetical to the political activism espoused by his friend William Morris. By unraveling the intertwining themes of the series -- the transformative dream vision, artistic labor, the decorative mode, and social egalitarianism -- the "Briar Rose" series is revealed instead to be dramatization of the struggle for personal, social, artistic, and even environmental awakening.
Vapour-liquid coexistence of an active Lennard-Jones fluid
NASA Astrophysics Data System (ADS)
Prymidis, Vasileios; Paliwal, Siddharth; Dijkstra, Marjolein; Filion, Laura
2016-09-01
We study a three-dimensional system of self-propelled Lennard-Jones particles using Brownian dynamics simulations. Using recent theoretical results for active matter, we calculate the pressure and report equations of state for the system. Additionally, we chart the vapour-liquid coexistence and show that the coexistence densities can be well described using simple power laws. Lastly, we demonstrate that our out-of-equilibrium system shows deviations from both the law of rectilinear diameters and the law of corresponding states.
Monte Carlo study of the shear modulus at the surface of a Lennard-Jones crystal
NASA Astrophysics Data System (ADS)
Eerden, J. P. v. d.; Knops, H. J. F.; Roos, A.
1992-01-01
In this paper, we give a microscopic definition of local elastic constants. We apply this to the numerical evaluation of the shear modulus of an interface which is sharp as compared with the interaction range. The algorithm is applied to a study of the (001) face of a face-centered-cubic (fcc) Lennard-Jones crystal. The vanishing of the shear modulus gives an estimate of the melting temperature of the first layer which is well below the bulk triple point. Some theoretical aspects of surface melting are briefly discussed.
Evaluation of Quantum Corrections to Second Virial Coefficient with Lennard-Jones (12-6) Potential
NASA Astrophysics Data System (ADS)
Mamedov, B. A.; Somuncu, E.
2016-10-01
The efficient method is developed for analytical evalualtion of quantum corrections to second virial coefficient with Lennard-Jones (12-6) potential. The quantum corrections to second virial coefficient played a significant role in the investigation of real gases in the low temperatures range. In this paper, we obtained a series of formula in terms of gamma and exponential integral functions which is one of the useful approaches for analytical evaluation of quantum corrections to second virial coefficient. The calculation results excellently agreement with of the literature data.
Determination of iron: In the presence of chromium and titanium with the jones reductor
Grimaldi, F.S.; Stevens, R.E.; Carron, M.K.
1943-01-01
Sulfuric acid solutions of titanous and chromous sulfates, obtained by passage through the Jones reductor, are oxidized by aeration for from 5 to 10 minutes in the presence of a trace of copper sulfate as a catalyst. Ferrous sulfate is essentially unoxidized and is titrated with permanganate after aeration. Best results are obtained by using 0.0003 millimole of copper sulfate in about 300 ml. of solution. Larger quantities of copper sulfate lead to slightly low results when both chromium and titanium are present.
Solubility Limits in Lennard-Jones Mixtures: Effects of Disparate Molecule Geometries
Dyer, Kippi M.; Perkyns, John S.; Pettitt, B. Montgomery
2016-01-01
In order to better understand general effects of the size and energy disparities between macromolecules and solvent molecules in solution, especially for macromolecular constructs self-assembled from smaller molecules, we use the first- and second-order exact bridge diagram extensions of the HNC integral equation theory to investigate single-component, binary, ternary, and quaternary mixtures of Lennard-Jones fluids. For pure fluids, we find that the HNCH3 bridge function integral equation (i.e., exact to third order in density) is necessary to quantitatively predict the pure gas and pure liquid sides of the coexistence region of the phase diagram of the Lennard-Jones fluid. For the mixtures, we find that the HNCH2 bridge function integral equation is sufficient to qualitatively predict solubility in the binary, ternary, and quaternary mixtures, up to the nominal solubility limit. The results, as limiting cases, should be useful to several problems, including accurate phase diagram predictions for complex mixtures, design of self-assembling nanostructures via solvent controls, and the solvent contributions to the conformational behavior of macromolecules in complex fluids. PMID:25621892
Morse, Lennard-Jones, and Kratzer Potentials: A Canonical Perspective with Applications.
Walton, Jay R; Rivera-Rivera, Luis A; Lucchese, Robert R; Bevan, John W
2016-10-12
Canonical approaches are applied to classic Morse, Lennard-Jones, and Kratzer potentials. Using the canonical transformation generated for the Morse potential as a reference, inverse transformations allow the accurate generation of the Born-Oppenheimer potential for the H2(+) ion, neutral covalently bound H2, van der Waals bound Ar2, and the hydrogen bonded one-dimensional dissociative coordinate in a water dimer. Similar transformations are also generated using the Lennard-Jones and Kratzer potentials as references. Following application of inverse transformations, vibrational eigenvalues generated from the Born-Oppenheimer potentials give significantly improved quantitative comparison with values determined from the original accurately known potentials. In addition, an algorithmic strategy based upon a canonical transformation to the dimensionless form applied to the force distribution associated with a potential is presented. The resulting canonical force distribution is employed to construct an algorithm for deriving accurate estimates for the dissociation energy, the maximum attractive force, and the internuclear separations corresponding to the maximum attractive force and the potential well.
Surface tension of short flexible Lennard-Jones chains: Corresponding states behavior.
Galliero, Guillaume
2010-08-21
Molecular dynamics simulations of surface tensions of short flexible Lennard-Jones chains, composed of 2, 3, 4, and 5 segments, have been performed in this work. Using the simulation results, it is shown that the reduced surface tension depends only on the chain length and the reduced temperature. As a consequence, simple three parameters corresponding states using the acentric factor is shown to yield an excellent estimation of the reduced surface tension of the flexible Lennard-Jones chain fluid model. In addition, it has been noticed that the reduced surface tension of this fluid model is a unique function of the coexisting liquid and vapor reduced densities (i.e., there exist a universal Parachor behavior) for all chain lengths tested. When applied to real fluids, this universal behavior holds rather well for a large class of real species which can be nonspherical, nonlinear, and even polar. Only the surface tension of hydrogen-bonding compounds seems to largely deviate from this universal Parachor behavior. These interesting features of the surface tension, written in appropriate scaled forms, can probably be used to improve molecular models, in particular, those on which modern molecular based equations of state rely on.
Solubility Limits in Lennard-Jones Mixtures: Effects of Disparate Molecule Geometries.
Dyer, Kippi M; Perkyns, John S; Pettitt, B Montgomery
2015-07-23
In order to better understand general effects of the size and energy disparities between macromolecules and solvent molecules in solution, especially for macromolecular constructs self-assembled from smaller molecules, we use the first- and second-order exact bridge diagram extensions of the HNC integral equation theory to investigate single-component, binary, ternary, and quaternary mixtures of Lennard-Jones fluids. For pure fluids, we find that the HNCH3 bridge function integral equation (i.e., exact to third order in density) is necessary to quantitatively predict the pure gas and pure liquid sides of the coexistence region of the phase diagram of the Lennard-Jones fluid. For the mixtures, we find that the HNCH2 bridge function integral equation is sufficient to qualitatively predict solubility in the binary, ternary, and quaternary mixtures, up to the nominal solubility limit. The results, as limiting cases, should be useful to several problems, including accurate phase diagram predictions for complex mixtures, design of self-assembling nanostructures via solvent controls, and the solvent contributions to the conformational behavior of macromolecules in complex fluids.
Barbante, Paolo; Frezzotti, Aldo; Gibelli, Livio
2014-12-09
The unsteady evaporation of a thin planar liquid film is studied by molecular dynamics simulations of Lennard-Jones fluid. The obtained results are compared with the predictions of a diffuse interface model in which capillary Korteweg contributions are added to hydrodynamic equations, in order to obtain a unified description of the liquid bulk, liquid-vapor interface and vapor region. Particular care has been taken in constructing a diffuse interface model matching the thermodynamic and transport properties of the Lennard-Jones fluid. The comparison of diffuse interface model and molecular dynamics results shows that, although good agreement is obtained in equilibrium conditions, remarkable deviations of diffuse interface model predictions from the reference molecular dynamics results are observed in the simulation of liquid film evaporation. It is also observed that molecular dynamics results are in good agreement with preliminary results obtained from a composite model which describes the liquid film by a standard hydrodynamic model and the vapor by the Boltzmann equation. The two mathematical model models are connected by kinetic boundary conditions assuming unit evaporation coefficient.
The potential energy landscape for crystallisation of a Lennard-Jones fluid
NASA Astrophysics Data System (ADS)
de Souza, Vanessa K.; Wales, David J.
2016-07-01
Crystallisation pathways are explored by direct analysis of the potential energy landscape for a system of Lennard-Jones particles with periodic boundary conditions. A database of minima and transition states linking liquid and crystalline states is constructed using discrete path sampling and the entire potential energy landscape from liquid to crystal is visualised. We demonstrate that there is a strong negative correlation between the number of atoms in the largest crystalline cluster and the potential energy. In common with previous results we find a strong bias towards the growth of FCC rather than HCP clusters, despite a very small potential energy difference. We characterise three types of perfect crystals with very similar energies: pure FCC, pure HCP, and combinations of FCC and HCP layers. There are also many slightly defective crystalline structures. The effect of the simulation box is analysed for a supercell containing 864 atoms. There are low barriers between some of the different crystalline structures via pathways involving sliding layers, and many different defective structures with FCC layers stacked at an angle to the periodic box. Finally, we compare a binary Lennard-Jones system and visualise the potential energy landscape from supercooled liquid to crystal.
Birefringence imaging of posterior eye by multi-functional Jones matrix optical coherence tomography
Sugiyama, Satoshi; Hong, Young-Joo; Kasaragod, Deepa; Makita, Shuichi; Uematsu, Sato; Ikuno, Yasushi; Miura, Masahiro; Yasuno, Yoshiaki
2015-01-01
A clinical grade prototype of posterior multifunctional Jones matrix optical coherence tomography (JM-OCT) is presented. This JM-OCT visualized depth-localized birefringence in addition to conventional cumulative phase retardation imaging through local Jones matrix analysis. In addition, it simultaneously provides a sensitivity enhanced scattering OCT, a quantitative polarization uniformity contrast, and OCT-based angiography. The probe beam is at 1-μm wavelength band. The measurement speed and the depth-resolution were 100,000 A-lines/s, and 6.6 μm in tissue, respectively. Normal and pathologic eyes are examined and several clinical features are revealed, which includes high birefringence in the choroid and lamina cribrosa, and birefringent layered structure of the sclera. The theoretical details of the depth-localized birefringence imaging and conventional phase retardation imaging are formulated. This formulation indicates that the birefringence imaging correctly measures a depth-localized single-trip phase retardation of a tissue, while the conventional phase retardation can provide correct single-trip phase retardation only for some specific types of samples. PMID:26713208
The fish and fisheries of Jones Bank and the wider Celtic Sea
NASA Astrophysics Data System (ADS)
Martinez, I.; Ellis, J. R.; Scott, B.; Tidd, A.
2013-10-01
The Celtic Sea is a diverse fishing ground that supports important commercial fisheries for a range of demersal fish, large and small-bodied pelagic fish and a variety of cephalopods and other shellfish. A regional overview of the main commercial fish stocks of the Celtic Sea and of the fish that occur in the vicinity of Jones Bank are provided through analyses of landings data from English and Welsh vessels, and from scientific trawl surveys. Dedicated smaller scale sampling via trawl surveys combined with baited cameras on and around the Jones Bank were also analysed to investigate the importance of sandbank habitats with attention paid to the differences in the species occurring on the top of the bank in comparison to adjacent off-bank habitats. Official landing statistics for UK (English and Welsh) vessels indicated that the predominant commercial demersal species in ICES Divisions VIIg,h (in terms of quantities landed) were anglerfish, megrim, pollack and skates (Rajidae). There were, however, regional differences in the distribution of fish and fisheries, and the area surrounding Jones Bank (ICES Rectangles 28E1 and 28E2) supports fisheries for megrim, anglerfish, skates, hake, ling and turbot, with otter trawl, gillnet and beam trawl the main gears used. Recent survey data collected with GOV (Grande Ouverture Verticale) trawl from the Celtic Sea (ICES Divisions VIIe-h, 2007-2010) were used to highlight the broad scale distribution of the main fish assemblages in the Celtic Sea. Analyses of the fish and cephalopod catches from these surveys indicated that there were four broad assemblages in the area, including (i) a region around the Cornwall (which will also be partly influenced by the necessity to use rockhopper ground gear on these rough grounds), (ii) the shallower regions of the north-western Celtic Sea (including parts of the Bristol Channel), (iii) the deeper parts of the outer shelf and (iv) the central Celtic Sea. These data also provided
Transfer coefficients for evaporation of a system with a Lennard-Jones long-range spline potential.
Ge, Jialin; Kjelstrup, S; Bedeaux, D; Simon, J M; Rousseau, B
2007-06-01
Surface transfer coefficients are determined by nonequilibrium molecular dynamics simulations for a Lennard-Jones fluid with a long-range spline potential. In earlier work [A. Røsjorde, J. Colloid Interface Sci. 240, 355 (2001); J. Xu, ibid. 299, 452 (2006)], using a short-range Lennard-Jones spline potential, it was found that the resistivity coefficients to heat and mass transfer agreed rather well with the values predicted by kinetic theory. For the long-range Lennard-Jones spline potential considered in this paper we find significant discrepancies from the values predicted by kinetic theory. In particular the coupling coefficient, and as a consequence the heat of transfer on the vapor side of the surface are much larger. Thermodynamic data for the liquid-vapor equilibrium confirmed the law of corresponding states for the surface, when it is described as an autonomous system. The importance of these findings for modelling phase transitions is discussed.
Pitt, Mark M
2012-01-01
The paper "High Noon for Microfinance Impact Evaluations" by Duvendack and Palmer-Jones replicates the papers of Chemin (2008) and Pitt and Khandker (1998) that estimate the impact of microfinance in Bangladesh. My paper replicates the Duvendack and Palmer-Jones replication and finds so many serious errors in their code and misrepresentations of the methods described in their paper that I conclude that their results are spurious and provide no evidence about the validity of either the papers of Chemin or Pitt and Khandker or on the effectiveness of microfinance.
Kasaboğlu, O; Tümer, C; Balci, S
2004-01-01
Hereditary gingival fibromatosis and sensorineural hearing loss in a 42-year-old man with Jones syndrome: Gingival fibromatosis is a rare disease, which can be seen as an isolated condition or associated with some uncommon syndromes. This case report describes the evaluation and treatment of a 42-year-old male patient with hereditary gingival fibromatosis, sensorineural hearing loss, undescended testis and maxillary odontogenic cyst (Jones Syndrome). Six years follow up of the index patient after the surgery revealed no recurrence of the gingival fibromatosis. This report also describes the anamnestic data of the patient's family that showed progressive deafness and gingival enlargement in three generations.
Polarization aberration modeling via Jones matrix in the context of OPC
NASA Astrophysics Data System (ADS)
Zhang, Qiaolin; Song, Hua; Lucas, Kevin
2007-10-01
The increasingly stringent demand for shrinkage of IC device dimensions has been pushing the development of new resolution enhancement technologies in micro-lithography. High NA and Ultra-High NA (NA>1.0) applications for low k I imaging strongly demand the adoption of polarized illumination as a resolution enhancement technology since proper illumination polarization configuration can greatly improve the image contrast hence pattern printing fidelity. For polarized illumination to be fully effective, ideally all the components in the optical system should not alter the polarization state during propagation from illuminator to wafer surface. In current OPC modeling tools, it is typically assumed that the amplitude and polarization state of the electric field do not change as it passes through the projection lens pupil. However, in reality, the projection lens pupil of the scanner does change the amplitude and the polarization state to some extent, and ignorance of projection pupil induced polarization state and amplitude changes may cause CD errors which are un-tolerable at the 45nm device generation and beyond. We developed an OPC-deployable modeling approach to model polarization aberration imposed by the projection lens pupil via Jones matrix format. This polarization aberration modeling capability has been integrated into the Synopsys OPC modeling tool, ProGen, and its accuracy and efficiency have been validated by comparing with an industry standard lithography simulator SolidE. Our OPC simulations show that the impact of projection lens pupil polarization aberrations on optical proximity effect (OPE) could be as large as several nanometers, which is not negligible given the extremely stringent CD error budget at 45nm node and beyond. This modeling approach is applicable to arbitrary polarization aberrations imposed by any components in the lithography system that can be characterized in Jones matrix format. Based on an experimentally measured Jones matrix
Eighth to sixteenth virial coefficients of the Lennard-Jones model.
Feng, Chao; Schultz, Andrew J; Chaudhary, Vipin; Kofke, David A
2015-07-28
We calculated virial coefficients BN, 8 ≤ N ≤ 16, of the Lennard-Jones (LJ) model using both the Mayer-sampling Monte Carlo method and direct generation of configurations, with Wheatley's algorithm for summation of clusters. For N = 8, 24 values are reported, and for N = 9, 12 values are reported, both for temperatures T in the range 0.6 ≤ T ≤ 40.0 (in LJ units). For each N in 10 ≤ N ≤ 16, one to four values are reported for 0.6 ≤ T ≤ 0.9. An approximate functional form for the temperature dependence of BN was developed, and fits of LJ BN(T) based on this form are presented for each coefficient, 4 ≤ N ≤ 9, using new and previously reported data.
Melting in 2D Lennard-Jones Systems: What Type of Phase Transition?
Patashinski, Alexander Z.; Orlik, Rafal; Mitus, Antonio C.; Grzybowski, Bartosz A.; Ratner, Mark A.
2010-12-09
A typical configuration of an equilibrium 2D system of 2500 Lennard-Jones particles at melting is found to be a mosaic of crystallites and amorphous clusters. This mosaic significantly changed at times around the period τ of local vibrations, while most particles retain their nearest neighbors for times much longer than τ. In a system of 2500 particles, we found no phase separation for length scales larger than that of a crystallite. With decreasing density, the number of small amorphous clusters increased, and proliferation and percolation of amorphous matter separated the crystalline-ordered parts so that correlations between local order orientations of remote crystallites disappeared. We suggest that the mosaic is a manifestation of diminished stability of the crystalline structure resulting from competition between attraction and repulsion forces.
Solid-liquid critical behavior of a cylindrically confined Lennard-Jones fluid.
Mochizuki, Kenji; Koga, Kenichiro
2015-07-28
Extensive molecular dynamics simulations have been performed to study the phase behavior of Lennard-Jones particles confined in a quasi-one-dimensional hydrophobic nanopore. We provide unambiguous evidence for a solid-liquid critical point by investigating (i) isotherms in the pressure-volume plane, (ii) the spontaneous solid-liquid phase separation below a certain temperature, (iii) diverging heat capacity and isothermal compressibility as a certain point is approached, (iv) continuous change of dynamical and structural properties above the point, (v) the finite-size scaling analysis of the density distribution below and above the point. The result combined with earlier studies of confined water suggests that the solid-liquid critical point is not uncommon in quasi-one- and quasi-two-dimensional fluids.
Droplet growth during vapor-liquid transition in a 2D Lennard-Jones fluid.
Midya, Jiarul; Das, Subir K
2017-01-14
Results for the kinetics of vapor-liquid phase transition have been presented from the molecular dynamics simulations of a single component two-dimensional Lennard-Jones fluid. The phase diagram for the model, primary prerequisite for this purpose, has been obtained via the Monte Carlo simulations. Our focus is on the region very close to the vapor branch of the coexistence curve. Quenches to such region provide morphology that consists of disconnected circular clusters in the vapor background. We identified that these clusters exhibit diffusive motion and grow via sticky collisions among them. The growth follows power-law behavior with time, exponent of which is found to be in nice agreement with a theoretical prediction.
Nicolini, Paolo; Guàrdia, Elvira; Masia, Marco
2013-11-14
In this work, ab initio parametrization of water force field is used to get insights into the functional form of empirical potentials to properly model the physics underlying dispersion interactions. We exploited the force matching algorithm to fit the interaction forces obtained with dispersion corrected density functional theory based molecular dynamics simulations. We found that the standard Lennard-Jones interaction potentials poorly reproduce the attractive character of dispersion forces. This drawback can be resolved by accounting for the distinctive short range behavior of dispersion interactions, multiplying the r(-6) term by a damping function. We propose two novel parametrizations of the force field using different damping functions. Structural and dynamical properties of the new models are computed and compared with the ones obtained from the non-damped force field, showing an improved agreement with reference first principle calculations.
Properties of the Lennard-Jones dimeric fluid in two dimensions: an integral equation study.
Urbic, Tomaz; Dias, Cristiano L
2014-03-07
The thermodynamic and structural properties of the planar soft-sites dumbbell fluid are examined by Monte Carlo simulations and integral equation theory. The dimers are built of two Lennard-Jones segments. Site-site integral equation theory in two dimensions is used to calculate the site-site radial distribution functions for a range of elongations and densities and the results are compared with Monte Carlo simulations. The critical parameters for selected types of dimers were also estimated. We analyze the influence of the bond length on critical point as well as tested correctness of site-site integral equation theory with different closures. The integral equations can be used to predict the phase diagram of dimers whose molecular parameters are known.
Dynamics of vacancies in two-dimensional Lennard-Jones crystals.
Yao, Zhenwei; de la Cruz, Monica Olvera
2014-12-01
Vacancies represent an important class of crystallographic defects, and their behaviors can be strongly coupled with relevant material properties. In this work, we study the dynamics of generic n-point vacancies in two-dimensional Lennard-Jones crystals in several thermodynamic states. Simulations reveal the spectrum of distinct, size-dependent vacancy dynamics, including the nonmonotonously varying diffusive mobilities of one-, two- and three-point vacancies, and several healing routines of linear vacancies. Specifically, we numerically observe significantly faster diffusion of the two-point vacancy that can be attributed to its rotational degree of freedom. The high mobility of the two-point vacancies opens the possibility of doping two-point vacancies into atomic materials to enhance atomic migration. The rich physics of vacancies revealed in this study may have implications in the engineering of defects in extensive crystalline materials for desired properties.
Temperature-dependent mechanisms of homogeneous crystal nucleation in quenced Lennard-Jones liquids
Peng, L.; Morris, James R; Lo, Y. C.
2008-01-01
We have observed homogeneous crystal nucleation in Lennard-Jones liquid by molecular dynamics simulations. A clear nucleation time delay has been observed at T=0.677T{sub m} and T=0.629T{sub m} indicating the presence of a barrier, in contrast to recent reports [Trudu et al., Phys. Rev. Lett. 97, 105701 (2006)]. The structure of nuclei observed in the previous results and in the present work is evidence of transient-time dominated nucleation, not of a spinodal. Very rapid nucleation is observed at T=0.484T{sub m}, indicating either a low (but finite) barrier or possibly a spinodal transformation. No spinodal effect has been observed in similar simulations of crystal nucleation in aluminum at any temperature [Aga et al., Phys. Rev. Lett. 96, 245701 (2006)], suggesting that different qualitative behaviors may be possible in what would seem to be similar potentials.
Determination of new Cu+, Cu2+, and Zn2+ Lennard-Jones ion parameters in acetonitrile.
Torras, Juan; Alemán, Carlos
2013-09-12
We present new Lennard-Jones (LJ) parameters for Cu(+), Cu(2+), and Zn(2+) ion-acetonitrile interactions. The adjustment of ion parameters is made to reproduce simultaneously experimental solvation free energy and structural properties, namely ion-N distance and coordination numbers. Initially, the methodology has been validated deriving parameters for well-studied Na(+) and Cl(-) ions in acetonitrile being compared with experimental and theoretical data. The transferability of parameters is checked by the calculation of thermodynamic and structural properties with three different acetonitrile models. The results obtained for transition metal ions show an overall agreement with reference values. The solvation free energy calculated with new LJ trained parameters using a six-site acetonitrile model, and two older three- and six-site acetonitrile models presents, respectively, percent differences of 0.4, 4.8, and 7.3% when compared with experimental values.
Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films.
Fernández, Eva M; Chacón, Enrique; MacDowell, Luis G; Tarazona, Pedro
2015-06-01
We use Monte Carlo simulations of a Lennard-Jones fluid adsorbed on a short-range planar wall substrate to study the fluctuations in the thickness of the wetting layer, and we get a quantitative and consistent characterization of their mesoscopic Hamiltonian, H[ξ]. We have observed important finite-size effects, which were hampering the analysis of previous results obtained with smaller systems. The results presented here support an appealing simple functional form for H[ξ], close but not exactly equal to the theoretical nonlocal proposal made on the basis a generic density-functional analysis by Parry and coworkers. We have analyzed systems under different wetting conditions, as a proof of principle for a method that provides a quantitative bridge between the molecular interactions and the phenomenology of wetting films at mesoscopic scales.
On the establishment of thermal diffusion in binary Lennard-Jones liquids
NASA Astrophysics Data System (ADS)
Ferrario, M.; Bonella, S.; Ciccotti, G.
2016-10-01
The establishment of thermal diffusion in an Ar-Kr Lennard-Jones mixture is investigated via dynamical non equilibrium molecular dynamics [G. Ciccotti, G. Jacucci, Phys. Rev. Lett. 35, 789 (1975)]. We observe, in particular, the evolution of the density and temperature fields of the system following the onset of the thermal gradient. In stationary conditions, we also compute the Soret coefficient of the mixture. This study confirms that dynamical non equilibrium molecular dynamics is an effective tool to gather information on transient phenomena, even though the full evolution of the mass and energy fluxes associated to the temperature and density fields requires, in this case, a more substantial numerical effort than the one employed here.
NASA Astrophysics Data System (ADS)
Kim, Tae Wan; Yun, Hee-Joong
2016-09-01
A fundamental concept in physics of polarization propagation of electromagnetic waves is newly understood as a cardinal keyword in quantum cryptography transport technology and cosmology. Recently, interactive visualization of the propagation mechanism of polarized electromagnetism in a medium with helicity has received attention from scientists in the age of information and communication. This study presents a new dynamic polarization platform that manipulates the polarization mode train of a transverse electromagnetic wave by using calculations with Jones vectors in the symbolic program Mathematica. The train of polarization modes is converted continuously through a desirable lineup of optical elements in the platform. The platform simulates a propagation process that satisfies Maxwell's two vector equations precisely with helicity in the vectorial nature of the electromagnetic wave.
Platform for Manipulating Polarization Modes Realized with Jones Vectors in MATHEMATICA
NASA Astrophysics Data System (ADS)
Choi, Yong-Dae; Kim, Bogyeong; Yun, Hee-Joong
2015-06-01
The fundamental conception in physics of the propagation of the electromagnetic wave polarization in matter is newly understood as the cardinal keyword in free-space quantum communication technology and cosmology in astrophysics. Interactive visualization of the propagation mechanism of polarized electromagnetism in a medium with its helicity has accordingly received attention from scientists exploiting the protocol of quantum key distribution (QKD) to guarantee unconditional security in cryptography communication. We have provided a dynamic polarization platform for presenting the polarization modes of a transverse electromagnetic wave, converting the state of polarization through the arrangement of optical elements, using Jones vectors calculations in Methematica. The platform graphically simulates the mechanism of production and propagation of the polarized waves in a medium while satisfying Maxwell's equations.
Variable soft sphere molecular model for inverse-power-law or Lennard-Jones potential
NASA Astrophysics Data System (ADS)
Koura, Katsuhisa; Matsumoto, Hiroaki
1991-10-01
The variable soft sphere (VSS) molecular model is introduced for both the viscosity and diffusion cross sections (coefficients) to be consistent with those of the inverse-power-law (IPL) or Lennard-Jones (LJ) potential. The VSS model has almost the same analytical and computational simplicity (computation time) as the variable hard sphere (VHS) model in the Monte Carlo simulation of rarefied gas flows. The null-collision Monte Carlo method is used to make comparative calculations for the molecular diffusion in a heat-bath gas and the normal shock wave structure in a simple gas. For the most severe test of the VSS model for the IPL potential, the softest practical model corresponding to the Maxwell molecule is chosen. The agreement in the molecular diffusion and shock wave structure between the VSS model and the IPL or LJ potential is remarkably good.
Accurate freezing and melting equations for the Lennard-Jones system.
Khrapak, Sergey A; Morfill, Gregor E
2011-03-07
Analyzing three approximate methods to locate liquid-solid coexistence in simple systems, an observation is made that all of them predict the same functional dependence of the temperature on density at freezing and melting of the conventional Lennard-Jones (LJ) system. The emerging equations can be written as T=Aρ(4)+Bρ(2) in normalized units. We suggest to determine the values of the coefficients A at freezing and melting from the high-temperature limit, governed by the inverse 12th power repulsive potential. The coefficients B can be determined from the triple point parameters of the LJ fluid. This produces freezing and melting equations which are exact in the high-temperature limit and at the triple point and show remarkably good agreement with numerical simulation data in the intermediate region.
New approach to the first-order phase transition of Lennard-Jones fluids.
Muguruma, Chizuru; Okamoto, Yuko; Mikami, Masuhiro
2004-04-22
The multicanonical Monte Carlo method is applied to a bulk Lennard-Jones fluid system to investigate the liquid-solid phase transition. We take the example of a system of 108 argon particles. The multicanonical weight factor we determined turned out to be reliable for the energy range between -7.0 and -4.0 kJ/mol, which corresponds to the temperature range between 60 and 250 K. The expectation values of the thermodynamic quantities obtained from the multicanonical production run by the reweighting techniques exhibit the characteristics of first-order phase transitions between liquid and solid states around 150 K. The present study reveals that the multicanonical algorithm is particularly suitable for analyzing the transition state of the first-order phase transition in detail.
Nucleation rates of Lennard-Jones clusters from growth and decay simulations
NASA Astrophysics Data System (ADS)
Vehkamäki, Hanna; Ford, Ian J.
2000-08-01
We have studied singles clusters of Lennard-Jones atoms using a novel Monte Carlo simulation technique. We computed canonical ensemble averages of the grand canonical growth and decay probabilities of the cluster as a function of the cluster size. The critical size is identified as the one for which growth and decay are equally probable. The size and average internal energy the critical cluster was found for different temperatures and vapor chemical potentials. We used this information together with nucleation theorems to predict the behavior of the nucleation rate as function of the two external parameters. Our results are in line with the results found in the literature, and roughly correspond to the predictions of classical theory.
Jones matrix analysis of dichroic phase retarders realized in soft matter composite materials.
Caputo, Roberto; Trebisacce, Ivan; De Sio, Luciano; Umeton, Cesare
2010-03-15
Materials showing birefringence and polarization selective absorption (dichroism) affect the polarization state of incoming light in a peculiar way, quite different from the one exhibited by phase retarders like waveplates. In this paper, we report on the characterization of a Polymer LIquid CRYstal Polymer Slices (POLICRYPS) diffraction grating used as a dichroic phase retarder; the dichroic behaviour of the grating is due to the polarization-dependent diffraction efficiency. Experimental data are validated with a theoretical model based on the Jones matrix formalism, while the grating behavior is modeled by means of the dichroic matrix. In this way, the birefringence of the analyzed structure is easily obtained. For comparison purposes, also two systems different from POLICRYPS have been fabricated and tested.
John Paul Jones: An Overlooked Autopsy Finding that May Explain His Terminal Illness.
Hamrell, Burt B
2016-03-01
A finding in the autopsy of John Paul Jones, the American Revolutionary War naval hero, may explain his terminal illness. During his last 2 years, he had a persistent productive cough and dyspnea. Ten days before death, he developed rapidly progressive dependent edema and ascites. He died in France in 1792. His body, preserved in alcohol in a lead coffin, was, in 1905, removed to the United States. Glomerulonephritis was noted on an autopsy, performed in France, but there was no comment then or since about ventricular wall thickness being the same in both ventricles at 5-6 mm. Hypertrophy and dilatation with biventricular failure followed by tissue shrinkage during 113 years in alcohol could have resulted in these ventricular wall findings. Systemic hypertension and left ventricular failure are consistent with his respiratory symptoms complicated perhaps by pulmonary emboli, right ventricular failure with tricuspid regurgitation, peripheral congestion, and jaundice.
Evaluation of higher order PMD effects using Jones matrix analytical models: a comparative study
NASA Astrophysics Data System (ADS)
Ferreira, M. F.
2006-04-01
A comparative study among the Jones matrix analytical models with high-order PMD is presented. The models that make use of an exponential expansion arrested up to second order or consider the dispersion vector as a Taylor series expansion do not give good results in the approximation of high-order PMD effects, because of the nonlimited behavior with respect to frequency of the modulus of their dispersion vectors. On the other hand, the analytical model which describes the dispersion vector as rotating on a circumference in the Stokes space is found to be the most accurate. Moreover, it can be used to obtain an analytical expression of the pulse broadening, which is often chosen as a quality-system parameter.
Droplet growth during vapor-liquid transition in a 2D Lennard-Jones fluid
NASA Astrophysics Data System (ADS)
Midya, Jiarul; Das, Subir K.
2017-01-01
Results for the kinetics of vapor-liquid phase transition have been presented from the molecular dynamics simulations of a single component two-dimensional Lennard-Jones fluid. The phase diagram for the model, primary prerequisite for this purpose, has been obtained via the Monte Carlo simulations. Our focus is on the region very close to the vapor branch of the coexistence curve. Quenches to such region provide morphology that consists of disconnected circular clusters in the vapor background. We identified that these clusters exhibit diffusive motion and grow via sticky collisions among them. The growth follows power-law behavior with time, exponent of which is found to be in nice agreement with a theoretical prediction.
Relativistic kinematics formulation of the polarization effects of Jones-Mueller matrices.
Franssens, Ghislain R
2015-02-01
The polarization of a partially coherent, transverse electric, electromagnetic plane wave is commonly represented by a Stokes vector. The similarity between Stokes vectors and four-momentum vectors in special relativity (SR) is studied in depth. The set of Stokes vectors naturally possesses a Euclidean and a Lorentzian geometry. The latter is used to express the polarization-altering properties of Jones-Mueller matrices in a simple and elegant way. In particular, it is shown that the action of a diattenuator on a Stokes vector can be understood in terms of the addition law for velocities from SR. An important simplification in the resulting mathematical expressions further arises if the degree of polarization of a Stokes vector is represented by a hyperbolic polarization angle. This then allows us to demonstrate that the output hyperbolic polarization angle is related to a diattenuator hyperbolic polarization angle and the input hyperbolic polarization angle by the hyperbolic law of cosines holding in a hyperbolic triangle.
Lyon, K F
1994-03-01
Lymphoplasmacytic stomatitis and gingivitis was diagnosed in an 8-year old female domestic shorthair. The cat had evidence of severe generalized inflammation of the oral cavity. Biopsy samples were evaluated and displayed a lichenoid, interface stomatitis which was predominantly lymphoplasmacytic. Serum protein electrophoresis confirmed a monoclonal gammopathy. Urine protein electrophoresis confirmed Bence-Jones proteinuria. Protein electrophoresis was used to diagnose monoclonal gammopathy (the production of a monoclonal immunoglobulin, or paraprotein, which is associated with a characteristic "M" protein spike on serum electrophoresis). Diseases associated with monoclonal gammopathy are similar in the dog and cat. Alkylating agent chemotherapy is used to rapidly reduce paraprotein concentrations in multiple myeloma. Multiple myeloma is the most common disorder associated with monoclonal gammopathy. This condition is less common in the cat, compared to the dog. This report examines the diagnosis and treatment of multiple myeloma in a cat presenting with severe stomatitis.
John Jones, M.D.: pioneer, patriot, and founder of American surgery.
Griesemer, Adam D; Widmann, Warren D; Forde, Kenneth A; Hardy, Mark A
2010-04-01
John Jones was a pioneer of American Surgery. Born in Long Island, New York in 1729, he received his medical degree in France from the University of Rheims. He returned to the colonies and helped to establish the medical school that would later become Columbia University's College of Physicians and Surgeons where he was appointed the first Professor of Surgery in the New World. He used his position to assert that surgeons trained in America should be familiar with all facets of medicine and not be mere technicians. Before the outbreak of the American Revolution, he wrote a surgical field manual, which was the first medical text published in America. A believer in the principles of the American Revolution, he would go on to count Benjamin Franklin and George Washington as his patients. Despite achieving many firsts in American medicine, his influence on surgical training is his most enduring legacy.
Clustering of Lennard-Jones particles in water: temperature and pressure effects.
Ferrara, Gastón; McCarthy, Andrés N; Grigera, J Raúl
2007-09-14
While the hydrophobic effect is, for many systems, one of the most relevant interactions, it may be said that in the case of biological systems this effect becomes of determinant importance. Although the matter has been analyzed extensively, certain aspects are yet to be elucidated. Hence, the study on the behavior of the hydrophobic effect with temperature, and particularly with pressure deserves further investigation; model systems may help us in the task. We have analyzed the behavior of Lennard-Jones particles in water by means of molecular dynamics simulation under different conditions of size, concentration, temperature, and pressure. Following the formation of particle aggregates we can observe an increase of the hydrophobic effect with temperature and a strong weakening of the effect at high pressures. The results agree with the experimental evidence and show the ability of molecular dynamics simulation to account for the behavior of nonpolar substances under different conditions, provided that the intermolecular interactions used are adequate.
Phase Transitions For Dilute Particle Systems with Lennard-Jones Potential
NASA Astrophysics Data System (ADS)
Collevecchio, Andrea; König, Wolfgang; Mörters, Peter; Sidorova, Nadia
2010-11-01
We consider a classical dilute particle system in a large box with pair-interaction given by a Lennard-Jones-type potential. The inverse temperature is picked proportionally to the logarithm of the particle density. We identify the free energy per particle in terms of a variational formula and show that this formula exhibits a cascade of phase transitions as the temperature parameter ranges from zero to infinity. Loosely speaking, the particle system separates into spatially distant components in such a way that within each phase all components are of the same size, which is the larger the lower the temperature. The main tool in our proof is a new large deviation principle for sparse point configurations.
Properties of the Lennard-Jones dimeric fluid in two dimensions: An integral equation study
Urbic, Tomaz; Dias, Cristiano L.
2014-03-07
The thermodynamic and structural properties of the planar soft-sites dumbbell fluid are examined by Monte Carlo simulations and integral equation theory. The dimers are built of two Lennard-Jones segments. Site-site integral equation theory in two dimensions is used to calculate the site-site radial distribution functions for a range of elongations and densities and the results are compared with Monte Carlo simulations. The critical parameters for selected types of dimers were also estimated. We analyze the influence of the bond length on critical point as well as tested correctness of site-site integral equation theory with different closures. The integral equations can be used to predict the phase diagram of dimers whose molecular parameters are known.
Dynamics of vacancies in two-dimensional Lennard-Jones crystals
NASA Astrophysics Data System (ADS)
Yao, Zhenwei; Olvera de La Cruz, Monica
2015-03-01
Vacancies represent an important class of crystallographic defects, and their behaviors can be strongly coupled with relevant material properties. We report the rich dynamics of vacancies in two-dimensional Lennard-Jones crystals in several thermodynamic states. Specifically, we numerically observe significantly faster diffusion of the 2-point vacancy with two missing particles in comparison with other types of vacancies; it opens the possibility of doping 2-point vacancies into atomic materials to enhance atomic migration. In addition, the resulting dislocations in the healing of a long vacancy suggest the intimate connection between vacancies and topological defects that may provide an extra dimension in the engineering of defects in extensive crystalline materials for desired properties. We thank the financial support from the U.S. Department of Commerce, National Institute of Standards and Technology, the Office of the Director of Defense Research and Engineering (DDR&E) and the Air Force Office of Scientific Research.
Taghizadeh, Ameneh; Keshavarzi, Ezat Tahmineh
2011-04-07
The aim of this work is to investigate the population inversion of binary asymmetric Lennard-Jones mixtures inside nanoslit pores due to confinement effects for both vapor and liquid phases. For this purpose we have used mean field fundamental measure theory, and the effect of different parameters such as interaction strength and size ratios of the components, confinement size, and thermodynamic state on the population distribution of molecules have been studied. It has been shown that in the case of bulk liquid mixtures, increasing the role of confinement effects can lead to preferential adsorption of the component with larger size and weaker intermolecular interactions into the nanopore in spite of its minority in the bulk which is referred as population inversion. This population inversion phenomenon is terminated by a sudden condensation which, interestingly, involves a simultaneous adsorption and desorption for more and less bulk concentrated species, respectively. We have demonstrated that this condensation phenomenon shifts to higher bulk densities with increasing the role of confinement effects such that in some cases population inversion is observable for the whole range of densities. In consideration of the conditions in which vapor Lennard-Jones mixtures undergo capillary condensation, the population distribution of components in the vapor- and liquidlike phases was studied. It has been shown that variation of parameters such as interaction strength and size ratios, temperature, and confinement size can lead to conditions in which capillary condensation is accompanying with a population inversion phenomenon. In these cases, whereas the composition of vaporlike phases is the same as bulk fluid, liquidlike phases are richer in the component with less bulk concentration.
Mairhofer, Jonas; Sadus, Richard J
2013-10-21
Molecular dynamics simulations are reported for the thermodynamic properties of n-m Lennard-Jones fluids, where n = 10 and 12, and m = 5 and 6. Results are reported for the thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient, and speed of sound at supercritical conditions covering a wide range of fluid densities. The thermodynamic criteria for maxima∕minima in the isochoric and isobaric heat capacities are identified and the simulation results are also compared with calculations from Lennard-Jones equations of state. The Johnson et al. [Mol. Phys. 78, 591 (1993)] equation of state can be used to reproduce all heat capacity phenomena reported [T. M. Yigzawe and R. J. Sadus, J. Chem. Phys. 138, 194502 (2013)] from molecular dynamics simulations for the 12-6 Lennard-Jones potential. Significantly, these calculations and molecular dynamics results for other n-m Lennard-Jones potentials support the existence of Cp minima at supercritical conditions. The values of n and m also have a significant influence on many other thermodynamic properties.
ERIC Educational Resources Information Center
Tomarken, Andrew J.; Zald, David H.
2009-01-01
C. S. Carver and E. Harmon-Jones have made an important contribution to the understanding of anger, its linkage to higher order dimensions of emotion, and potential neurobiological substrates. The authors believe, however, that their model and future research conducted to test it would be improved by a more precise explication and parsing of the…
ERIC Educational Resources Information Center
Smith, Valinda C.
This final performance report for the Elizabeth Jones Library literacy project begins with a section that provides quantitative data. The next section compares actual accomplishments to the following project goals and related objectives for fiscal year 1992: (1) to provide a versatile workplace literacy program useful to any business in the…
ERIC Educational Resources Information Center
Connell, Mary
2012-01-01
Cross, Fine, Jones, and Walsh (2012) provided a thoughtful review and critique of a book chapter describing the interview process at Child Advocacy Centers. They observed some of the ways that concerns raised in that chapter are being addressed and described revised guidelines that further clarify issues. Ongoing research and examination of the…
of state . Calcu lations are made of various pressures of equilibrium products from detonation of RDX. (Author)...priori estimate of the system parameters. It is an extension of the work on the three-shell modification of the Lennard Jones - Devonshire equation
NASA Astrophysics Data System (ADS)
Mairhofer, Jonas; Sadus, Richard J.
2013-10-01
Molecular dynamics simulations are reported for the thermodynamic properties of n-m Lennard-Jones fluids, where n = 10 and 12, and m = 5 and 6. Results are reported for the thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient, and speed of sound at supercritical conditions covering a wide range of fluid densities. The thermodynamic criteria for maxima/minima in the isochoric and isobaric heat capacities are identified and the simulation results are also compared with calculations from Lennard-Jones equations of state. The Johnson et al. [Mol. Phys. 78, 591 (1993)] equation of state can be used to reproduce all heat capacity phenomena reported [T. M. Yigzawe and R. J. Sadus, J. Chem. Phys. 138, 194502 (2013)] from molecular dynamics simulations for the 12-6 Lennard-Jones potential. Significantly, these calculations and molecular dynamics results for other n-m Lennard-Jones potentials support the existence of Cp minima at supercritical conditions. The values of n and m also have a significant influence on many other thermodynamic properties.
ERIC Educational Resources Information Center
Friedman, Ronald S.; Forster, Jens
2011-01-01
In an integrative review, we concluded that implicit affective cues--rudimentary stimuli associated with the onset of arousing positive or negative emotional states and/or with appraisals that the environment is benign or threatening--automatically moderate the scope of attention (Friedman & Forster, 2010). In their comment, Harmon-Jones, Gable,…
NASA Astrophysics Data System (ADS)
Asano, Yuta; Fuchizaki, Kazuhiro
2017-02-01
The melting curve of the modified Lennard-Jones system, which has been obtained by equating the free energies between the solid and liquid phases, was reinvestigated using the nonequilibrium relaxation method. The latter method satisfactorily reproduced the previous result with much simplified procedures.
Excess entropy and crystallization in Stillinger-Weber and Lennard-Jones fluids.
Dhabal, Debdas; Nguyen, Andrew Huy; Singh, Murari; Khatua, Prabir; Molinero, Valeria; Bandyopadhyay, Sanjoy; Chakravarty, Charusita
2015-10-28
Molecular dynamics simulations are used to contrast the supercooling and crystallization behaviour of monatomic liquids that exemplify the transition from simple to anomalous, tetrahedral liquids. As examples of simple fluids, we use the Lennard-Jones (LJ) liquid and a pair-dominated Stillinger-Weber liquid (SW16). As examples of tetrahedral, water-like fluids, we use the Stillinger-Weber model with variable tetrahedrality parameterized for germanium (SW20), silicon (SW21), and water (SW(23.15) or mW model). The thermodynamic response functions show clear qualitative differences between simple and water-like liquids. For simple liquids, the compressibility and the heat capacity remain small on isobaric cooling. The tetrahedral liquids in contrast show a very sharp rise in these two response functions as the lower limit of liquid-phase stability is reached. While the thermal expansivity decreases with temperature but never crosses zero in simple liquids, in all three tetrahedral liquids at the studied pressure, there is a temperature of maximum density below which thermal expansivity is negative. In contrast to the thermodynamic response functions, the excess entropy on isobaric cooling does not show qualitatively different features for simple and water-like liquids; however, the slope and curvature of the entropy-temperature plots reflect the heat capacity trends. Two trajectory-based computational estimation methods for the entropy and the heat capacity are compared for possible structural insights into supercooling, with the entropy obtained from thermodynamic integration. The two-phase thermodynamic estimator for the excess entropy proves to be fairly accurate in comparison to the excess entropy values obtained by thermodynamic integration, for all five Lennard-Jones and Stillinger-Weber liquids. The entropy estimator based on the multiparticle correlation expansion that accounts for both pair and triplet correlations, denoted by S(trip), is also studied. S
Epibenthic assemblages in the Celtic Sea and associated with the Jones Bank
NASA Astrophysics Data System (ADS)
Ellis, J. R.; Martinez, I.; Burt, G. J.; Scott, B. E.
2013-10-01
The epibenthic assemblages in the Celtic Sea are described from the catches from 2 m beam trawl surveys undertaken from 2000 to 2009. During this period 154 samples were collected. The most ubiquitous species in the study area were the natantid shrimps Processa spp. and Crangon allmanni, the hermit crabs Pagurus prideaux and Anapagurus laevis, sand star Astropecten irregularis and spotted dragonet Callionymus maculatus. Multivariate community analyses indicated that catches (numbers per tow) were distributed across six assemblages, two of which were predominant in the study area. Most catches were attributed to either a 'shelf edge assemblage', which was widespread in deeper waters (114-423 m water depth) or an 'outer shelf assemblage' that occurred across much of the Celtic Sea north of 49°N in waters 49-175 m deep. The dominant species along the edge of the continental shelf were the hormathid anemome Actinauge richardi, sea spider Pycnogonum littorale (which associated with A. richardi), Devonshire cup coral Caryophyllia smithii and the swimming crab Macropipus tuberculatus. The dominant species in the outer shelf assemblage included P. prideaux, C. allmanni, A. laevis and common starfish Asterias rubens. Stations closer to shore were relatively distinct and catches in this 'inner shelf assemblage' were composed primarily of an inshore fauna (e.g. Ophiura ophiura, C. allmanni and Liocarcinus holsatus). Stations in the southern part of the survey grid were also relatively distinct ('southern Celtic Sea assemblage'), and several large echinoderms (Porania pulvillus, Stichastrella rosea and Anseropoda placenta) dominated at these sites. Three of the deepest stations were also relatively distinct, as were a group of stations in the muddy habitat of the Celtic Deep and comparable grounds elsewhere in the region, where Nucula sulcata and Alpheus glaber were characteristic. Catches on the shallower parts of the Jones Bank (and on another bank in the region) were
Excess entropy and crystallization in Stillinger-Weber and Lennard-Jones fluids
NASA Astrophysics Data System (ADS)
Dhabal, Debdas; Nguyen, Andrew Huy; Singh, Murari; Khatua, Prabir; Molinero, Valeria; Bandyopadhyay, Sanjoy; Chakravarty, Charusita
2015-10-01
Molecular dynamics simulations are used to contrast the supercooling and crystallization behaviour of monatomic liquids that exemplify the transition from simple to anomalous, tetrahedral liquids. As examples of simple fluids, we use the Lennard-Jones (LJ) liquid and a pair-dominated Stillinger-Weber liquid (SW16). As examples of tetrahedral, water-like fluids, we use the Stillinger-Weber model with variable tetrahedrality parameterized for germanium (SW20), silicon (SW21), and water (SW23.15 or mW model). The thermodynamic response functions show clear qualitative differences between simple and water-like liquids. For simple liquids, the compressibility and the heat capacity remain small on isobaric cooling. The tetrahedral liquids in contrast show a very sharp rise in these two response functions as the lower limit of liquid-phase stability is reached. While the thermal expansivity decreases with temperature but never crosses zero in simple liquids, in all three tetrahedral liquids at the studied pressure, there is a temperature of maximum density below which thermal expansivity is negative. In contrast to the thermodynamic response functions, the excess entropy on isobaric cooling does not show qualitatively different features for simple and water-like liquids; however, the slope and curvature of the entropy-temperature plots reflect the heat capacity trends. Two trajectory-based computational estimation methods for the entropy and the heat capacity are compared for possible structural insights into supercooling, with the entropy obtained from thermodynamic integration. The two-phase thermodynamic estimator for the excess entropy proves to be fairly accurate in comparison to the excess entropy values obtained by thermodynamic integration, for all five Lennard-Jones and Stillinger-Weber liquids. The entropy estimator based on the multiparticle correlation expansion that accounts for both pair and triplet correlations, denoted by Strip, is also studied. Strip is a
Excess entropy and crystallization in Stillinger-Weber and Lennard-Jones fluids
Dhabal, Debdas; Chakravarty, Charusita; Nguyen, Andrew Huy; Molinero, Valeria; Singh, Murari; Khatua, Prabir; Bandyopadhyay, Sanjoy
2015-10-28
Molecular dynamics simulations are used to contrast the supercooling and crystallization behaviour of monatomic liquids that exemplify the transition from simple to anomalous, tetrahedral liquids. As examples of simple fluids, we use the Lennard-Jones (LJ) liquid and a pair-dominated Stillinger-Weber liquid (SW{sub 16}). As examples of tetrahedral, water-like fluids, we use the Stillinger-Weber model with variable tetrahedrality parameterized for germanium (SW{sub 20}), silicon (SW{sub 21}), and water (SW{sub 23.15} or mW model). The thermodynamic response functions show clear qualitative differences between simple and water-like liquids. For simple liquids, the compressibility and the heat capacity remain small on isobaric cooling. The tetrahedral liquids in contrast show a very sharp rise in these two response functions as the lower limit of liquid-phase stability is reached. While the thermal expansivity decreases with temperature but never crosses zero in simple liquids, in all three tetrahedral liquids at the studied pressure, there is a temperature of maximum density below which thermal expansivity is negative. In contrast to the thermodynamic response functions, the excess entropy on isobaric cooling does not show qualitatively different features for simple and water-like liquids; however, the slope and curvature of the entropy-temperature plots reflect the heat capacity trends. Two trajectory-based computational estimation methods for the entropy and the heat capacity are compared for possible structural insights into supercooling, with the entropy obtained from thermodynamic integration. The two-phase thermodynamic estimator for the excess entropy proves to be fairly accurate in comparison to the excess entropy values obtained by thermodynamic integration, for all five Lennard-Jones and Stillinger-Weber liquids. The entropy estimator based on the multiparticle correlation expansion that accounts for both pair and triplet correlations, denoted by S{sub trip
Calero, C.; Knorowski, C.; Travesset, A.
2016-03-22
We investigate a general method to calculate the free energy of crystalline solids by considering the harmonic approximation and quasistatically switching the anharmonic contribution. The advantage of this method is that the harmonic approximation provides an already very accurate estimate of the free energy, and therefore the anharmonic term is numerically very small and can be determined to high accuracy. We further show that the anharmonic contribution to the free energy satisfies a number of exact inequalities that place constraints on its magnitude and allows approximate but fast and accurate estimates. The method is implemented into a readily available general software by combining the code HOODLT (Highly Optimized Object Oriented Dynamic Lattice Theory) for the harmonic part and the molecular dynamics (MD) simulation package HOOMD-blue for the anharmonic part. We use the method to calculate the low temperature phase diagram for Lennard-Jones particles. We demonstrate that hcp is the equilibrium phase at low temperature and pressure and obtain the coexistence curve with the fcc phase, which exhibits reentrant behavior. Furthermore, several implications of the method are discussed.
Nucleation of liquid droplets and voids in a stretched Lennard-Jones fcc crystal.
Baidakov, Vladimir G; Tipeev, Azat O
2015-09-28
The method of molecular dynamics simulation has been used to investigate the phase decay of a metastable Lennard-Jones face-centered cubic crystal at positive and negative pressures. It is shown that at high degrees of metastability, crystal decay proceeds through the spontaneous formation and growth of new-phase nuclei. It has been found that there exists a certain boundary temperature. Below this temperature, the crystal phase disintegrates as the result of formation of voids, and above, as a result of formation of liquid droplets. The boundary temperature corresponds to the temperature of cessation of a crystal-liquid phase equilibrium when the melting line comes in contact with the spinodal of the stretched liquid. The results of the simulations are interpreted in the framework of classical nucleation theory. The thermodynamics of phase transitions in solids has been examined with allowance for the elastic energy of stresses arising owing to the difference in the densities of the initial and the forming phases. As a result of the action of elastic forces, at negative pressures, the boundary of the limiting superheating (stretching) of a crystal approaches the spinodal, on which the isothermal bulk modulus of dilatation becomes equal to zero. At the boundary of the limiting superheating (stretching), the shape of liquid droplets and voids is close to the spherical one.
Calero, C; Knorowski, C; Travesset, A
2016-03-28
We investigate a general method to calculate the free energy of crystalline solids by considering the harmonic approximation and quasistatically switching the anharmonic contribution. The advantage of this method is that the harmonic approximation provides an already very accurate estimate of the free energy, and therefore the anharmonic term is numerically very small and can be determined to high accuracy. We further show that the anharmonic contribution to the free energy satisfies a number of exact inequalities that place constraints on its magnitude and allows approximate but fast and accurate estimates. The method is implemented into a readily available general software by combining the code HOODLT (Highly Optimized Object Oriented Dynamic Lattice Theory) for the harmonic part and the molecular dynamics (MD) simulation package HOOMD-blue for the anharmonic part. We use the method to calculate the low temperature phase diagram for Lennard-Jones particles. We demonstrate that hcp is the equilibrium phase at low temperature and pressure and obtain the coexistence curve with the fcc phase, which exhibits reentrant behavior. Several implications of the method are discussed.
Tolman length and rigidity constants of the Lennard-Jones fluid.
Wilhelmsen, Øivind; Bedeaux, Dick; Reguera, David
2015-02-14
It is well-known that the surface tension of small droplets and bubbles deviates significantly from that at the planar interface. In this work, we analyze the leading corrections in the curvature expansion of the surface tension, i.e., the Tolman length and the rigidity constants, using a "hybrid" square gradient theory, where the local Helmholtz energy density is described by an accurate equation of state. We particularize this analysis for the case of the truncated and shifted Lennard-Jones fluid, and are then able to reproduce the surface tensions and Tolman length from recent molecular dynamics simulations within their accuracy. The obtained constants in the curvature expansion depend little on temperature, except in the vicinity of the critical point. When the bubble/droplet radius becomes comparable to the interfacial width at coexistence, the critical bubble/droplet prefers to change its density, rather than to decrease its size, and the curvature expansion is no longer sufficient to describe the change in surface tension. We find that the radius of the bubble/droplet in this region is proportional to the correlation length between fluctuations in the liquid-phase.
Freezing and melting line invariants of the Lennard-Jones system.
Costigliola, Lorenzo; Schrøder, Thomas B; Dyre, Jeppe C
2016-06-07
The invariance of several structural and dynamical properties of the Lennard-Jones (LJ) system along the freezing and melting lines is interpreted in terms of isomorph theory. First the freezing/melting lines of the LJ system are shown to be approximated by isomorphs. Then we show that the invariants observed along the freezing and melting isomorphs are also observed on other isomorphs in the liquid and crystalline phases. The structure is probed by the radial distribution function and the structure factor and dynamics are probed by the mean-square displacement, the intermediate scattering function, and the shear viscosity. Studying these properties with reference to isomorph theory explains why the known single-phase melting criteria hold, e.g., the Hansen-Verlet and the Lindemann criteria, and why the Andrade equation for the viscosity at freezing applies, e.g., for most liquid metals. Our conclusion is that these empirical rules and invariants can all be understood from isomorph theory and that the invariants are not peculiar to the freezing and melting lines, but hold along all isomorphs.
Surface tension of the two center Lennard-Jones plus point dipole fluid.
Werth, Stephan; Horsch, Martin; Hasse, Hans
2016-02-07
Molecular dynamics simulations are used for systematically studying the surface tension of the two center Lennard-Jones plus point dipole (2CLJD) model fluid. In a dimensionless representation, this model fluid has two parameters describing the elongation and the dipole moment. These parameters were varied in the entire range relevant for describing real fluids resulting in a grid of 38 individual models. For each model, the surface tension was determined at temperatures between 60% and 90% of the critical temperature. For completeness, the vapor pressure and the saturated densities were also determined. The latter results agree well with the literature data, whereas for the surface tension, only few data were previously available. From the present results, an empirical correlation for the surface tension of the 2CLJD model as a function of the model parameters is developed. The correlation is used to predict the surface tension of 46 2CLJD molecular models from the literature, which were adjusted to bulk properties, but not to interfacial properties. The results are compared to the experimental data. The molecular models overestimate the surface tension, and deviations between the predictions and experimental data are below 12% on average.
Effect of confinement on the solid-liquid coexistence of Lennard-Jones fluid.
Das, Chandan K; Singh, Jayant K
2013-11-07
The solid-liquid coexistence of a Lennard-Jones fluid confined in slit pores of variable pore size, H, is studied using molecular dynamics simulations. Three-stage pseudo-supercritical transformation path of Grochola [J. Chem. Phys. 120(5), 2122 (2004)] and multiple histogram reweighting are employed for the confined system, for various pore sizes ranging from 20 to 5 molecular diameters, to compute the solid-liquid coexistence. The Gibbs free energy difference is evaluated using thermodynamic integration method by connecting solid-liquid phases under confinement via one or more intermediate states without any first order phase transition among them. Thermodynamic melting temperature is found to oscillate with wall separation, which is in agreement with the behavior seen for kinetic melting temperature evaluated in an earlier study. However, thermodynamic melting temperature for almost all wall separations is higher than the bulk case, which is contrary to the behavior seen for the kinetic melting temperature. The oscillation founds to decay at around H = 12, and beyond that pore size dependency of the shift in melting point is well represented by the Gibbs-Thompson equation.
Effect of Size Polydispersity on the Nature of Lennard-Jones Liquids.
Ingebrigtsen, Trond S; Tanaka, Hajime
2015-08-27
Polydisperse fluids are encountered everywhere in biological and industrial processes. These fluids naturally show a rich phenomenology exhibiting fractionation and shifts in critical point and freezing temperatures. We study here the effect of size polydispersity on the basic nature of Lennard-Jones (LJ) liquids, which represent most molecular liquids without hydrogen bonds, via two- and three-dimensional molecular dynamics computer simulations. A single-component liquid constituting spherical particles and interacting via the LJ potential is known to exhibit strong correlations between virial and potential energy equilibrium fluctuations at constant volume. This correlation significantly simplifies the physical description of the liquid, and these liquids are now known as Roskilde-simple (RS) liquids. We show that this simple nature of the single-component LJ liquid is preserved even for very high polydispersities (above 40% polydispersity for the studied uniform distribution). We also investigate isomorphs of moderately polydisperse LJ liquids. Isomorphs are curves in the phase diagram of RS liquids along which structure, dynamics, and some thermodynamic quantities are invariant in dimensionless units. We find that isomorphs are a good approximation even for polydisperse LJ liquids. The theory of isomorphs thus extends readily to size polydisperse fluids and can be used to improve even further the understanding of these intriguing systems.
Molecular dynamics study of nanobubbles in the equilibrium Lennard-Jones fluid.
Zhukhovitskii, D I
2013-10-28
We employ a model, in which the density fluctuations in a bulk liquid are represented as presence of the clusters of molecules with the lowered number of nearest neighbors (number of bonds). The nanobubble size distribution is calculated on the basis of a close analogy between the surface part of the work of formation for a cluster and for a nanobubble. The pre-exponential factor for this distribution is related to the fluid compressibility. Estimates made for different liquids show that it can be noticeably different from that adopted in the classical nucleation theory (CNT). Molecular dynamics (MD) simulation is performed for a liquid inside a macroscopic droplet of molecules interacting via the Lennard-Jones potential plus a long-range tail. The nanobubbles are identified by clusters of bond-deficient particles with the optimum number of bonds that provide the maximum nanobubble number density and maximum resolvable nanobubble equimolar size. The results of MD simulation are in qualitatively better agreement with proposed theory than with CNT.
Effect of Energy Polydispersity on the Nature of Lennard-Jones Liquids.
Ingebrigtsen, Trond S; Tanaka, Hajime
2016-08-11
In the companion paper [ Ingebrigtsen , T. S. ; Tanaka , H. J. Phys. Chem. B 2015 , 119 , 11052 ] the effect of size polydispersity on the nature of Lennard-Jones (LJ) liquids, which represent most molecular liquids without hydrogen bonds, was studied. More specifically, it was shown that even highly size polydisperse LJ liquids are Roskilde-simple (RS) liquids. RS liquids are liquids with strong correlation between constant volume equilibrium fluctuations of virial and potential energy and are simpler than other types of liquids. Moreover, it was shown that size polydisperse LJ liquids have isomorphs to a good approximation. Isomorphs are curves in the phase diagram of RS liquids along which structure, dynamics, and some thermodynamic quantities are invariant in dimensionless (reduced) units. In this paper, we study the effect of energy polydispersity on the nature of LJ liquids. We show that energy polydisperse LJ liquids are RS liquids. However, a tendency of particle segregation, which increases with the degree of polydispersity, leads to a loss of strong virial-potential energy correlation but is mitigated by increasing temperature and/or density. Isomorphs are a good approximation also for energy polydisperse LJ liquids, although particle-resolved quantities display a somewhat poorer scaling compared to the mean quantities along the isomorph.
Benjamin, Ronald; Horbach, Jürgen
2013-08-28
Different computational techniques in combination with molecular dynamics computer simulation are used to determine the wall-liquid and the wall-crystal interfacial free energies of a modified Lennard-Jones (LJ) system in contact with a solid wall. Two different kinds of solid walls are considered: a flat structureless wall and a structured wall consisting of an ideal crystal with the particles rigidly attached to fcc lattice sites. Interfacial free energies are determined by a thermodynamic integration scheme, the anisotropy of the pressure tensor, the non-equilibrium work method based on Bennett acceptance criteria, and a method using Cahn's adsorption equations based on the interfacial thermodynamics of Gibbs. For the flat wall, interfacial free energies as a function of different densities of the LJ liquid and as a function of temperature along the coexistence curve are calculated. In the case of a structured wall, the interaction strength between the wall and the LJ system and the lattice constant of the structured wall are varied. Using the values of the wall-liquid and wall-crystal interfacial energies along with the value for the crystal-liquid interfacial free energy determined previously for the same system by the "cleaving potential method," we obtain the contact angle as a function of various parameters; in particular, the conditions are found under which partial wetting occurs.
Effect of confinement on the solid-liquid coexistence of Lennard-Jones Fluid
Das, Chandan K.; Singh, Jayant K.
2013-11-07
The solid-liquid coexistence of a Lennard-Jones fluid confined in slit pores of variable pore size, H, is studied using molecular dynamics simulations. Three-stage pseudo-supercritical transformation path of Grochola [J. Chem. Phys. 120(5), 2122 (2004)] and multiple histogram reweighting are employed for the confined system, for various pore sizes ranging from 20 to 5 molecular diameters, to compute the solid-liquid coexistence. The Gibbs free energy difference is evaluated using thermodynamic integration method by connecting solid-liquid phases under confinement via one or more intermediate states without any first order phase transition among them. Thermodynamic melting temperature is found to oscillate with wall separation, which is in agreement with the behavior seen for kinetic melting temperature evaluated in an earlier study. However, thermodynamic melting temperature for almost all wall separations is higher than the bulk case, which is contrary to the behavior seen for the kinetic melting temperature. The oscillation founds to decay at around H = 12, and beyond that pore size dependency of the shift in melting point is well represented by the Gibbs-Thompson equation.
A Hybrid Vehicle Detection Method Based on Viola-Jones and HOG + SVM from UAV Images.
Xu, Yongzheng; Yu, Guizhen; Wang, Yunpeng; Wu, Xinkai; Ma, Yalong
2016-08-19
A new hybrid vehicle detection scheme which integrates the Viola-Jones (V-J) and linear SVM classifier with HOG feature (HOG + SVM) methods is proposed for vehicle detection from low-altitude unmanned aerial vehicle (UAV) images. As both V-J and HOG + SVM are sensitive to on-road vehicles' in-plane rotation, the proposed scheme first adopts a roadway orientation adjustment method, which rotates each UAV image to align the roads with the horizontal direction so the original V-J or HOG + SVM method can be directly applied to achieve fast detection and high accuracy. To address the issue of descending detection speed for V-J and HOG + SVM, the proposed scheme further develops an adaptive switching strategy which sophistically integrates V-J and HOG + SVM methods based on their different descending trends of detection speed to improve detection efficiency. A comprehensive evaluation shows that the switching strategy, combined with the road orientation adjustment method, can significantly improve the efficiency and effectiveness of the vehicle detection from UAV images. The results also show that the proposed vehicle detection method is competitive compared with other existing vehicle detection methods. Furthermore, since the proposed vehicle detection method can be performed on videos captured from moving UAV platforms without the need of image registration or additional road database, it has great potentials of field applications. Future research will be focusing on expanding the current method for detecting other transportation modes such as buses, trucks, motors, bicycles, and pedestrians.
A Hybrid Vehicle Detection Method Based on Viola-Jones and HOG + SVM from UAV Images
Xu, Yongzheng; Yu, Guizhen; Wang, Yunpeng; Wu, Xinkai; Ma, Yalong
2016-01-01
A new hybrid vehicle detection scheme which integrates the Viola-Jones (V-J) and linear SVM classifier with HOG feature (HOG + SVM) methods is proposed for vehicle detection from low-altitude unmanned aerial vehicle (UAV) images. As both V-J and HOG + SVM are sensitive to on-road vehicles’ in-plane rotation, the proposed scheme first adopts a roadway orientation adjustment method, which rotates each UAV image to align the roads with the horizontal direction so the original V-J or HOG + SVM method can be directly applied to achieve fast detection and high accuracy. To address the issue of descending detection speed for V-J and HOG + SVM, the proposed scheme further develops an adaptive switching strategy which sophistically integrates V-J and HOG + SVM methods based on their different descending trends of detection speed to improve detection efficiency. A comprehensive evaluation shows that the switching strategy, combined with the road orientation adjustment method, can significantly improve the efficiency and effectiveness of the vehicle detection from UAV images. The results also show that the proposed vehicle detection method is competitive compared with other existing vehicle detection methods. Furthermore, since the proposed vehicle detection method can be performed on videos captured from moving UAV platforms without the need of image registration or additional road database, it has great potentials of field applications. Future research will be focusing on expanding the current method for detecting other transportation modes such as buses, trucks, motors, bicycles, and pedestrians. PMID:27548179
Pressure Profile for an Associating Lennard-Jones Fluid Confined in a Spherical Cavity.
Wang, Li-Yuan; Gu, Fang; Wang, Hai-Jun; Sun, Zong-Li
2017-03-09
We present the pressure tensor of an associating Lennard-Jones (LJ) fluid confined in a spherical cavity of hard wall, where a high-order density correlation has been taken into account. To give the two-body association potential for calculating the pressure tensor, an angle-average of site-site attraction over all orientations of two particles is performed. Furthermore, the classical density functional theory is employed to obtain the density profile of the confined fluid, by which the normal and tangential pressure profiles are illustrated under various conditions to show the dependence of the pressure tensor on the association strength, number of associating sites, radius of cavity, and bulk density. As an application, the corresponding surface tension is calculated. It is shown that under a strong association interaction (both association strength and the number of associating sites are large), the pressure profiles are depleted from the wall of the cavity instead of the oscillatory behavior under a weak association interaction. Such a tendency is mainly determined by the competition between association interaction and excluded volume interaction. Therefore, the aggregation state and related properties of an associating LJ fluid within a confinement of nanoscale can be efficiently regulated by the association interaction.
Selected hydrogeologic and water-quality data from Jones Beach Island, Long Island, New York
Scorca, M.P.; Reilly, T.E.; Franke, O.L.
1995-01-01
A data-collection site was instrumented on Jones Beach Island, a barrier island south of Long Island, N.Y., to study local freshwater/ saltwater relations in the shallow ground-water system. A geologic test boring revealed about 88 feet of well-sorted glacial outwash sand above about 15 feet of Gardiners Clay, which directly overlies silty sand of the Magothy Formation. Tidal effects on water levels in Great South Bay, the upper glacial aquifer, and the Magothy aquifer were observed and quantified with a tidal gage in the bay and analog water-level recorders in the wells.Chloride concentrations in the upper Magothy aquifer were higher than expected--about 270 mg/L (milligrams per liter), and those in the upper glacial aquifer were 17,000 to 19,000 mg/L, about the same as in Great South Bay. Estimates of pressure and freshwater equivalent heads indicate that, at the data-collection site, freshwater is discharging upward from the Magothy aquifer into the salty upper glacial aquifer, but dilution by this freshwater is undetectable. The reason for the elevated chloride concentration in the Magothy aquifer cannot be determined from available hydrogeologic information.
Nucleation of liquid droplets and voids in a stretched Lennard-Jones fcc crystal
Baidakov, Vladimir G. Tipeev, Azat O.
2015-09-28
The method of molecular dynamics simulation has been used to investigate the phase decay of a metastable Lennard-Jones face-centered cubic crystal at positive and negative pressures. It is shown that at high degrees of metastability, crystal decay proceeds through the spontaneous formation and growth of new-phase nuclei. It has been found that there exists a certain boundary temperature. Below this temperature, the crystal phase disintegrates as the result of formation of voids, and above, as a result of formation of liquid droplets. The boundary temperature corresponds to the temperature of cessation of a crystal–liquid phase equilibrium when the melting line comes in contact with the spinodal of the stretched liquid. The results of the simulations are interpreted in the framework of classical nucleation theory. The thermodynamics of phase transitions in solids has been examined with allowance for the elastic energy of stresses arising owing to the difference in the densities of the initial and the forming phases. As a result of the action of elastic forces, at negative pressures, the boundary of the limiting superheating (stretching) of a crystal approaches the spinodal, on which the isothermal bulk modulus of dilatation becomes equal to zero. At the boundary of the limiting superheating (stretching), the shape of liquid droplets and voids is close to the spherical one.
Polisetty, S; Scheffler, J; Sahoo, S; Wang, Yi; Mukherjee, T; He, Xi; Binek, Ch
2008-05-01
We present a comparative study on an experimental and theoretical optimization of magneto-optical Kerr setups based on photoelastic modulation and phase sensitive detector methodology. The first and second harmonics, I omega,2 omega, of the reflected light intensity are measured for a CoO/Co magnetic reference film. The magnetic field dependence of the optical off-diagonal Fresnel reflection coefficients rps and rsp follows the sample magnetization. Different Kerr setups provide various dependencies of I omega,2 omega on the reflection coefficients and, hence, on the Kerr ellipticity epsilon K and rotation theta K. Jones matrix formalism has been used to analyze the impact of a systematic variation of relative analyzer and polarizer orientations with respect to each other and with respect to the retardation axis of the modulator involved in longitudinal Kerr setups for incoming s-polarized light. We find one particular setup which maximizes I(omega) as well as I2 omega and maximizes the signal-to-noise ratio. Inefficient setups are characterized by I omega,2 omega intensities involving large nonmagnetic contributions of rp and rs.
A Jones matrix formalism for simulating three-dimensional polarized light imaging of brain tissue.
Menzel, M; Michielsen, K; De Raedt, H; Reckfort, J; Amunts, K; Axer, M
2015-10-06
The neuroimaging technique three-dimensional polarized light imaging (3D-PLI) provides a high-resolution reconstruction of nerve fibres in human post-mortem brains. The orientations of the fibres are derived from birefringence measurements of histological brain sections assuming that the nerve fibres—consisting of an axon and a surrounding myelin sheath—are uniaxial birefringent and that the measured optic axis is oriented in the direction of the nerve fibres (macroscopic model). Although experimental studies support this assumption, the molecular structure of the myelin sheath suggests that the birefringence of a nerve fibre can be described more precisely by multiple optic axes oriented radially around the fibre axis (microscopic model). In this paper, we compare the use of the macroscopic and the microscopic model for simulating 3D-PLI by means of the Jones matrix formalism. The simulations show that the macroscopic model ensures a reliable estimation of the fibre orientations as long as the polarimeter does not resolve structures smaller than the diameter of single fibres. In the case of fibre bundles, polarimeters with even higher resolutions can be used without losing reliability. When taking the myelin density into account, the derived fibre orientations are considerably improved.
Local structures in a computer-generated liquid. Two-dimensional Lennard-Jones liquid
NASA Astrophysics Data System (ADS)
Mitus, Antoni C.; Patashinskii, Alexander Z.; Sokolowski, Stefan
1991-06-01
We study the local structures in a 2D Lennard-Jones liquid of 2500 atoms near the melting line ( ϱ ∗ = 0.76 , T ∗ = 0.47 ) with the help of methods of mathematical statistics based on an earlier proposed probabilistic approach. We analyze the local structures in individual configurations and study the time evolution of patterns of matter which is close to the solid hexagonal structure. We conclude that the model liquid displays two types of local structure: hexagonal and “chaotic”. The first one corresponds to the fluctuations of the hexagon with root-mean-square fluctuations ξ of atoms equal to ξ = 0.14-0.16 while the second one can be represented by a strongly fluctuating (ξ = 0.25-0.30) “defect” pattern. We discuss the consequences of the physical picture of the liquid as a locally ordered two-structure system for the methodology of computer simulations and for theories of the 2D liquid phase.
Calero, C.; Knorowski, C.; Travesset, A.
2016-03-22
We investigate a general method to calculate the free energy of crystalline solids by considering the harmonic approximation and quasistatically switching the anharmonic contribution. The advantage of this method is that the harmonic approximation provides an already very accurate estimate of the free energy, and therefore the anharmonic term is numerically very small and can be determined to high accuracy. We further show that the anharmonic contribution to the free energy satisfies a number of exact inequalities that place constraints on its magnitude and allows approximate but fast and accurate estimates. The method is implemented into a readily available generalmore » software by combining the code HOODLT (Highly Optimized Object Oriented Dynamic Lattice Theory) for the harmonic part and the molecular dynamics (MD) simulation package HOOMD-blue for the anharmonic part. We use the method to calculate the low temperature phase diagram for Lennard-Jones particles. We demonstrate that hcp is the equilibrium phase at low temperature and pressure and obtain the coexistence curve with the fcc phase, which exhibits reentrant behavior. Furthermore, several implications of the method are discussed.« less
Single-site Lennard-Jones models via polynomial chaos surrogates of Monte Carlo molecular simulation
NASA Astrophysics Data System (ADS)
Kadoura, Ahmad; Siripatana, Adil; Sun, Shuyu; Knio, Omar; Hoteit, Ibrahim
2016-06-01
In this work, two Polynomial Chaos (PC) surrogates were generated to reproduce Monte Carlo (MC) molecular simulation results of the canonical (single-phase) and the NVT-Gibbs (two-phase) ensembles for a system of normalized structureless Lennard-Jones (LJ) particles. The main advantage of such surrogates, once generated, is the capability of accurately computing the needed thermodynamic quantities in a few seconds, thus efficiently replacing the computationally expensive MC molecular simulations. Benefiting from the tremendous computational time reduction, the PC surrogates were used to conduct large-scale optimization in order to propose single-site LJ models for several simple molecules. Experimental data, a set of supercritical isotherms, and part of the two-phase envelope, of several pure components were used for tuning the LJ parameters (ɛ, σ). Based on the conducted optimization, excellent fit was obtained for different noble gases (Ar, Kr, and Xe) and other small molecules (CH4, N2, and CO). On the other hand, due to the simplicity of the LJ model used, dramatic deviations between simulation and experimental data were observed, especially in the two-phase region, for more complex molecules such as CO2 and C2 H6.
Kadoura, Ahmad; Siripatana, Adil; Sun, Shuyu; Knio, Omar; Hoteit, Ibrahim
2016-06-07
In this work, two Polynomial Chaos (PC) surrogates were generated to reproduce Monte Carlo (MC) molecular simulation results of the canonical (single-phase) and the NVT-Gibbs (two-phase) ensembles for a system of normalized structureless Lennard-Jones (LJ) particles. The main advantage of such surrogates, once generated, is the capability of accurately computing the needed thermodynamic quantities in a few seconds, thus efficiently replacing the computationally expensive MC molecular simulations. Benefiting from the tremendous computational time reduction, the PC surrogates were used to conduct large-scale optimization in order to propose single-site LJ models for several simple molecules. Experimental data, a set of supercritical isotherms, and part of the two-phase envelope, of several pure components were used for tuning the LJ parameters (ε, σ). Based on the conducted optimization, excellent fit was obtained for different noble gases (Ar, Kr, and Xe) and other small molecules (CH4, N2, and CO). On the other hand, due to the simplicity of the LJ model used, dramatic deviations between simulation and experimental data were observed, especially in the two-phase region, for more complex molecules such as CO2 and C2 H6.
Weighted density-functional theory for simple fluids: Prewetting of a Lennard-Jones fluid
NASA Astrophysics Data System (ADS)
Sweatman, M. B.
2002-01-01
The prewetting of a Lennard-Jones fluid is studied using weighted density-functional theory. The intrinsic Helmholtz free-energy functional is separated into repulsive and attractive contributions. An accurate functional for hard spheres is used for the repulsive functional and a weighted density-functional method is used for the attractive part. The results for this theory are compared against mean-field density-functional theory, the theory of Velasco and Tarazona [E. Velasco and P. Tarazona, J. Chem. Phys. 91, 7916 (1989)] and grand canonical ensemble simulation results. The results demonstrate that the weighted density functional for attractive forces may offer a significant increase in accuracy over the other theories. The density-functional and simulation results also indicate that a previous estimate of the wetting temperature for a model of the interaction of argon with solid carbon dioxide, obtained from simulations [J. E. Finn and P. A. Monson, Phys. Rev. A, 39, 6402 (1989)], is incorrect. The weighted density-functional method indicates that triple-point prewetting is observed for this model potential.
High Precision Calculations of the Lennard-Jones Lattice Constants for Five Lattices
NASA Astrophysics Data System (ADS)
Stein, Matthew
2017-01-01
The total potential energy of a crystal as described by the Lennard-Jones (L-J) potential depends in part upon the calculation of lattice constants. Knowing these constants to high precision is useful for prediction of the lattice type and simulation of crystals such as rare-gas solids or germanium detectors, but reaching higher precision is computationally costly and challenging. Presented here is the extension of the precision of the lattice constants, Lp, up to 32 decimal digits, and in some cases corrections from previous publication. The Lp terms are given for 4 <= p <= 30 in the simple cubic, face-centered cubic, body-centered cubic, hexagonal-close-pack, and diamond lattices. This precision was obtained through the use of careful parallelization technique, exploitation of the symmetries of each lattice, and the ``onionization'' of the simulated crystal. The results of this computation, along with the tools and algorithm strategies to make this computation possible, are explained in detail graphically.
Enhancement of the droplet nucleation in a dense supersaturated Lennard-Jones vapor
NASA Astrophysics Data System (ADS)
Zhukhovitskii, D. I.
2016-05-01
The vapor-liquid nucleation in a dense Lennard-Jones system is studied analytically and numerically. A solution of the nucleation kinetic equations, which includes the elementary processes of condensation/evaporation involving the lightest clusters, is obtained, and the nucleation rate is calculated. Based on the equation of state for the cluster vapor, the pre-exponential factor is obtained. The latter diverges as a spinodal is reached, which results in the nucleation enhancement. The work of critical cluster formation is calculated using the previously developed two-parameter model (TPM) of small clusters. A simple expression for the nucleation rate is deduced and it is shown that the work of cluster formation is reduced for a dense vapor. This results in the nucleation enhancement as well. To verify the TPM, a simulation is performed that mimics a steady-state nucleation experiments in the thermal diffusion cloud chamber. The nucleating vapor with and without a carrier gas is simulated using two different thermostats for the monomers and clusters. The TPM proves to match the simulation results of this work and of other studies.
Enhancement of the droplet nucleation in a dense supersaturated Lennard-Jones vapor.
Zhukhovitskii, D I
2016-05-14
The vapor-liquid nucleation in a dense Lennard-Jones system is studied analytically and numerically. A solution of the nucleation kinetic equations, which includes the elementary processes of condensation/evaporation involving the lightest clusters, is obtained, and the nucleation rate is calculated. Based on the equation of state for the cluster vapor, the pre-exponential factor is obtained. The latter diverges as a spinodal is reached, which results in the nucleation enhancement. The work of critical cluster formation is calculated using the previously developed two-parameter model (TPM) of small clusters. A simple expression for the nucleation rate is deduced and it is shown that the work of cluster formation is reduced for a dense vapor. This results in the nucleation enhancement as well. To verify the TPM, a simulation is performed that mimics a steady-state nucleation experiments in the thermal diffusion cloud chamber. The nucleating vapor with and without a carrier gas is simulated using two different thermostats for the monomers and clusters. The TPM proves to match the simulation results of this work and of other studies.
A multiscale transport model for binary Lennard Jones mixtures in slit nanopores
NASA Astrophysics Data System (ADS)
Bhadauria, Ravi; Aluru, N. R.
2016-11-01
We present a quasi-continuum multiscale hydrodynamic transport model for one dimensional isothermal, non-reacting binary mixture confined in slit shaped nanochannels. We focus on species transport equation that includes the viscous dissipation and interspecies diffusion term of the Maxwell-Stefan form. Partial viscosity variation is modeled by van der Waals one fluid approximation and the Local Average Density Method. We use friction boundary conditions where the wall-species friction parameter is computed using a novel species specific Generalized Langevin Equation model. The transport model accuracy is tested by predicting the velocity profiles of Lennard-Jones (LJ) methane-hydrogen and LJ methane-argon mixtures in graphene slit channels of different width. The resultant slip length from the continuum model is found to be invariant of channel width for a fixed mixture molar concentration. The mixtures considered are observed to behave as single species pseudo fluid, with the friction parameter displaying a linear dependence on the molar composition. The proposed model yields atomistic level accuracy with continuum scale efficiency.
Widom line for the liquid-gas transition in Lennard-Jones system.
Brazhkin, V V; Fomin, Yu D; Lyapin, A G; Ryzhov, V N; Tsiok, E N
2011-12-08
The locus of extrema (ridges) for heat capacity, thermal expansion coefficient, compressibility, and density fluctuations for model particle systems with Lennard-Jones (LJ) potential in the supercritical region have been obtained. It was found that the ridges for different thermodynamic values virtually merge into a single Widom line at T < 1.1T(c) and P < 1.5P(c) and become practically completely smeared at T < 2.5T(c) and P < 10P(c), where T(c) and P(c) are the critical temperature and pressure. The ridge for heat capacity approaches close to critical isochore, whereas the lines of extrema for other values correspond to density decrease. The lines corresponding to the supercritical maxima for argon and neon are in good agreement with the computer simulation data for LJ fluid. The behavior of the ridges for LJ fluid, in turn, is close to that for the supercritical van der Waals fluid, which is indicative of a fairly universal behavior of the Widom line for a liquid-gas transition.
Pai, Sung Jin; Bae, Young Chan
2010-10-21
A simple and analytical pair potential function was developed to represent the osmotic pressures in aqueous protein/salt systems under various conditions. Based on a hard core Lennard-Jones (HCLJ) potential model, the new potential function considers various interactions by extending the attractive Lennard-Jones potential. A temperature-dependent coefficient term was introduced to take into account the specific properties of given materials. Comparison of the new potential function with the HCLJ model in hydrocarbon and water systems showed that consideration of the temperature dependence in the potential function was effective, especially for strong polar systems such as water. To predict the osmotic pressures of aqueous lysozyme/(NH(4))(2)SO(4) solutions of various ionic strength and pH, the energy parameters of lysozyme were correlated with the experimental cloud point temperature. The proposed model agreed fairly well with the experimental osmotic pressure data with only previously obtained parameters.
NASA Astrophysics Data System (ADS)
Pai, Sung Jin; Bae, Young Chan
2010-10-01
A simple and analytical pair potential function was developed to represent the osmotic pressures in aqueous protein/salt systems under various conditions. Based on a hard core Lennard-Jones (HCLJ) potential model, the new potential function considers various interactions by extending the attractive Lennard-Jones potential. A temperature-dependent coefficient term was introduced to take into account the specific properties of given materials. Comparison of the new potential function with the HCLJ model in hydrocarbon and water systems showed that consideration of the temperature dependence in the potential function was effective, especially for strong polar systems such as water. To predict the osmotic pressures of aqueous lysozyme/(NH4)2SO4 solutions of various ionic strength and pH, the energy parameters of lysozyme were correlated with the experimental cloud point temperature. The proposed model agreed fairly well with the experimental osmotic pressure data with only previously obtained parameters.
NASA Astrophysics Data System (ADS)
Gu, Rongbao; Shao, Yanmin
2016-07-01
In this paper, a new concept of multi-scales singular value decomposition entropy based on DCCA cross correlation analysis is proposed and its predictive power for the Dow Jones Industrial Average Index is studied. Using Granger causality analysis with different time scales, it is found that, the singular value decomposition entropy has predictive power for the Dow Jones Industrial Average Index for period less than one month, but not for more than one month. This shows how long the singular value decomposition entropy predicts the stock market that extends Caraiani's result obtained in Caraiani (2014). On the other hand, the result also shows an essential characteristic of stock market as a chaotic dynamic system.
Warshavsky, Vadim B.; Song, Xueyu
2008-07-18
Free energies and correlation functions of liquid and solid hard-sphere (HS) mixtures are calculated using the fundamental measure density functional theory. Using the thermodynamic perturbation theory the free energies of solid and liquid Lennard-Jones (LJ) mixtures are obtained from correlation functions of HS systems within a single theoretical approach. The resulting azeotrope- and spindle-type solid-liquid phase diagrams of HS and LJ binary mixtures are in good agreement with the corresponding ones from computer simulations.
Wennberg, Christian L; Murtola, Teemu; Hess, Berk; Lindahl, Erik
2013-08-13
The accuracy of electrostatic interactions in molecular dynamics advanced tremendously with the introduction of particle-mesh Ewald (PME) summation almost 20 years ago. Lattice summation electrostatics is now the de facto standard for most types of biomolecular simulations, and in particular, for lipid bilayers, it has been a critical improvement due to the large charges typically present in zwitterionic lipid headgroups. In contrast, Lennard-Jones interactions have continued to be handled with increasingly longer cutoffs, partly because few alternatives have been available despite significant difficulties in tuning cutoffs and parameters to reproduce lipid properties. Here, we present a new Lennard-Jones PME implementation applied to lipid bilayers. We confirm that long-range contributions are well approximated by dispersion corrections in simple systems such as pentadecane (which makes parameters transferable), but for inhomogeneous and anisotropic systems such as lipid bilayers there are large effects on surface tension, resulting in up to 5.5% deviations in area per lipid and order parameters-far larger than many differences for which reparameterization has been attempted. We further propose an approximation for combination rules in reciprocal space that significantly reduces the computational cost of Lennard-Jones PME and makes accurate treatment of all nonbonded interactions competitive with simulations employing long cutoffs. These results could potentially have broad impact on important applications such as membrane proteins and free energy calculations.
May, Helge-Otmar; Mausbach, Peter
2012-03-01
The behavior of thermodynamic response functions and the thermodynamic scalar curvature in the supercritical region have been studied for a Lennard-Jones fluid based on a revised modified Benedict-Webb-Rubin equation of state. Response function extrema are sometimes used to estimate the Widom line, which is characterized by the maxima of the correlation lengths. We calculated the Widom line for the Lennard-Jones fluid without using any response function extrema. Since the volume of the correlation length is proportional to the Riemannian thermodynamic scalar curvature, the locus of the Widom line follows the slope of maximum curvature. We show that the slope of the Widom line follows the slope of the isobaric heat capacity maximum only in the close vicinity of the critical point and that, therefore, the use of response function extrema in this context is problematic. Furthermore, we constructed the vapor-liquid coexistence line for the Lennard-Jones fluid using the fact that the correlation length, and therefore the thermodynamic scalar curvature, must be equal in the two coexisting phases. We compared the resulting phase envelope with those from simulation data where multiple histogram reweighting was used and found striking agreement between the two methods.
The impact of surface area, volume, curvature, and Lennard-Jones potential to solvation modeling.
Nguyen, Duc D; Wei, Guo-Wei
2017-01-05
This article explores the impact of surface area, volume, curvature, and Lennard-Jones (LJ) potential on solvation free energy predictions. Rigidity surfaces are utilized to generate robust analytical expressions for maximum, minimum, mean, and Gaussian curvatures of solvent-solute interfaces, and define a generalized Poisson-Boltzmann (GPB) equation with a smooth dielectric profile. Extensive correlation analysis is performed to examine the linear dependence of surface area, surface enclosed volume, maximum curvature, minimum curvature, mean curvature, and Gaussian curvature for solvation modeling. It is found that surface area and surfaces enclosed volumes are highly correlated to each other's, and poorly correlated to various curvatures for six test sets of molecules. Different curvatures are weakly correlated to each other for six test sets of molecules, but are strongly correlated to each other within each test set of molecules. Based on correlation analysis, we construct twenty six nontrivial nonpolar solvation models. Our numerical results reveal that the LJ potential plays a vital role in nonpolar solvation modeling, especially for molecules involving strong van der Waals interactions. It is found that curvatures are at least as important as surface area or surface enclosed volume in nonpolar solvation modeling. In conjugation with the GPB model, various curvature-based nonpolar solvation models are shown to offer some of the best solvation free energy predictions for a wide range of test sets. For example, root mean square errors from a model constituting surface area, volume, mean curvature, and LJ potential are less than 0.42 kcal/mol for all test sets. © 2016 Wiley Periodicals, Inc.
Spontaneous cavitation in a Lennard-Jones liquid at negative pressures.
Baidakov, V G; Bobrov, K S
2014-05-14
We report a molecular dynamics (MD) study of homogeneous bubble nucleation in a Lennard-Jones liquid under a negative pressure (cavitation). The rate of bubble nucleation has been determined in the range 2 x 10(-9) < J(*) = Jσ(4)(m/ε)(1/2) < 6 x 10(-6) by the mean lifetime method at temperatures T(*) = kBT/ε = 0.35, 0.4, 0.5, 0.6, 0.7, 0.8, 0.4, 0.5, 0.6, 0.7, 0.8. In molecular dynamics simulation calculations have also been made of the coefficient of bubble size diffusion, the Zeldovich nonequilibrium factor, and the radius of a critical nucleus R*. Different approaches to the determination of the nucleation rate in a stretched liquid have been considered in the framework of classical nucleation theory (CNT). The values of J obtained in MD simulation are by 8-20 orders higher than those predicted by CNT. The work of formation of a critical bubble and the dependence of surface tension γ(R*) at the critical bubble-liquid interface have been determined by data of MD simulation from CNT. The values of γ obtained have been approximated by an extended Tolman formula that takes into account, besides a linear correction, also the quadratic in curvature terms. The Tolman length δ∞ is negative and equals -(0.1-0.2)σ. The coefficient at 1/R*(2) is positive and does not exceed σ(2).
Crystallization of Lennard-Jones nanodroplets: From near melting to deeply supercooled.
Malek, Shahrazad M A; Morrow, Gregory P; Saika-Voivod, Ivan
2015-03-28
We carry out molecular dynamics (MD) and Monte Carlo (MC) simulations to characterize nucleation in liquid clusters of 600 Lennard-Jones particles over a broad range of temperatures. We use the formalism of mean first-passage times to determine the rate and find that Classical Nucleation Theory (CNT) predicts the rate quite well, even when employing simple modelling of crystallite shape, chemical potential, surface tension, and particle attachment rate, down to the temperature where the droplet loses metastability and crystallization proceeds through growth-limited nucleation in an unequilibrated liquid. Below this crossover temperature, the nucleation rate is still predicted when MC simulations are used to directly calculate quantities required by CNT. Discrepancy in critical embryo sizes obtained from MD and MC arises when twinned structures with five-fold symmetry provide a competing free energy pathway out of the critical region. We find that crystallization begins with hcp-fcc stacked precritical nuclei and differentiation to various end structures occurs when these embryos become critical. We confirm that using the largest embryo in the system as a reaction coordinate is useful in determining the onset of growth-limited nucleation and show that it gives the same free energy barriers as the full cluster size distribution once the proper reference state is identified. We find that the bulk melting temperature controls the rate, even though the solid-liquid coexistence temperature for the droplet is significantly lower. The value of surface tension that renders close agreement between CNT and direct rate determination is significantly lower than what is expected for the bulk system.
Taylor, Mark P; Ye, Yuting; Adhikari, Shishir R
2015-11-28
The conformation of a polymer chain in solution is coupled to the local structure of the surrounding solvent and can undergo large changes in response to variations in solvent density and temperature. The many-body effects of solvent on the structure of an n-mer polymer chain can be formally mapped to an exact n-body solvation potential. Here, we use a pair decomposition of this n-body potential to construct a set of two-body potentials for a Lennard-Jones (LJ) polymer chain in explicit LJ solvent. The solvation potentials are built from numerically exact results for 5-mer chains in solvent combined with an approximate asymptotic expression for the solvation potential between sites that are distant along the chain backbone. These potentials map the many-body chain-in-solvent problem to a few-body single-chain problem and can be used to study a chain of arbitrary length, thereby dramatically reducing the computational complexity of the polymer chain-in-solvent problem. We have constructed solvation potentials at a large number of state points across the LJ solvent phase diagram including the vapor, liquid, and super-critical regions. We use these solvation potentials in single-chain Monte Carlo (MC) simulations with n ≤ 800 to determine the size, intramolecular structure, and scaling behavior of chains in solvent. To assess our results, we have carried out full chain-in-solvent MC simulations (with n ≤ 100) and find that our solvation potential approach is quantitatively accurate for a wide range of solvent conditions for these chain lengths.
Intracytoplasmic and surface-bound immunoglobulins in "nonsecretory" and Bence-Jones myeloma.
Preud'Homme, J L; Hurez, D; Danon, F; Brouet, J C; Seligmann, M
1976-01-01
Immunoglobulins were studied at the cellular level by direct immunofluorescence in twenty-five patients with 'nonsecretory' myeloma and thirty-six patiens with Bence-Jones (BJ) myeloma. The results were compared with those obtained in a control group of thirty-six patients with common secretory myeloma. A monoclonal Ig (IgG in eighteen, IgA in three and kappa chains only in three cases) was found in the cytoplasm of the plasma cells from all the patients with 'nonsecretory' myeloma, with a striking dysbalance in the staining brightness for the heavy and the light chains. A similar dysbalance in staining was also observed for plasma cell surface Ig chains but in the opposite way. In twenty patients with BJ myeloma studied for cytoplasmic Ig only, determinants of a heavy chain were clearly found in four cases. When surface Ig were studied also, the production of gamma chains in addition to the light chain could be ascertained in six of sixteen cases. In addition, IgM with the same light chain type as the BJ protein was detected at the cell surface on plasma cells and lymphocytes in two of these sixteen patients. 'Monoclonal' populations of B lymphocytes bearing the same Ig chains as those produced by the myeloma cells were detectable in five of eleven 'nonsecretory' myeloma and in five of sixteen BJ myeloma patients. Normal blood B lymphocytes were in decreased number, particularly when a 'monoclonal' lymphocytic population was detected. Data are discussed which suggest that plasma cells from most patients with 'nonsecretory' myeloma might synthesize and secrete Ig molecules with structurally abnormal chains that are then quickly degraded. PMID:822974
Specifics of freezing of Lennard-Jones fluid confined to molecularly thin layers
NASA Astrophysics Data System (ADS)
Vishnyakov, Aleksey; Neimark, Alexander V.
2003-04-01
Freezing of a Lennard-Jones fluid between solid surfaces was studied using grand canonical Monte Carlo and molecular dynamics simulations. We explored the formation of frozen phases of hexagonal and orthorhombic symmetry in mono-, bi-, and tri-layer structures. The freezing transition, the type of lattice, and translational and orientational ordering were identified on the basis of orientational order parameters, in-plane two-body and three-body translational correlation functions, orientational correlation functions, and analysis of molecular mobilities. We have found that the freezing temperature is a nonmonotonous function of the pore width: orthorhombic bi-layer freezes at lower temperatures than hexagonal monolayer and hexagonal bi-layer. As the pore width increases, the transition from a hexagonal monolayer to an orthorhombic bi-layer occurred via disordered liquidlike and quasi-long-range four-fold ordered bi-layers. The latter, "quadratic" structure is characterized by an algebraically decaying four-fold orientational correlation function. The transition from crystalline hexagonal bi-layer to orthorhombic tri-layer occurs through a bi-layer structure with two uncoupled hexagonal monolayers. The quadratic phase was observed also as an intermediate structure during freezing of a liquidlike bi-layer into an orthorhombic quasi-crystal. The formation of the quadratic phase was associated with step-wise densification of fluid, a sharp increase of the local orientational order parameter, and a significant reduction of fluid mobility. In the process of solidification, the system passed through a sequence of high-density jammed structures, in which the four-fold symmetry developed progressively, as the temperature decreased.
Hu, Xiaoli; Guo, Huihui; He, Yan; Wang, Shan; Zhang, Lingling; Wang, Shi; Huang, Xiaoting; Roy, Scott William; Lu, Wei; Hu, Jingjie; Bao, Zhenmin
2010-01-01
The scallop is an economically important sea food prized for its large and delicious adductor muscle. Studying the molecular basis of scallop muscle growth is important for both scallop breeding and our understanding of muscle mass regulation in bivalve. Myostatin (MSTN) is a conserved negative regulator of muscle growth and development. Here we report the MSTN gene from Zhikong scallop (Chlamys farreri Jones et Preston 1904). The C. farreri MSTN consists of 11651 nucleotides encoding 457 amino acids. The gene has a 3-exon/2-intron structure that is conserved with vertebrate homologs. The exons are 586, 380 and 408 bp in length, respectively, and separated by introns of 5086 and 1518 bp. The protein sequence contains characteristic conserved residues including a cleavage motif of proteolysis (RXXR) and nine cysteines. Three transcription initiation sites were found at 62, 146, and 296 bp upstream of the translation start codon ATG. In silico analysis of the promoter region identified a TATA-box and several muscle-specific regulatory elements including COMP, MEF2s, MTBFs and E-boxes. Minisatellite DNA was found in intron 1. By fluorescence in situ hybridization (FISH), the gene was mapped to the long arm of a pair of middle subtelocentric chromosome. Quantitative analysis of MSTN transcripts in embryos/larvae indicated high expression level in gastrulae and limited expression at other stages. In adult scallops, MSTN is predominantly expressed in striated muscle, with different expression levels in other tissues. Our data provide valuable genomic and expression information which will aid the further study on scallop MSTN function and MSTN evolution.
Jones, Amanda L; Sutcliffe, Iain C; Goodfellow, Michael
2013-06-01
Recently we proposed that Rhodococcus equi (Magnusson 1923) Goodfellow and Alderson 1977 be transferred to a novel genus, Prescottia, as Prescottia equi comb. nov. However, in accordance with Principle 2 and Rule 51b(4) of the Bacteriological Code (1990 Revision), the bacterial genus name Prescottia Jones et al. 2013 is deemed illegitimate as this name has been used previously for a plant genus within the family Orchidaceae. Consequently, a new genus name, Prescottella gen. nov. is proposed for the bacterial taxon and a new combination Prescottella equi comb. nov. is proposed for the type species.
Generalized coupling parameter expansion: application to square well and Lennard-Jones fluids.
Sai Venkata Ramana, A
2013-07-28
The coupling parameter expansion in thermodynamic perturbation theory of simple fluids is generalized to include the derivatives of bridge function with respect to coupling parameter. We applied seventh order version of the theory to Square-Well (SW) and Lennard-Jones (LJ) fluids using Sarkisov Bridge function. In both cases, the theory reproduced the radial distribution functions obtained from integral equation theory (IET) and simulations with good accuracy. Also, the method worked inside the liquid-vapor coexistence region where the IETs are known to fail. In the case of SW fluids, the use of Carnahan-Starling expression for Helmholtz free energy density of Hard-Sphere reference system has improved the liquid-vapor phase diagram (LVPD) over that obtained from IET with the same bridge function. The derivatives of the bridge function are seen to have significant effect on the liquid part of the LVPD. For extremely narrow SW fluids, we found that the third order theory is more accurate than the higher order versions. However, considering the convergence of the perturbation series, we concluded that the accuracy of the third order version is a spurious result. We also obtained the surface tension for SW fluids of various ranges. Results of present theory and simulations are in good agreement. In the case of LJ fluids, the equation of state obtained from the present method matched with that obtained from IET with negligible deviation. We also obtained LVPD of LJ fluid from virial and energy routes and found that there is slight inconsistency between the two routes. The applications lead to the following conclusions. In cases where reference system properties are known accurately, the present method gives results which are very much improved over those obtained from the IET with the same bridge function. In cases where reference system data is not available, the method serves as an alternative way of solving the Ornstein-Zernike equation with a given closure relation
Properties of Organic Liquids when Simulated with Long-Range Lennard-Jones Interactions.
Fischer, Nina M; van Maaren, Paul J; Ditz, Jonas C; Yildirim, Ahmet; van der Spoel, David
2015-07-14
In order to increase the accuracy of classical computer simulations, existing methodologies may need to be adapted. Hitherto, most force fields employ a truncated potential function to model van der Waals interactions, sometimes augmented with an analytical correction. Although such corrections are accurate for homogeneous systems with a long cutoff, they should not be used in inherently inhomogeneous systems such as biomolecular and interface systems. For such cases, a variant of the particle mesh Ewald algorithm (Lennard-Jones PME) was already proposed 20 years ago (Essmann et al. J. Chem. Phys. 1995, 103, 8577-8593), but it was implemented only recently (Wennberg et al. J. Chem. Theory Comput. 2013, 9, 3527-3537) in a major simulation code (GROMACS). The availability of this method allows surface tensions of liquids as well as bulk properties to be established, such as density and enthalpy of vaporization, without approximations due to truncation. Here, we report on simulations of ≈150 liquids (taken from a force field benchmark: Caleman et al. J. Chem. Theory Comput. 2012, 8, 61-74) using three different force fields and compare simulations with and without explicit long-range van der Waals interactions. We find that the density and enthalpy of vaporization increase for most liquids using the generalized Amber force field (GAFF, Wang et al. J. Comput. Chem. 2004, 25, 1157-1174) and the Charmm generalized force field (CGenFF, Vanommeslaeghe et al. J. Comput. Chem. 2010, 31, 671-690) but less so for OPLS/AA (Jorgensen and Tirado-Rives, Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 6665-6670), which was parametrized with an analytical correction to the van der Waals potential. The surface tension increases by ≈10(-2) N/m for all force fields. These results suggest that van der Waals attractions in force fields are too strong, in particular for the GAFF and CGenFF. In addition to the simulation results, we introduce a new version of a web server, http
Liquid-liquid interfacial properties of a symmetrical Lennard-Jones binary mixture.
Martínez-Ruiz, F J; Moreno-Ventas Bravo, A I; Blas, F J
2015-09-14
We determine the interfacial properties of a symmetrical binary mixture of equal-sized spherical Lennard-Jones molecules, σ11 = σ22, with the same dispersive energy between like species, ϵ11 = ϵ22, but different dispersive energies between unlike species low enough to induce phase separation. We use the extensions of the improved version of the inhomogeneous long-range corrections of Janec̆ek [J. Phys. Chem. B 110, 6264 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] and Martínez-Ruiz et al. [J. Chem. Phys. 141, 184701 (2014)], to deal with the interaction energy and microscopic components of the pressure tensor. We perform Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of the symmetrical mixture with different cut-off distances rc and in combination with the inhomogeneous long-range corrections. The pressure tensor is obtained using the mechanical (virial) and thermodynamic route. The liquid-liquid interfacial tension is also evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the test-area methodology. This allows to check the validity of the recent extensions presented to deal with the contributions due to long-range corrections for intermolecular energy and pressure tensor in the case of binary mixtures that exhibit liquid-liquid immiscibility. In addition to the pressure tensor and the surface tension, we also obtain density profiles and coexistence densities and compositions as functions of pressure, at a given temperature. According to our results, the main effect of increasing the cut-off distance rc is to sharpen the liquid-liquid interface and to increase the width of the biphasic coexistence region. Particularly interesting is the presence of a relative minimum in the total density profiles of the symmetrical mixture. This minimum is related with a desorption of the molecules
Effect of molecular flexibility of Lennard-Jones chains on vapor-liquid interfacial properties.
Blas, F J; Moreno-Ventas Bravo, A I; Algaba, J; Martínez-Ruiz, F J; MacDowell, L G
2014-03-21
We have determined the interfacial properties of short fully flexible chains formed from tangentially bonded Lennard-Jones monomeric units from direct simulation of the vapor-liquid interface. The results obtained are compared with those corresponding to rigid-linear chains formed from the same chain length, previously determined in the literature [F. J. Blas, A. I. M.-V. Bravo, J. M. Míguez, M. M. Piñeiro, and L. G. MacDowell, J. Chem. Phys. 137, 084706 (2012)]. The full long-range tails of the potential are accounted for by means of an improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 129, 6264 (2006)] proposed recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2008)] valid for spherical as well as for rigid and flexible molecular systems. Three different model systems comprising of 3, 5, and 6 monomers per molecule are considered. The simulations are performed in the canonical ensemble, and the vapor-liquid interfacial tension is evaluated using the test-area method. In addition to the surface tension, we also obtained density profiles, coexistence densities, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the chain length and rigidity on these properties. According to our results, the main effect of increasing the chain length (at fixed temperature) is to sharpen the vapor-liquid interface and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness decreases and the surface tension increases as the molecular chains get longer. Comparison between predictions for fully flexible and rigid-linear chains, formed by the same number of monomeric units, indicates that the main effects of increasing the flexibility, i.e., passing from a rigid-linear to a fully flexible chain, are: (a) to decrease the difference between the liquid and vapor densities; (b) to decrease the critical temperature and
Liquid-liquid interfacial properties of a symmetrical Lennard-Jones binary mixture
Martínez-Ruiz, F. J.; Blas, F. J.; Moreno-Ventas Bravo, A. I.
2015-09-14
We determine the interfacial properties of a symmetrical binary mixture of equal-sized spherical Lennard-Jones molecules, σ{sub 11} = σ{sub 22}, with the same dispersive energy between like species, ϵ{sub 11} = ϵ{sub 22}, but different dispersive energies between unlike species low enough to induce phase separation. We use the extensions of the improved version of the inhomogeneous long-range corrections of Janecek [J. Phys. Chem. B 110, 6264 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] and Martínez-Ruiz et al. [J. Chem. Phys. 141, 184701 (2014)], to deal with the interaction energy and microscopic components of the pressure tensor. We perform Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of the symmetrical mixture with different cut-off distances r{sub c} and in combination with the inhomogeneous long-range corrections. The pressure tensor is obtained using the mechanical (virial) and thermodynamic route. The liquid-liquid interfacial tension is also evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the test-area methodology. This allows to check the validity of the recent extensions presented to deal with the contributions due to long-range corrections for intermolecular energy and pressure tensor in the case of binary mixtures that exhibit liquid-liquid immiscibility. In addition to the pressure tensor and the surface tension, we also obtain density profiles and coexistence densities and compositions as functions of pressure, at a given temperature. According to our results, the main effect of increasing the cut-off distance r{sub c} is to sharpen the liquid-liquid interface and to increase the width of the biphasic coexistence region. Particularly interesting is the presence of a relative minimum in the total density profiles of the symmetrical mixture. This minimum is related
Liquid-liquid interfacial properties of a symmetrical Lennard-Jones binary mixture
NASA Astrophysics Data System (ADS)
Martínez-Ruiz, F. J.; Moreno-Ventas Bravo, A. I.; Blas, F. J.
2015-09-01
We determine the interfacial properties of a symmetrical binary mixture of equal-sized spherical Lennard-Jones molecules, σ11 = σ22, with the same dispersive energy between like species, ɛ11 = ɛ22, but different dispersive energies between unlike species low enough to induce phase separation. We use the extensions of the improved version of the inhomogeneous long-range corrections of Janec̆ek [J. Phys. Chem. B 110, 6264 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] and Martínez-Ruiz et al. [J. Chem. Phys. 141, 184701 (2014)], to deal with the interaction energy and microscopic components of the pressure tensor. We perform Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of the symmetrical mixture with different cut-off distances rc and in combination with the inhomogeneous long-range corrections. The pressure tensor is obtained using the mechanical (virial) and thermodynamic route. The liquid-liquid interfacial tension is also evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the test-area methodology. This allows to check the validity of the recent extensions presented to deal with the contributions due to long-range corrections for intermolecular energy and pressure tensor in the case of binary mixtures that exhibit liquid-liquid immiscibility. In addition to the pressure tensor and the surface tension, we also obtain density profiles and coexistence densities and compositions as functions of pressure, at a given temperature. According to our results, the main effect of increasing the cut-off distance rc is to sharpen the liquid-liquid interface and to increase the width of the biphasic coexistence region. Particularly interesting is the presence of a relative minimum in the total density profiles of the symmetrical mixture. This minimum is related with a desorption of the molecules
Lundrigan, Sarah E. M.; Saika-Voivod, Ivan
2009-09-14
We perform molecular dynamics (MD) and Monte Carlo computer simulations to test the ability of the recently developed formalism of mean first-passage time (MFPT) [J. Wedekind, R. Strey, and D. Reguera, J. Chem. Phys. 126, 134103 (2007); J. Wedekind and D. Reguera, J. Phys. Chem. B 112, 11060 (2008)] to characterize crystal nucleation in the Lennard-Jones liquid. We find that the nucleation rate, critical embryo size, Zeldovich factor, attachment rate, and the nucleation barrier profile obtained from MFPT all compare very well to the same quantities calculated using other methods. Furthermore, we find that the nucleation rate obtained directly through MD closely matches the prediction of classical nucleation theory.
NASA Astrophysics Data System (ADS)
Lundrigan, Sarah E. M.; Saika-Voivod, Ivan
2009-09-01
We perform molecular dynamics (MD) and Monte Carlo computer simulations to test the ability of the recently developed formalism of mean first-passage time (MFPT) [J. Wedekind, R. Strey, and D. Reguera, J. Chem. Phys. 126, 134103 (2007); J. Wedekind and D. Reguera, J. Phys. Chem. B 112, 11060 (2008)] to characterize crystal nucleation in the Lennard-Jones liquid. We find that the nucleation rate, critical embryo size, Zeldovich factor, attachment rate, and the nucleation barrier profile obtained from MFPT all compare very well to the same quantities calculated using other methods. Furthermore, we find that the nucleation rate obtained directly through MD closely matches the prediction of classical nucleation theory.
NASA Astrophysics Data System (ADS)
Henderson, Der-Ming Duh Douglas; Rowley, Richard L.
Some effects of deviations from the Lorentz-Berthelot (LB) combining rules for LennardJones binary mixtures are studied with a model in which both constituents have the same size and energy interaction parameters but the cross interaction deviates substantially from the LB rules. A single temperature and density and two compositions are studied by molecular dynamics simulations and the recently proposed Duh-Haymet-Henderson (DHH) intergral equation theory. The agreement is satisfactory in both cases. The excess volume and enthalpy of mixing are also studied systematically with the DHH theory. Some interesting phenomena are observed for these no-LB mixtures.
Separdar, L; Davatolhagh, S
2013-02-01
We investigate the static structure and diffusive dynamics of binary Lennard-Jones mixture upon supercooling in the presence of gold nanoparticle within the framework of the mode-coupling theory of the dynamic glass transition in the direct space by means of constant-NVT molecular dynamics simulations. It is found that the presence of gold nanoparticle causes the energy per particle and the pressure of this system to decrease with respect to the bulk binary Lennard-Jones mixture. Furthermore, the presence of nanoparticle has a direct effect on the liquid structure and causes the peaks of the radial distribution functions to become shorter with respect to the bulk binary Lennard-Jones liquid. The dynamics of the liquid at a given density is found to be consistent with the mode-coupling theory (MCT) predictions in a certain range at low temperatures. In accordance with the idealized MCT, the diffusion constants D(T) show a power-law behavior at low temperatures for both types of binary Lennard-Jones (BLJ) particles as well as the gold atoms comprising the nanoparticle. The mode-coupling crossover temperature T(c) is the same for all particle types; however, T(c)=0.4 is reduced with respect to that of the bulk BLJ liquid, and the γ exponent is found to depend on the particle type. The existence of the nanoparticle causes the short-time β-relaxation regime to shorten and the range of validity of the MCT shrinks with respect to the bulk BLJ. It is also found that at intermediate and low temperatures the curves of the mean-squared displacements (MSDs) versus tD(T) fall onto a master curve. The MSDs follow the master curve in an identical time range with the long-time α-relaxation regime of the mode-coupling theory. By obtaining the viscosity, it is observed that the Stokes-Einstein relation remains valid at high and intermediate temperatures but breaks down as the temperatures approach T(c) as a result of the cooperative motion or activated processes.
NASA Astrophysics Data System (ADS)
Maddox, M. W.; Gubbins, K. E.
1997-12-01
A combination of grand canonical Monte Carlo and molecular dynamics simulation techniques are used to study the freezing and melting of Lennard-Jones methane in several different cylindrical pores. Two different types of pore wall are considered; a strongly attractive wall, and a weakly attractive wall, each with pore diameters in the range 1.5-3.5 nm. Freezing point depression is observed in the case of the weakly attractive pores, in agreement with several experimental studies. Freezing point elevation is observed at the walls of the strongly attractive pore, but freezing point depression occurs at the center of such pores, due to geometrical constraints.
NASA Astrophysics Data System (ADS)
Polak, Wiesław Z.
2016-08-01
Simulated growth of four global-minimum Lennard-Jones clusters of sizes N = 561, 823, 850 and 923, representing multishell icosahedra and decahedron, always leads to formation of regular polyicosahedral clusters. Observation of cluster structure evolution revealed that new atoms form anti-Mackay islands spreading over the cluster surface by making strong island-island junctions at cluster edges. Analysis of potential energies of atoms composing different local structures shows that energy-driven preference for decahedral arrangement of several atoms initiating the junction of pentagonal symmetry on the cluster surface is responsible for kinetic effect in the cluster growth.
NASA Astrophysics Data System (ADS)
Tarzimanov, A. A.; Klinov, A. V.; Malygin, A. V.; Nurgalieva, A. A.
2008-08-01
Integral equation theory was used to study the binary distribution functions of the excess properties of three-component Lennard-Jones mixtures. The results obtained for the behavior of the excess functions of caloric properties (internal energy, enthalpy, and isochoric heat capacity) are reported. The influence of the third component with various potential parameters on excess functions was studied. Calculations were performed for systems under super-and subcritical conditions with different sizes of molecules, σ1/σ2 = 1 4, and attraction energies between them, ɛ1/ɛ2 = 1 4. The results were compared with numerical experiment data to find that the approach used was fairly accurate
NASA Astrophysics Data System (ADS)
Kim, Sun Ung; Monroe, Charles W.
2014-09-01
The inverse problem of parameterizing intermolecular potentials given macroscopic transport and thermodynamic data is addressed. Procedures are developed to create arbitrary-precision algorithms for transport collision integrals, using the Lennard-Jones (12-6) potential as an example. Interpolation formulas are produced that compute these collision integrals to four-digit accuracy over the reduced-temperature range 0.3≤T*≤400, allowing very fast computation. Lennard-Jones parameters for neon, argon, and krypton are determined by simultaneously fitting the observed temperature dependences of their viscosities and second virial coefficients-one of the first times that a thermodynamic and a dynamic property have been used simultaneously for Lennard-Jones parameterization. In addition to matching viscosities and second virial coefficients within the bounds of experimental error, the determined Lennard-Jones parameters are also found to predict the thermal conductivity and self-diffusion coefficient accurately, supporting the value of the Lennard-Jones (12-6) potential for noble-gas transport-property correlation.
Kim, Sun Ung; Monroe, Charles W.
2014-09-15
The inverse problem of parameterizing intermolecular potentials given macroscopic transport and thermodynamic data is addressed. Procedures are developed to create arbitrary-precision algorithms for transport collision integrals, using the Lennard-Jones (12–6) potential as an example. Interpolation formulas are produced that compute these collision integrals to four-digit accuracy over the reduced-temperature range 0.3≤T{sup ⁎}≤400, allowing very fast computation. Lennard-Jones parameters for neon, argon, and krypton are determined by simultaneously fitting the observed temperature dependences of their viscosities and second virial coefficients—one of the first times that a thermodynamic and a dynamic property have been used simultaneously for Lennard-Jones parameterization. In addition to matching viscosities and second virial coefficients within the bounds of experimental error, the determined Lennard-Jones parameters are also found to predict the thermal conductivity and self-diffusion coefficient accurately, supporting the value of the Lennard-Jones (12–6) potential for noble-gas transport-property correlation.
Explicit expression for the Stokes-Einstein relation for pure Lennard-Jones liquids.
Ohtori, Norikazu; Ishii, Yoshiki
2015-01-01
An explicit expression of the Stokes-Einstein (SE) relation in molecular scale has been determined for pure Lennard-Jones (LJ) liquids on the saturated vapor line using a molecular dynamics calculation with the Green-Kubo formula, as Dη(sv)=kTξ(-1)(N/V)(1/3), where D is the self-diffusion coefficient, η(sv) the shear viscosity, k the Boltzmann constant, T the temperature, ξ the constant, and N the particle number included in the system volume V. To this end, the dependence of D and η(sv) on packing fraction, η, and T has been determined so as to complete their scaling equations. The equations for D and η(sv) in these states are m(-1/2)(N/V)(-1/3)(1-η)(4)ε(-1/2)T and m(1/2)(N/V)(2/3)(1-η)(-4)ε(1/2)T(0), respectively, where m and ε are the atomic mass and characteristic parameter of energy used in the LJ potentials, respectively. The equations can well describe the behaviors of D and η(sv) for both the LJ and the real rare-gas liquids. The obtained SE relation justifies the theoretical equation proposed by Eyring and Ree, although the value of ξ is slightly different from that given by them. The difference of the obtained expression from the original SE relation, Dη(sv)=(kT/2π)σ(-1), where σ means the particle size, is the presence of the η(1/3) term, since (N/V)(1/3)=(6/π)(1/3)σ(-1)η(1/3). Since the original SE relation is based on the fluid mechanics for continuum media, allowing the presence of voids in liquids is the origin of the η(1/3) term. Therefore, also from this viewpoint, the present expression is more justifiable in molecular scale than the original SE relation. As a result, the η(1/3) term cancels out the σ dependence from the original SE relation. The present result clearly shows that it is not necessary to attribute the deviation from the original SE relation to any temperature dependence of particle size or to introduce the fractional SE relation for pure LJ liquids. It turned out that the η dependence of both D and
NASA Astrophysics Data System (ADS)
Duh, Der-Ming; Henderson, Douglas
1996-05-01
The pure Lennard-Jones fluid and various binary mixtures of Lennard-Jones fluids are studied by both molecular dynamics simulation and with a new integral equation which is based on that proposed by Duh and Haymet recently [J. Chem. Phys. 103, 2625 (1995)]. The structural and thermodynamic properties calculated from this integral equation show excellent agreement with simulations for both pure fluids and mixtures under the conditions which we have studied. For mixtures, the effect of deviations from the Lorentz-Berthelot (LB) mixing rules for the interaction parameters between unlike species is studied. Positive deviations from the nonadditivity of the molecular cores leads to an entropy driven tendency for the species to separate. This tendency persists even in the presence of a deviation from the LB rule for the energy parameter which enhances the attraction of the unlike species. On the other hand, in the case of negative deviations from nonadditivity, the tendency for association may be either energy or entropy driven, depending on the size ratio.
Scaling of the viscosity of the Lennard-Jones chain fluid model, argon, and some normal alkanes.
Galliero, Guillaume; Boned, Christian; Fernández, Josefa
2011-02-14
In this work, we have tested the efficiency of two scaling approaches aiming at relating shear viscosity to a single thermodynamic quantity in dense fluids, namely the excess entropy and the thermodynamic scaling methods. Using accurate databases, we have applied these approaches first to a model fluid, the flexible Lennard-Jones chain fluid (from the monomer to the hexadecamer), then to real fluids, such as argon and normal alkanes. To enlarge noticeably the range of thermodynamics conditions for which these scaling methods are applicable, we have shown that the use of the residual viscosity instead of the total viscosity is preferable in the scaling procedures. It has been found that both approaches, using the adequate scaling, are suitable for the Lennard-Jones chain fluid model for a wide range of thermodynamic conditions whatever the chain length when scaling law exponents and prefactors are adjusted for each chain length. Furthermore, these results were found to be well respected by the corresponding real fluids.
Sousa, J M G; Ferreira, A L; Barroso, M A
2012-05-07
The solid-fluid coexistence properties of the n - 6 Lennard-Jones system, n from 7 to 12, are reported. The procedure relies on determining Helmholtz free energy curves as a function of volume for each phase independently, from several NVT simulations, and then connecting it to points of known absolute free energy. For n = 12 this requires connecting the simulated points to states of very low densities on the liquid phase, and to a harmonic crystal for the solid phase, which involves many extra simulations for each temperature. For the reference points of the remaining systems, however, the free energy at a given density and temperature can be calculated relative to the n = 12 system. The method presented here involves a generalization of the multiple histogram method to combine simulations performed with different potentials, provided they visit overlapping regions of the phase space, and allows for a precise calculation of relative free energies. The densities, free energies, average potential energies, pressure, and chemical potential at coexistence are presented for up to T∗ = 5.0 and new estimations of the triple points are given for the n - 6 Lennard-Jones system.
Hoang, Hai; Galliero, Guillaume
2013-12-04
This work aims at providing a tractable approach to model the local shear viscosity of strongly inhomogeneous dense fluids composed of spherical molecules, in which the density variations occur on molecular distance. The proposed scheme, which relies on the local density average model, has been applied to the quasi-hard-sphere, the Week-Chandler-Andersen and the Lennard-Jones fluids. A weight function has been developed to deal with the hard-sphere fluid given the specificities of momentum exchange. To extend the approach to the smoothly repulsive potential, we have taken into account that the non-local contributions to the viscosity due to the interactions of particles separated by a given distance are temperature dependent. Then, using a simple perturbation scheme, the approach is extended to the Lennard-Jones fluids. It is shown that the viscosity profiles of inhomogeneous dense fluids deduced from this approach are consistent with those directly computed by non-equilibrium molecular dynamics simulations.
Flory-Huggins parameter χ, from binary mixtures of Lennard-Jones particles to block copolymer melts.
Chremos, Alexandros; Nikoubashman, Arash; Panagiotopoulos, Athanassios Z
2014-02-07
In this contribution, we develop a coarse-graining methodology for mapping specific block copolymer systems to bead-spring particle-based models. We map the constituent Kuhn segments to Lennard-Jones particles, and establish a semi-empirical correlation between the experimentally determined Flory-Huggins parameter χ and the interaction of the model potential. For these purposes, we have performed an extensive set of isobaric-isothermal Monte Carlo simulations of binary mixtures of Lennard-Jones particles with the same size but with asymmetric energetic parameters. The phase behavior of these monomeric mixtures is then extended to chains with finite sizes through theoretical considerations. Such a top-down coarse-graining approach is important from a computational point of view, since many characteristic features of block copolymer systems are on time and length scales which are still inaccessible through fully atomistic simulations. We demonstrate the applicability of our method for generating parameters by reproducing the morphology diagram of a specific diblock copolymer, namely, poly(styrene-b-methyl methacrylate), which has been extensively studied in experiments.
Leonardi, Erminia; D'Aguanno, Bruno; Angeli, Celestino
2011-03-21
The thermodiffusive behavior of a Lennard-Jones binary mixture has been studied by using nonequilibrium molecular dynamics. In particular, the dependence of the Soret coefficient, S(T), on the temperature and composition has been investigated, exploring a wide range of temperatures from 1000 K to the condensation temperature of the mixture. In a previous paper the dependence of S(T) on the temperature and the composition was studied for Lennard-Jones binary mixtures presenting mixing/demixing (consolute) phase transition, and the results allowed the formulation of a very simple expression with the computed values of S(T) in the one phase region outside the critical region closely fitted by the function [T - T(c)(x(1))](-1), with T(c)(x(1)) the demixing temperature of the mixture under study. The results of the present work show that the same expression of S(T) can be found for the one phase region outside the evaporation/condensation region but now with T(c) representing the condensation temperature of the mixture under study.
NASA Astrophysics Data System (ADS)
Chang, Jaeeon; Sandler, Stanley I.
2004-10-01
We propose Lennard-Jones potential parameters for interatomic interactions of linear and branched alkanes based on matching the results of Gibbs ensemble simulations of vapor-liquid equilibria to experimental data. The alkane model is similar as in the OPLS-AA [W. L. Jorgensen, D. S. Maxwell, and J. Tirado-Rives, J. Am. Chem. Soc. 118, 11225 (1996)], but multiple atom types for carbon based on the number of covalently bonded hydrogen atoms are necessary to accurately reproduce liquid densities and enthalpies of vaporization with the errors of 2.1% and 3.3%, respectively, for hydrocarbons of various chain lengths and structures. We find that the attraction energies of the carbon atoms are almost proportional to the number of covalent hydrogen atoms with each increasing the carbon energy parameter by ≈0.033 kcal/mol. Though the present force field outperforms the OPLS-AA force field for alkanes we studied, systematic deviations for vapor pressures are still observed with errors of 15%-30%, and critical temperatures are slightly underestimated. We think that these shortcomings are probably due to the inadequacy of the two-parameter Lennard-Jones potential, and especially its behavior at short distances.
Flory-Huggins parameter χ, from binary mixtures of Lennard-Jones particles to block copolymer melts
Chremos, Alexandros; Nikoubashman, Arash Panagiotopoulos, Athanassios Z.
2014-02-07
In this contribution, we develop a coarse-graining methodology for mapping specific block copolymer systems to bead-spring particle-based models. We map the constituent Kuhn segments to Lennard-Jones particles, and establish a semi-empirical correlation between the experimentally determined Flory-Huggins parameter χ and the interaction of the model potential. For these purposes, we have performed an extensive set of isobaric–isothermal Monte Carlo simulations of binary mixtures of Lennard-Jones particles with the same size but with asymmetric energetic parameters. The phase behavior of these monomeric mixtures is then extended to chains with finite sizes through theoretical considerations. Such a top-down coarse-graining approach is important from a computational point of view, since many characteristic features of block copolymer systems are on time and length scales which are still inaccessible through fully atomistic simulations. We demonstrate the applicability of our method for generating parameters by reproducing the morphology diagram of a specific diblock copolymer, namely, poly(styrene-b-methyl methacrylate), which has been extensively studied in experiments.
NASA Astrophysics Data System (ADS)
Heffelfinger David, Grant S.; Ford, M.
A new algorithm to enable the implementation of dual control volume grand canonical molecular dynamics (DCV-GCMD) on massively parallel (MP) architectures is presented. DCVGCMD can be thought of as hybridization of molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) and was developed recently to make possible the simulation of gradient-driven diffusion. The method has broad application to such problems as membrane separations, drug delivery systems, diffusion in polymers and zeolites, etc. The massively parallel algorithm for the DCV-GCMD method has been implemented in a code named LADERA which employs the short range Lennard-Jones potential for pure fluids and multicomponent mixtures including bulk and confined (single pore as well as amorphous solid materials) systems. Like DCV-GCMD, LADERA's MP algorithm can be thought of as a hybridization of two different algorithms, spatial MD and spatial GCMC. The DCV-GCMD method is described fully followed by the DCV-GCMD parallel algorithm employed in LADERA. The scaling characteristics of the new MP algorithm are presented together with the results of the application of LADERA to ternary and quaternary Lennard-Jones mixtures.
Flory-Huggins parameter χ, from binary mixtures of Lennard-Jones particles to block copolymer melts
NASA Astrophysics Data System (ADS)
Chremos, Alexandros; Nikoubashman, Arash; Panagiotopoulos, Athanassios Z.
2014-02-01
In this contribution, we develop a coarse-graining methodology for mapping specific block copolymer systems to bead-spring particle-based models. We map the constituent Kuhn segments to Lennard-Jones particles, and establish a semi-empirical correlation between the experimentally determined Flory-Huggins parameter χ and the interaction of the model potential. For these purposes, we have performed an extensive set of isobaric-isothermal Monte Carlo simulations of binary mixtures of Lennard-Jones particles with the same size but with asymmetric energetic parameters. The phase behavior of these monomeric mixtures is then extended to chains with finite sizes through theoretical considerations. Such a top-down coarse-graining approach is important from a computational point of view, since many characteristic features of block copolymer systems are on time and length scales which are still inaccessible through fully atomistic simulations. We demonstrate the applicability of our method for generating parameters by reproducing the morphology diagram of a specific diblock copolymer, namely, poly(styrene-b-methyl methacrylate), which has been extensively studied in experiments.
NASA Astrophysics Data System (ADS)
Brian Pitts, J.
James L. Anderson analyzed the novelty of Einstein's theory of gravity as its lack of "absolute objects." Michael Friedman's related work has been criticized by Roger Jones and Robert Geroch for implausibly admitting as absolute the timelike 4-velocity field of dust in cosmological models in Einstein's theory. Using Rosen-Sorkin Lagrange multiplier trick, I complete Anna Maidens's argument that the problem is not solved by prohibiting variation of absolute objects in an action principle. Recalling Anderson's proscription of "irrelevant" variables, I generalize that proscription to locally irrelevant variables that do no work in some places in some models. This move vindicates Friedman's intuitions and removes the Jones-Geroch counterexample: some regions of some models of gravity with dust are dust-free and so naturally lack a timelike 4-velocity, so diffeomorphic equivalence to (1,0,0,0) is spoiled. Torretti's example involving constant curvature spaces is shown to have an absolute object on Anderson's analysis, viz., the conformal spatial metric density. The previously neglected threat of an absolute object from an orthonormal tetrad used for coupling spinors to gravity appears resolvable by eliminating irrelevant fields. However, given Anderson's definition, GTR itself has an absolute object (as Robert Geroch has observed recently): a change of variables to a conformal metric density and a scalar density shows that the latter is absolute.
Pitt, Mark M.
2013-01-01
The paper “High Noon for Microfinance Impact Evaluations” by Duvendack and Palmer-Jones replicates the papers of Chemin (2008) and Pitt and Khandker (1998) that estimate the impact of microfinance in Bangladesh. My paper replicates the Duvendack and Palmer-Jones replication and finds so many serious errors in their code and misrepresentations of the methods described in their paper that I conclude that their results are spurious and provide no evidence about the validity of either the papers of Chemin or Pitt and Khandker or on the effectiveness of microfinance. PMID:24833807
Kulinskii, V L
2010-10-07
We analyze the interrelation between the coexistence curve of the Lennard-Jones fluid and the Ising model in two and three dimensions within the global isomorphism approach proposed earlier [V. L. Kulinskii, J. Phys. Chem. B 114, 2852 (2010)]. In case of two dimensions, we use the exact Onsager result to construct the binodal of the corresponding Lennard-Jones fluid and compare it with the results of the simulations. In the three-dimensional case, we use available numerical results for the Ising model for the corresponding mapping. The possibility to observe the singularity of the binodal diameter is discussed.
NASA Astrophysics Data System (ADS)
Staśkiewicz, B.; Okrasiński, W.
2012-04-01
We propose a simple analytical form of the vapor-liquid equilibrium curve near the critical point for Lennard-Jones fluids. Coexistence densities curves and vapor pressure have been determined using the Van der Waals and Dieterici equation of state. In described method the Bernoulli differential equations, critical exponent theory and some type of Maxwell's criterion have been used. Presented approach has not yet been used to determine analytical form of phase curves as done in this Letter. Lennard-Jones fluids have been considered for analysis. Comparison with experimental data is done. The accuracy of the method is described.
NASA Astrophysics Data System (ADS)
Temelkov, K. A.; Slaveeva, S. I.; Fedchenko, Yu I.
2016-03-01
Thermal conductivities of helium, neon, bromine, and hydrogen are calculated on the basis of the (12-6) Lennard-Jones interaction approximation. Where necessary for a more precise approximation, a generalized (n-m) Lennard-Jones interaction potential is used. Thermal conductivities of binary gas systems are calculated and compared through two different empirical methods for the case of gas discharges in He, Ne, and Ne-He mixtures with small admixtures of bromine and hydrogen. A new simple method is proposed for the thermal conductivity determination for the 3- and 4-component gas mixtures of our interest.
Crew of STS-98, L to R: Mission Specialists Robert L. Curbeam, Thomas D. Jones, and Marsha S. Ivins,
NASA Technical Reports Server (NTRS)
2001-01-01
The crew of STS-98 poses for a group photo shortly before leaving NASA's Dryden Flight Research Center after a successful landing of the Space Shuttle Atlantis the day before. L to R: Mission Specialists Robert L. Curbeam, Thomas D. Jones, and Marsha S. Ivins, Commander Kenneth D. Cockrell, and Pilot Mark L. Polansky. Space Shuttle Atlantis landed at 12:33 p.m. February 20, 2001, on the runway at Edwards Air Force Base, California, where NASA's Dryden Flight Research Center is located. The mission, which began February 7, logged 5.3 million miles as the shuttle orbited earth while delivering the Destiny science laboratory to the International Space Station. Inclement weather conditions in Florida prompted the decision to land Atlantis at Edwards. The last time a space shuttle landed at Edwards was Oct. 24, 2000.
Yamanari, Masahiro; Tsuda, Satoru; Kokubun, Taiki; Shiga, Yukihiro; Omodaka, Kazuko; Aizawa, Naoko; Yokoyama, Yu; Himori, Noriko; Kunimatsu-Sanuki, Shiho; Maruyama, Kazuichi; Kunikata, Hiroshi; Nakazawa, Toru
2016-01-01
Estimation of polarimetric parameters has been a fundamental issue to assess biological tissues that have form birefringence or polarization scrambling in polarization-sensitive optical coherence tomography (PS-OCT). We present a mathematical framework to provide a maximum likelihood estimation of the target covariance matrix and its incoherent target decomposition to estimate a Jones matrix of a dominant scattering mechanism, called Cloude-Pottier decomposition, thereby deriving the phase retardation and the optic axis of the sample. In addition, we introduce entropy that shows the randomness of the polarization property. Underestimation of the entropy at a low sampling number is mitigated by asymptotic quasi maximum likelihood estimator. A bias of the entropy from random noises is corrected to show only the polarization property inherent in the sample. The theory is validated with experimental measurements of a glass plate and waveplates, and applied to the imaging of a healthy human eye anterior segment as an image filter. PMID:27699120
Benjamin, Ronald; Horbach, Jürgen
2015-07-07
Kinetics of crystal-growth is investigated along the solid-liquid coexistence line for the (100), (110), and (111) orientations of the Lennard-Jones (LJ) and Weeks-Chandler-Andersen (WCA) fcc crystal-liquid interface, using non-equilibrium molecular dynamics simulations. A slowing down of the growth kinetics along the coexistence line is observed, which is due to the decrease of the melting enthalpy with increasing coexistence temperature and pressure. Other quantities such as the melting pressure and liquid self-diffusion coefficient have a comparatively lesser impact on the kinetic growth coefficient. Growth kinetics of the LJ and WCA potentials become similar at large values of the melting temperature and pressure, when both resemble a purely repulsive soft-sphere potential. Classical models of crystallization from the melt are in reasonable qualitative agreement with our simulation data. Finally, several one-phase empirical melting/freezing rules are studied with respect to their validity along the coexistence line.
NASA Astrophysics Data System (ADS)
Shiba, H.; Onuki, A.
We examine the changeover in the particle configurations and the dynamics in dense Lennard-Jones binary mixtures composed of small and large particles. By varying the composition at a low temperature, we realize crystal with defects, polycrystal with small grains, and glass with various degrees of disorder. In particular, we show configurations where small crystalline regions composed of the majority species are enclosed by percolated amorphous layers composed of the two species. We visualize the dynamics of configuration changes using the method of bond breakage and following the particle displacements. In quiescent jammed states, the dynamics is severely slowed down and is highly heterogeneous at any compositions. We apply shear flow by relative motions of boundary layers. Then plastic deformations multiply occur in relatively fragile regions, growing into large-scale shear bands where the strain is highly localized. Such bands appear on short time scales and evolve on l ong time scales with finite lifetimes.
Yamanari, Masahiro; Tsuda, Satoru; Kokubun, Taiki; Shiga, Yukihiro; Omodaka, Kazuko; Aizawa, Naoko; Yokoyama, Yu; Himori, Noriko; Kunimatsu-Sanuki, Shiho; Maruyama, Kazuichi; Kunikata, Hiroshi; Nakazawa, Toru
2016-09-01
Estimation of polarimetric parameters has been a fundamental issue to assess biological tissues that have form birefringence or polarization scrambling in polarization-sensitive optical coherence tomography (PS-OCT). We present a mathematical framework to provide a maximum likelihood estimation of the target covariance matrix and its incoherent target decomposition to estimate a Jones matrix of a dominant scattering mechanism, called Cloude-Pottier decomposition, thereby deriving the phase retardation and the optic axis of the sample. In addition, we introduce entropy that shows the randomness of the polarization property. Underestimation of the entropy at a low sampling number is mitigated by asymptotic quasi maximum likelihood estimator. A bias of the entropy from random noises is corrected to show only the polarization property inherent in the sample. The theory is validated with experimental measurements of a glass plate and waveplates, and applied to the imaging of a healthy human eye anterior segment as an image filter.
Figure-eight choreographies of the equal mass three-body problem with Lennard-Jones-type potentials
NASA Astrophysics Data System (ADS)
Fukuda, Hiroshi; Fujiwara, Toshiaki; Ozaki, Hiroshi
2017-03-01
We report on figure-eight choreographic solutions to a system of three identical particles interacting through a potential of Lennard-Jones-type 1/{{r}12}-1/{{r}6} , where r is distance between the particles. By numerical search, we found there are a multitude of such solutions. A series of them are close to a figure-eight solutions to a homogeneous system with no 1/r 12 term in the potential. The rest are very different, and have several points with large curvatures in their figure-eight orbits at which particles are repelled. Here figure-eight choreographies are periodic motions whose shape is symmetric in both horizontal and vertical axes, starting with an isosceles triangle configuration and going back to an isosceles triangle configuration with opposite direction through Euler configuration. Thus the lobe of such a figure-eight may be complex in shape, and need not be convex.
Gittleman, J.; Estacio, P.; O'Brien, D.; Montopoli, M.
1991-06-01
In response to a request for technical assistance from the Alabama Health Department, possible hazardous working conditions at the G.T. Jones Tire and Battery Distributing Company (SIC-5093), Birmingham, Alabama were evaluated. The company employed 15 persons in battery breaking and recycling. Twelve of the workers had blood lead (7439921) levels over 60 micrograms/deciliter (microg/dl) and the average of the last three blood levels exceeded 50microg/dl for 13 of the employees. Blood lead levels greater than 60 were associated with biochemical evidence of impaired heme synthesis and impaired renal function. Fourteen workers had elevated zinc protoporphyrin (ZPP) levels over 100microg/dl consistent with moderate lead poisoning. Three had ZPPs over 600 microg/dl, consistent with severe lead poisoning. The authors conclude that a health hazard existed from overexposure to lead. The authors recommend measures to reduce exposures.
NASA Astrophysics Data System (ADS)
Hajigeorgiou, Photos G.
2016-12-01
An analytical model for the diatomic potential energy function that was recently tested as a universal function (Hajigeorgiou, 2010) has been further modified and tested as a suitable model for direct-potential-fit analysis. Applications are presented for the ground electronic states of three diatomic molecules: oxygen, carbon monoxide, and hydrogen fluoride. The adjustable parameters of the extended Lennard-Jones potential model are determined through nonlinear regression by fits to calculated rovibrational energy term values or experimental spectroscopic line positions. The model is shown to lead to reliable, compact and simple representations for the potential energy functions of these systems and could therefore be classified as a suitable and attractive model for direct-potential-fit analysis.
Makita, Shuichi; Kurokawa, Kazuhiro; Hong, Young-Joo; Miura, Masahiro; Yasuno, Yoshiaki
2016-01-01
This paper describes a complex correlation mapping algorithm for optical coherence angiography (cmOCA). The proposed algorithm avoids the signal-to-noise ratio dependence and exhibits low noise in vasculature imaging. The complex correlation coefficient of the signals, rather than that of the measured data are estimated, and two-step averaging is introduced. Algorithms of motion artifact removal based on non perfusing tissue detection using correlation are developed. The algorithms are implemented with Jones-matrix OCT. Simultaneous imaging of pigmented tissue and vasculature is also achieved using degree of polarization uniformity imaging with cmOCA. An application of cmOCA to in vivo posterior human eyes is presented to demonstrate that high-contrast images of patients’ eyes can be obtained. PMID:27446673
Maddox, M.W.; Gubbins, K.E.
1997-12-01
A combination of grand canonical Monte Carlo and molecular dynamics simulation techniques are used to study the freezing and melting of Lennard-Jones methane in several different cylindrical pores. Two different types of pore wall are considered; a strongly attractive wall, and a weakly attractive wall, each with pore diameters in the range 1.5{endash}3.5 nm. Freezing point depression is observed in the case of the weakly attractive pores, in agreement with several experimental studies. Freezing point elevation is observed at the walls of the strongly attractive pore, but freezing point depression occurs at the center of such pores, due to geometrical constraints. {copyright} {ital 1997 American Institute of Physics.}
NASA Astrophysics Data System (ADS)
Hardy, Robert J.; Day, Michael A.; Shukla, Ramesh C.; Cowley, E. Roger
1994-04-01
The equations for determining the free energy of a solid with two-body interactions in the uncorrelated-factors approximation (UFA) are derived from the correlated-factors theorem. A self-consistent choice of the parameters in the harmonic Hamiltonian causes the approximation to be accurate through second order. The specific heat, thermal expansion, and bulk modulus of an fcc Lennard-Jones solid with nearest-neighbor interactions only are calculated in the UFA and the results are compared with the predictions of lowest-order and improved self-consistent phonon theory (SC1 and ISC), perturbation theory through fourth order, and other approximations. The predictions of the UFA are in very good agreement with new classical Monte Carlo estimates and with recent effective potential Monte Carlo results. The calculational effort required in the UFA is similar to that in SC1, while the accuracy of the predictions is similar to that of ISC.
Zimmerman, Paul M; Head-Gordon, Martin; Bell, Alexis T
2011-06-14
Quantum mechanics/molecular mechanics (QM/MM) models are an appealing method for performing zeolite simulations. In QM/MM, a small cluster chosen to encompass the active center is described by QM, while the rest of the zeolite is described by MM. In the present study, we demonstrate that the charges and Lennard-Jones parameters on Si and O must be chosen properly for QM/MM calculations of adsorption energies and activation energies to agree closely with full QM calculations. The selection of parameters for Si and O is based on using the ωB97X-D functional for DFT calculations of the QM region, which is effective in capturing the effects of van der Waals interactions. A comparison of the heats of adsorption for a variety of adsorbates and activation energies for the cracking of propane and butane reveals that energies derived from QM/MM calculation carried out with appropriately selected MM parameters agree to within an rms error of ∼1.5 kcal/mol with QM calculations. To avoid reparametrization for new substrates, Lennard-Jones zeolite parameters are chosen to be compatible with existing CHARMM parameters. Transferability of these parameters is demonstrated by tests utilizing the B3LYP density functional and simulations of MFI and FAU zeolites. Moreover, the computational time for QM/MM calculations is considerably lower than that for QM calculations, and the ratio of computational times decreases rapidly with increasing size of the cluster used to represent the zeolite.
Wilson, D Scott; Lee, Lloyd L
2005-07-22
We explore the vapor-liquid phase behavior of binary mixtures of Lennard-Jones-type molecules where one component is supercritical, given the system temperature. We apply the self-consistency approach to the Ornstein-Zernike integral equations to obtain the correlation functions. The consistency checks include not only thermodynamic consistencies (pressure consistency and Gibbs-Duhem consistency), but also pointwise consistencies, such as the zero-separation theorems on the cavity functions. The consistencies are enforced via the bridge functions in the closure which contain adjustable parameters. The full solution requires the values of not only the monomer chemical potentials, but also the dimer chemical potentials present in the zero-separation theorems. These are evaluated by the direct chemical-potential formula [L. L. Lee, J. Chem. Phys. 97, 8606 (1992)] that does not require temperature nor density integration. In order to assess the integral equation accuracy, molecular-dynamics simulations are carried out alongside the states studied. The integral equation results compare well with simulation data. In phase calculations, it is important to have pressure consistency and valid chemical potentials, since the matching of phase boundaries requires the equality of the pressures and chemical potentials of both the liquid and vapor phases. The mixtures studied are methane-type and pentane-type molecules, both characterized by effective Lennard-Jones potentials. Calculations on one isotherm show that the integral equation approach yields valid answers as compared with the experimental data of Sage and Lacey. To study vapor-liquid phase behavior, it is necessary to use consistent theories; any inconsistencies, especially in pressure, will vitiate the phase boundary calculations.
ERIC Educational Resources Information Center
Pike, Mark A.
2011-01-01
This article presents the author's reply to the comments of Bragg, Allington, Simmons and Jones to his article "Transaction and transformation at Trinity" (Pike, 2010) wherein he reported a case study of Trinity Academy, which serves a former mining community and social priority area near Doncaster in South Yorkshire. In 2008, just…
Johnson, W.R.; Dzuba, V.A.; Safronova, U.I.; Safronova, M.S.
2004-02-01
A finite-field scaling method is applied to evaluate the Lennard-Jones interaction constant C{sub 3} for alkali-metal atoms. The calculations are based on the relativistic single-double approximation in which single and double excitations of Dirac-Hartree-Fock wave functions are included to all orders in perturbation theory.
ERIC Educational Resources Information Center
Friend, Colleen
2012-01-01
Cross, Fine, Jones, and Walsh's (2012) article "Mental Health Professionals in Children's Advocacy Centers: Is There Role Conflict?" challenges two recent publications' criticisms that child advocacy centers create role conflict for mental health professionals and explains how child advocacy centers actually work, describing the different roles…
ERIC Educational Resources Information Center
Helms, J. Christopher; Corbett, Robert J.
This activity guide, developed to provide hands-on environmental education activities geared to Jones Lake State Park in North Carolina, is targeted for grades 6, 7, and 8 and meets curriculum objectives in the standard course of study established by the North Carolina Department of Public Instruction. Three types of activities are included:…
ERIC Educational Resources Information Center
Vuoksimaa, Eero; Kaprio, Jaakko
2010-01-01
The lack of sex difference in left-handedness in Scandinavian countries reported by Papadatou-Pastou, Martin, Munafo, and Jones (2008) is questioned. We investigated the sex difference in left-handedness in two Finnish, one Norwegian, and one Swedish population-based sample not included in the Papadatou-Pastou et al. (2008) meta-analysis. The…
ERIC Educational Resources Information Center
Parker, R. Clyde
1981-01-01
In the revocation of Bob Jones University's tax exemption because of prohibition of interracial dating, these questions are addressed: Has the IRS the authority to interpret public policy, and if so, may it impinge on free exercise of religious beliefs that favor some organizations over others? (Author/MSE)
Kikugawa, Gota; Ando, Shotaro; Suzuki, Jo; Naruke, Yoichi; Nakano, Takeo; Ohara, Taku
2015-01-14
In the present study, molecular dynamics (MD) simulations on the monatomic Lennard-Jones liquid in a periodic boundary system were performed in order to elucidate the effect of the computational domain size and shape on the self-diffusion coefficient measured by the system. So far, the system size dependence in cubic computational domains has been intensively investigated and these studies showed that the diffusion coefficient depends linearly on the inverse of the system size, which is theoretically predicted based on the hydrodynamic interaction. We examined the system size effect not only in the cubic cell systems but also in rectangular cell systems which were created by changing one side length of the cubic cell with the system density kept constant. As a result, the diffusion coefficient in the direction perpendicular to the long side of the rectangular cell significantly increases more or less linearly with the side length. On the other hand, the diffusion coefficient in the direction along the long side is almost constant or slightly decreases. Consequently, anisotropy of the diffusion coefficient emerges in a rectangular cell with periodic boundary conditions even in a bulk liquid simulation. This unexpected result is of critical importance because rectangular fluid systems confined in nanospace, which are present in realistic nanoscale technologies, have been widely studied in recent MD simulations. In order to elucidate the underlying mechanism for this serious system shape effect on the diffusion property, the correlation structures of particle velocities were examined.
NASA Astrophysics Data System (ADS)
Separdar, L.; Davatolhagh, S.
2016-12-01
Molecular dynamics simulations at constant (N , V , T) are used to study the mutual effects of gold nanoparticles on the structure and dynamics of Kob-Andersen binary Lennard-Jones (BLJ) liquid within the framework of mode coupling theory of dynamic glass transition in the reciprocal space. The results show the 'softening' effect of the gold nanoparticles on the liquid dynamics in terms of (i) reducing the mode coupling crossover temperature Tc with respect to that of the bulk BLJ (i.e. BLJ without nanoparticles), (ii) decreasing the time interval of β-relaxation, and (iii) decreasing the exponent γ characterizing the power-law behavior of the α-relaxation time. This softening effect is explained in terms of the van der Waals attraction between the gold atoms comprising the nanoparticle and the BLJ host atoms, such that adsorption of host atoms onto the nanoparticle surface creates more space or free-volume for the other atoms to diffuse. By the same token interactions of purely excluded-volume-type are expected to result in the opposite effect. It is also noted that, much unlike BLJ host particles, the dynamics of gold nanoparticles is much less dependent on the wave-vector and that it exhibits a nearly exponential behavior in the α-relaxation regime.
Wennberg, Christian L; Murtola, Teemu; Páll, Szilárd; Abraham, Mark J; Hess, Berk; Lindahl, Erik
2015-12-08
Long-range lattice summation techniques such as the particle-mesh Ewald (PME) algorithm for electrostatics have been revolutionary to the precision and accuracy of molecular simulations in general. Despite the performance penalty associated with lattice summation electrostatics, few biomolecular simulations today are performed without it. There are increasingly strong arguments for moving in the same direction for Lennard-Jones (LJ) interactions, and by using geometric approximations of the combination rules in reciprocal space, we have been able to make a very high-performance implementation available in GROMACS. Here, we present a new way to correct for these approximations to achieve exact treatment of Lorentz-Berthelot combination rules within the cutoff, and only a very small approximation error remains outside the cutoff (a part that would be completely ignored without LJ-PME). This not only improves accuracy by almost an order of magnitude but also achieves absolute biomolecular simulation performance that is an order of magnitude faster than any other available lattice summation technique for LJ interactions. The implementation includes both CPU and GPU acceleration, and its combination with improved scaling LJ-PME simulations now provides performance close to the truncated potential methods in GROMACS but with much higher accuracy.
NASA Astrophysics Data System (ADS)
Lima, N. W.; Gutierres, L. I.; Gonzalez, R. I.; Müller, S.; Thomaz, R. S.; Bringa, E. M.; Papaléo, R. M.
2016-11-01
In this paper, the surface effects of individual heavy ions impacting thin polymerlike films were investigated, using molecular dynamics simulations with the finite extensible nonlinear elastic (FENE) potential to describe the molecular chains. The perturbation introduced by the ions in the lattice was modeled assuming that the initial excitation energy in the ion track is converted into an effective temperature, as in a thermal spike. The track was heated only within the film thickness h , leaving a nonexcited substrate below. The effect of decreasing thickness on cratering and sputtering was evaluated. The results were compared to experimental data of thin polymer films bombarded by MeV-GeV ions and to simulations performed with the Lennard-Jones potential. While several qualitative results observed in the experiments were also seen in the simulations, irrespective of the potential used, there are important differences observed on FENE films. Crater dimensions, rim volume, and sputtering yields are substantially reduced, and a threshold thickness for molecular ejection appears in FENE simulations. This is attributed to the additional restrictions on mass transport out of the excited track region imposed by interchain interactions (entanglements) and by the low mobility of the molten phase induced by the spike.
Gordiz, Kiarash; Henry, Asegun
2015-12-17
To date, the established methods that describe thermal interface conductance (TIC) and include mode-level dependence have not included anharmonicity. The current intuition is therefore based on the behavior in the harmonic limit, whereby the extent of overlap in the bulk phonon density of states (DoS) (e.g., frequency overlap) dictates the TIC and more frequency overlap leads to higher TIC. Here, we study over 2,000 interfaces described by the Lennard-Jones potential using equilibrium molecular dynamics simulations, whereby we systematically change the mass and stiffness of each side. We show that the trends in TIC do not generally follow that of the bulk phonon DoS overlap, but instead more closely follow the vibrational power spectrum overlap for the interfacial atoms. We then identify the frequency overlap in the interfacial power spectra as an improved descriptor for understanding the qualitative trends in TIC. Although improved, the results show that the basic intuition of frequency overlap is still insufficient to explain all of the features, as the remaining variations are shown to arise from anharmonicity, which is a critical effect to include in interface calculations above cryogenic temperatures.
Frangione, B; Moloshok, T; Prelli, F; Solomon, A
1985-01-01
Serologic, structural, and genetic analyses have shown that the constant (C) region of human kappa light chains is encoded by a single gene, whereas that of lambda chains is encoded by multiple genes. We have determined the complete C region amino acid sequence of two monoclonal lambda VI light chains, Bence Jones proteins Sut and Mor. The C region of lambda chains Sut and Mor consists of 105 residues, as is characteristic for human lambda light chains, of which 102 are identical in sequence. Protein Sut has the C region sequence associated with the C lambda isotype Mcg-, Kern-, Oz+ and represents a product of the C lambda 3 (Kern-, Oz+) gene. Protein Mor has a C region sequence associated with Mcg-, Kern-, and Oz- proteins but differs from protein Sut by the presence of three amino acid interchanges at positions 168, 176, and 194. These substitutions distinguish protein Mor from lambda chains encoded by the C lambda 1 (Mcg+), C lambda 2 (Kern-, Oz-), and C lambda 3 (Kern-, Oz+) genes and provide further evidence for polymorphism of the human C lambda genome. The gene encoding the C region sequence of lambda chain Mor is designated CMor lambda. PMID:3923477
NASA Astrophysics Data System (ADS)
Das, Subir K.; Puri, Sanjay; Horbach, Jürgen; Binder, Kurt
2006-03-01
We use molecular dynamics (MD) to simulate an unstable homogeneous mixture of binary fluids (AB), confined in a slit pore of width D . The pore walls are assumed to be flat and structureless and attract one component of the mixture (A) with the same strength. The pairwise interactions between the particles are modeled by the Lennard-Jones potential, with symmetric parameters that lead to a miscibility gap in the bulk. In the thin-film geometry, an interesting interplay occurs between surface enrichment and phase separation. We study the evolution of a mixture with equal amounts of A and B, which is rendered unstable by a temperature quench. We find that A-rich surface enrichment layers form quickly during the early stages of the evolution, causing a depletion of A in the inner regions of the film. These surface-directed concentration profiles propagate from the walls towards the center of the film, resulting in a transient layered structure. This layered state breaks up into a columnar state, which is characterized by the lateral coarsening of cylindrical domains. The qualitative features of this process resemble results from previous studies of diffusive Ginzburg-Landau-type models [S. K. Das, S. Puri, J. Horbach, and K. Binder, Phys. Rev. E 72, 061603 (2005)], but quantitative aspects differ markedly. The relation to spinodal decomposition in a strictly two-dimensional geometry is also discussed.
Kang, S.-N.; De Sprenger Rover, W.B.; Walton, N.P.
2012-01-01
ABSTRACT Purpose: Radiological measurement scores are used by orthopaedic physiotherapists in triage and surveillance of patients with degenerative changes of the tibiofemoral and patellofemoral joints. The purpose of this study was to estimate the intra- and inter-observer reliability of a radiological measurement score to assess patellofemoral joint osteoarthritis, the Jones Patellofemoral Osteoarthritis Score (JPOS), with an orthopaedic physiotherapist and three grades of junior surgeons/doctors. Methods: A total of 390 skyline X-rays of the patellofemoral joint were reviewed on 2 occasions, 4 weeks apart, by an orthopaedic physiotherapist, 2 orthopaedic surgeons, and an orthopaedic doctor. Intra- and inter-observer reliability of the JPOS was calculated using a weighted kappa analysis. Results: The results indicated that while there was good overall intra-observer agreement for this measurement score for all assessors, inter-observer reliability was generally poor between the orthopaedic physiotherapist and the orthopaedic surgeons/doctor. Conclusion: Our findings call into question the use of the JPOS by orthopaedic physiotherapists working in triage or orthopaedic surveillance programmes with other orthopaedic clinicians. PMID:23729961
Georgescu, Ionuţ; Brown, Sandra E; Mandelshtam, Vladimir A
2013-04-07
In order to address the issue of whether neon liquid in coexistence with its gas phase can be mapped to a quantum Lennard-Jones (LJ) fluid, we perform a series of simulations using Gibbs ensemble Monte Carlo for a range of de Boer quantum parameters Λ=ℏ/(σ√(mε)). The quantum effects are incorporated by implementing the variational gaussian wavepacket method, which provides an efficient numerical framework for estimating the quantum density at thermal equilibrium. The computed data for the LJ liquid is used to produce its phase diagram as a function of the quantum parameter, 0.065 ≤ Λ ≤ 0.11. These data are then used to fit the experimental phase diagram for neon liquid. The resulting parameters, ε = 35.68 ± 0.03 K and σ = 2.7616 ± 0.0005 Å (Λ = 0.0940), of the LJ pair potential are optimized to best represent liquid neon in coexistence with its gas phase for a range of physically relevant temperatures. This multi-temperature approach towards fitting and assessing a pair-potential is much more consistent than merely fitting a single data point, such as a melting temperature or a second virial coefficient.
Lyke, W.L.; Winner, M.D.
1990-01-01
Unconsolidated sediments in Onslow and Jones Counties, North Carolina overlie crystalline basement rocks and range in thickness from about 700 ft to more than 1,800 ft, thickening toward the east. This material is composed of permeable sand and limestone interlayered with relatively impermeable clay and silt beds. Sediments are divided into two groups: aquifers in Quaternary-, and Tertiary-aged rocks and aquifers in Cretaceous-aged rocks. Aquifers in the Cretaceous rocks provide most of the groundwater for public supplies and are the focus of this report. The aquifers in Cretaceous rocks are the Peedee, Black Creek, upper Cape Fear, and lower Cape Fear aquifers, which are composed of beds or groups of beds of sand and gravel. Each aquifer is overlain by a clay and silt bed, that impedes the flow of water between aquifers. The thickness of Cretaceous hydrogeologic units ranges from about 700 ft to more than 1, 300 ft. Hydrogeologic units are correlated using 60 geophysical logs and accompanying drillers ' logs along with water level and water quality data. Three hydrogeologic sections demonstrate the continuity of the aquifers and confining units, show water levels and chloride concentration in water from test intervals, and delineate where chloride concentration in water exceeds 250 mg/L within each aquifer. Maps of each aquifer in Cretaceous rocks show altitude of its top, thickness, sand percentage, and the transition from freshwater to saltwater. Maps of the confining units show thickness and sand percentage of each.
NASA Astrophysics Data System (ADS)
Gordiz, Kiarash; Henry, Asegun
2015-12-01
To date, the established methods that describe thermal interface conductance (TIC) and include mode-level dependence have not included anharmonicity. The current intuition is therefore based on the behavior in the harmonic limit, whereby the extent of overlap in the bulk phonon density of states (DoS) (e.g., frequency overlap) dictates the TIC and more frequency overlap leads to higher TIC. Here, we study over 2,000 interfaces described by the Lennard-Jones potential using equilibrium molecular dynamics simulations, whereby we systematically change the mass and stiffness of each side. We show that the trends in TIC do not generally follow that of the bulk phonon DoS overlap, but instead more closely follow the vibrational power spectrum overlap for the interfacial atoms. We then identify the frequency overlap in the interfacial power spectra as an improved descriptor for understanding the qualitative trends in TIC. Although improved, the results show that the basic intuition of frequency overlap is still insufficient to explain all of the features, as the remaining variations are shown to arise from anharmonicity, which is a critical effect to include in interface calculations above cryogenic temperatures.
The role of fcc tetrahedral subunits in the phase behavior of medium sized Lennard-Jones clusters.
Saika-Voivod, Ivan; Poon, Louis; Bowles, Richard K
2010-08-21
The free energy of a 600-atom Lennard-Jones cluster is calculated as a function of surface and bulk crystallinity in order to study the structural transformations that occur in the core of medium sized clusters. Within the order parameter range studied, we find the existence of two free energy minima at temperatures near freezing. One minimum, at low values of both bulk and surface order, belongs to the liquid phase. The second minimum exhibits a highly ordered core with a disordered surface and is related to structures containing a single fcc-tetrahedral subunit, with an edge length of seven atoms (l=7), located in the particle core. At lower temperatures, a third minimum appears at intermediate values of the bulk order parameter which is shown to be related to the formation of multiple l=6 tetrahedra in the core of the cluster. We also use molecular dynamics simulations to follow a series of nucleation events and find that the clusters freeze to structures containing l=5, 6, 7, and 8 sized tetrahedra as well as those containing no tetrahedral units. The structural correlations between bulk and surface order with the size of the tetrahedral units in the cluster core are examined. Finally, the relationships between the formation of fcc tetrahedral subunits in the core, the phase behavior of medium sized clusters and the nucleation of noncrystalline global structures such as icosahedra and decahedra are discussed.
Gordiz, Kiarash; Henry, Asegun
2015-01-01
To date, the established methods that describe thermal interface conductance (TIC) and include mode-level dependence have not included anharmonicity. The current intuition is therefore based on the behavior in the harmonic limit, whereby the extent of overlap in the bulk phonon density of states (DoS) (e.g., frequency overlap) dictates the TIC and more frequency overlap leads to higher TIC. Here, we study over 2,000 interfaces described by the Lennard-Jones potential using equilibrium molecular dynamics simulations, whereby we systematically change the mass and stiffness of each side. We show that the trends in TIC do not generally follow that of the bulk phonon DoS overlap, but instead more closely follow the vibrational power spectrum overlap for the interfacial atoms. We then identify the frequency overlap in the interfacial power spectra as an improved descriptor for understanding the qualitative trends in TIC. Although improved, the results show that the basic intuition of frequency overlap is still insufficient to explain all of the features, as the remaining variations are shown to arise from anharmonicity, which is a critical effect to include in interface calculations above cryogenic temperatures. PMID:26678793
NASA Astrophysics Data System (ADS)
Li, Hailong; Liu, Jianguo; Huang, Xiaoting; Wang, Dan; Zhang, Zhifeng
2014-08-01
DAX1, a member of nuclear receptor superfamily, has a function in the sex determination and gonadal differentiation of several vertebrate species. However, little information about DAX1 of invertebrates is available. Here we cloned a homolog of scallop ( Chlamys farreri Jones and Preston 1904) dax1, Cf-dax1, and determined its expression characteristics at mRNA and protein levels. The cDNA sequence of Cf-dax1 was 2093 bp in length, including 1404 bp open reading frame (ORF) encoding 467 amino acids. Unlike those of vertebrates, no conserved LXXLL-related motif was found in the putative DNA binding region of Cf-DAX1. Fluorescence in situ hybridization showed that Cf-dax1 located on the short arm of a pair of subtelocentric chromosomes. Tissue distribution analysis using semi-quantitative RT-PCR revealed that Cf-dax1 expressed widely in adult scallop tissues, with the highest expression level found in adductor muscle, moderate level in mantle, gill and testis, and low level in kidney, ovary and hepatopancreas. The result of quantitative real-time PCR indicated that the expression of Cf-dax1 was significantly higher ( P<0.05) in testis than in ovary at the same stage, showing a sex-dimorphic expression pattern. Furthermore, immunohistochemical detection found that Cf-DAX1 mainly located in spermatogonia and spermatocytes of testis and in oogonia and oocytes of ovary, implying that DAX1 may involve in gametogenesis of bivalves.
Peng, Lu Jian; Morris, James R; Aga, Rachel S
2010-08-28
Large scale simulations of crystal nucleation from the liquid are performed using the Lennard-Jones potential to determine the time required for nucleation. By considering both transient and finite-size effects, we for the first time successfully predict the nucleation time without any parameter fitting in the Lennard-Jones system. All necessary parameters are derived from separate, equilibrium simulations. At small undercoolings, large system size effects are observed. The required system size is not only determined by the size of the critical nuclei, but also the characteristic spacing between them. Two distinct nucleation regions are predicted by theory and observed by the simulations, which are dominated by the transient time and the steady-state nucleation time, respectively.
Bárcenas, M; Reyes, Y; Romero-Martínez, A; Odriozola, G; Orea, P
2015-02-21
Coexistence and interfacial properties of a triangle-well (TW) fluid are obtained with the aim of mimicking the Lennard-Jones (LJ) potential and approach the properties of noble gases. For this purpose, the scope of the TW is varied to match vapor-liquid densities and surface tension. Surface tension and coexistence curves of TW systems with different ranges were calculated with replica exchange Monte Carlo and compared to those data previously reported in the literature for truncated and shifted (STS), truncated (ST), and full Lennard-Jones (full-LJ) potentials. We observed that the scope of the TW potential must be increased to approach the STS, ST, and full-LJ properties. In spite of the simplicity of TW expression, a remarkable agreement is found. Furthermore, the variable scope of the TW allows for a good match of the experimental data of argon and xenon.
Jones, Ross L
2014-03-01
In 1926, Frederic Wood Jones, professor of Anatomy at the University of Adelaide and a leading figure in the British anatomical world, took a Rockefeller Foundation funded trip to the United States in order to inspect anatomy programmes and medical museums and to meet leading figures in the anatomical and anthropological world. His later reflections paint a picture of a discipline in transition. Physical anthropology and gross anatomy were coming to a crisis point in the United States, increasingly displaced by research in histology, embryology and radiological anatomy. Meanwhile, in Britain and its colonial outposts, anatomists such as Wood Jones were attempting to re-invigorate the discipline in the field, studying biological specimens as functional and active agents in their particular milieus, but with human dissection at the core. Thus, an examination of this trip allows us to see how the interaction between two traditions in anatomy informed the process of the development of human biology in this critical period.
Leorri, E.; Martin, R.; McLaughlin, P.
2006-01-01
The benthic foraminiferal record of marshes located along western Delaware Bay (St. Jones Estuary, USA) reflects the response of estuaries to sea-level and paleoclimate change during the Holocene. System tracts are recognized and within them parasequences based on sedimentological and foraminiferal assemblages identification. The parasequences defined by foraminiferal assemblages appear correlative with rapid Holocene climate changes that are of worldwide significance: 6000-5000, 4200-3800, 3500-2500, 1200-1000, and 600??cal years BP. Following postglacial sea-level rise, modern subestuaries and marshes in the region began to develop between 6000 and 4000??years BP, depending on their proximity to the mouth of Delaware Bay and coastal geomorphology. Initial sediments were fluvial in origin, with freshwater marshes established around 4000??years BP. The subsequent sea-level transgression occurred sufficiently slowly that freshwater marshes alternated with salt marshes at the same sites to around 3000??years BP. Locally another two transgressions are identified at 1800 and 1000??years BP respectively. Marine influence increased in the estuaries until 600??years BP (Little Ice Age), when regression occurred. Sea-level began to rise again during the mid-19th Century at the end of the Little Ice Age, when marshes became established. The presence of a sand lens in the upper and middle estuary and the reduction in the number of tests in the top samples in cores from the same area also suggest an anthropogenic influence. The estuary infill resulted in a sharp transgressive sequence, represented by salt marsh foraminiferal assemblages in the upper part of the cores. The increase in marsh foraminifera in both areas suggests an increase in marine influence that might be due to the transgression beginning at the end of the Little Ice Age about 150-180??years ago coupled with anthropogenic straightening of the channel in 1913. ?? 2006 Elsevier B.V. All rights reserved.
NASA Astrophysics Data System (ADS)
Matsumoto, Hiroaki
2002-12-01
The variable sphere (VS) molecular model for the Monte Carlo simulation of rarefied gas flow is introduced to provide consistency for diffusion and viscosity cross-sections with those of any realistic intermolecular potential. It is then applied to the inverse power law (IPL) and Lennard-Jones (LJ) potentials. The VS model has a much simpler scattering law than either the variable hard sphere (VHS) or variable soft sphere (VSS) models; also, it has almost the same computational efficiency as the VHS and VSS models. A simulation of velocity relaxation in a homogeneous space and two comparative simulations of molecular diffusion in a homogeneous heat-bath gas and normal shock wave structure in a monatomic gas are made to examine VS model validity. The relaxation to a Maxwellian distribution function and equipartition between all degrees of freedom are well established; good agreement is shown in the molecular diffusion and shock wave structure between the VS model and the IPL and LJ potentials. The VS model is combined with the statistical inelastic cross-section (SICS) model and applied to simulation of translational and rotational energy relaxation in a homogeneous space. The VS model shows the relaxation of Maxwellian and Boltzmann distribution functions and equipartition between all degrees of freedom. Comparative calculation between the VS model with the SICS (VS-SICS) model and the VSS model with the SICS (VSS-SICS) model is made for rotational relaxation in a nitrogen normal shock wave. Good agreement is shown in the shock wave structure and rotational energy distribution function between the VS-SICS model and the VSS-SICS model. This study demonstrates that diffusion and viscosity cross-sections, rather than the scattering law of each molecular collision, affect macroscopic transport phenomena.
Zhou, Shiqi
2010-09-09
Local self-consistent Ornstein-Zernike (OZ) integral equation theory (IET) provides a rapid and easy route for obtaining independently thermodynamic and structural information for a single state point. Because of neglect of information of neighboring state points in determining a self-consistent adjustable parameter performance of the local self-consistent OZ IET is somewhat vulnerable and worthy of intensive investigation. For this reason, we have performed Monte Carlo simulations to obtain thermodynamic and structural properties of fluid with a generalized Lennard-Jones potential, and the present simulation results are employed to verify the quality of a local version of a recently developed global self-consistent OZ IET and a local expression for computation of excess chemical potential directly from the structural functions of the state point of interest. Comprehensive comparison and analysis demonstrate the following (i) the present local self-consistent OZ IET performs quite well for calculation of pressure and excess internal energy; (ii) using the same structural functions from the present local self-consistent OZ IET, the previously derived local expression by the present author has by and large the same accuracy in calculating the excess chemical potential as an exact virial formula for the pressure; (iii) although the excellent performance exhibited for the above thermodynamic quantities persists to very low temperature and very short-ranged potential and remains even in the liquid-solid coexistence region, the excess Helmholtz free energy calculated from the pressure and excess chemical potential shows evident inaccuracy for a density-temperature combination deep in the liquid-solid coexistence region, and this makes it necessary to derive a local formulation for the excess free energy.
Espinosa, J R; Young, J M; Jiang, H; Gupta, D; Vega, C; Sanz, E; Debenedetti, P G; Panagiotopoulos, A Z
2016-10-21
Direct coexistence molecular dynamics simulations of NaCl solutions and Lennard-Jones binary mixtures were performed to explore the origin of reported discrepancies between solubilities obtained by direct interfacial simulations and values obtained from the chemical potentials of the crystal and solution phases. We find that the key cause of these discrepancies is the use of crystal slabs of insufficient width to eliminate finite-size effects. We observe that for NaCl crystal slabs thicker than 4 nm (in the direction perpendicular to the interface), the same solubility values are obtained from the direct coexistence and chemical potential routes, namely, 3.7 ± 0.2 molal at T = 298.15 K and p = 1 bar for the JC-SPC/E model. Such finite-size effects are absent in the Lennard-Jones system and are likely caused by surface dipoles present in the salt crystals. We confirmed that μs-long molecular dynamics runs are required to obtain reliable solubility values from direct coexistence calculations, provided that the initial solution conditions are near the equilibrium solubility values; even longer runs are needed for equilibration of significantly different concentrations. We do not observe any effects of the exposed crystal face on the solubility values or equilibration times. For both the NaCl and Lennard-Jones systems, the use of a spherical crystallite embedded in the solution leads to significantly higher apparent solubility values relative to the flat-interface direct coexistence calculations and the chemical potential values. Our results have broad implications for the determination of solubilities of molecular models of ionic systems.
NASA Astrophysics Data System (ADS)
Espinosa, J. R.; Young, J. M.; Jiang, H.; Gupta, D.; Vega, C.; Sanz, E.; Debenedetti, P. G.; Panagiotopoulos, A. Z.
2016-10-01
Direct coexistence molecular dynamics simulations of NaCl solutions and Lennard-Jones binary mixtures were performed to explore the origin of reported discrepancies between solubilities obtained by direct interfacial simulations and values obtained from the chemical potentials of the crystal and solution phases. We find that the key cause of these discrepancies is the use of crystal slabs of insufficient width to eliminate finite-size effects. We observe that for NaCl crystal slabs thicker than 4 nm (in the direction perpendicular to the interface), the same solubility values are obtained from the direct coexistence and chemical potential routes, namely, 3.7 ± 0.2 molal at T = 298.15 K and p = 1 bar for the JC-SPC/E model. Such finite-size effects are absent in the Lennard-Jones system and are likely caused by surface dipoles present in the salt crystals. We confirmed that μs-long molecular dynamics runs are required to obtain reliable solubility values from direct coexistence calculations, provided that the initial solution conditions are near the equilibrium solubility values; even longer runs are needed for equilibration of significantly different concentrations. We do not observe any effects of the exposed crystal face on the solubility values or equilibration times. For both the NaCl and Lennard-Jones systems, the use of a spherical crystallite embedded in the solution leads to significantly higher apparent solubility values relative to the flat-interface direct coexistence calculations and the chemical potential values. Our results have broad implications for the determination of solubilities of molecular models of ionic systems.
Kaukonen, M; Gulans, A; Havu, P; Kauppinen, E
2012-03-05
Lennard-Jones (LJ) parameters are derived for classical nonpolarizable force fields for carbon nanotubes (CNTs) and for CNT-water interaction from van der Waals (vdW) enhanced density functional calculations. The new LJ parameters for carbon-carbon interactions are of the same order as those previously used in the literature but differ significantly for CNT-water interactions. This may partially originate from the fact that in addition to pure vdW interactions the polarization and other quantum mechanics effects are embedded into the LJ-potential.
Hess, Peter
2014-08-07
An improved microscopic cleavage model, based on a Morse-type and Lennard-Jones-type interaction instead of the previously employed half-sine function, is used to determine the maximum cleavage strength for the brittle materials diamond, tungsten, molybdenum, silicon, GaAs, silica, and graphite. The results of both interaction potentials are in much better agreement with the theoretical strength values obtained by ab initio calculations for diamond, tungsten, molybdenum, and silicon than the previous model. Reasonable estimates of the intrinsic strength are presented for GaAs, silica, and graphite, where first principles values are not available.
NASA Astrophysics Data System (ADS)
Mamedov, Bahtiyar A.; Somuncu, Elif; Askerov, Iskender M.
2016-08-01
In this work, a new theoretical approach is proposed for calculating fourth virial coefficient with Leonard-Jones potential. The established algorithm can be used to evaluate the thermodynamics properties and the intermolecular interaction potentials of liquids and gases with an improved accuracy. Note that the evaluation of the high-order virial coefficients is very valuable for accurate calculation of thermodynamic parameters. By using the suggested method, the fourth virial coefficient of CH4, Ar,C2H6 and SF6 molecules are evaluated. The calculation results are useful for accurate interpretation of the experimental data and of the determination of related physical properties.
Li, Pengfei; Roberts, Benjamin P; Chakravorty, Dhruva K; Merz, Kenneth M
2013-06-11
Metal ions play significant roles in biological systems. Accurate molecular dynamics (MD) simulations on these systems require a validated set of parameters. Although there are more detailed ways to model metal ions, the nonbonded model, which employs a 12-6 Lennard-Jones (LJ) term plus an electrostatic potential is still widely used in MD simulations today due to its simple form. However, LJ parameters have limited transferability due to different combining rules, various water models and diverse simulation methods. Recently, simulations employing a Particle Mesh Ewald (PME) treatment for long-range electrostatics have become more and more popular owing to their speed and accuracy. In the present work we have systematically designed LJ parameters for 24 +2 metal (M(II)) cations to reproduce different experimental properties appropriate for the Lorentz-Berthelot combining rules and PME simulations. We began by testing the transferability of currently available M(II) ion LJ parameters. The results showed that there are differences between simulations employing Ewald summation with other simulation methods and that it was necessary to design new parameters specific for PME based simulations. Employing the thermodynamic integration (TI) method and performing periodic boundary MD simulations employing PME, allowed for the systematic investigation of the LJ parameter space. Hydration free energies (HFEs), the ion-oxygen distance in the first solvation shell (IOD) and coordination numbers (CNs) were obtained for various combinations of the parameters of the LJ potential for four widely used water models (TIP3P, SPC/E, TIP4P and TIP4PEW). Results showed that the three simulated properties were highly correlated. Meanwhile, M(II) ions with the same parameters in different water models produce remarkably different HFEs but similar structural properties. It is difficult to reproduce various experimental values simultaneously because the nonbonded model underestimates the
NASA Astrophysics Data System (ADS)
Schaink, H. M.; Hoheisel, C.
1992-12-01
An analytical equation of state for Lennard-Jones mixtures has recently been derived using a perturbation theory with an additive hard sphere mixture (i.e., for the collision diameter d12=(d11+d22)/2) as a reference system. Here we generalize this equation of state using a nonadditive hard sphere mixture as a reference system. Even for Lennard-Jones mixtures that obey the Lorentz-Berthelot mixing rules [σ12=(σ11+σ22)/2 and ɛ12 =√ɛ11ɛ22 ], we find that our generalized theory shows an improvement in the predictions of the excess Gibbs free energy and the excess volume compared to the old version of the theory. For several non-Lorentz-Berthelot mixtures the phase diagrams predicted by the equations of state with recent Gibbs-ensemble Monte Carlo and new molecular dynamics results were compared. In this comparison the van der Waals 1-fluid model as well as an effective hard sphere model were considered. In this work only the fluid-fluid phase behavior was studied. For mixtures characterized by non-Lorentz-Berthelot energy parameters the generalization of the original equation of state gives the best predictions. For a mixture characterized by a relatively large nonadditivity in the repulsion parameters the 1-fluid approximation is best. As a by-product this study yields a generalization of the MIX1 equation of state for mixtures of nonadditive hard spheres with d11≠d22.
Costigliola, Lorenzo; Schrøder, Thomas B; Dyre, Jeppe C
2016-06-21
The recent theoretical prediction by Maimbourg and Kurchan [e-print arXiv:1603.05023 (2016)] that for regular pair-potential systems the virial potential-energy correlation coefficient increases towards unity as the dimension d goes to infinity is investigated for the standard 12-6 Lennard-Jones fluid. This is done by computer simulations for d = 2, 3, 4 going from the critical point along the critical isotherm/isochore to higher density/temperature. In both cases the virial potential-energy correlation coefficient increases significantly. For a given density and temperature relative to the critical point, with increasing number of dimension the Lennard-Jones system conforms better to the hidden-scale-invariance property characterized by high virial potential-energy correlations (a property that leads to the existence of isomorphs in the thermodynamic phase diagram, implying that it becomes effectively one-dimensional in regard to structure and dynamics). The present paper also gives the first numerical demonstration of isomorph invariance of structure and dynamics in four dimensions. Our findings emphasize the need for a universally applicable 1/d expansion in liquid-state theory; we conjecture that the systems known to obey hidden scale invariance in three dimensions are those for which the yet-to-be-developed 1/d expansion converges rapidly.
Lin, Shueei-Muh; Liauh, Chihng-Tsung; Wang, Wen-Rong; Ho, Shing-Huei
2006-04-01
The role of higher cantilever modes is important to obtain some material contrast. The analysis of AFM subjected to a short-range force can improve greatly the studies of surface topography and interaction energies and interaction forces, especially for chemical and biological materials. When the tip-sample distance is in the order of inter-atomic spacing, the short-range tip-sample force is usually simulated by the Lennard-Jones model. In this study, the analytical method to determine the frequency shift of AFM subjected to the Lennard-Jones force is proposed. The closed-form solution of the partial differential equation with a nonlinear boundary condition is derived and then the corresponding frequency shifts of higher modes can be determined easily. Moreover, the conventional perturbation method is usually used to determine the frequency shift, but only for the first mode. This is because the original continuous beam system is transformed into a discrete lumped-masses model. Although the above disadvantages exist, the lumped-masses model is simple and intuitive. Using the principle of dynamic strain energy, the conventional perturbation method is revised successfully to determine the frequency shifts of higher modes. The assessment of the generalized perturbation method and the proposed method is made. Finally, the effects of several parameters on the first three frequency shifts are investigated.
Urrutia, Ignacio; Paganini, Iván E
2016-05-07
We formulate a straightforward scheme of statistical mechanics for inhomogeneous systems that includes the virial series in powers of the activity for the grand free energy and density distributions. There, cluster integrals formulated for inhomogeneous systems play a main role. We center on second order terms that were analyzed in the case of hard-wall confinement, focusing in planar, spherical, and cylindrical walls. Further analysis was devoted to the Lennard-Jones system and its generalization, the 2k-k potential. For these interaction potentials, the second cluster integral was evaluated analytically. We obtained the fluid-substrate surface tension at second order for the planar, spherical, and cylindrical confinement. Spherical and cylindrical cases were analyzed using a series expansion in the radius including higher order terms. We detected a lnR/R(2) dependence of the surface tension for the standard Lennard-Jones system confined by spherical and cylindrical walls, no matter if particles are inside or outside of the hard walls. The analysis was extended to bending and Gaussian curvatures, where exact expressions were also obtained.
NASA Astrophysics Data System (ADS)
Chen, Yuh-Ing; Huang, Chi-Shen; Liu, Jann-Yenq
2015-12-01
We investigated the temporal-spatial hazard of the earthquakes after the 1999 September 21 MW = 7.7 Chi-Chi shock in a continental region of Taiwan. The Reasenberg-Jones (RJ) model (Reasenberg and Jones, 1989, 1994) that combines the frequency-magnitude distribution (Gutenberg and Richter, 1944) and time-decaying occurrence rate (Utsu et al., 1995) is conventionally employed for assessing the earthquake hazard after a large shock. However, it is found that the b values in the frequency-magnitude distribution of the earthquakes in the study region dramatically decreased from background values after the Chi-Chi shock, and then gradually increased up. The observation of a time-dependent frequency-magnitude distribution motivated us to propose a modified RJ model (MRJ) to assess the earthquake hazard. To see how the models perform on assessing short-term earthquake hazard, the RJ and MRJ models were separately used to sequentially forecast earthquakes in the study region. To depict the potential rupture area for future earthquakes, we further constructed relative hazard (RH) maps based on the two models. The Receiver Operating Characteristics (ROC) curves (Swets, 1988) finally demonstrated that the RH map based on the MRJ model was, in general, superior to the one based on the original RJ model for exploring the spatial hazard of earthquakes in a short time after the Chi-Chi shock.
NASA Astrophysics Data System (ADS)
Bales, M. K.; Goff, J. A.; Austin, J. A.; Flood, R. D.; Christensen, B. A.; Browne, C. M.; Saustrup, S.
2013-12-01
Hurricane Sandy struck the Northeast coast of the United States on October 29, 2012. Although sustained winds were downgraded to ~70 kts upon landfall, the vast area of the storm along with the direction of impact resulted in major storm-surge flooding and damage, as well as significant changes to the morphology of the coast-line, altering the characteristics of major barrier islands, inlets, and estuaries. A January 2013 post-storm survey aboard the R/V Pritchard, conducted by the University of Texas Institute for Geophysics, Stony Brook University, and Adelphi University, sought to investigate the impact of this post-tropical cyclone on the southwestern coast of Long Island, NY which sustained storm surges of up to 4 m above normal sea level. The objective of this project is to gain insight on the sedimentological volume changes and bathymetrical alterations made on the seafloor within Jones Inlet and the immediate estuaries behind Jones Beach and Long Beach Island. By studying these changes we hope to gain a better understanding of how large cyclonic storms alter sediment volumes and seafloor topography within major inlets and estuarine systems. These modifications can be observed in post-storm multibeam swath bathymetry and backscatter when compared to similar pre-storm data collected in 2010 by Stony Brook University. Post-storm CHIRP seismic reflection data were also collected, in order to define stratigraphic geometries, as well as grab samples to determine grain size distributions and ground truth for the backscatter data. The acoustic reflections imaged in the CHIRP data allow basal reflectors and dominate horizons to be traced throughout the inlet and estuaries. Our analysis focuses on (1) defining and quantifying areas of deposition and erosion from before-and-after bathymetry data; (2) comparing bedform patterns and grain size distributions from before-and-after backscatter and grab sample analysis; and (3) defining stratal geometries of the shallow
Devanathan, Ram
2016-05-01
Five decades ago, Gordon Moore, who would go on to co-found Intel Corporation, made a prescient observation about the exponential advance of semiconductor technology with a corresponding decrease in device cost. His prediction about the pace of doubling of the number of transistors in an integrated circuit came to be known eponymously as Moore’s law and has held true for 50 years. He also foresaw, way back in 1965, the development of home computers, electronic controls in automobiles, portable communications systems, and electronic wrist watches. Moore’s fascinating life, characterized by relentless innovation, charity and breathtaking humility, is the subject of this comprehensive authorized biography. The enthralling narrative is the product of collaboration between an academic (Thackray), a technology historian (Brock) and a journalist (Jones), and draws its material from numerous interviews, Moore’s meticulously maintained notes and professional records, personal papers, industry data, published volumes, and news accounts.
Adidharma, Hertanto; Tan, Sugata P
2016-07-07
Canonical Monte Carlo simulations on face-centered cubic (FCC) and hexagonal closed packed (HCP) Lennard-Jones (LJ) solids are conducted at very low temperatures (0.10 ≤ T(∗) ≤ 1.20) and high densities (0.96 ≤ ρ(∗) ≤ 1.30). A simple and robust method is introduced to determine whether or not the cutoff distance used in the simulation is large enough to provide accurate thermodynamic properties, which enables us to distinguish the properties of FCC from that of HCP LJ solids with confidence, despite their close similarities. Free-energy expressions derived from the simulation results are also proposed, not only to describe the properties of those individual structures but also the FCC-liquid, FCC-vapor, and FCC-HCP solid phase equilibria.
Xantheas, Sotiris S; Werhahn, Jasper C
2014-08-14
Based on the formulation of the analytical expression of the potential V(r) describing intermolecular interactions in terms of the dimensionless variables r* = r/r(m) and ɛ* = V/ɛ, where r(m) is the separation at the minimum and ɛ the well depth, we propose more generalized scalable forms for the commonly used Mie, Lennard-Jones, Morse, and Buckingham exponential-6 potential energy functions. These new generalized forms have an additional parameter from the original forms and revert to the original ones for some choice of that parameter. In this respect, the original forms of those potentials can be considered as special cases of the more general forms that are introduced. We also propose a scalable, non-revertible to the original one, 4-parameter extended Morse potential.
NASA Astrophysics Data System (ADS)
Abbaspour, Mohsen; Akbarzadeh, Hamed; Salemi, Sirous; Abroodi, Mousarreza
2016-11-01
By considering the anisotropic pressure tensor, two separate equations of state (EoS) as functions of the density, temperature, and carbon nanotube (CNT) diameter have been proposed for the radial and axial directions for the confined Lennard-Jones (LJ) fluid into (11,11), (12,10), and (19,0) CNTs from 120 to 600 K using molecular dynamics (MD) simulations. We have also investigated the effects of the pore size, pore loading, chirality, and temperature on some of the structural and dynamical properties of the confined LJ fluid into (11,11), (12,10), (19,0), and (19,19) CNTs such as the radial density profile and self-diffusion coefficient. We have also determined the EoS for the confined LJ fluid into double and triple walled CNTs.
NASA Astrophysics Data System (ADS)
Matsumoto, Hiroaki; Koura, Katsuhisa
1991-12-01
The velocity distribution functions (VDF's) in an argon normal shock wave at an upstream high Mach number 7.183 and low temperature 16 K are calculated using the null-collision direct-simulation Monte Carlo method for the Lennard-Jones (LJ) potential to compare with the experimental results of Holtz and Muntz (1983). The convolved VDF's for the LJ potential are in reasonable agreement with the measured data in early and late regions of the shock wave but significantly different in the middle region. This discrepancy cannot be explained by a possible uncertainty in the potential well depth. Moreover, the difference in the convolved VDF's between the LJ potential and the softest and hardest unrealistic molecular models with no attractive force, i.e., the Maxwell molecule and hard sphere, is much smaller than the discrepancy between the experiments and Monte Carlo calculations.
NASA Astrophysics Data System (ADS)
Matsumoto, Hiroaki; Koura, Katsuhisa
1991-12-01
The velocity distribution functions (VDF's) in an argon normal shock wave at an upstream high Mach number 7.183 and low temperature 16 K are calculated using the null-collision direct-simulation Monte Carlo method for the Lennard-Jones (LJ) potential to compare with the experimental results of Holtz and Muntz [Phys. Fluids 26, 2425 (1983)]. The convolved VDF's for the LJ potential are in reasonable agreement with the measured data in early and late regions of the shock wave but significantly different in the middle region. This discrepancy cannot be explained by a possible uncertainty in the potential well depth. Moreover, the difference in the convolved VDF's between the LJ potential and the softest and hardest unrealistic molecular models with no attractive force, i.e., the Maxwell molecule and hard sphere, is much smaller than the discrepancy between the experiments and Monte Carlo calculations.
NASA Astrophysics Data System (ADS)
Bomont, Jean-Marc; Hansen, Jean-Pierre; Pastore, Giorgio
2015-10-01
The structural and thermodynamic behavior of a deeply supercooled Lennard-Jones liquid, and its random first-order transition (RFOT) to an ideal glass is investigated, using a system of two weakly coupled replicas and the hypernetted chain integral equation for the pair structure of this symmetric binary system. A systematic search in the density-temperature plane points to the existence of two glass branches below a density-dependent threshold temperature. The branch of lower free energy exhibits a rapid growth of the structural overlap order parameter upon cooling and may be identified with the ideal glass phase conjectured by several authors for both spin and structural glasses. The RFOT, signaled by a sharp discontinuity of the order parameter, is predicted to be weakly first order from a thermodynamic viewpoint. The transition temperature Tcr increases rapidly with density and approximately obeys a scaling relation valid for a reference system of particles interacting via a purely repulsive 1 /r18 potential.
Oderji, Hassan Yousefi; Ding, Hongbin; Behnejad, Hassan
2011-06-01
The second self-diffusion and viscosity virial coefficients of the Lennard-Jones (LJ) fluid were calculated by a detailed evaluation of the velocity and shear-stress autocorrelation functions using equilibrium molecular dynamics simulations at low and moderate densities. Accurate calculation of these coefficients requires corresponding transport coefficient values with low degrees of uncertainty. These were obtained via very long simulations by increasing the number of particles and by using the knowledge of correlation functions in the Green-Kubo method in conjunction with their corresponding generalized Einstein relations. The values of the self-diffusion and shear viscosity coefficients have been evaluated for systems with reduced densities between 0.0005 and 0.05 and reduced temperatures from 0.7 to 30.0. This provides a new insight into the transport coefficients beyond what can be offered by the Rainwater-Friend theory, which has not been developed for the self-diffusion coefficient.
Xantheas, Sotiris S.; Werhahn, Jasper C.
2014-08-14
Based on the formulation of the analytical expression of the potential V(r) describing intermolecular interactions in terms of the dimensionless variables r*=r/rm and !*=V/!, where rm is the separation at the minimum and ! the well depth, we propose more generalized scalable forms for the commonly used Lennard-Jones, Mie, Morse and Buckingham exponential-6 potential energy functions (PEFs). These new generalized forms have an additional parameter from and revert to the original ones for some choice of that parameter. In this respect, the original forms can be considered as special cases of the more general forms that are introduced. We also propose a scalable, but nonrevertible to the original one, 4-parameter extended Morse potential.
Polak, W
2008-03-01
Liquid Lennard-Jones clusters of 14 different sizes from N=55-923 atoms were cooled down in Monte Carlo simulations (40 runs for each size) to the reduced temperature T* = 0.05 . Structural analysis and visualization were applied for classification of the internal structure of all 560 final clusters. Small clusters revealed the presence of the multishell icosahedra or regular polyicosahedra. In larger clusters, beginning from N=309 , the noncrystalline atom ordering is often replaced by the formation of defected crystalline clusters in the form of layered face-centered cubic-hexagonal close-packed (fcc-hcp) clusters or defected layered clusters with some additional nonparallel hcp overlayers. The presence of regular polyicosahedral clusters, relatively numerous even at the largest analyzed sizes, is attributed to kinetic effects in structure formation.
NASA Astrophysics Data System (ADS)
Lakrad, Faouzi
2016-03-01
We study the nonlinear vibrations of an AFM system, modeled as a linear mass-spring-damper system, under the Lennard-Jones forces and an imposed harmonic base displacement. The frequency of this latter is very low with respect to the natural fundamental frequency of the system. The invariant slow manifolds of the system are approximated and their bifurcations are investigated. It is shown that two dynamic saddle-node bifurcations, during one period of the base oscillation, of the contact and the noncontact invariant slow manifolds are responsible for triggering the tapping mode. It is also shown that these dynamic bifurcations govern the contact time between the probe and the sample during the tapping mode.
Sakurai-Chin, Chanhyok; Ubara, Yoshifumi; Suwabe, Tatsuya; Hoshino, Junichi; Yonaha, Tomoki; Hasegawa, Eiko; Sumida, Keiichi; Hiramatsu, Rikako; Yamanouchi, Masayuki; Hayami, Noriko; Yamauchi, Junji; Tominaga, Naoyuki; Sawa, Naoki; Takemoto, Fumi; Masuoka, Kazuhiro; Takaichi, Kenmei; Oohashi, Kenichi
2010-10-01
A 45-year-old Japanese woman had been diagnosed with monoclonal gammopathy of undetermined significance (MGUS) featuring urinary Bence-Jones protein of the lambda type (BJP-lambda) for 11 years. She then developed eyelid purpura, dyspnea, and flank pain. Abdominal CT scans revealed renal infarction. Biopsy of the kidney, heart, jejunum, and skin demonstrated amyloid deposits in the vessel walls, but not in the glomeruli. She was diagnosed as having AL amyloidosis with IgD-lambda monoclonal gammopathy and BJP-lambda. Autologous stem cell transplantation (SCT) was done after chemotherapy with vincristine, daunorubicin, dexamethasone (VAD), and high-dose melphalan (HDM). This reduced the IgD level from 156 to 0.1 mg/dL, along with the disappearance of BJP, despite cerebral infarction during chemotherapy. We recommend SCT for patients with IgD-associated AL amyloidosis.
NASA Astrophysics Data System (ADS)
Adidharma, Hertanto; Tan, Sugata P.
2016-07-01
Canonical Monte Carlo simulations on face-centered cubic (FCC) and hexagonal closed packed (HCP) Lennard-Jones (LJ) solids are conducted at very low temperatures (0.10 ≤ T∗ ≤ 1.20) and high densities (0.96 ≤ ρ∗ ≤ 1.30). A simple and robust method is introduced to determine whether or not the cutoff distance used in the simulation is large enough to provide accurate thermodynamic properties, which enables us to distinguish the properties of FCC from that of HCP LJ solids with confidence, despite their close similarities. Free-energy expressions derived from the simulation results are also proposed, not only to describe the properties of those individual structures but also the FCC-liquid, FCC-vapor, and FCC-HCP solid phase equilibria.
Terzyan, Simon S; Bourne, Christina R; Ramsland, Paul A; Bourne, Philip C; Edmundson, Allen B
2003-01-01
Crystals of a human (Sea) Bence-Jones dimer were produced in a capillary by vapor diffusion under microgravity conditions in the 9 day US Space Shuttle Mission STS-95. In comparison to ground-based experiments, nucleation was facile and spontaneous in space. Appearance of a very large (8 x 1.6 x 1.0 mm) crystal in a short time period is a strong endorsement for the use of microgravity to produce crystals sufficiently large for neutron diffraction studies. The Sea dimer crystallized in the orthorhombic space group P2(1)2(1)2(1), with a = 48.9 A, b = 85.2 A, and c = 114.0 A. The crystals grown in microgravity exhibited significantly lower mosaicities than those of ground-based crystals and the X-ray diffraction data had a lower overall B factor. Three-dimensional structures determined by X-ray analysis at two temperatures (100 and 293 K) were indistinguishable from those obtained from ground-based crystals. However, both the crystallographic R factor and the free R factor were slightly lower in the models derived from crystals produced in microgravity. The major difference between the two crystal growth systems is a lack of convection and sedimentation in a microgravity environment. This environment resulted in the growth of much larger, higher-quality crystals of the Sea Bence-Jones protein. Structurally, heretofore unrecognized grooves on the external surfaces of the Sea and other immunoglobulin-derived fragments are regular features and may offer supplementary binding regions for super antigens and other elongated ligands in the bloodstream and perivascular tissues.
NASA Astrophysics Data System (ADS)
Malykin, G. B.; Pozdnyakova, V. I.
2017-01-01
Using the method of Jones matrices, we have calculated parameters of elliptic screw polarization modes (ESPMs). ESPM formalism has been proposed by V.L. Ginzburg for an optical medium with unperturbed linear birefringence and circular birefringence induced by twisting of the medium. The evolution of the polarization state of radiation (PSR) in relation to the length of the examined optical medium has been considered, which is important for twisted single-mode optical fibers and cholesteric liquid crystals. We have shown that the problem can be substantially simplified if the evolution of ESPMs is considered in a screw coordinate system comoving with the twist of the optical medium. In particular, we have shown that a curve on the Poincaré sphere mapping the evolution of the PSR for natural (normal) waves of the examined optical medium in the screw coordinate system degenerates into a point. For comparison, we have found natural waves of this medium in a fixed (laboratory) coordinate system and considered the evolution of their PSR, which is represented by a complex curve on the Poincaré sphere. Also, the evolution of the PSR of improper waves passed through the examined optical medium has been studied in both the fixed and the screw coordinate systems.
Munaò, Gianmarco; Costa, Dino; Caccamo, Carlo
2016-10-19
Inspired by significant improvements obtained for the performances of the polymer reference interaction site model (PRISM) theory of the fluid phase when coupled with 'molecular closures' (Schweizer and Yethiraj 1993 J. Chem. Phys. 98 9053), we exploit a matrix generalization of this concept, suitable for the more general RISM framework. We report a preliminary test of the formalism, as applied to prototype square-well homonuclear diatomics. As for the structure, comparison with Monte Carlo shows that molecular closures are slightly more predictive than their 'atomic' counterparts, and thermodynamic properties are equally accurate. We also devise an application of molecular closures to models interacting via continuous, soft-core potentials, by using well established prescriptions in liquid state perturbation theories. In the case of Lennard-Jones dimers, our scheme definitely improves over the atomic one, providing semi-quantitative structural results, and quite good estimates of internal energy, pressure and phase coexistence. Our finding paves the way to a systematic employment of molecular closures within the RISM framework to be applied to more complex systems, such as molecules constituted by several non-equivalent interaction sites.
Bomont, Jean-Marc; Hansen, Jean-Pierre; Pastore, Giorgio
2015-10-01
The structural and thermodynamic behavior of a deeply supercooled Lennard-Jones liquid, and its random first-order transition (RFOT) to an ideal glass is investigated, using a system of two weakly coupled replicas and the hypernetted chain integral equation for the pair structure of this symmetric binary system. A systematic search in the density-temperature plane points to the existence of two glass branches below a density-dependent threshold temperature. The branch of lower free energy exhibits a rapid growth of the structural overlap order parameter upon cooling and may be identified with the ideal glass phase conjectured by several authors for both spin and structural glasses. The RFOT, signaled by a sharp discontinuity of the order parameter, is predicted to be weakly first order from a thermodynamic viewpoint. The transition temperature T(cr) increases rapidly with density and approximately obeys a scaling relation valid for a reference system of particles interacting via a purely repulsive 1/r(18) potential.
Peng, L.; Morris, James R; Aga, Rachel
2010-01-01
Large scale simulations of crystal nucleation from the liquid are performed using the Lennard-Jones potential, to determine the time required for nucleation. By considering both transient and finite-size effects, we successfully predict the nucleation time within order of magnitude without any parameter fitting. All necessary parameters are derived from separate, equilibrium simulations. At smaller undercoolings, large system sizes are required, not only to accommodate large critical nuclei, but also to control statistical effects that are controlled by the density of critical nuclei. Two distinct nucleation regions are observed in the simulations, which are dominated by transient time and steady state nucleation time, respectively. At deep undercoolings, we still show consistency between predicted transient times and simulated nucleation times, which suggests that the short nucleation times in simulations are due to a small barrier to nucleation, rather than spinodal transformation that have been previously predicted. We compare with similar, previous results on a model of Al, which does not show such rapid nucleation at low temperatures, and suggest that the differences are due to the behavior of the reduced barrier G*/kBT.
NASA Astrophysics Data System (ADS)
Munaò, Gianmarco; Costa, Dino; Caccamo, Carlo
2016-10-01
Inspired by significant improvements obtained for the performances of the polymer reference interaction site model (PRISM) theory of the fluid phase when coupled with ‘molecular closures’ (Schweizer and Yethiraj 1993 J. Chem. Phys. 98 9053), we exploit a matrix generalization of this concept, suitable for the more general RISM framework. We report a preliminary test of the formalism, as applied to prototype square-well homonuclear diatomics. As for the structure, comparison with Monte Carlo shows that molecular closures are slightly more predictive than their ‘atomic’ counterparts, and thermodynamic properties are equally accurate. We also devise an application of molecular closures to models interacting via continuous, soft-core potentials, by using well established prescriptions in liquid state perturbation theories. In the case of Lennard-Jones dimers, our scheme definitely improves over the atomic one, providing semi-quantitative structural results, and quite good estimates of internal energy, pressure and phase coexistence. Our finding paves the way to a systematic employment of molecular closures within the RISM framework to be applied to more complex systems, such as molecules constituted by several non-equivalent interaction sites.
NASA Astrophysics Data System (ADS)
Tau, M.; Parola, A.; Pini, D.; Reatto, L.
1995-09-01
The hierarchical reference theory (HRT) is applied to the Lennard-Jones fluid below the critical temperature Tc. This study completes a previous one performed above Tc using the same kind of approximate closure for the direct correlation function. Results for several thermodynamic quantities and for the two-particle correlations are reported and compared both with other theories and with simulation data. In the two-phase region the theory correctly yields rigorously flat isotherms; this feature allows a straightforward and accurate determination of the coexistence curve without resorting to the Maxwell construction. In the critical region our analysis is consistent with the previously developed one for T>Tc and displays nontrivial critical exponents. We also study a fluid with the Girifalco model potential for C60. The critical point of the liquid-vapor transition is found at Tc=2138 K and ρc=0.50 nm-3. When the HRT result is supplemented with Verlet's freezing criterion a triple point is found at Tt=1979 K and ρt=0.848 nm-3.
Bowers, Jeffrey S
2016-10-01
In Bowers (2016), I argued that there are (a) practical problems with educational neuroscience (EN) that explain why there are no examples of EN improving teaching and (b) principled problems with the logic motivating EN that explain why it is likely that there never will be. In the following article, I consider the main responses raised by both Gabrieli (2016) and Howard-Jones et al. (2016) and find them all unconvincing. Following this exchange, there are still no examples of EN providing new insights to teaching in the classroom, there are still no examples of EN providing new insights to remedial instructions for individuals, and, as I detail in this article, there is no evidence that EN is useful for the diagnosis of learning difficulties. The authors have also failed to address the reasons why EN is unlikely to benefit educational outcomes in the future. Psychology, by contrast, can (and has) made important discoveries that can (and should) be used to improve teaching and diagnostic tests for learning difficulties. This is not a debate about whether science is relevant to education, rather it is about what sort of science is relevant. (PsycINFO Database Record
Vorselaars, Bart
2015-03-21
Liquid free energies are computed by integration along a path from a reference system of known free energy, using a strong localization potential. A particular choice of localization pathway is introduced, convenient for use in molecular dynamics codes, and which achieves accurate results without the need to include the identity-swap or relocation Monte Carlo moves used in previous studies. Moreover, an adaptive timestep is introduced to attain the reference system. Furthermore, a center-of-mass correction that is different from previous studies and phase-independent is incorporated. The resulting scheme allows computation of both solid and liquid free energies with only minor differences in simulation protocol. This is used to re-visit solid-liquid equilibrium in a system of short semi-flexible Lennard-Jones chain molecules. The computed melting curve is demonstrated to be consistent with direct co-existence simulations and computed hysteresis loops, provided that an entropic term arising from unsampled solid states is included.
NASA Astrophysics Data System (ADS)
Vorselaars, Bart
2015-03-01
Liquid free energies are computed by integration along a path from a reference system of known free energy, using a strong localization potential. A particular choice of localization pathway is introduced, convenient for use in molecular dynamics codes, and which achieves accurate results without the need to include the identity-swap or relocation Monte Carlo moves used in previous studies. Moreover, an adaptive timestep is introduced to attain the reference system. Furthermore, a center-of-mass correction that is different from previous studies and phase-independent is incorporated. The resulting scheme allows computation of both solid and liquid free energies with only minor differences in simulation protocol. This is used to re-visit solid-liquid equilibrium in a system of short semi-flexible Lennard-Jones chain molecules. The computed melting curve is demonstrated to be consistent with direct co-existence simulations and computed hysteresis loops, provided that an entropic term arising from unsampled solid states is included.
NASA Astrophysics Data System (ADS)
Matsumoto, Akira
2014-12-01
The thermodynamic functions for Lennard-Jones (9,6) gases with a hard core that are evaluated till the third virial coefficients, are investigated at an isobaric process. Some thermodynamic functions are analytically expressed as functions of intensive variables, temperature, and pressure. Some thermodynamic quantities for carbon dioxide are calculated numerically and drawn graphically. In critical states, the heat capacity diverges to infinity at the critical point while the Gibbs free energy, volume, enthalpy, and entropy are continuous at the critical point. In the coexistence of two phases, the boiling temperatures and the enthalpy changes of vaporization are obtained by numerical calculations for 20 substances. The Gibbs free energy indicates a polygonal line; entropy, volume, and enthalpy jump from the liquid to gaseous phase at the boiling point. The heat capacity does not diverge to infinity but shows a finite discrepancy at boiling point. This suggests that a first-order phase transition at the boiling point and a second-order phase transition may occur at the critical point.
Lin, Shih-Jie; Lin, Po-Chun; Kuo, Feng-Chih; Peng, Kuo-Ti; Huang, Kuo-Chin
2017-01-01
Long-term data and information indicating whether minimally invasive surgery (MIS) approaches are safe and effective with total hip arthroplasty (THA) are lacking. Between 2004 and 2006, 75 patients with alcohol-related osteonecrosis of the femoral head (ONFH) who underwent 75 THAs with the two-incision approach were studied. The medical records, radiographic parameters, and functional outcomes were collected prospectively. All data were compared with those for matched patients who underwent a modified Watson-Jones (WJ) approach. THA using the two-incision approach was associated with longer operation time, more blood loss, more lateral femoral cutaneous nerve injury, and more periprosthetic femoral fractures (p < 0.05 for all four) than the modified WJ approach. The Harris Hip Score (HHS) and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) increased significantly from the period preoperatively to 6 weeks postoperatively and thereafter up to the last follow-up in both groups. However, there were no significant differences in terms of radiographic parameters and functional outcomes between the two groups throughout the study period. Both the two-incision and the modified WJ approach provided satisfactory results and survival rates at a mean follow-up of 10.8 years. A prospective, randomized, large-scale cohort study is still warranted for evidence-based recommendations. PMID:28386565
NASA Astrophysics Data System (ADS)
Labovitch, Andrew
This dissertation examined electric utility CEO compensation during the years 2000 through 2011 for United States owned and operated companies. To determine the extent to which agency theory may apply to electric utility CEO compensation, this examination segmented the industry by four types of company financial metrics: revenue, earnings, stock price and the Dow Jones Utility Average; by five categories of CEO compensation: base salary, bonus, stock grants, all other compensation and total compensation; and by four categories of company size as measured by revenue: large, medium, small and the industry as a whole. Electric utility CEO compensation data was analyzed with the financial metrics to determine correlations. No type of compensation was highly correlated to any of the financial metrics for any size industry segment indicating that there was little agency. CEO compensation in large electric utility companies was higher than compensation in medium and smaller companies even though the CEOs at larger companies earned less per dollar of revenue and per dollar of earnings than their counterparts in smaller companies.
Hafskjold, Bjørn
2017-01-01
A binary isotope mixture of Lennard-Jones/spline particles at equilibrium was perturbed by a sudden change in the system's boundary temperatures. The system's response was determined by non-equilibrium molecular dynamics (NEMD). Three transient processes were studied: 1) The propagation of a pressure (shock) wave, 2) heat diffusivity and conduction, and 3) thermal diffusion (the Ludwig-Soret effect). These three processes occur at different time scales, which makes it possible to separate them in one single NEMD run. The system was studied in liquid, supercritical, and dense gas states with various forms and strengths of the thermal perturbation. The results show that heat was initially transported by two separate mechanisms: 1) heat diffusion as described by the transient heat equation and 2) as a consequence of a pressure wave. The pressure wave travelled faster than the speed of sound, generating a shock wave in the system. Local equilibrium was found in the transient phase, even with very strong perturbations and in the shock front. Although the mass separation due to the Ludwig-Soret effect developed much slower than the pressure and temperature fields in the system at large, it was found that the Soret coefficient could be accurately determined from the initial phase of the transient and close to the heat source. This opens the possibility of a new way to analyse results from transient experiments and thereby minimize effects of gravity and convection due to buoyancy.
Thomson, Jeffery K; Pawel, Steven J
2015-01-01
Creep-strength-enhanced-ferritic (CSEF) steels have been widely implemented as water wall alloy materials in the coal-fired power industry for many years. The stress corrosion cracking (SCC) behavior of this class of materials is currently of significant interest to the industry due to recent failures. To better understand the test methods used to characterize SCC behavior in the laboratory, three representative CSEF alloys (T23, T24, and T92) were subjected to two SCC test protocols: the Jones Test set forth in DIN 50915, and the C-ring SCC test set forth in ASTM G38-01. Samples were tested in either the as-received (normalized + tempered) condition or in the normalized condition (quenched from 1065 C). Samples were exposed to aerated water in one test case and de-aerated water in a second test case for a period of 7 days at 200 C. It was found that for both test protocols, the normalized condition with aerated water led to severe cracking for all three alloys, whereas no evidence of cracking was found for the other conditions.
NASA Astrophysics Data System (ADS)
Somasi, Sweta; Khomami, Bamin; Lovett, Ronald
2001-04-01
We introduce a new molecular dynamics simulation path to easily calculate solid-vapor surface free energies. The method is illustrated with explicit calculations of the surface free energies of a face-centered-cubic (fcc) crystal (the [110], [111], and [100] surfaces) and a hexagonal-close-packed (hcp) crystal (the [111] surface) of Lennard-Jones atoms. We verify that, because of the reduced symmetry at interfaces, simulation of the surface structure and free energy requires a large cutoff distance for the range of the pair potential. To estimate when a growing crystal resolves the fcc/hcp structural ambiguity, we observe the binding free energy and dynamics of clusters of adatoms on [111] surfaces of fcc and hcp crystals. A structural distinction only appears when clusters become large enough that their slow translational motion allows a structural relaxation of the crystal's surface. From the observed distribution over cluster structures we deduce thermodynamic parameters that can be used to model the equilibrium between fcc-like clusters and hcp-like clusters on [111] surfaces and the rate of transformation between these.
NASA Astrophysics Data System (ADS)
Lechuga-Sanabria, Fidelmar; Chapela, Gustavo A.; Quintana-H, Jacqueline
2013-10-01
The map of low and high density phases of an idealized system, the infinitely hard zigzag line model with two Lennard-Jones (LJ) sites is presented. LJ sites are added to a previous model composed of the infinitely hard zigzag line shape particles, R.A. Perusqía, J. Peón, J. Quintana, Physica A 345 (1) (2005) 130-142. The attractions and the molecular volume added to this system through the LJ sites create a more realistic model and, as a consequence, a richer phase behavior is obtained. Although the volume of the LJ sites is quite small it is enough to produce solid phases, absent in the original model. On the other hand the smectic phase that was present in the hard system was not found in this case. Two molecular conformations are chosen to provide a comparison with the previous model. The isothermal-isobaric is used to establish the thermodynamic regions of the different molecular self aggregations and to compare them to already published results.
Rizzo, Antonio; Cappelli, Chiara; Jansík, Branislav; Jonsson, Dan; Sałek, Paweł; Coriani, Sonia; Agren, Hans
2004-11-08
We present the results of an extended study of five birefringences--Kerr, Cotton-Mouton, Buckingham, Jones, and Magnetoelectric--on benzene in the gas phase. The relevant molecular quantities--first-order properties, linear, quadratic, and cubic response functions--are computed employing the density-functional theory (DFT) response theory, with a choice of functionals. In some cases, different functionals are employed for the wave-function computational step and for the subsequent analytical response calculation to determine the combination yielding at the same time the optimal energy and energy derivative results. Augmented correlation consistent basis sets of double and triple zeta quality are used. The DFT results are compared to those obtained at the Hartree-Fock level and in some cases within a coupled cluster singles and doubles electronic structure model. The study tries to assess the ability of the DFT response theory to describe a wide range of properties in a system of rather large size and high complexity. The relative strength of the five birefringences for plausible experimental conditions is determined and, when possible, comparison is made with the results of the measurements.
Georgescu, Ionuţ; Mandelshtam, Vladimir A
2012-10-14
The theory of self-consistent phonons (SCP) was originally developed to address the anharmonic effects in condensed matter systems. The method seeks a harmonic, temperature-dependent Hamiltonian that provides the "best fit" for the physical Hamiltonian, the "best fit" being defined as the one that optimizes the Helmholtz free energy at a fixed temperature. The present developments provide a scalable O(N) unified framework that accounts for anharmonic effects in a many-body system, when it is probed by either thermal (ℏ → 0) or quantum fluctuations (T → 0). In these important limits, the solution of the nonlinear SCP equations can be reached in a manner that requires only the multiplication of 3N × 3N matrices, with no need of diagonalization. For short range potentials, such as Lennard-Jones, the Hessian, and other related matrices are highly sparse, so that the scaling of the matrix multiplications can be reduced from O(N(3)) to ~O(N). We investigate the role of quantum effects by continuously varying the de-Boer quantum delocalization parameter Λ and report the N-Λ (T = 0), and also the classical N-T (Λ = 0) phase diagrams for sizes up to N ~ 10(4). Our results demonstrate that the harmonic approximation becomes inadequate already for such weakly quantum systems as neon clusters, or for classical systems much below the melting temperatures.
NASA Astrophysics Data System (ADS)
Vogelsang, R.; Hoheisel, C.
1987-02-01
Molecular-dynamics (MD) calculations are reported for three thermodynamic states of a Lennard-Jones fluid. Systems of 2048 particles and 105 integration steps were used. The transverse current autocorrelation function, Ct(k,t), has been determined for wave vectors of the range 0.5<||k||σ<1.5. Ct(k,t) was fitted by hydrodynamic-type functions. The fits returned k-dependent decay times and shear viscosities which showed a systematic behavior as a function of k. Extrapolation to the hydrodynamic region at k=0 gave shear viscosity coefficients in good agreement with direct Green-Kubo results obtained in previous work. The two-exponential model fit for the memory function proposed by other authors does not provide a reasonable description of the MD results, as the fit parameters show no systematic wave-vector dependence, although the Ct(k,t) functions are somewhat better fitted. Similarly, the semiempirical interpolation formula for the decay time based on the viscoelastic concept proposed by Akcasu and Daniels fails to reproduce the correct k dependence for the wavelength range investigated herein.
2000-06-01
in the Ambulatory Data System (ADS) for the Internal Medicine Clinic at Bayne-Jones Army Community Hospital, Fort Polk, Louisiana. A secondary purpose...Analysis of the financial data indicated that the hospital was minimally at risk for either fraudulent billing or loss of revenue. However, as the Internal ... Medicine Clinic only accounts for 6.3% of outpatient workload, coding behaviors similar to those observed practiced in other high volume clinics would
Wynuveen, R.A.; Smith, W.H.; Sholeen, C.M.; Flynn, K.F.
1984-08-01
The US Department of Energy (DOE) has implemented a program to decontaminate radioactively contaminated sites that were formerly utilized by the Manhattan Engineer District (MED) and/or the Atomic Energy Commission (AEC) for activities that included handling of radioactive material. This program is referred to as the ''Formerly Utilized Sites Remedial Action Program'' (FUSRAP). Among these sites are Jones Chemical Laboratory, Ryerson Physical Laboratory, Kent Chemical Laboratory, and Eckhart Hall of The University of Chicago, Chicago, Illinois. Since 1977, the University of Chicago decontaminated Kent Chemical Laboratory as part of a facilities renovation program. All areas of Eckhart Hall, Ryerson Physical Laboratory, and Jones Chemical Laboratory that had been identified as contaminated in excess of current guidelines in the 1976-1977 surveys were decontaminated to levels where no contamination could be detected relative to natural backgrounds. All areas that required defacing to achieve this goal were restored to their original condition. The radiological evaluation of the sewer system, based primarily on the radiochemical analyses of sludge and water samples, indicated that the entire sewer system is potentially contaminated. While this evaluation was defined as part of this project, the decontamination of the sewer system was not included in the purview of this effort. The documentation included in this report substantiates the judgment that all contaminated areas identified in the earlier reports in the three structures included in the decontamination effort (Eckhart Hall, Ryerson Physical Laboratory, and Jones Chemical Laboratory) were cleaned to levels commensurate with release for unrestricted use.
Fujiwara, K.; Shibahara, M.
2014-07-21
A classical molecular dynamics simulation was conducted for a system composed of fluid molecules between two planar solid surfaces, and whose interactions are described by the 12-6 Lennard-Jones form. This paper presents a general description of the pressure components and interfacial tension at a fluid-solid interface obtained by the perturbative method on the basis of statistical thermodynamics, proposes a method to consider the pressure components tangential to an interface which are affected by interactions with solid atoms, and applies this method to the calculation system. The description of the perturbative method is extended to subsystems, and the local pressure components and interfacial tension at a liquid-solid interface are obtained and examined in one- and two-dimensions. The results are compared with those obtained by two alternative methods: (a) an evaluation of the intermolecular force acting on a plane, and (b) the conventional method based on the virial expression. The accuracy of the numerical results is examined through the comparison of the results obtained by each method. The calculated local pressure components and interfacial tension of the fluid at a liquid-solid interface agreed well with the results of the two alternative methods at each local position in one dimension. In two dimensions, the results showed a characteristic profile of the tangential pressure component which depended on the direction tangential to the liquid-solid interface, which agreed with that obtained by the evaluation of the intermolecular force acting on a plane in the present study. Such good agreement suggests that the perturbative method on the basis of statistical thermodynamics used in this study is valid to obtain the local pressure components and interfacial tension at a liquid-solid interface.
Oh, Inrok; Choi, Saehyun; Jung, YounJoon; Kim, Jun Soo
2015-08-28
Phase separation in a biological cell nucleus occurs in a heterogeneous environment filled with a high density of chromatins and thus it is inevitably influenced by interactions with chromatins. As a model system of nuclear body formation in a cell nucleus filled with chromatins, we simulate the phase separation of a low-density Lennard-Jones (LJ) fluid interacting with a long, condensed polymer chain. The influence of the density variation of LJ particles above and below the phase boundary and the role of attractive interactions between LJ particles and polymer segments are investigated at a fixed value of strong self-interaction between LJ particles. For a density of LJ particles above the phase boundary, phase separation occurs and a dense domain of LJ particles forms irrespective of interactions with the condensed polymer chain whereas its localization relative to the polymer chain is determined by the LJ-polymer attraction strength. Especially, in the case of moderately weak attractions, the domain forms separately from the polymer chain and subsequently associates with the polymer chain. When the density is below the phase boundary, however, the formation of a dense domain is possible only when the LJ-polymer attraction is strong enough, for which the domain grows in direct contact with the interacting polymer chain. In this work, different growth behaviors of LJ particles result from the differences in the density of LJ particles and in the LJ-polymer interaction, and this work suggests that the distinct formation of activity-dependent and activity-independent nuclear bodies (NBs) in a cell nucleus may originate from the differences in the concentrations of body-specific NB components and in their interaction with chromatins.
Sumi, Tomonari; Maruyama, Yutaka; Mitsutake, Ayori; Koga, Kenichiro
2016-06-14
In the conventional classical density functional theory (DFT) for simple fluids, an ideal gas is usually chosen as the reference system because there is a one-to-one correspondence between the external field and the density distribution function, and the exact intrinsic free-energy functional is available for the ideal gas. In this case, the second-order density functional Taylor series expansion of the excess intrinsic free-energy functional provides the hypernetted-chain (HNC) approximation. Recently, it has been shown that the HNC approximation significantly overestimates the solvation free energy (SFE) for an infinitely dilute Lennard-Jones (LJ) solution, especially when the solute particles are several times larger than the solvent particles [T. Miyata and J. Thapa, Chem. Phys. Lett. 604, 122 (2014)]. In the present study, we propose a reference-modified density functional theory as a systematic approach to improve the SFE functional as well as the pair distribution functions. The second-order density functional Taylor series expansion for the excess part of the intrinsic free-energy functional in which a hard-sphere fluid is introduced as the reference system instead of an ideal gas is applied to the LJ pure and infinitely dilute solution systems and is proved to remarkably improve the drawbacks of the HNC approximation. Furthermore, the third-order density functional expansion approximation in which a factorization approximation is applied to the triplet direct correlation function is examined for the LJ systems. We also show that the third-order contribution can yield further refinements for both the pair distribution function and the excess chemical potential for the pure LJ liquids.
Baidakov, Vladimir G
2016-02-21
The process of bubble nucleation in a Lennard-Jones (LJ) liquid is studied by molecular dynamics (MD) simulation. The bubble nucleation rate J is determined by the mean life-time method at temperatures above that of the triple point in the region of negative pressures. The results of simulation are compared with classical nucleation theory (CNT) and modified classical nucleation theory (MCNT), in which the work of formation of a critical bubble is determined in the framework of the van der Waals-Cahn-Hilliard gradient theory (GT). It has been found that the values of J obtained in MD simulation systematically exceed the data of CNT, and this excess in the nucleation rate reaches 8-10 orders of magnitude close to the triple point temperature. The results of MCNT are in satisfactory agreement with the data of MD simulation. To describe the properties of vapor-phase nuclei in the framework of GT, an equation of state has been built up which describes stable, metastable and labile regions of LJ fluids. The surface tension of critical bubbles γ has been found from CNT and data of MD simulation as a function of the radius of curvature of the surface of tension R*. The dependence γ(R*) has also been calculated from GT. The Tolman length has been determined, which is negative and in modulus equal to ≈(0.1 - 0.2) σ. The paper discusses the applicability of the Tolman formula to the description of the properties of critical nuclei in nucleation.
Ohtori, Norikazu; Ishii, Yoshiki
2015-10-28
Explicit expressions of the self-diffusion coefficient, D(i), and shear viscosity, η(sv), are presented for Lennard-Jones (LJ) binary mixtures in the liquid states along the saturated vapor line. The variables necessary for the expressions were derived from dimensional analysis of the properties: atomic mass, number density, packing fraction, temperature, and the size and energy parameters used in the LJ potential. The unknown dependence of the properties on each variable was determined by molecular dynamics (MD) calculations for an equimolar mixture of Ar and Kr at the temperature of 140 K and density of 1676 kg m(-3). The scaling equations obtained by multiplying all the single-variable dependences can well express D(i) and η(sv) evaluated by the MD simulation for a whole range of compositions and temperatures without any significant coupling between the variables. The equation for Di can also explain the dual atomic-mass dependence, i.e., the average-mass and the individual-mass dependence; the latter accounts for the "isotope effect" on Di. The Stokes-Einstein (SE) relation obtained from these equations is fully consistent with the SE relation for pure LJ liquids and that for infinitely dilute solutions. The main differences from the original SE relation are the presence of dependence on the individual mass and on the individual energy parameter. In addition, the packing-fraction dependence turned out to bridge another gap between the present and original SE relations as well as unifying the SE relation between pure liquids and infinitely dilute solutions.
Phillips, Carolyn L.; Crozier, Paul S.
2009-08-21
Two-temperature models are used to represent the interaction between atoms and free electrons during thermal transients such as radiation damage, laser heating, and cascade simulations. In this paper, we introduce an energy-conserving version of an inhomogeneous finite reservoir two-temperature model using a Langevin thermostat to communicate energy between the electronic and atomic subsystems. This energy-conserving modification allows the inhomogeneous two-temperature model to be used for longer and larger simulations and simulations of small energy phenomena, without introducing nonphysical energy fluctuations that may affect simulation results. We test this model on the annealing of Frenkel defects. We find that Frenkel defect annealing is largely indifferent to the electronic subsystem, unless the electronic subsystem is very tightly coupled to the atomic subsystem. We also consider radiation damage due to local deposition of heat in two idealized systems. We first consider radiation damage in a large face-centered-cubic Lennard-Jones (LJ) single-component crystal that readily recrystallizes. Second, we consider radiation damage in a large binary glass-forming LJ crystal that retains permanent damage. We find that the electronic subsystem parameters can influence the way heat is transported through the system and have a significant impact on the number of defects after the heat deposition event. We also find that the two idealized systems have different responses to the electronic subsystem. The single-component LJ system anneals most rapidly with an intermediate electron-ion coupling and a high electronic thermal conductivity. If sufficiently damaged, the binary glass-forming LJ system retains the least permanent damage with both a high electron-ion coupling and a high electronic thermal conductivity. In general, we find that the presence of an electronic gas can affect short and long term material annealing.
NASA Astrophysics Data System (ADS)
Fujiwara, K.; Shibahara, M.
2014-07-01
A classical molecular dynamics simulation was conducted for a system composed of fluid molecules between two planar solid surfaces, and whose interactions are described by the 12-6 Lennard-Jones form. This paper presents a general description of the pressure components and interfacial tension at a fluid-solid interface obtained by the perturbative method on the basis of statistical thermodynamics, proposes a method to consider the pressure components tangential to an interface which are affected by interactions with solid atoms, and applies this method to the calculation system. The description of the perturbative method is extended to subsystems, and the local pressure components and interfacial tension at a liquid-solid interface are obtained and examined in one- and two-dimensions. The results are compared with those obtained by two alternative methods: (a) an evaluation of the intermolecular force acting on a plane, and (b) the conventional method based on the virial expression. The accuracy of the numerical results is examined through the comparison of the results obtained by each method. The calculated local pressure components and interfacial tension of the fluid at a liquid-solid interface agreed well with the results of the two alternative methods at each local position in one dimension. In two dimensions, the results showed a characteristic profile of the tangential pressure component which depended on the direction tangential to the liquid-solid interface, which agreed with that obtained by the evaluation of the intermolecular force acting on a plane in the present study. Such good agreement suggests that the perturbative method on the basis of statistical thermodynamics used in this study is valid to obtain the local pressure components and interfacial tension at a liquid-solid interface.
van Westen, Thijs; Oyarzún, Bernardo; Vlugt, Thijs J H; Gross, Joachim
2015-06-28
We develop an equation of state (EoS) for describing isotropic-nematic (IN) phase equilibria of Lennard-Jones (LJ) chain fluids. The EoS is developed by applying a second order Barker-Henderson perturbation theory to a reference fluid of hard chain molecules. The chain molecules consist of tangentially bonded spherical segments and are allowed to be fully flexible, partially flexible (rod-coil), or rigid linear. The hard-chain reference contribution to the EoS is obtained from a Vega-Lago rescaled Onsager theory. For the description of the (attractive) dispersion interactions between molecules, we adopt a segment-segment approach. We show that the perturbation contribution for describing these interactions can be divided into an "isotropic" part, which depends only implicitly on orientational ordering of molecules (through density), and an "anisotropic" part, for which an explicit dependence on orientational ordering is included (through an expansion in the nematic order parameter). The perturbation theory is used to study the effect of chain length, molecular flexibility, and attractive interactions on IN phase equilibria of pure LJ chain fluids. Theoretical results for the IN phase equilibrium of rigid linear LJ 10-mers are compared to results obtained from Monte Carlo simulations in the isobaric-isothermal (NPT) ensemble, and an expanded formulation of the Gibbs-ensemble. Our results show that the anisotropic contribution to the dispersion attractions is irrelevant for LJ chain fluids. Using the isotropic (density-dependent) contribution only (i.e., using a zeroth order expansion of the attractive Helmholtz energy contribution in the nematic order parameter), excellent agreement between theory and simulations is observed. These results suggest that an EoS contribution for describing the attractive part of the dispersion interactions in real LCs can be obtained from conventional theoretical approaches designed for isotropic fluids, such as a Perturbed
Ohtori, Norikazu; Ishii, Yoshiki
2015-10-28
Explicit expressions of the self-diffusion coefficient, D{sub i}, and shear viscosity, η{sub sv}, are presented for Lennard-Jones (LJ) binary mixtures in the liquid states along the saturated vapor line. The variables necessary for the expressions were derived from dimensional analysis of the properties: atomic mass, number density, packing fraction, temperature, and the size and energy parameters used in the LJ potential. The unknown dependence of the properties on each variable was determined by molecular dynamics (MD) calculations for an equimolar mixture of Ar and Kr at the temperature of 140 K and density of 1676 kg m{sup −3}. The scaling equations obtained by multiplying all the single-variable dependences can well express D{sub i} and η{sub sv} evaluated by the MD simulation for a whole range of compositions and temperatures without any significant coupling between the variables. The equation for D{sub i} can also explain the dual atomic-mass dependence, i.e., the average-mass and the individual-mass dependence; the latter accounts for the “isotope effect” on D{sub i}. The Stokes-Einstein (SE) relation obtained from these equations is fully consistent with the SE relation for pure LJ liquids and that for infinitely dilute solutions. The main differences from the original SE relation are the presence of dependence on the individual mass and on the individual energy parameter. In addition, the packing-fraction dependence turned out to bridge another gap between the present and original SE relations as well as unifying the SE relation between pure liquids and infinitely dilute solutions.
Fujiwara, K; Shibahara, M
2014-07-21
A classical molecular dynamics simulation was conducted for a system composed of fluid molecules between two planar solid surfaces, and whose interactions are described by the 12-6 Lennard-Jones form. This paper presents a general description of the pressure components and interfacial tension at a fluid-solid interface obtained by the perturbative method on the basis of statistical thermodynamics, proposes a method to consider the pressure components tangential to an interface which are affected by interactions with solid atoms, and applies this method to the calculation system. The description of the perturbative method is extended to subsystems, and the local pressure components and interfacial tension at a liquid-solid interface are obtained and examined in one- and two-dimensions. The results are compared with those obtained by two alternative methods: (a) an evaluation of the intermolecular force acting on a plane, and (b) the conventional method based on the virial expression. The accuracy of the numerical results is examined through the comparison of the results obtained by each method. The calculated local pressure components and interfacial tension of the fluid at a liquid-solid interface agreed well with the results of the two alternative methods at each local position in one dimension. In two dimensions, the results showed a characteristic profile of the tangential pressure component which depended on the direction tangential to the liquid-solid interface, which agreed with that obtained by the evaluation of the intermolecular force acting on a plane in the present study. Such good agreement suggests that the perturbative method on the basis of statistical thermodynamics used in this study is valid to obtain the local pressure components and interfacial tension at a liquid-solid interface.
NASA Astrophysics Data System (ADS)
Aerssens, M.; Gusarov, A.; Moreau, P.; Malard, P.; Massaut, V.; Mégret, P.; Wuilpart, M.
2012-04-01
Fibre optical current sensor (FOCS) is a promising alternative to inductive sensors for the measurement of the plasma current in future thermonuclear fusion reactors. Standard FOCS relies on the measurement of the state of polarisation (SOP) of light at the output of an optical bre surrounding a current. Because of the Faraday eect, magnetic eld induced by electrical current rotates the SOP of light travelling into the bre. According to the Ampere's theorem this rotation is proportional to the surrounded current. In future tokamaks like ITER and DEMO, the plasma current will be suciently high to generate a rotation of the SOP higher than 2 radians. These conditions may lead to uncertainties on the determination of the plasma current if no post processing is performed. In this paper we propose a solution with a Polarisation Optical Time Domain Re ectometer (POTDR) setup allowing both unambiguous plasma current measurement and also local magnetic eld measurements. This measurement is based on the assessment of the SOP rotation of the Rayleigh backscattered POTDR signal. Thanks to the presence of an input polarizer, SOP variations are converted into power uctuations that contain information about the distribution of the magnetic eld and therefore about the plasma current. Using the Jones formalism we have developed a model accounting for the modication of the SOP of light travelling into the optical bre and the evolution of the POTDR signal. In parallel experimental PODTR measurements have been performed on the Tore Supra tokamak situated at CEA Cadarache in France. A comparison between the models and the experimental results conrms the capability of the system to measure the plasma current and the local magnetic eld even if further data post processing are still required.
Directional Jones and Stokes Vectors
2005-08-28
implies invariance with respect to two Euclidean isometry transformations which preserve the metrics in the separate factors of spacetime : Reflection...of two different spacetime coordinate systems, related by a reflection of the time coordinate, namely t --+ t = -t (and x --+ k = x). T is self
Martínez-Ruiz, F J; Blas, F J; Mendiboure, B; Moreno-Ventas Bravo, A I
2014-11-14
We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264-6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r(c) = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r(c) = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness
Martínez-Ruiz, F. J.; Blas, F. J.; Mendiboure, B.; Moreno-Ventas Bravo, A. I.
2014-11-14
We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264–6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r{sub c} = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r{sub c} = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the interfacial
Garrido, José Matías; Quinteros-Lama, Héctor; Piñeiro, Manuel M; Mejía, Andrés; Segura, Hugo
2014-07-07
This work focuses on the application of a two-way approach, where Molecular Dynamics (MD) simulations and the Square Gradient Theory (SGT) have been used for describing the phase and interface behavior of binary and ternary Lennard-Jones (LJ) mixtures, along a condition of three-phase equilibrium. The unequivocal correspondence between MD and SGT has been achieved by using the global phase diagram of binary mixtures composed by equally sized Lennard-Jones molecules, from which representative molecular parameters for Type-I, Type-II, and Type-III systems have been determined. The so selected binaries have been used then to scale the behavior of a ternary mixture characterized by complex phase equilibrium patterns. For the case of the theoretical SGT approach applied to the Lennard-Jones equation of state was used for predicting phase equilibrium and interfacial properties. In addition the corresponding MD simulations of these macroscopic properties have been conducted for the LJ potential by using equivalent molecular parameters and conditions than in the theoretical approach. Excellent agreement has been observed between the predictions obtained from theory and simulations. Particularly, our results concerning the characterization of the three phase line of a binary Type-III mixture indicate that the bulk liquid (α) and the bulk gas (G) regions are sharply separated by a bulk liquid region (β) for all the explored temperature, pressure, and concentration conditions. The structural analysis of these bulk phases reveals that a secondary liquid phase (β) perfectly wets the liquid-gas interface (α-G), as previously found for Type-II mixture [A. Mejía and L. F. Vega, J. Chem. Phys. 124, 244505 (2006)]. The exploration along the three-phase line for the ternary mixture shows good agreement between SGT and MD. Particularly, we observed the specific influence of a third component in the phase and interface behavior. From all the previous results, we conclude that the
Sanford, Jordan M.; Harrison, Arnell S.; Wiese, Dana S.; Flocks, James G.
2009-01-01
In June of 1990 and July of 1991, the U.S. Geological Survey (USGS) conducted geophysical surveys to investigate the shallow geologic framework of the Mississippi-Alabama-Florida shelf in the northern Gulf of Mexico, from Mississippi Sound to the Florida Panhandle. Work was done onboard the Mississippi Mineral Resources Institute R/V Kit Jones as part of a project to study coastal erosion and offshore sand resources. This report is part of a series to digitally archive the legacy analog data collected from the Mississippi-Alabama SHelf (MASH). The MASH data rescue project is a cooperative effort by the USGS and the Minerals Management Service (MMS). This report serves as an archive of high-resolution scanned Tagged Image File Format (TIFF) and Graphics Interchange Format (GIF) images of the original boomer paper records, navigation files, trackline maps, Geographic Information System (GIS) files, cruise logs, and formal Federal Geographic Data Committee (FGDC) metadata.
Ibuki, Kazuyasu; Ueno, Masakatsu
2006-04-07
The validity of a Fokker-Planck-Kramers equation (FPKE) treatment of the rate of diffusion-controlled reaction at short times [K. Ibuki and M. Ueno, J. Chem. Phys. 119, 7054 (2003)] is tested in a supercritical Lennard-Jones fluid over a wide density range by comparing it with the Langevin dynamics and molecular dynamics simulations and other theories. The density n range studied is 0.323n(c)< or =n< or =2.58n(c) and the temperature 1.52T(c), where n(c) and T(c) are the critical density and temperature, respectively. For the rate of bimolecular reactions, the transition between the collision-limited and diffusion-limited regimes is expected to take place in this density range. The simulations show that the rate constant decays with time extensively at high densities, and that the magnitude of decay decreases gradually with decreasing density. The decay profiles of the rate constants obtained by the simulations are reproduced reasonably well by the FPKE treatment in the whole density range studied if a continuous velocity distribution is used in solving the FPKE approximately. If a discontinuous velocity distribution is used instead of the continuous one, the FPKE treatment leads to a rate constant much larger than the simulation results at medium and low densities. The rate constants calculated from the Smoluchowski-Collins-Kimball (SCK) theory based on the diffusion equation are somewhat smaller than the simulation results in medium and low densities when the intrinsic rate constant is chosen to adjust the steady state rate constant in the low density limit to that derived by the kinetic collision theory. The discrepancy is relatively small, so that the SCK theory provides a useful guideline for a qualitative discussion of the density effect on the rate constant.
NASA Astrophysics Data System (ADS)
Mella, Massimo
2008-06-01
In this work, an improved approach for computing cluster dissociation rates using Monte Carlo (MC) simulations is proposed and a discussion is provided on its applicability as a function of environmental variables (e.g., temperature). With an analytical transformation of the integrals required to compute variational transition state theory (vTST) dissociation rates, MC estimates of the expectation value for the Dirac delta δ(qrc-qc) have been made free of the discretization error that is present when a prelimit form for δ is used. As a by-product of this transformation, the statistical error associated with <δ(qrc-qc)> is reduced making this step in the calculation of vTST rates substantially more efficient (by a factor of 4-2500, roughly). The improved MC procedure is subsequently employed to compute the dissociation rate for Lennard-Jones clusters X13-nYn (n=0-3) as a function of temperature (T), composition, and X-Y interaction strength. The X13-nYn family has been previously studied as prototypical set of systems for which it may be possible to select and stabilize structures different from the icosahedral global minimum of X13. It was found that both the dissociation rate and the dissociation mechanism, as suggested by the statistical simulations, present a marked dependence on n, T, and the nature of Y. In particular, it was found that a vacancy is preferentially formed close to a surface impurity when the X-Y interaction is weaker than the X-X one whatever the temperature. Differently, the mechanism was found to depend on T for stronger X-Y interactions, with vacancies being formed opposite to surface impurities at higher temperature. These behaviors are a reflex of the important role played by the surface fluctuations in defining the properties of clusters.
Spencer Jones, Sir Harold (1890-1960)
NASA Astrophysics Data System (ADS)
Murdin, P.
2000-11-01
Astronomer, born in London, England. He was chief assistant to Frank Dyson at Greenwich and worked at the Royal Observatory at the Cape of Good Hope. Following in the tracks of DAVID GILL, he repeated Gill's photographic survey of the southern sky (Cape Photographic Catalogue, CPC). He then organized the international project to determine Earth-Sun distance by repeated measurements of the asteroi...
Matthew Jones House: Recommendations for Treatment
2016-04-01
the cooling control function of the first floor system so that the system functions as a heating and ventilating (H&V) system . 9c. Replace the...recommenda- tions for MJH treatment by taking into account conditions and budget. The work’s scope included the roofing, masonry, and HVAC systems ...The NCPTT provided two reports, a preliminary recommendation for the roofing system (TAR-2015-5) and a final report (TAR-2015-6) that incor- porates
NASA Astrophysics Data System (ADS)
Reif, Maria M.; Hünenberger, Philippe H.
2011-04-01
The raw single-ion solvation free energies computed from atomistic (explicit-solvent) simulations are extremely sensitive to the boundary conditions and treatment of electrostatic interactions used during these simulations. However, as shown recently [M. A. Kastenholz and P. H. Hünenberger, J. Chem. Phys. 124, 224501 (2006), 10.1529/biophysj.106.083667; M. M. Reif and P. H. Hünenberger, J. Chem. Phys. 134, 144103 (2010)], the application of appropriate correction terms permits to obtain methodology-independent results. The corrected values are then exclusively characteristic of the underlying molecular model including in particular the ion-solvent van der Waals interaction parameters, determining the effective ion size and the magnitude of its dispersion interactions. In the present study, the comparison of calculated (corrected) hydration free energies with experimental data (along with the consideration of ionic polarizabilities) is used to calibrate new sets of ion-solvent van der Waals (Lennard-Jones) interaction parameters for the alkali (Li+, Na+, K+, Rb+, Cs+) and halide (F-, Cl-, Br-, I-) ions along with either the SPC or the SPC/E water models. The experimental dataset is defined by conventional single-ion hydration free energies [Tissandier et al., J. Phys. Chem. A 102, 7787 (1998), 10.1021/jp982638r; Fawcett, J. Phys. Chem. B 103, 11181] along with three plausible choices for the (experimentally elusive) value of the absolute (intrinsic) hydration free energy of the proton, namely, Δ G_hyd^{ominus }[H+] = -1100, -1075 or -1050 kJ mol-1, resulting in three sets L, M, and H for the SPC water model and three sets LE, ME, and HE for the SPC/E water model (alternative sets can easily be interpolated to intermediate Δ G_hyd^{ominus }[H+] values). The residual sensitivity of the calculated (corrected) hydration free energies on the volume-pressure boundary conditions and on the effective ionic radius entering into the calculation of the correction terms is
Reif, Maria M.; Huenenberger, Philippe H.
2011-04-14
The raw single-ion solvation free energies computed from atomistic (explicit-solvent) simulations are extremely sensitive to the boundary conditions and treatment of electrostatic interactions used during these simulations. However, as shown recently [M. A. Kastenholz and P. H. Huenenberger, J. Chem. Phys. 124, 224501 (2006); M. M. Reif and P. H. Huenenberger, J. Chem. Phys. 134, 144103 (2010)], the application of appropriate correction terms permits to obtain methodology-independent results. The corrected values are then exclusively characteristic of the underlying molecular model including in particular the ion-solvent van der Waals interaction parameters, determining the effective ion size and the magnitude of its dispersion interactions. In the present study, the comparison of calculated (corrected) hydration free energies with experimental data (along with the consideration of ionic polarizabilities) is used to calibrate new sets of ion-solvent van der Waals (Lennard-Jones) interaction parameters for the alkali (Li{sup +}, Na{sup +}, K{sup +}, Rb{sup +}, Cs{sup +}) and halide (F{sup -}, Cl{sup -}, Br{sup -}, I{sup -}) ions along with either the SPC or the SPC/E water models. The experimental dataset is defined by conventional single-ion hydration free energies [Tissandier et al., J. Phys. Chem. A 102, 7787 (1998); Fawcett, J. Phys. Chem. B 103, 11181] along with three plausible choices for the (experimentally elusive) value of the absolute (intrinsic) hydration free energy of the proton, namely, {Delta}G{sub hyd} {sup O-minus} [H{sup +}]=-1100, -1075 or -1050 kJ mol{sup -1}, resulting in three sets L, M, and H for the SPC water model and three sets L{sub E}, M{sub E}, and H{sub E} for the SPC/E water model (alternative sets can easily be interpolated to intermediate {Delta}G{sub hyd} {sup O-minus} [H{sup +}] values). The residual sensitivity of the calculated (corrected) hydration free energies on the volume-pressure boundary conditions and on the effective
Velocity autocorrelation functions of Lennard-Jones fluids
NASA Technical Reports Server (NTRS)
Tsang, T.; Tang, H.
1977-01-01
By a self-consistent procedure, the velocity autocorrelation functions of both liquid and gaseous argon have been calculated without introducing any arbitrary parameters. The results are in satisfactory agreement with computer experiments. The correlation functions are primarily determined by the nearest-neighbor coordination. Because of the strong hard-core repulsion, the behaviors are more vibratory and damp out quickly at high densities and are more diffusive at lower densities.
Sy Montgomery: Part Indiana Jones and Part Emily Dickinson
ERIC Educational Resources Information Center
Young, Terrell A.
2008-01-01
As important as accuracy may be to nonfiction writers, few have taken such risks as Sy Montgomery in gathering information for her articles, books, and films. In this profile article, Young recounts many of the risks and adventures Montgomery has taken for the sake of accurate and impassioned writing. Montgomery says, "I consider my books love…
Matthew Jones House: Historic Maintenance and Repair Manual
2014-08-01
231 Figure 205. Close-up of wood trim against brick wall in the porch tower (ERDC- CERL, 2012...left as is, further damage will result. The two wood fireplace mantels are currently either lying on the cellar floor or propped against a damp...building and landscape features against arson and vandalism be- fore rehabilitation work begin, i.e., erecting protective fencing and installing alarm
Bridget Jones Meets Mr. Darcy: Challenges of Contemporary Fiction
ERIC Educational Resources Information Center
Alsop, Justine
2007-01-01
This exploratory study seeks to investigate the collection practices of English Literature librarians with regard to contemporary fiction, including popular genres such as detective fiction and "chick lit". Results of an online survey suggest literature librarians are increasingly receptive to the acquisition of popular genres and identify the…
Honorable Stephanie Tubbs Jones College Fire Prevention Act
Rep. Fudge, Marcia L. [D-OH-11
2009-04-28
05/20/2010 Received in the Senate and Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:
Idiosyncratic risk in the Dow Jones Eurostoxx50 Index
NASA Astrophysics Data System (ADS)
Daly, Kevin; Vo, Vinh
2008-07-01
Recent evidence by Campbell et al. [J.Y. Campbell, M. Lettau B.G. Malkiel, Y. Xu, Have individual stocks become more volatile? An empirical exploration of idiosyncratic risk, The Journal of Finance (February) (2001)] shows an increase in firm-level volatility and a decline of the correlation among stock returns in the US. In relation to the Euro-Area stock markets, we find that both aggregate firm-level volatility and average stock market correlation have trended upwards. We estimate a linear model of the market risk-return relationship nested in an EGARCH(1, 1)-M model for conditional second moments. We then show that traditional estimates of the conditional risk-return relationship, that use ex-post excess-returns as the conditioning information set, lead to joint tests of the theoretical model (usually the ICAPM) and of the Efficient Market Hypothesis in its strong form. To overcome this problem we propose alternative measures of expected market risk based on implied volatility extracted from traded option prices and we discuss the conditions under which implied volatility depends solely on expected risk. We then regress market excess-returns on lagged market implied variance computed from implied market volatility to estimate the relationship between expected market excess-returns and expected market risk.We investigate whether, as predicted by the ICAPM, the expected market risk is the main factor in explaining the market risk premium and the latter is independent of aggregate idiosyncratic risk.
Schaad, Norman W; Postnikova, Elena; Lacy, George H; Sechler, Aaron; Agarkova, Irina; Stromberg, Paul E; Stromberg, Verlyn K; Vidaver, Anne K
2005-08-01
, respectively, Xanthomonas smithii subsp. citri (ex Hasse, 1915) sp. nov. nom. rev. comb. nov., Xanthomonas fuscans subsp. aurantifolii (ex Gabriel et al., 1989) sp. nov. nom. rev. comb. nov., and Xanthomonas alfalfae subsp. citrumelo (ex Riker and Jones) Gabriel et al., 1989 nov. rev. comb. nov. Furthermore, based on the analysis of 40 strains of 19 other xanthomonads, we propose to reclassify X. campestris pv. malvacearum (ex Smith, 1901) Dye 1978 as X. smithii subsp. smithii sp. nov. comb. nov. nom. nov.; X. campestris pv. alfalfae (ex Riker and Jones) Dye 1978 as X. alfalfae subsp. alfalfae (ex Riker et al., 1935) sp. nov. nov. rev.; and "var. fuscans" (ex Burkholder 1930) of X. campestris pv. phaseoli (ex Smith, 1897) as X. fuscans subsp. fuscans sp. nov.
The Barrie Jones Lecture—Eye care for the neglected population: challenges and solutions
Rao, G N
2015-01-01
Globally, pockets of ‘neglected populations' do not have access to basic health-care services and carry a much greater risk of blindness and visual impairment. While large-scale public health approaches to control blindness due to vitamin A deficiency, onchocerciasis, and trachoma are successful, other causes of blindness still take a heavy toll in the population. High-quality comprehensive eye care that is equitable is the approach that needs wide-scale application to alleviate this inequity. L V Prasad Eye Institute of India developed a multi-tier pyramidal model of eye care delivery that encompasses all levels from primary to advanced tertiary (quaternary). This has demonstrated the feasibility of ‘Universal Eye Health Coverage' covering promotive, preventive, corrective, and rehabilitative aspects of eye care. Using human resources with competency-based training, effective and cost-effective care could be provided to many disadvantaged people. PMID:25567375
NASA Astrophysics Data System (ADS)
Salian, Umesh A.
1998-04-01
The cumulated distribution of velocity components of atoms of a cluster in a constant energy classical molecular dynamics simulation is found to fit very well with Maxwellian distribution. This enables, with carefully prepared initial configurations, a cluster as small as containing just four atoms to be viewed to constitute a canonical ensemble in itself. In addition, the statistical distribution of velocity components provides an unambiguous, independent and robust method of obtaining the thermodynamic temperature of an isolated system. The temperature thus obtained differs from the conventionally used kinetic temperature by a fixed factor of (3N-6)/(3N), implications of which are discussed. A new procedure of sampling the configurational energy landscape is introduced, and the "heat capacity" curve computed using this method—which is actually the second moment of the potential energy fluctuations as a function of cluster kinetic energy—exhibits its usefulness by clearly demonstrating the two stage melting of Ar55.
A multiscale transport model for Lennard-Jones binary mixtures based on interfacial friction.
Bhadauria, Ravi; Aluru, N R
2016-08-21
We propose a one-dimensional isothermal hydrodynamic transport model for non-reacting binary mixtures in slit shaped nanochannels. The coupled species momentum equations contain viscous dissipation and interspecies friction term of Maxwell-Stefan form. Species partial viscosity variations in the confinement are modeled using the van der Waals one fluid approximation and the local average density method. Species specific macroscopic friction coefficient based Robin boundary conditions are provided to capture the species wall slip effects. The value of this friction coefficient is computed using a species specific generalized Langevin formulation. Gravity driven flow of methane-hydrogen and methane-argon mixtures confined between graphene slit shaped nanochannels are considered as examples. The proposed model yields good quantitative agreement with the velocity profiles obtained from the non-equilibrium molecular dynamics simulations. The mixtures considered are observed to behave as single species pseudo fluid, with the interfacial friction displaying linear dependence on molar composition of the mixture. The results also indicate that the different species have different slip lengths, which remain unchanged with the channel width.
A multiscale transport model for Lennard-Jones binary mixtures based on interfacial friction
NASA Astrophysics Data System (ADS)
Bhadauria, Ravi; Aluru, N. R.
2016-08-01
We propose a one-dimensional isothermal hydrodynamic transport model for non-reacting binary mixtures in slit shaped nanochannels. The coupled species momentum equations contain viscous dissipation and interspecies friction term of Maxwell-Stefan form. Species partial viscosity variations in the confinement are modeled using the van der Waals one fluid approximation and the local average density method. Species specific macroscopic friction coefficient based Robin boundary conditions are provided to capture the species wall slip effects. The value of this friction coefficient is computed using a species specific generalized Langevin formulation. Gravity driven flow of methane-hydrogen and methane-argon mixtures confined between graphene slit shaped nanochannels are considered as examples. The proposed model yields good quantitative agreement with the velocity profiles obtained from the non-equilibrium molecular dynamics simulations. The mixtures considered are observed to behave as single species pseudo fluid, with the interfacial friction displaying linear dependence on molar composition of the mixture. The results also indicate that the different species have different slip lengths, which remain unchanged with the channel width.
Comment on Cross, Fine, Jones, and Walsh (2012): We Are Now on the Same Page
ERIC Educational Resources Information Center
Goldstein, Seth L.
2012-01-01
Role conflict has been an issue in the intervention of child abuse cases since the beginning of the alliance drawn between the legal and mental health professions. In child abuse cases, clearly defined roles will prevent an attack on the process, thereby providing successful interventions to protect children. The child advocacy center concept is…
Environmental Assessment Bank Stabilization along St. Jones River Dover Air Force Base, Delaware
2008-12-01
type is Sassafras Loam, two to five percent slopes. All areas of this soil type are prime farmland; however, the dedicated land use of the site...and is not ponded. The water table is deeper than six feet. Sassafras Loam is not a hydric soil (University of Delaware 2005). 3.5 Socioeconomics
Landulfo, Gabriel Alves; Pevidor, Luisa Viana; Luz, Hermes Ribeiro; Faccini, João Luiz Horácio; Nunes, Pablo Henrique; Barros-Battesti, Darci Moraes
2013-01-01
Ornithodoros mimon is an argasid tick common on Chiroptera in the Neotropical region, where it also bites humans aggressively. Here we describe for the first time all nymphal instars (N1, N2 and N3) of O. mimon based on optical and scanning electron microscopy. Although the nymphal instars of O. mimon resemble each other closely, there are characters that differentiate them: the N3 are taller that N1 and N2; the genital primordium occurs in some N2 and all N3; the spiracular plate in N1 and N2 is cone-like, but in N3 it is semicircular; and the submarginal dorsal groove is less distinct in N1 but more evident in N3. Nymphs of 0. mimon closely resemble the bat-associated species of the genus Ornithodoros included in the Alectorobius group. We review prior descriptions of nymphs of the Alectorobius group and make comparisons with nymphs of O. minon, highlighting characters with diagnostic information, such as the idiosomal shape, presence of discs and hood and absence subapical protuberance of tarsus I. The description of nymphal instars of O. mimon herein presented, improves the taxonomy of the family Argasidae, performing a work more detailed about the immature stage of this species.
Efficient Resource Utilization in the Bayne-Jones Army Community Hospital Emergency Room
1990-08-07
turnaround ~times; limiting non-essential tests; creating triage 4 j nurse protocols to order x-ray and lab tests; creating i an independent "fast track...1972) found mean visit times of 135.9 minutes for patients who required both lab and x-ray studies and physician consultation; 87.1 minutes if only...physician consultation was required; 74.4 minutes if only lab /x-ray were required; and an average visit time of 51.8 minutes if the patient had neither
Tunnicliffe, Verena; St Germain, Candice; Hilário, Ana
2014-01-01
We examine the nature of variation in a hot vent tubeworm, Ridgeia piscesae, to determine how phenotypes are maintained and how reproductive potential is dictated by habitat. This foundation species at northeast Pacific hydrothermal sites occupies a wide habitat range in a highly heterogeneous environment. Where fluids supply high levels of dissolved sulphide for symbionts, the worm grows rapidly in a "short-fat" phenotype characterized by lush gill plumes; when plumes are healthy, sperm package capture is higher. This form can mature within months and has a high fecundity with continuous gamete output and a lifespan of about three years in unstable conditions. Other phenotypes occupy low fluid flux habitats that are more stable and individuals grow very slowly; however, they have low reproductive readiness that is hampered further by small, predator cropped branchiae, thus reducing fertilization and metabolite uptake. Although only the largest worms were measured, only 17% of low flux worms were reproductively competent compared to 91% of high flux worms. A model of reproductive readiness illustrates that tube diameter is a good predictor of reproductive output and that few low flux worms reached critical reproductive size. We postulate that most of the propagules for the vent fields originate from the larger tubeworms that live in small, unstable habitat patches. The large expanses of worms in more stable low flux habitat sustain a small, but long-term, reproductive output. Phenotypic variation is an adaptation that fosters both morphological and physiological responses to differences in chemical milieu and predator pressure. This foundation species forms a metapopulation with variable growth characteristics in a heterogeneous environment where a strategy of phenotypic variation bestows an advantage over specialization.
Federal Register 2010, 2011, 2012, 2013, 2014
2010-07-26
... publications to a foreign country, nor did the workers produce a component part that was used by a firm that..., and any Konica facility. The petitioner did not supply facts not previously considered; nor provide... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF...
Federal Register 2010, 2011, 2012, 2013, 2014
2011-03-10
... red-cockaded woodpecker and associated wildlife species of concern. Prescribed burning and timber thinning are used to ensure that quality pine habitat is maintained for red-cockaded woodpeckers... compatible wildlife-dependent public use opportunities. We will continue to monitor and manage the...
75 FR 26979 - Piedmont National Wildlife Refuge, Jones and Jasper Counties, GA
Federal Register 2010, 2011, 2012, 2013, 2014
2010-05-13
..., we would continue to monitor and manage the red-cockaded woodpecker population to achieve our goal... opportunities. We would continue to monitor and manage the red-cockaded woodpecker population, but would... dragonflies, crayfish, and mussels. We would continue to collect quail, turkey, and deer data through...
An EQT-based cDFT approach for a confined Lennard-Jones fluid mixture
Motevaselian, M. H.; Mashayak, S. Y.; Aluru, N. R.
2015-09-28
Empirical potential-based quasi-continuum theory (EQT) provides a route to incorporate atomistic detail into continuum framework such as the Nernst-Planck equation. EQT can also be used to construct a grand potential functional for classical density functional theory (cDFT). The combination of EQT and cDFT provides a simple and fast approach to predict the inhomogeneous density, potential profiles, and thermodynamic properties of confined fluids. We extend the EQT-cDFT approach to confined fluid mixtures and demonstrate it by simulating a mixture of methane and hydrogen inside slit-like channels of graphene. We show that the EQT-cDFT predictions for the structure of the confined fluid mixture compare well with the molecular dynamics simulation results. In addition, our results show that graphene slit nanopores exhibit a selective adsorption of methane over hydrogen.
VizieR Online Data Catalog: LMC & SMC evolved stars detected with Herschel (Jones+, 2015)
NASA Astrophysics Data System (ADS)
Jones, O. C.; Meixner, M.; Sargent, B. A.; Boyer, M. L.; Sewilo, M.; Hony, S.; Roman-Duval, J.
2016-01-01
Far-IR and sub-mm observations of the MC were taken as part of the HERITAGE Key Project (Meixner et al. 2013, J/AJ/146/62) using the Photodetector Array Camera and Spectrometer (PACS) and the Spectral and Photometric Imaging Receiver (SPIRE) on the Herschel Space Observatory. The optical UBVI and near-IR JHKs photometry comes from the Magellanic Clouds Photometric Survey (MCPS; Zaritsky et al. 1997AJ....114.1002Z); the Infrared Survey Facility (IRSF) MC Point Source Survey (Kato et al. 2007, II/288), the Two Micron All-Sky Survey (2MASS; Skrutskie et al. 2006, VII/233), and the 2MASS 6X Deep Point Source Catalog (6X2MASS; Cutri & 2MASS Team 2004, II/281). We also obtained supplementary mid-IR data from the AKARI LMC point source catalog (Kato et al. 2007, II/288; Ita et al. 2008PASJ...60S.435I) and the WISE all-sky catalog (Wright et al. 2010, II/311). (1 data file).
The Barrie Jones Lecture-Eye care for the neglected population: challenges and solutions.
Rao, G N
2015-01-01
Globally, pockets of 'neglected populations' do not have access to basic health-care services and carry a much greater risk of blindness and visual impairment. While large-scale public health approaches to control blindness due to vitamin A deficiency, onchocerciasis, and trachoma are successful, other causes of blindness still take a heavy toll in the population. High-quality comprehensive eye care that is equitable is the approach that needs wide-scale application to alleviate this inequity. L V Prasad Eye Institute of India developed a multi-tier pyramidal model of eye care delivery that encompasses all levels from primary to advanced tertiary (quaternary). This has demonstrated the feasibility of 'Universal Eye Health Coverage' covering promotive, preventive, corrective, and rehabilitative aspects of eye care. Using human resources with competency-based training, effective and cost-effective care could be provided to many disadvantaged people.
Lean Six Sigma: Optimizing Operating Room Utilization at Bayne-Jones Army Community Hospital
2006-07-01
thank the Group Practice Managers at David Grant Medical Center for providing me with an Air Force perspective, LTC Bruce Shahbaz for developing my...6,898.16 $11,561.81 4 Diseases & Dism fthe Bood, Blood Foming Organs, Iny ogcal Dsordrs 1.09 0.68 7 $3,42230 $3,191.14 7 MNyopiferative DOeases and
Tunnicliffe, Verena; St. Germain, Candice; Hilário, Ana
2014-01-01
We examine the nature of variation in a hot vent tubeworm, Ridgeia piscesae, to determine how phenotypes are maintained and how reproductive potential is dictated by habitat. This foundation species at northeast Pacific hydrothermal sites occupies a wide habitat range in a highly heterogeneous environment. Where fluids supply high levels of dissolved sulphide for symbionts, the worm grows rapidly in a “short-fat” phenotype characterized by lush gill plumes; when plumes are healthy, sperm package capture is higher. This form can mature within months and has a high fecundity with continuous gamete output and a lifespan of about three years in unstable conditions. Other phenotypes occupy low fluid flux habitats that are more stable and individuals grow very slowly; however, they have low reproductive readiness that is hampered further by small, predator cropped branchiae, thus reducing fertilization and metabolite uptake. Although only the largest worms were measured, only 17% of low flux worms were reproductively competent compared to 91% of high flux worms. A model of reproductive readiness illustrates that tube diameter is a good predictor of reproductive output and that few low flux worms reached critical reproductive size. We postulate that most of the propagules for the vent fields originate from the larger tubeworms that live in small, unstable habitat patches. The large expanses of worms in more stable low flux habitat sustain a small, but long-term, reproductive output. Phenotypic variation is an adaptation that fosters both morphological and physiological responses to differences in chemical milieu and predator pressure. This foundation species forms a metapopulation with variable growth characteristics in a heterogeneous environment where a strategy of phenotypic variation bestows an advantage over specialization. PMID:25337895
Interplay between crystallization and glass transition in binary Lennard-Jones mixtures
NASA Astrophysics Data System (ADS)
Banerjee, Atreyee; Chakrabarty, Suman; Bhattacharyya, Sarika Maitra
2013-09-01
In this work we explore the interplay between crystallization and glass transition in different binary mixtures by changing their inter-species interaction length and also the composition. We find that only those systems which form bcc crystal in the equimolar mixture and whose global structure for larger xA (xA = 0.6, where xA is the mole fraction of the bigger particles) is a mixed fcc + bcc phase, do not crystallize at this higher composition. However, the systems whose equimolar structure is a variant of fcc (NaCl type crystal) and whose global structure at larger xA is a mixed NaCl + fcc phase, crystallize easily to this mixed structure. We find that the stability against crystallization of this "bcc zone" is due to the frustration between the locally preferred structure (LPS) and the mixed bcc + fcc crystal. Our study suggests that when the global structure is a mixed crystal where a single species contributes to both the crystal forms and where the two crystal forms have large difference in some order parameter related to that species then this induces frustration between the LPS and the global structure. This frustration makes the systems good glass former. When xA is further increased (0.70 ⩽ xA < 0.90) the systems show a tendency towards mixed fcc crystal formation. However, the "bcc zone" even for this higher composition is found to be sitting at the bottom of a V shaped phase diagram formed by two different variants of the fcc crystal structure, leading to its stability against crystallization.
Interplay between crystallization and glass transition in binary Lennard-Jones mixtures.
Banerjee, Atreyee; Chakrabarty, Suman; Bhattacharyya, Sarika Maitra
2013-09-14
In this work we explore the interplay between crystallization and glass transition in different binary mixtures by changing their inter-species interaction length and also the composition. We find that only those systems which form bcc crystal in the equimolar mixture and whose global structure for larger x(A) (x(A) = 0.6, where x(A) is the mole fraction of the bigger particles) is a mixed fcc + bcc phase, do not crystallize at this higher composition. However, the systems whose equimolar structure is a variant of fcc (NaCl type crystal) and whose global structure at larger x(A) is a mixed NaCl + fcc phase, crystallize easily to this mixed structure. We find that the stability against crystallization of this "bcc zone" is due to the frustration between the locally preferred structure (LPS) and the mixed bcc + fcc crystal. Our study suggests that when the global structure is a mixed crystal where a single species contributes to both the crystal forms and where the two crystal forms have large difference in some order parameter related to that species then this induces frustration between the LPS and the global structure. This frustration makes the systems good glass former. When x(A) is further increased (0.70 ≤ x(A) < 0.90) the systems show a tendency towards mixed fcc crystal formation. However, the "bcc zone" even for this higher composition is found to be sitting at the bottom of a V shaped phase diagram formed by two different variants of the fcc crystal structure, leading to its stability against crystallization.
The Jones Commission - DoD Study of the Military Commissary System. Volume 2. Appendices
1989-12-18
District and Heidelberg Commissary Mannheim- Spinelli Distribution Center Mannheim Commissary 21 July - Wildflecken (plus annex), Bad Kissingen...Merchandise Management Branch Ms. Chris Windsor Chief, Budget Branch Ms. Jean Doonan Chief, Accounting Branch Mr. Robert Martinez Chief, Management Branch Mr