Reductive dechlorination of perchloroethylene using anaerobic sequencing batch biofilm reactors (AnSBBR)

1997 ◽  
Vol 35 (1) ◽  
pp. 49-56 ◽  
Author(s):  
P. J. Hirl ◽  
R. L. Irvine
Keyword(s):  
Reductive Dechlorination ◽  
Physiological State ◽  
Accurate Method ◽  
The United States ◽  
Daily Basis ◽  
Biofilm Reactor ◽  
Microbial Consortia ◽  
Biofilm Reactors ◽  
Chlorinated Organic ◽  
The Many

Chlorinated organic solvents, such as perchloroethylene (PCE) and trichloroethylene (TCE), rank in the top five of the groundwater pollutants found in the United States. During the past year, the Anaerobic Sequencing Batch Biofilm Reactor (AnSBBR) was used to select for, enrich, and modify the physiological state of one or more of the many possible microbial consortia that can participate in the reductive dechlorination of PCE. Reactors enriched on lactate or acetate were able to dechlorinate 10.5 mg (63.3 μmoles) of PCE to cis-1,2-dichloroethylene (cDCE) on a daily basis. When methanol was used as the electron donor PCE, TCE, and cDCE were detectable in the reactor at the end of a 24 hour cycle. An AnSBBR fed only H2/CO2 was able to mediate the dechlorination of PCE to TCE, cDCE, and vinyl chloride (VC). Chloride measurements provided for a reliable and accurate method for the quantification of reductive dechlorination when the sorption of the chlorinated ethylenes affected the direct measurement of these compounds.

Applying the Devil's Works in a Holy Cause: Working-Class Popular Culture and the Salvation Army in the United States, 1879-1900

1997 ◽  
Vol 7 (2) ◽  
pp. 195-223
Author(s):  
Lillian Taiz
Keyword(s):  
United States ◽  
New York ◽  
New York City ◽  
Popular Culture ◽  
York City ◽  
The United States ◽  
Salvation Army ◽  
Public Meeting ◽  
The Many ◽  
Sunday Evening

Forty-eight hours after they landed in New York City in 1880, a small contingent of the Salvation Army held their first public meeting at the infamous Harry Hill's Variety Theater. The enterprising Hill, alerted to the group's arrival from Britain by newspaper reports, contacted their leader, Commissioner George Scott Railton, and offered to pay the group to “do a turn” for “an hour or two on … Sunday evening.” In nineteenth-century New York City, Harry Hill's was one of the best known concert saloons, and reformers considered him “among the disreputable classes” of that city. His saloon, they said, was “nothing more than one of the many gates to hell.”

Phosphorus Release Kinetics in Biofilm Reactors

1992 ◽  
Vol 26 (3-4) ◽  
pp. 567-576 ◽  
Author(s):  
F. A. Ruiz-Treviño ◽  
S. González-Martínez ◽  
C. Doria-Serrano ◽  
M. Hernández-Esparza
Keyword(s):  
Phosphorus Removal ◽  
Release Kinetics ◽  
Phosphorus Release ◽  
Organic Substrate ◽  
Biofilm Reactor ◽  
Substrate Uptake ◽  
Biofilm Reactors ◽  
Initial Substrate ◽  
Linear Behaviour ◽  
Substrate Concentrations

This paper presents the kinetic analysis, using Generalized Power-Law equations to describe the results of an experimental investigation conducted on a batch submerged biofilm reactor for phosphorus removal under an anaerobic/aerobic cycle. The observed rates and amounts of phosphorus release and organic substrate uptake in the anaerobic phase leads to a kinetic model in which these two variables are dependent on each other with a non-linear behaviour and reach equilibrium values in both cases, at different times and are function of rate constants ratio. The model has a good fit with experimental data except for C uptake at anaerobic contact times longer than four hours, where other kinetics are implied. Kinetic parameters were obtained with different initial substrate concentrations, anaerobic contact cycles, and type of substrates.

The Conference on Security and Cooperation in Europe and Other European Fora on Migration

1994 ◽  
Vol 28 (3) ◽  
pp. 580-590
Author(s):  
Jan Niessen
Keyword(s):  
Human Rights ◽  
The United States ◽  
Eastern European ◽  
Scientific Cooperation ◽  
High Commissioner ◽  
Protection Of Human Rights ◽  
Prevention Center ◽  
The Many ◽  
The Cold War ◽  
General Secretary

In the 1970s, during the Cold War era, European and North American states began a dialogue in Helsinki which became known as the Conference on Security and Cooperation in Europe (CSCE), or the Helsinki process. For Western states the CSCE served as a platform to raise questions related to security in Europe and the protection of human rights and fundamental freedoms. Eastern European states considered the CSCE as a means to secure the postwar borders and an opportunity to discuss economic and scientific cooperation. Today, 51 European States, plus the United States of America and Canada, participate in this process. Notwithstanding the many and often intense political tensions between the West and the East during those twenty years, quite a number of conferences, seminars and other meetings were held and a great many agreements were adopted and documents issued, dealing with matters related to CSCE's three main areas of concern: security in Europe; cooperation in the fields of economics, science, technology and environment; the promotion of human rights. In response to the fundamental changes in Europe in the late 1980s, the CSCE was given a new impetus and its operational framework was broadened. CSCE offices were established in Prague (CSCE Secretariat), Vienna (Conflict Prevention Center) and Warsaw (Office of Democratic Institutions and Human Rights) with the aim to strengthen and monitor compliance with CSCE commitments, especially in the area of human rights. A Parliamentary Assembly was established and met twice, first in Budapest and then in Helsinki. A General Secretary and a High Commissioner on Minorities were appointed, with offices in Vienna and The Hague, respectively.

scholarly journals The Dynamic Response of Nitrogen Transformation to the Dissolved Oxygen Variations in the Simulated Biofilm Reactor

2021 ◽  
Vol 18 (7) ◽  
pp. 3633
Author(s):  
Qianqian Lu ◽  
Nannan Zhang ◽  
Chen Chen ◽  
Miao Zhang ◽  
Dehua Zhao ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Copy Number ◽  
Stable State ◽  
Quantitative Relationship ◽  
Nitrogen Transformation ◽  
Biofilm Reactor ◽  
Short Term ◽  
Nirs Gene ◽  
Biofilm Reactors ◽  
Recovery Times

Lab-scale simulated biofilm reactors, including aerated reactors disturbed by short-term aeration interruption (AE-D) and non-aerated reactors disturbed by short-term aeration (AN-D), were established to study the stable-state (SS) formation and recovery after disturbance for nitrogen transformation in terms of dissolved oxygen (DO), removal efficiency (RE) of NH4+-N and NO3−-N and activity of key nitrogen-cycle functional genes amoA and nirS (RNA level abundance, per ball). SS formation and recovery of DO were completed in 0.56–7.75 h after transition between aeration (Ae) and aeration stop (As). In terms of pollutant REs, new temporary SS formation required 30.7–52.3 h after Ae and As interruptions, and seven-day Ae/As interruptions required 5.0% to 115.5% longer recovery times compared to one-day interruptions in AE-D and AN-D systems. According to amoA activity, 60.8 h were required in AE-D systems to establish new temporary SS after As interruptions, and RNA amoA copies (copy number/microliter) decreased 88.5%, while 287.2 h were required in AN-D systems, and RNA amoA copies (copy number/microliter) increased 36.4 times. For nirS activity, 75.2–85.8 h were required to establish new SSs after Ae and As interruptions. The results suggested that new temporary SS formation and recovery in terms of DO, pollutant REs and amoA and nirS gene activities could be modelled by logistic functions. It is concluded that temporary SS formation and recovery after Ae and As interruptions occurred at asynchronous rates in terms of DO, pollutant REs and amoA and nirS gene activities. Because of DO fluctuations, the quantitative relationship between gene activity and pollutant RE remains a challenge.

scholarly journals Challenges in Bridge Health Monitoring: A Review

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4336
Author(s):  
Piervincenzo Rizzo ◽  
Alireza Enshaeian
Keyword(s):  
United States ◽  
Health Monitoring ◽  
Highway Bridges ◽  
The United States ◽  
Anomalous Behavior ◽  
Existing Structures ◽  
Bridge Health Monitoring ◽  
Using Data ◽  
The Many ◽  
Major Factors

Bridge health monitoring is increasingly relevant for the maintenance of existing structures or new structures with innovative concepts that require validation of design predictions. In the United States there are more than 600,000 highway bridges. Nearly half of them (46.4%) are rated as fair while about 1 out of 13 (7.6%) is rated in poor condition. As such, the United States is one of those countries in which bridge health monitoring systems are installed in order to complement conventional periodic nondestructive inspections. This paper reviews the challenges associated with bridge health monitoring related to the detection of specific bridge characteristics that may be indicators of anomalous behavior. The methods used to detect loss of stiffness, time-dependent and temperature-dependent deformations, fatigue, corrosion, and scour are discussed. Owing to the extent of the existing scientific literature, this review focuses on systems installed in U.S. bridges over the last 20 years. These are all major factors that contribute to long-term degradation of bridges. Issues related to wireless sensor drifts are discussed as well. The scope of the paper is to help newcomers, practitioners, and researchers at navigating the many methodologies that have been proposed and developed in order to identify damage using data collected from sensors installed in real structures.

John Leighton Stuart and U.S.-Chinese Communist Rapprochement in 1949: Was There Another “Lost Chance in China”?

1982 ◽  
Vol 89 ◽  
pp. 74-96 ◽  
Author(s):  
Yu-ming Shaw
Keyword(s):  
United States ◽  
Cold War ◽  
The United States ◽  
Mao Zedong ◽  
Working Relationship ◽  
Republic Of China ◽  
The Many ◽  
The One ◽  
June July ◽  
The Cold War

Reverend John Leighton Stuart (1876–1962) served as U.S. ambassador to China from July 1946 until August 1949. In the many discussions of his ambassadorship the one diplomatic mission that has aroused the most speculation and debate was his abortive trip to Beijing, contemplated in June–July 1949, to meet with Mao Zedong and Zhou Enlai. Some students of Sino-American relations have claimed that had this trip been made the misunderstanding and subsequent hostility between the United States and the People's Republic of China in the post-1949 period could have been avoided; therefore, the unmaking of this trip constituted another “lost chance in China” in establishing a working relationship between the two countries. But others have thought that given the realities of the Cold War in 1949 and the internal political constraints existing in each country, no substantial result could have been gained from such a trip. Therefore, the thesis of a “lost chance in China” was more an unfounded speculation than a credible affirmation.

The U.S. Health Delivery System: Inefficient and Unfair to Children

1997 ◽  
Vol 23 (2-3) ◽  
pp. 319-337
Author(s):  
Loretta M. Kopelman ◽  
Michael G. Palumbo
Keyword(s):  
United States ◽  
Health Care ◽  
Universal Access ◽  
The United States ◽  
Industrialized Countries ◽  
Health Care Resources ◽  
Health Delivery ◽  
Hip Replacements ◽  
The Many ◽  
Older Citizens

What proportion of health care resources should go to programs likely to benefit older citizens, such as treatments for Alzheimer’s disease and hip replacements, and what share should be given to programs likely to benefit the young, such as prenatal and neonatal care? What portion should go to rare but severe diseases that plague the few, or to common, easily correctable illnesses that afflict the many? What percentage of funds should go to research, rehabilitation or to intensive care? Many nations have made such hard choices about how to use their limited funds for health care by explicitly setting priorities based on their social commitments. In the United States, however, allocation of health care resources has largely been left to personal choice and market forces. Although the United States spends around 14% of its gross national product (GNP) on health care, the United States and South Africa are the only two industrialized countries that fail to provide citizens with universal access.

End-of-Life Care behind Bars

2002 ◽  
Vol 10 (3) ◽  
pp. 233-241 ◽  
Author(s):  
Phyllis B. Taylor
Keyword(s):  
United States ◽  
End Of Life ◽  
End Of Life Care ◽  
The United States ◽  
Chronic Illnesses ◽  
Direct Result ◽  
Life Care ◽  
Prison Health ◽  
The Many ◽  
Changing Demographics

More people than ever before are being incarcerated in the United States. Many inmates are infected with HIV and hepatitis C. Sentences are increasing in length. Prison health care is now having to cope with the many chronic illnesses associated with an ill and aging population. The growth of end-of-life care programs in corrections in the United States is a direct result of the changing demographics of inmates. This article examines the need for end-of-life care behind bars and discusses selected hospice programs.

Nitritification and Denitritification of High-Strength Ammonium and Nitrite Wastewater with Biofilm Reactors

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1417-1425 ◽  
Author(s):  
Sheng-Kun Chen ◽  
Chin-Kun Juaw ◽  
Sheng-Shung Cheng
Keyword(s):  
Benzoic Acid ◽  
Organic Compounds ◽  
Draft Tube ◽  
Fixed Bed ◽  
High Strength ◽  
Biofilm Reactor ◽  
Biological Processes ◽  
Biofilm Reactors ◽  
Nitrite Removal ◽  
In Series

Two sets of fixed-film biological processes were operated separately for nitritification of amnonium and for denitritification of nitrite associated with organic compounds. High strength amnonium wastewater (50-1000 mg NH4+-N/l) could be effectively nitritified by a draft-tube fluidized bed which was operated at an extremely high loading of 1.0 kg NH4−1-N/m3.day with 95% amnonium conversion and 60 to 95% nitrite formation. Additionally, a biofilm fixed-bed was employed to denitritify the high strength nitrite (200 to 1000 mg NO2−-N/l) associated with organic compounds of glucose, acetate and benzoic acid. Complete nitrite removal could be achieved with sufficient HRT and COD/NO2−-N ratio. The conversion ratios were estimated experimentally at 2.5 for glucose and acetate, and 2.0 g ∆COD/g ∆NO2−-N for benzoic acid. A proposed process of an aerobic nitritifying biofilm reactor combined with an anoxic denitritifying biofilm reactor in series could be employed for complete nitrogen removal.

An accurate method to include lubrication forces in numerical simulations of dense Stokesian suspensions

2015 ◽  
Vol 769 ◽  
pp. 369-386 ◽  
Author(s):  
A. Lefebvre-Lepot ◽  
B. Merlet ◽  
T. N. Nguyen
Keyword(s):  
Short Range ◽  
Degrees Of Freedom ◽  
Computational Cost ◽  
Parameter Tuning ◽  
Accurate Method ◽  
Spherical Particles ◽  
Particle Model ◽  
Stokesian Dynamics ◽  
New Feature ◽  
The Many

We address the problem of computing the hydrodynamic forces and torques among $N$ solid spherical particles moving with given rotational and translational velocities in Stokes flow. We consider the original fluid–particle model without introducing new hypotheses or models. Our method includes the singular lubrication interactions which may occur when some particles come close to one another. The main new feature is that short-range interactions are propagated to the whole flow, including accurately the many-body lubrication interactions. The method builds on a pre-existing fluid solver and is flexible with respect to the choice of this solver. The error is the error generated by the fluid solver when computing non-singular flows (i.e. with negligible short-range interactions). Therefore, only a small number of degrees of freedom are required and we obtain very accurate simulations within a reasonable computational cost. Our method is closely related to a method proposed by Sangani & Mo (Phys. Fluids, vol. 6, 1994, pp. 1653–1662) but, in contrast with the latter, it does not require parameter tuning. We compare our method with the Stokesian dynamics of Durlofsky et al. (J. Fluid Mech., vol. 180, 1987, pp. 21–49) and show the higher accuracy of the former (both by analysis and by numerical experiments).

Sign in / Sign up

Export Citation Format

Share Document