Behavioral contagion

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Behavioral_contagion 

Behavioral contagion is a form of social contagion involving the spread of behavior through a group. It refers to the propensity for a person to copy a certain behavior of others who are either in the vicinity, or whom they have been exposed to. The term was originally used by Gustave Le Bon in his 1895 work The Crowd: A Study of the Popular Mind to explain undesirable aspects of behavior of people in crowds. In the digital age, behavioral contagion is also concerned with the spread of online behavior and information. A variety of behavioral contagion mechanisms were incorporated in models of collective human behavior.

Behavioral contagion has been attributed to a variety of different factors. Often it is distinguished from collective behavior that arises from a direct attempt at social influence. A prominent theory involves the reduction of restraints, put forth by Fritz Redl in 1949 and analyzed in depth by Ladd Wheeler in 1966. Social psychologists acknowledge a number of other factors, which influence the likelihood of behavioral contagion occurring, such as deindividuation (Festinger, Pepitone, & Newcomb, 1952) and the emergence of social norms (Turner, 1964). In 1980, Freedman et al. have focused on the effects of physical factors on contagion, in particular, density and number.

J. O. Ogunlade (1979, p. 205) describes behavioral contagion as a "spontaneous, unsolicited and uncritical imitation of another's behavior" that occurs when certain variables are met: a) the observer and the model share a similar situation or mood (this is one way behavioral contagion can be readily applied to mob psychology); b) the model's behavior encourages the observer to review his condition and to change it; c) the model's behavior would assist the observer to resolve a conflict by reducing restraints, if copied; and d) the model is assumed to be a positive reference individual.

Types of contagion

Social contagion can occur through threshold models that assume that an individual needs to be convinced by a fraction of their social contacts above a given threshold to adopt a novel behaviour. Therefore, the number of exposures will not increase chances of contagion unless the number of source exposures pass a certain threshold. The threshold value can divide contagion processes to two types: 1) Simple contagion and 2) Complex contagion.

Simple contagion

The individual needs only one person displaying the novel behaviour to copy. For instance, cars travel in groups on a two-lane highway since the car in each cluster travels at a slower speed than the car behind it. This relative speed spreads through other cars who slow down to match the speed of the car in front.

Complex contagion

The individual needs to be in contact with two or more sources exhibiting the novel behaviour. This is when copying behaviours needs reinforcement or encouragement from multiple sources. Multiple sources, especially close friends, can make imitation legitimate, credible and worthwhile due to collective effort put in. Examples of complex contagions can be copying risky behaviour or joining social movements and riots.

Factors

Strength of ties

Social contagion in simple contagion models occurs most effectively through 'weak' and 'long' ties between social contacts. A 'weak' tie between two people means they do not interact as frequently and do not influence each other as close friends. However, a relationally 'weak' tie is structurally strong if it is 'long' because it connects socially distant people, showing greater outreach than a relationally 'strong' tie. These 'long' ties allow the flow of new information increasing rate of transmission that relationally strong ties cannot do. Even though close friends can strongly influence each other, they will not help each other learn about new opportunities, ideas or behaviours in socially distant settings if they all know the same things. Few 'weak' and 'long' ties can help spread information quickly between two socially distant strong networks of people. 'Strong' ties within those networks can help spread information amongst the peers.

On the other hand, complex social contagion processes require multiple sources of influence. This is not possible with few 'weak' ties: they need to be long and multiple in number to increase the probability of imitation between socially distant networks.

Structural equivalence

However, social contagion can also occur in the absence of any ties during competition. This happens when two people are structurally equivalent i.e., they occupy the same position in a social network and have the same pattern of relationships with the same people. For instance, two students publishing the same kind of research under the same professor are structurally equivalent. The more similar their relations are with other people i.e. the more substitutable they are with one another, the more they will copy what the other is doing, if it makes them look better, to stay ahead of competition.

Reduction of restraints

Behavioral contagion is a result of the reduction of fear or restraints – aspects of a group or situation which prevent certain behaviors from being performed. Restraints are typically group-derived, meaning that the "observer", the individual wishing to perform a certain behavior, is constrained by the fear of rejection by the group, who would view this behavior as a "lack of impulse control".

An individual (the "observer") wants to perform some behavior, but that behavior would violate the unspoken and accepted rules of the group or situation they are in; these rules are the restraints preventing the observer from performing that action. Once the restraints are broken or reduced the observer is then "free" to perform the behavior; this is achieved by the "intervention" of the model. The model is another individual, in the same group or situation as the observer, who performs the behavior which the observer wished to perform. Stephenson and Fielding (1971) describe this effect as "[Once] one member of a gathering has performed a commonly desired action, the payoffs for similar action or nonaction are materially altered. ... [The] initiator, by his action, establishes an inequitable advantage over the other members of the gathering which they may proceed to nullify by following his example."

Density and number

Density refers to the amount of space available to a person – high density meaning there is less space per person – and number refers to the size of the group. Freedman (1975) put forth the intensification theory, which posits that high density makes the other people in a group more salient features of the environment, this magnifying the individual's reaction to them. Research has shown that high density does in fact increase the likelihood of contagion (Freedman, 1975; Freedman, Birsky, & Cavoukian, 1980). Number also has an effect on contagion, but to a lesser degree than density.

Local trend imitation

However, the probability that an individual will copy a behaviour can also decrease with higher density and number of neighbours. For instance, a person might praise and go to a restaurant with good food based on others’ recommendations but avoid it when it becomes over-crowded. This depicts the local trend imitation phenomenon i.e. the adoption probability first increases with increase in number of adopted neighbours and then decreases.

Identity of the model

Stephenson and Fielding (1971) state that the identity of the model is a factor that influences contagion (p. 81). Depending on the behavior, sex of the model may be a factor in the contagion of that behavior being performed by other individuals – particularly in instances of adult models performing aggressive behavior in the presence of children-observers (Bandura, Ross, & Ross, 1963) {Imitation of film-mediated aggressive models}. In this particular series of experiments – Albert Bandura's Bobo doll experiments from 1961 and 1963 – where the behavior of children was studied after the children watched an adult model punching a bobo doll and the model received a reward, a punishment, or there were no consequences, the analyses revealed that the male model influenced the participants' behavior to a greater extent than did the female model; this was true for both the aggressive and the nonaggressive male models (p. 581).

Dominant leaders

Aggressive behaviour or using coercion, fear or intimidation to imitate a behaviour is known as dominance. People are likely to follow dominant leaders to avoid the cost of punishment. However, such behaviour is more influential amongst children rather than adults: coercive children are thought to be more likeable whereas coercive adults are less likeable and, hence, influential.

Prestigious influencers

While dominant behaviour is displayed in the animal kingdom as well, prestigious behaviour is unique to humans. Unlike animals, we understand the intentions behind someone's actions rather than just being able to copy their movements precisely. This is important since it is easier to learn from the best models rather than learning by ourselves: We might know which behaviour contributes to someone's success at mastering a skill. Hence, we look to see who everyone else is copying i.e. we tend to copy prestigious individuals. Prestigious people enjoy a high degree of influence and respect and are generally the people with the most information.

Ordinary people

A study done on the rate of information transmission via retweets on Twitter found that popular people i.e. people with a large following, are 'inefficient hubs' in spreading concepts. The more followers someone has, the more overloaded they are with information and lower the chances that they will retweet a particular message due to limited attention. Hence, rate of social contagion slows down.

Rather, social contagion can amplify amongst 'ordinary' users with low following if they are closely connected in a peer network. People are more likely to retweet messages by close friends to facilitate social bonding. Peers also have higher similar interests and are more influenced by each other than an 'ordinary' and 'popular' user who do not have mutual ties. Hence, social contagion can occur efficiently amongst tight community structures, in the absence of prestigious and dominant leaders.

Media

Mass media can greatly influence people's opinions and amplify social contagion by reporting stories from socially distant and unconnected networks. They can help to turn minority opinions into the popular opinion, independent of the degree of connectivity between people.

Moreover, Bandura (1977) showed that children can learn and imitate fictitious characters on television.

Personality of the observer

Ogunlade (1979) found that extroverts, who are described as impulsive and sociable individuals, are more likely to be susceptible to contagion than introverted individuals, who are described as reserved and emotionally controlled.

Social norms

Gino, Ayal and Ariely (2009) state that an important factor influencing contagion is the degree to which the observer identifies with the others of the group (p. 394). When identification with the rest of the group is strong, the behaviors of the others will have a larger influence.

However, high homophily or the likelihood of being connected to others with similar interests, can lead to both minority and majority groups overestimating their sizes and vice versa. This can cause people to falsely predict the frequency of their behaviour in the real world since they estimate based on their personal networks. When people overestimate the frequency of a particular behaviour, they may think that they are following social norms and, hence, are less willing to change. Encouraging interactions within heterophilic rather than homophilic social networks can facilitate social contagion more.

Similarities and differences with other types of social influence

Contagion is only one of a myriad of types of social influence.

Conformity / social pressures

Conformity is a type of social influence that is very similar to contagion. It is almost identical to another type of social influence, "pressures toward uniformity" (social pressures) (Festinger, 1954), which differ only in the research techniques they are associated with (Wheeler, 1966, p. 182).

Both conformity and contagion involve some sort of conflict, but differ in the roles other individuals play in that conflict. In conformity, the other individuals of the group try to pressure the observer into performing a behavior; the model then performs some other behavior in the vicinity of the observer. This results in the observer creating restraints against the pressured behavior and a conflict between the pressured behavior and the behavior performed by the model. In the end, the observer either performs the model's behavior his-/herself, rejects the model, or pressures the model to perform the original pressured behavior (Wheeler, Table 1). In contagion, the model's behavior results in the removing of restraints and the resolving of the conflict, while in conformity, the model's behavior results in the creation of restraints and of the conflict.

Social facilitation

See also: Social facilitation in animals

Social facilitation, another type of social influence, is distinguished from contagion, as well as from conformity and social pressures, by the lack of any marked conflict. It is said to occur when the performance of an instinctive pattern of behavior by an individual acts as a releaser for the same behavior in others, and so initiates the same line of action in the whole group (Thorpe, 1956, p. 120). Bandura and Walters (1963, p. 79), give the example of an adult, who has lost the unique aspects of the dialect of the region where they were raised, returns for a visit and "regains" those previously lost patterns of speech. Starch (1911) referred to this phenomenon as an "unintentional or unconscious imitation".

Imitation

Imitation is different from contagion in that it is learned via reward and punishment and is generalized across situations. Imitation can also be a generic term for contagion, conformity, social pressures, and social facilitation.

(Wheeler, 1966, Table 1)	Dynamics of selected influence processes
Stages in influence process	Behavioral contagion	Social pressures and conformity	Social facilitation
Observer's initial conditions	Instigated to BN*. Internal restraints against BN.	Instigated to BP*. No restraints.	No restraints against BN or BP. No instigation to BN or BP.
Model's behavior	Model performs BN.	Model performs BN.	Model performs BN.
Hypothetical processes	Reduction of model's restraints against BN. Fear reduction.	Creation of restraints against BP. Conflict between BN and BP.	Cognitive-behavioral chaining, CS* elicits CR*, inertia overcome.
Observer's behavior	Observer performs BN.	Observer performs BN (or rejects model or induces model to perform BP).	Observer performs BN.

• BN = initial behavior
• BP = pressured behavior
• CS = conditioned stimulus
• CR = conditioned response

Competition contagion on non-competitors

While behavioral contagion is largely about how people might be affected by observations of the expressions or behavior of others, research has also found contagion in the context of a competition where mere awareness of an ongoing competition can have an influence on noncompetitors' task performance, without any information about the actual behavior of the competitors.

Research

Effects of group pressure

Behavioral contagion, largely discussed in the behaviors of crowds, and closely related to emotional contagion, plays a large role in gatherings of two or more people. In the original Milgram experiment on obedience, for example, where participants, who were in a room with only the experimenter, were ordered to administer increasingly more severe electrical shocks as punishment to a person in another room (from here on referred to as the "victim"), the conflict or social restraint experienced by the participants was the obligation to not disobey the experimenter – even when shocking the victim to the highest shock level given, a behavior which the participants saw as opposing their personal and social ideals (Milgram, 1965, p. 129).

Milgram also conducted two other experiments, replications of his original obedience experiment, with the intent being to analyze the effect of group behavior on participants: instead of the subject being alone with the experimenter, two confederates were utilized. In the first of the two experiments, "Groups for Disobedience", the confederates defied the experimenter and refused to punish the victim (p. 130). This produced a significant effect on the obedience of the participants: in the original experiment, 26 of the 40 participants administered the maximum shock; in the disobedient groups experiment, only 4 of 40 participants administered the highest level of voltage (Table 1). Despite this high correlation between shock level administered and the obedience of the group in the disobedient groups experiment, there was no significant correlation for the second of the replicated experiments: "Obedient Groups", where the confederates did not disobey the experimenter and, when the participant voiced angst regarding the experiment and wished to stop administering volts to the victim, the confederates voiced their disapproval (p. 133). Milgram concludes the study by remarking that "the insertion of group pressure in a direction opposite that of the experimenter's commands produces a powerful shift toward the group. Changing the group movement does not yield a comparable shift in the [participant's] performance. The group success in one case and failure in another can be traced directly to the configuration of motive and social forces operative in the starting situation." That is, if the group's attitudes are similar to or compatible with the participant's/observer's, there is a greater likelihood that the participant/observer will join with the group (p. 134).

Overweight and obesity

Network phenomena are relevant to obesity, which appears to spread through social ties. Teenagers of US Army families assigned to counties with higher obesity rates were more likely to become overweight or obese in a 2018 study. This effect could not be explained by self-selection (homophily) or shared built environments and is attributed to social contagion.

Synthetic fuel

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Synthetic_fuel 

 

Side-by-side comparison of FT synthetic fuel and conventional fuel. The synthetic fuel is extremely clear because of the near-total absence of sulfur and aromatics.

Synthetic fuel or synfuel is a liquid fuel, or sometimes gaseous fuel, obtained from either syngas, a mixture of carbon monoxide and hydrogen, or a mixture of carbon dioxide and hydrogen. The syngas could be derived from gasification of solid feedstocks such as coal or biomass or by reforming of natural gas. Alternatively a mixture of carbon dioxide from the atmosphere and green hydrogen could be used for an almost climate neutral production of synthetic fuels.

Common ways for refining synthetic fuels include the Fischer–Tropsch conversion, methanol to gasoline conversion, or direct coal liquefaction.

As of July 2019, worldwide commercial synthetic fuels production capacity was over 240,000 barrels per day (38,000 m³/d), with numerous new projects in construction or development, such as Carbon Engineering.

Classification and principles

The term 'synthetic fuel' or 'synfuel' has several different meanings and it may include different types of fuels. More traditional definitions, such as the definition given by the International Energy Agency, define 'synthetic fuel' or 'synfuel' as any liquid fuel obtained from coal or natural gas. In its Annual Energy Outlook 2006, the Energy Information Administration defines synthetic fuels as fuels produced from coal, natural gas, or biomass feedstocks through chemical conversion into synthetic crude and/or synthetic liquid products. A number of synthetic fuel's definitions include fuels produced from biomass, and industrial and municipal waste. The definition of synthetic fuel also allows oil sands and oil shale as synthetic fuel sources, and in addition to liquid fuels, synthesized gaseous fuels are also considered to be synthetic fuels: in his 'Synthetic fuels handbook' petrochemist James G. Speight included liquid and gaseous fuels as well as clean solid fuels produced by conversion of coal, oil shale or tar sands, and various forms of biomass, although he admits that in the context of substitutes for petroleum-based fuels it has even wider meaning. Depending on the context, methanol, ethanol and hydrogen may also be included.

Synthetic fuels are produced by the chemical process of conversion. Conversion methods could be direct conversion into liquid transportation fuels, or indirect conversion, in which the source substance is converted initially into syngas which then goes through additional conversion process to become liquid fuels. Basic conversion methods include carbonization and pyrolysis, hydrogenation, and thermal dissolution.

History

Ruins of the German synthetic petrol plant (Hydrierwerke Pölitz AG) in Police, Poland

 

See also: Oil Campaign of World War II and Synthetic Liquid Fuels Program

The process of direct conversion of coal to synthetic fuel originally developed in Germany. Friedrich Bergius developed the Bergius process, which received a patent in 1913. Karl Goldschmidt invited Bergius to build an industrial plant at his factory, the Th. Goldschmidt AG (part of Evonik Industries from 2007), in 1914. Production began in 1919.

Indirect coal conversion (where coal is gasified and then converted to synthetic fuels) was also developed in Germany - by Franz Fischer and Hans Tropsch in 1923. During World War II (1939-1945), Germany used synthetic-oil manufacturing (German: Kohleverflüssigung) to produce substitute (Ersatz) oil products by using the Bergius process (from coal), the Fischer–Tropsch process (water gas), and other methods (Zeitz used the TTH and MTH processes). In 1931 the British Department of Scientific and Industrial Research located in Greenwich, England, set up a small facility where hydrogen gas was combined with coal at extremely high pressures to make a synthetic fuel.

The Bergius process plants became Nazi Germany's primary source of high-grade aviation gasoline, synthetic oil, synthetic rubber, synthetic methanol, synthetic ammonia, and nitric acid. Nearly one third of the Bergius production came from plants in Pölitz (Polish: Police) and Leuna, with 1/3 more in five other plants (Ludwigshafen had a much smaller Bergius plant which improved "gasoline quality by dehydrogenation" using the DHD process).

Synthetic fuel grades included "T.L. [jet] fuel", "first quality aviation gasoline", "aviation base gasoline", and "gasoline - middle oil"; and "producer gas" and diesel were synthesized for fuel as well (converted armored tanks, for example, used producer gas). By early 1944 German synthetic-fuel production had reached more than 124,000 barrels per day (19,700 m³/d) from 25 plants, including 10 in the Ruhr Area. In 1937 the four central Germany lignite coal plants at Böhlen, Leuna, Magdeburg/Rothensee, and Zeitz, along with the Ruhr Area bituminous coal plant at Scholven/Buer, produced 4.8 million barrels (760×10³ m³) of fuel. Four new hydrogenation plants (German: Hydrierwerke) were subsequently erected at Bottrop-Welheim (which used "Bituminous coal tar pitch"), Gelsenkirchen (Nordstern), Pölitz, and, at 200,000 tons/yr Wesseling. Nordstern and Pölitz/Stettin used bituminous coal, as did the new Blechhammer plants. Heydebreck synthesized food oil, which was tested on concentration camp prisoners. After Allied bombing of Germany's synthetic-fuel production plants (especially in May to June 1944), the Geilenberg Special Staff used 350,000 mostly foreign forced-laborers to reconstruct the bombed synthetic-oil plants, and, in an emergency decentralization program, the Mineralölsicherungsplan [de] (1944-1945), to build 7 underground hydrogenation plants with bombing protection (none were completed). (Planners had rejected an earlier such proposal, expecting that Axis forces would win the war before the bunkers would be completed.) In July 1944 the "Cuckoo" project underground synthetic-oil plant (800,000 m²) was being "carved out of the Himmelsburg" north of the Mittelwerk, but the plant remained unfinished at the end of World War II. Production of synthetic fuel became even more vital for Nazi Germany when Soviet Red Army forces occupied the Ploiești oilfields in Romania on 24 August 1944, denying Germany access to its most important natural oil source.

Indirect Fischer–Tropsch ("FT") technologies were brought to the United States after World War II, and a 7,000 barrels per day (1,100 m³/d) plant was designed by HRI and built in Brownsville, Texas. The plant represented the first commercial use of high-temperature Fischer–Tropsch conversion. It operated from 1950 to 1955, when it was shut down after the price of oil dropped due to enhanced production and huge discoveries in the Middle East.

In 1949 the U.S. Bureau of Mines built and operated a demonstration plant for converting coal to gasoline in Louisiana, Missouri. Direct coal conversion plants were also developed in the US after World War II, including a 3 TPD plant in Lawrenceville, New Jersey, and a 250-600 TPD Plant in Catlettsburg, Kentucky.

In later decades the Republic of South Africa established a state oil company including a large synthetic fuel establishment.

Processes

The numerous processes that can be used to produce synthetic fuels broadly fall into three categories: Indirect, Direct, and Biofuel processes.

This is a listing of many of the different technologies used in 2009 for synthetic fuel production. Please note that although this list was compiled for coal to liquids technologies, many of the same processes can also be used with biomass or natural gas feedstocks.

Indirect conversion

Main article: Gas to liquids

Indirect conversion has the widest deployment worldwide, with global production totaling around 260,000 barrels per day (41,000 m³/d), and many additional projects under active development.

Indirect conversion broadly refers to a process in which biomass, coal, or natural gas is converted to a mix of hydrogen and carbon monoxide known as syngas either through gasification or steam methane reforming, and that syngas is processed into a liquid transportation fuel using one of a number of different conversion techniques depending on the desired end product.

The primary technologies that produce synthetic fuel from syngas are Fischer–Tropsch synthesis and the Mobil process (also known as Methanol-To-Gasoline, or MTG). In the Fischer–Tropsch process syngas reacts in the presence of a catalyst, transforming into liquid products (primarily diesel fuel and jet fuel) and potentially waxes (depending on the FT process employed).

The process of producing synfuels through indirect conversion is often referred to as coal-to-liquids (CTL), gas-to-liquids (GTL) or biomass-to-liquids (BTL), depending on the initial feedstock. At least three projects (Ohio River Clean Fuels, Illinois Clean Fuels, and Rentech Natchez) are combining coal and biomass feedstocks, creating hybrid-feedstock synthetic fuels known as Coal and Biomass To Liquids (CBTL).

Indirect conversion process technologies can also be used to produce hydrogen, potentially for use in fuel cell vehicles, either as slipstream co-product, or as a primary output.

Direct conversion

Direct conversion refers to processes in which coal or biomass feedstocks are converted directly into intermediate or final products, avoiding the conversion to syngas via gasification. Direct conversion processes can be broadly broken up into two different methods: Pyrolysis and carbonization, and hydrogenation.

Hydrogenation processes

See also: Bergius process

One of the main methods of direct conversion of coal to liquids by hydrogenation process is the Bergius process. In this process, coal is liquefied by heating in the presence of hydrogen gas (hydrogenation). Dry coal is mixed with heavy oil recycled from the process. Catalysts are typically added to the mixture. The reaction occurs at between 400 °C (752 °F) to 500 °C (932 °F) and 20 to 70 MPa hydrogen pressure. The reaction can be summarized as follows:

${\displaystyle n{\rm {C}}+(n+1){\rm {H}}_{2}\rightarrow {\rm {C}}_{n}{\rm {H}}_{2n+2}}$

After World War I several plants were built in Germany; these plants were extensively used during World War II to supply Germany with fuel and lubricants.

The Kohleoel Process, developed in Germany by Ruhrkohle and VEBA, was used in the demonstration plant with the capacity of 200 ton of lignite per day, built in Bottrop, Germany. This plant operated from 1981 to 1987. In this process, coal is mixed with a recycle solvent and iron catalyst. After preheating and pressurizing, H₂ is added. The process takes place in tubular reactor at the pressure of 300 bar and at the temperature of 470 °C (880 °F). This process was also explored by SASOL in South Africa.

In 1970-1980s, Japanese companies Nippon Kokan, Sumitomo Metal Industries and Mitsubishi Heavy Industries developed the NEDOL process. In this process, a mixture of coal and recycled solvent is heated in the presence of iron-based catalyst and H₂. The reaction takes place in tubular reactor at temperature between 430 °C (810 °F) and 465 °C (870 °F) at the pressure 150-200 bar. The produced oil has low quality and requires intensive upgrading. H-Coal process, developed by Hydrocarbon Research, Inc., in 1963, mixes pulverized coal with recycled liquids, hydrogen and catalyst in the ebullated bed reactor. Advantages of this process are that dissolution and oil upgrading are taking place in the single reactor, products have high H:C ratio, and a fast reaction time, while the main disadvantages are high gas yield, high hydrogen consumption, and limitation of oil usage only as a boiler oil because of impurities.

The SRC-I and SRC-II (Solvent Refined Coal) processes were developed by Gulf Oil and implemented as pilot plants in the United States in the 1960s and 1970s. The Nuclear Utility Services Corporation developed hydrogenation process which was patented by Wilburn C. Schroeder in 1976. The process involved dried, pulverized coal mixed with roughly 1wt% molybdenum catalysts. Hydrogenation occurred by use of high temperature and pressure syngas produced in a separate gasifier. The process ultimately yielded a synthetic crude product, Naphtha, a limited amount of C₃/C₄ gas, light-medium weight liquids (C₅-C₁₀) suitable for use as fuels, small amounts of NH₃ and significant amounts of CO₂. Other single-stage hydrogenation processes are the Exxon donor solvent process, the Imhausen High-pressure Process, and the Conoco Zinc Chloride Process.

A number of two-stage direct liquefaction processes have been developed. After the 1980s only the Catalytic Two-stage Liquefaction Process, modified from the H-Coal Process; the Liquid Solvent Extraction Process by British Coal; and the Brown Coal Liquefaction Process of Japan have been developed.

Chevron Corporation developed a process invented by Joel W. Rosenthal called the Chevron Coal Liquefaction Process (CCLP). It is unique due to the close-coupling of the non-catalytic dissolver and the catalytic hydroprocessing unit. The oil produced had properties that were unique when compared to other coal oils; it was lighter and had far fewer heteroatom impurities. The process was scaled-up to the 6 ton per day level, but not proven commercially.

Pyrolysis and carbonization processes

See also: Karrick process

There are a number of different carbonization processes. The carbonization conversion occurs through pyrolysis or destructive distillation, and it produces condensable coal tar, oil and water vapor, non-condensable synthetic gas, and a solid residue-char. The condensed coal tar and oil are then further processed by hydrogenation to remove sulfur and nitrogen species, after which they are processed into fuels.

The typical example of carbonization is the Karrick process. The process was invented by Lewis Cass Karrick in the 1920s. The Karrick process is a low-temperature carbonization process, where coal is heated at 680 °F (360 °C) to 1,380 °F (750 °C) in the absence of air. These temperatures optimize the production of coal tars richer in lighter hydrocarbons than normal coal tar. However, the produced liquids are mostly a by-product and the main product is semi-coke, a solid and smokeless fuel.

The COED Process, developed by FMC Corporation, uses a fluidized bed for processing, in combination with increasing temperature, through four stages of pyrolysis. Heat is transferred by hot gases produced by combustion of part of the produced char. A modification of this process, the COGAS Process, involves the addition of gasification of char. The TOSCOAL Process, an analogue to the TOSCO II oil shale retorting process and Lurgi-Ruhrgas process, which is also used for the shale oil extraction, uses hot recycled solids for the heat transfer.

Liquid yields of pyrolysis and Karrick processes are generally low for practical use for synthetic liquid fuel production. Furthermore, the resulting liquids are of low quality and require further treatment before they can be used as motor fuels. In summary, there is little possibility that this process will yield economically viable volumes of liquid fuel.

Biofuels processes

One example of a Biofuel-based synthetic fuel process is Hydrotreated Renewable Jet (HRJ) fuel. There are a number of variants of these processes under development, and the testing and certification process for HRJ aviation fuels is beginning.

There are two such process under development by UOP. One using solid biomass feedstocks, and one using bio-oil and fats. The process using solid second-generation biomass sources such as switchgrass or woody biomass uses pyrolysis to produce a bio-oil, which is then catalytically stabilized and deoxygenated to produce a jet-range fuel. The process using natural oils and fats goes through a deoxygenation process, followed by hydrocracking and isomerization to produce a renewable Synthetic Paraffinic Kerosene jet fuel.

Oil sand and oil shale processes

See also: Synthetic crude and Shale oil extraction

Synthetic crude may also be created by upgrading bitumen (a tar like substance found in oil sands), or synthesizing liquid hydrocarbons from oil shale. There are a number of processes extracting shale oil (synthetic crude oil) from oil shale by pyrolysis, hydrogenation, or thermal dissolution.

Commercialization

Main article: Synthetic fuel commercialization

Worldwide commercial synthetic fuels plant capacity is over 240,000 barrels per day (38,000 m³/d), including indirect conversion Fischer–Tropsch plants in South Africa (Mossgas, Secunda CTL), Qatar {Oryx GTL}, and Malaysia (Shell Bintulu), and a Mobil process (Methanol to Gasoline) plant in New Zealand.

Sasol, a company based in South Africa operates the world's only commercial Fischer–Tropsch coal-to-liquids facility at Secunda, with a capacity of 150,000 barrels per day (24,000 m³/d).

Economics

The economics of synthetic fuel manufacture vary greatly depending the feedstock used, the precise process employed, site characteristics such as feedstock and transportation costs, and the cost of additional equipment required to control emissions. The examples described below indicate a wide range of production costs between $20/BBL for large-scale gas-to-liquids, to as much as $240/BBL for small-scale biomass-to-liquids + Carbon Capture and Sequestration.

In order to be economically viable, projects must do much better than just being competitive head-to-head with oil. They must also generate a sufficient return on investment to justify the capital investment in the project.

CTL/CBTL/BTL economics

According to a December 2007 study, a medium scale (30,000 BPD) coal-to-liquids plant (CTL) sited in the US using bituminous coal, is expected to be competitive with oil down to roughly $52–56/bbl crude-oil equivalent. Adding carbon capture and sequestration to the project was expected to add an additional $10/BBL to the required selling price, though this may be offset by revenues from enhanced oil recovery, or by tax credits, or the eventual sale of carbon credits.

A recent NETL study examined the relative economics of a number of different process configurations for the production of indirect FT fuels using biomass, coal, and CCS. This study determined a price at which the plant would not only be profitable, but also make a sufficient return to yield a 20% return on the equity investment required to build the plant.

This chapter details an analysis which derives the Required Selling Price (RSP) of the FT diesel fuels produced in order to determine the economic feasibility and relative competitiveness of the different plant options. A sensitivity analysis was performed to determine how carbon control regulations such as an emissions trading scheme for transportation fuels would affect the price of both petroleum-derived diesel and FT diesel from the different plants. The key findings of these analyses were: (1) CTL plants equipped with CCS are competitive at crude oil prices as low as $86 per barrel and have less life cycle GHG emissions than petroleum-derived diesel. These plants become more economically competitive as carbon prices increase. (2) The incremental cost of adding simple CCS is very low (7 cents per gallon) because CO₂ capture is an inherent part of the FT process. This becomes the economically preferred option at carbon prices above $5/mtCO₂eq.27 (3) BTL systems are hindered by limited biomass availability which affects the maximum plant size, thereby limiting potential economies of scale. This, combined with relatively high biomass costs results in FT diesel prices which are double that of other configurations: $6.45 to $6.96/gal compared to $2.56 to $2.82/gal for CTL and 15wt% CBTL systems equipped with CCS.

The conclusion reached based on these findings was that both the CTL with CCS and the 8wt% to 15wt% CBTL with CCS configurations may offer the most pragmatic solutions to the nation's energy strategy dilemma: GHG emission reductions which are significant (5% to 33% below the petroleum baseline) at diesel RSPs that are only half as much as the BTL options ($2.56 to $2.82 per gallon compared to $6.45 to $6.96 per gallon for BTL). These options are economically feasible when crude oil prices are $86 to $95 per barrel.

These economics can change in the event that plentiful low-cost biomass sources can be found, lowing the cost of biomass inputs, and improving economies of scale.

Economics for solid feedstock indirect FT process plants are further confused by carbon regulation. Generally, since permitting a CTL plant without CCS will likely be impossible, and CTL+CCS plants have a lower carbon footprint than conventional fuels, carbon regulation is expected to be balance-positive for synthetic fuel production. But it impacts the economics of different process configurations in different ways. The NETL study picked a blended CBTL process using 5-15% biomass alongside coal as the most economical in a range of carbon price and probable future regulation scenarios. Because of scale and cost constraints, pure BTL processes did not score well until high carbon prices were assumed, though again this may improve with better feedstocks and more efficient larger scale projects.

Chinese direct coal liquefaction economics

Shenhua Group recently reported that their direct coal liquefaction process is competitive with oil prices above $60 per barrel. Previous reports have indicated an anticipated cost of production of less than $30 per barrel, based on a direct coal liquefaction process, and a coal mining cost of under $10/ton. In October 2011, actual price of coal in China was as high as $135/ton.

Security considerations

A central consideration for the development of synthetic fuel is the security factor of securing domestic fuel supply from domestic biomass and coal. Nations that are rich in biomass and coal can use synthetic fuel to off-set their use of petroleum derived fuels and foreign oil.

Environmental considerations

The environmental footprint of a given synthetic fuel varies greatly depending on which process is employed, what feedstock is used, what pollution controls are employed, and what the transportation distance and method are for both feedstock procurement and end-product distribution.

In many locations, project development will not be possible due to permitting restrictions if a process design is chosen that does not meet local requirements for clean air, water, and increasingly, lifecycle carbon emissions.

Lifecycle greenhouse gas emissions

Among different indirect FT synthetic fuels production technologies, potential emissions of greenhouse gasses vary greatly. Coal to liquids ("CTL") without carbon capture and sequestration ("CCS") is expected to result in a significantly higher carbon footprint than conventional petroleum-derived fuels (+147%). On the other hand, biomass-to-liquids with CCS could deliver a 358% reduction in lifecycle greenhouse gas emissions. Both of these plants fundamentally use gasification and FT conversion synthetic fuels technology, but they deliver wildly divergent environmental footprints.

Lifecycle carbon emissions profiles of various fuels, including many synthetic fuels. Coal and biomass co-conversion to transportation fuels, Michael E. Reed, DOE NETL Office of Fossil Energy, Oct 17 2007

Generally, CTL without CCS has a higher greenhouse gas footprint. CTL with CCS has a 9-15% reduction in lifecycle greenhouse gas emissions compared to that of petroleum derived diesel.

CBTL+CCS plants that blend biomass alongside coal while sequestering carbon do progressively better the more biomass is added. Depending on the type of biomass, the assumptions about root storage, and the transportation logistics, at conservatively 40% biomass alongside coal, CBTL+CCS plants achieve a neutral lifecycle greenhouse gas footprint. At more than 40% biomass, they begin to go lifecycle negative, and effectively store carbon in the ground for every gallon of fuels that they produce.

Ultimately BTL plants employing CCS could store massive amounts of carbon while producing transportation fuels from sustainably produced biomass feedstocks, although there are a number of significant economic hurdles, and a few technical hurdles that would have to be overcome to enable the development of such facilities.

Serious consideration must also be given to the type and method of feedstock procurement for either the coal or biomass used in such facilities, as reckless development could exacerbate environmental problems caused by mountaintop removal mining, land use change, fertilizer runoff, food vs. fuels concerns, or many other potential factors. Or they could not, depending entirely on project-specific factors on a plant-by-plant basis.

A study from U.S. Department of Energy National Energy Technology Laboratory with much more in-depth information of CBTL life-cycle emissions "Affordable Low Carbon Diesel from Domestic Coal and Biomass".

Hybrid hydrogen-carbon processes have also been proposed recently as another closed-carbon cycle alternative, combining 'clean' electricity, recycled CO, H₂ and captured CO₂ with biomass as inputs as a way of reducing the biomass needed.

Fuels emissions

The fuels produced by the various synthetic fuels process also have a wide range of potential environmental performance, though they tend to be very uniform based on the type of synthetic fuels process used (i.e. the tailpipe emissions characteristics of Fischer–Tropsch diesel tend to be the same, though their lifecycle greenhouse gas footprint can vary substantially based on which plant produced the fuel, depending on feedstock and plant level sequestration considerations.)

In particular, Fischer–Tropsch diesel and jet fuels deliver dramatic across-the-board reductions in all major criteria pollutants such as SOx, NOx, Particulate Matter, and Hydrocarbon emissions. These fuels, because of their high level of purity and lack of contaminants, further enable the use of advanced emissions control equipment that has been shown to virtually eliminate HC, CO, and PM emissions from diesel vehicles.

In testimony before the Subcommittee on Energy and Environment of the U.S. House of Representatives the following statement was made by a senior scientist from Rentech:

F-T fuels offer numerous benefits to aviation users. The first is an immediate reduction in particulate emissions. F-T jet fuel has been shown in laboratory combusters and engines to reduce PM emissions by 96% at idle and 78% under cruise operation. Validation of the reduction in other turbine engine emissions is still under way. Concurrent to the PM reductions is an immediate reduction in CO₂ emissions from F-T fuel. F-T fuels inherently reduce CO₂ emissions because they have higher energy content per carbon content of the fuel, and the fuel is less dense than conventional jet fuel allowing aircraft to fly further on the same load of fuel.

The "cleanness" of these FT synthetic fuels is further demonstrated by the fact that they are sufficiently non-toxic and environmentally benign as to be considered biodegradable. This owes primarily to the near-absence of sulfur and extremely low level of aromatics present in the fuel.

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  Using Fischer–Tropsch diesel results in dramatic across the board tailpipe emissions reductions relative to conventional fuels

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  Using Fischer–Tropsch jet fuels have been proven to dramatically reduce particulate and other aircraft emissions

Sustainability

One concern commonly raised about the development of synthetic fuels plants is sustainability. Fundamentally, transitioning from oil to coal or natural gas for transportation fuels production is a transition from one inherently depletable geologically limited resource to another.

One of the positive defining characteristics of synthetic fuels production is the ability to use multiple feedstocks (coal, gas, or biomass) to produce the same product from the same plant. In the case of hybrid BCTL plants, some facilities are already planning to use a significant biomass component alongside coal. Ultimately, given the right location with good biomass availability, and sufficiently high oil prices, synthetic fuels plants can be transitioned from coal or gas, over to a 100% biomass feedstock. This provides a path forward towards a renewable fuel source and possibly more sustainable, even if the plant originally produced fuels solely from coal, making the infrastructure forwards-compatible even if the original fossil feedstock runs out.

Some synthetic fuels processes can be converted to sustainable production practices more easily than others, depending on the process equipment selected. This is an important design consideration as these facilities are planned and implemented, as additional room must be left in the plant layout to accommodate whatever future plant change requirements in terms of materials handling and gasification might be necessary to accommodate a future change in production profile.

Collaborative information seeking

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Collaborative_information_seeking

Collaborative information seeking (CIS) is a field of research that involves studying situations, motivations, and methods for people working in collaborative groups for information seeking projects, as well as building systems for supporting such activities. Such projects often involve information searching or information retrieval (IR), information gathering, and information sharing. Beyond that, CIS can extend to collaborative information synthesis and collaborative sense-making.

Background

Seeking for information is often considered a solo activity, but there are many situations that call for people working together for information seeking. Such situations are typically complex in nature, and involve working through several sessions exploring, evaluating, and gathering relevant information. Take for example, a couple going on a trip. They have the same goal, and in order to accomplish their goal, they need to seek out several kinds of information, including flights, hotels, and sightseeing. This may involve them working together over multiple sessions, exploring and collecting useful information, and collectively making decisions that help them move toward their common goal.

It is a common knowledge that collaboration is either necessary or highly desired in many activities that are complex or difficult to deal with for an individual. Despite its natural appeal and situational necessity, collaboration in information seeking is an understudied domain. The nature of the available information and its role in our lives have changed significantly, but the methods and tools that are used to access and share that information in collaboration have remained largely unaltered. People still use general-purpose systems such as email and IM for doing CIS projects, and there is a lack of specialized tools and techniques to support CIS explicitly.

There are also several models to explain information seeking and information behavior, but the areas of collaborative information seeking and collaborative information behavior remain understudied. On the theory side, Shah has presented C5 Model for studying collaborative situations, including information seeking. On the practical side, a few specialized systems for supporting CIS have emerged in the recent past, but their usage and evaluations have underwhelmed. Despite such limitations, the field of CIS has been getting a lot of attention lately, and several promising theories and tools have come forth. Multiple reviews of CIS related literature are written by Shah. Shah's book provides a comprehensive review of this field, including theories, models, systems, evaluation, and future research directions. Other books in this area include one by Morris and Teevan, as well as Foster's book on collaborative information behavior. and Hansen, Shah, and Klas's edited book on CIS.

Theories

Depending upon what one includes or excludes while talking about CIS, we have many or hardly any theories. If we consider the past work on the groupware systems, many interesting insights can be obtained about people working on collaborative projects, the issues they face, and the guidelines for system designers. One of the notable works is by Grudin, who laid out eight design principles for developers of groupware systems.

The discussion below is primarily based on some of the recent works in the field of computer supported cooperative work CSCW, collaborative IR, and CIS.

Definitions and terminology

The literature is filled with works that use terms such as collaborative information retrieval, social searching, concurrent search, collaborative exploratory search, co-browsing, collaborative information behavior, collaborative information synthesis, and collaborative information seeking, which are often used interchangeably.

There are several definitions of such related or similar terms in the literature. For instance, Foster defined collaborative IR as "the study of the systems and practices that enable individuals to collaborate during the seeking, searching, and retrieval of information." Shah defined CIS as a process of collaboratively seeking information that is "defined explicitly among the participants, interactive, and mutually beneficial." While there is still a lack of a definition or a terminology that is universally accepted, but most agree that CIS is an active process, as opposed to collaborative filtering, where a system connects the users based on their passive involvement (e.g., buying similar products on Amazon).

Models of collaboration

Foley and Smeaton defined two key aspects of collaborative information seeking as division of labor and the sharing of knowledge. Division of labor allows collaborating searchers to tackle larger problems by reducing the duplication of effort (e.g., finding documents that one's collaborator has already discovered). The sharing of knowledge allows searchers to influence each other's activities as they interact with the retrieval system in pursuit of their (often evolving) information need. This influence can occur in real time if the collaborative search system supports it, or it can occur in a turn-taking, asynchronous manner if that is how interaction is structured.

Teevan et al. characterized two classes of collaboration, task-based vs. trait-based. Task-based collaboration corresponds to intentional collaboration; trait-based collaboration facilitates the sharing of knowledge through inferred similarity of information need.

Situations, motivations, and methods

One of the important issues to study in CIS is the instance, reason, and the methods behind a collaboration. For instance, Morris, using a survey with 204 knowledge workers at a large technology company found that people often like and want to collaborate, but they do not find specialized tools to help them in such endeavors. Some of the situations for doing collaborative information seeking in this survey were travel planning, shopping, and literature search. Shah, similarly, using personal interviews, identified three main reasons why people collaborate.

1. Requirement/setup. Sometimes a group of people are "forced" to collaborate. Example includes a merger between two companies.
2. Division of labor. Working together may help the participants to distribute the workload. Example includes a group of students working on a class project.
3. Diversity of skills. Often people get together because they could not individually possess the required set of skills. Example includes co-authorship, where different authors bring different set of skills to the table.

As far as the tools and/or methods for CIS are concerned, both Morris and Shah found that email is still the most used tool. Other popular methods are face-to-face meetings, IM, and phone or conference calls. In general, the choice of the method or tool for our respondents depended on their situation (co-located or remote), and objective (brainstorming or working on independent parts).

Space-time organization of CIS systems and methods

The classical way of organizing collaborative activities is based on two factors: location and time. Recently Hansen & Jarvelin and Golovchinsky, Pickens, & Back also classified approaches to collaborative IR using these two dimensions of space and time. See "Browsing is a Collaborative Process", where the authors depict various library activities on these two dimensions. As we can see from this figure, the majority of collaborative activities in conventional libraries are co-located and synchronous, whereas collaborative activities relating to digital libraries are more remote and synchronous. Social information filtering, or collaborative filtering, as we saw earlier, is a process benefitting from other users' actions in the past; thus, it falls under asynchronous and mostly remote domain. These days email also serves as a tool for doing asynchronous collaboration among users who are not co-located. Chat or IM (represented as 'internet' in the figure) helps to carry out synchronous and remote collaboration.

Rodden, similarly, presented a classification of CSCW systems using the form of interaction and the geographical nature of cooperative systems. Further, Rodden & Blair presented an important characteristic to all CSCW systems – control. According to the authors, two predominant control mechanisms have emerged within CSCW systems: speech act theory systems, and procedure based systems. These mechanisms are tightly coupled with the kind of control the system can support in a collaborative environment (discussed later).

Often researchers also talk about other dimensions, such as intentionality and depth of mediation (system mediated or user mediated), while classifying various CIS systems.

Control, communication, and awareness

Three components specific to group-work or collaboration that are highly predominant in the CIS or CSCW literature are control, communication, and awareness. In this section key definitions and related works for these components will be highlighted. Understanding their roles can also help us address various design issues with CIS systems.

Control

Rodden identified the value of control in CSCW systems and listed a number of projects with their corresponding schemes for implementing for control. For instance, the COSMOS project had a formal structure to represent control in the system. They used roles to represent people or automatons, and rules to represent the flow and processes. The roles of the people could be a supervisor, processor, or analyst. Rules could be a condition that a process needs to satisfy in order to start or finish. Due to such a structure seen in projects like COSMOS, Rodden classified these control systems as procedural based systems. The control penal was every effort to seeking people and control others in this method used for highly responsible people take control of another network system was supply chine managements or transformation into out connection processor information

Communication

This is one of the most critical components of any collaboration. In fact, Rodden (1991) identified message or communication systems as the class of systems in CSCW that is most mature and most widely used.

Since the focus here is on CIS systems that allow its participants to engage in an intentional and interactive collaboration, there must be a way for the participants to communicate with each other. What is interesting to note is that often, collaboration could begin by letting a group of users communicate with each other. For instance, Donath & Robertson presented a system that allows a user to know that others were currently viewing the same webpage and communicate with those people to initiate a possible collaboration or at least a co-browsing experience. Providing communication capabilities even in an environment that was not originally designed for carrying out collaboration is an interesting way of encouraging collaboration.

Awareness

Awareness, in the context of CSCW, has been defined as "an understanding of the activities of others, which provides a context for your own activity". The following four kinds of awareness are often discussed and addressed in the CSCW literature:

1. Group awareness. This kind of awareness includes providing information to each group member about the status and activities of the other collaborators at a given time.
2. Workspace awareness. This refers to a common workspace that the group has where they can bring and discuss their findings, and create a common product.
3. Contextual awareness. This type of awareness relates to the application domain, rather than the users. Here, we want to identify what content is useful for the group, and what the goals are for the current project.
4. Peripheral awareness. This relates to the kind of information that has resulted from personal and the group's collective history, and should be kept separate from what a participant is currently viewing or doing.

Shah and Marchionini studied awareness as provided by interface in collaborative information seeking. They found that one needs to provide "right" (not too little, not too much, and appropriate for the task at hand) kind of awareness to reduce the cost of coordination and maximize the benefits of collaboration.

Systems

A number of specialized systems have been developed back from the days of the groupware systems to today's Web 2.0 interfaces. A few such examples, in chronological order, are given below.

Ariadne

Twidale et al. developed Ariadne to support the collaborative learning of database browsing skills. In addition to enhancing the opportunities and effectiveness of the collaborative learning that already occurred, Ariadne was designed to provide the facilities that would allow collaborations to persist as people increasingly searched information remotely and had less opportunity for spontaneous face-to-face collaboration.

Ariadne was developed in the days when Telnet-based access to library catalogs was a common practice. Building on top of this command-line interface, Ariadne could capture the users’ input and the database’s output, and form them into a search history that consisted of a series of command-output pairs. Such a separation of capture and display allowed Ariadne to work with various forms of data capture methods.

To support complex browsing processes in collaboration, Ariadne presented a visualization of the search process. This visualization consisted of thumbnails of screens, looking like playing cards, which represented command-output pairs. Any such card can be expanded to reveal its details. The horizontal axis on Ariadne’s display represented time, and the vertical axis showed information on the semantics of the action it represented: the top row for the top level menus, the middle row for specifying a search, and the bottom row for looking at particular book details.

This visualization of the search process in Ariadne makes it possible to annotate, discuss with colleagues around the screen, and distribute to remote collaborators for asynchronous commenting easily and effectively. As we saw in the previous section, having access to one’s history as well as the history of one’s collaborators are very crucial to effective collaboration. Ariadne implements these requirements with the features that let one visualize, save, and share a search process. In fact, the authors found one of the advantages of search visualization was the ability to recap previous searching sessions easily in a multi-session exploratory searching.

SearchTogether

More recently, one of the collaborative information seeking tools that have caught a lot of attention is SearchTogether, developed by Morris and Horvitz. The design of this tool was motivated by a survey that the researchers did with 204 knowledge workers, in which they discovered the following.

• A majority of respondents wanted to collaborate while searching on the Web.
• The most common ways of collaborating in information seeking tasks are sending emails back and forth, using IM to exchange links and query terms, and using phone calls while looking at a Web browser.
• Some of the most popular Web searching tasks on which people like to collaborate are planning travels or social events, making expensive purchases, researching medical conditions, and looking for information related to a common project.

Based on the survey responses, and the current and desired practices for collaborative search, the authors of SearchTogether identified three key features for supporting people’s collaborative information behavior while searching on the Web: awareness, division of labor, and persistence. Let us look at how these three features are implemented.

SearchTogether instantiates awareness in several ways, one of which is per-user query histories. This is done by showing each group member’s screen name, his/her photo and queries in the “Query Awareness” region. The access to the query histories is immediate and interactive, as clicking on a query brings back the results of that query from when it was executed. The authors identified query awareness as a very important feature in collaborative searching, which allows group members to not only share their query terms, but also learn better query formulation techniques from one another.

Another component of SearchTogether that facilitates awareness is the display of page-specific metadata. This region includes several pieces of information about the displayed page, including group members who viewed the given page, and their comments and ratings. The authors claim that such visitation information can help one either choose to avoid a page already visited by someone in the group to reduce the duplication of efforts, or perhaps choose to visit such pages, as they provide a sign of promising leads as indicated by the presence of comments and/or ratings.

Division of labor in SearchTogether is implemented in three ways: (1) “Split Search” allows one to split the search results among all online group members in a round-robin fashion, (2) “Multi-Engine Search” takes a query and runs it on n different search engines, where n is the number of online group members, (3) manual division of labor can be facilitated using integrated IM.

Finally, the persistence feature in SearchTogether is instantiated by storing all the objects and actions, including IM conversations, query histories, recommendation queues, and page-specific metadata. Such data about all the group members are available to each member when he/she logs in. This allows one to easily carry a multi-session collaborative project.

Cerchiamo

Cerchiamo is a collaborative information seeking tool that explores issues related to algorithmic mediation of information seeking activities and how collaborators' roles can be used to structure the user interface. Cerchiamo introduced the notion of algorithmic mediation, that is, the ability of the system to collect input asynchronously from multiple collaborating searchers, and to use these multiple streams of input to affect the information that is being retrieved and displayed to the searchers.

Cerchiamo collected judgments of relevance from multiple collaborating searchers and used those judgments to create a ranked list of items that were potentially relevant to the information need. This algorithm prioritized items that were retrieved by multiple queries and that were retrieved by queries that also retrieved many other relevant documents. This rank fusion is just one way in which a search system that manages activities of multiple collaborating searchers can combine their inputs to generate results that are better than those produced by individuals working independently.

Cerchiamo implemented two roles—Prospector and Miner—that searchers could assume. Each role had an associated interface. The Prospector role/interface focused on running many queries and making a few judgments of relevance for each query to explore the information space. The Miner role/interface focused on making relevance judgments on a ranked list of items selected from items retrieved by all queries in the current session. This combination of roles allowed searchers to explore and exploit the information space, and led teams to discover more unique relevant documents than pairs of individuals working separately.

Coagmento

Coagmento (Latin for "working together") is a new and unique system that allows a group of people work together for their information seeking tasks without leaving their browsers. Coagmento has been developed with a client-server architecture, where the client is implemented as a Firefox plug-in that helps multiple people working in collaboration to communicate, and search, share and organize information. The server component stores and provides all the objects and actions collected from the client. Due to this decoupling, Coagmento provides a flexible architecture that allows its users to be co-located or remote, working synchronously or asynchronously, and use different platforms.

Coagmento includes a toolbar and a sidebar. The toolbar has several buttons that helps one collect information and be aware of the progress in a given collaboration. The toolbar has three major parts:

• Buttons for collecting information and making annotations. These buttons help one save or remove a webpage, make annotations on a webpage, and highlight and collect text snippets.
• Page-specific statistics. The middle portion of the toolbar shows various statistics, such as the number of views, annotations, and snippets, for the displayed page. A user can click on a given statistic and obtain more information. For instance, clicking on the number of snippets will bring up a window that shows all the snippets collected by the collaborators from the displayed page.
• Project-specific statistics. The last portion of the toolbar displays task/project name and various statistics, including number of pages visited and saved, about the current project. Clicking on that portion brings up the workspace where one can view all the collected objects (pages and snippets) brought in by the collaborators for that project.

The sidebar features a chat window, under which there are three tabs with the history of search engine queries, saved pages and snippets. With each of these objects, the user who created or collected that object is shown. Anyone in the group can access an object by clicking on it. For instance, one can click on a query issued by anyone in the group to re-run that query and bring up the results in the main browser window.

An Android (operating system) app for Coagmento can be found in the Android Market.

Cosme

Fernandez-Luna et al. introduce Cosme (COde Search MEeting) as a NetBeans IDE plug-in that enables remote team of software developers to collaborate in real time during source-code search sessions. The COSME design was motivated by early studies of C. Foley, M. R. Morris, C. Shah, among others researchers, and by habits of software developers identified in a survey of 117 universities students and professors related with projects of software development, as well as to computer programmers of some companies. The five more commons collaborative search habits (or related to it) of the interviewees was:

• Revision of problems by the team in the workstation of one of them.
• Suggest addresses of Web pages that they have already visited previously, digital books stored in some FTP, or source files of a version control system.
• Send emails with algorithms or explanatory text.
• Division of search tasks among each member of the team for sharing the final result.
• Store relevant information in individual workstation.

COSME is designed to enable either synchronous or asynchronous, but explicit remote collaboration among team developers with shared technical information needs. Its client user interface include a search panel that lets developers to specify queries, division of labor principle (possible combination include the use of different search engines, ranking fusion, and split algorithms), searching field (comments, source-code, class or methods declaration), and the collection type (source-code files or digital documentation). The sessions panel wraps the principal options to management the collaborative search sessions, which consists in a team of developers working together to satisfy their shared technical information needs. For example, a developer can use the embedded chat room to negotiate the creation of a collaborative search session, and show comments of the current and historical search results. The implementation of Cosme was based on CIRLab (Collaborative Information Retrieval Laboratory) instantiation, a groupware framework for CIS research and experimentation, Java as programming language, NetBeans IDE Platform as plug-in base, and Amenities (A MEthodology for aNalysis and desIgn of cooperaTIve systEmS) as software engineering methodology.

Open-source application frameworks and toolkits

CIS systems development is a complex task, which involves software technologies and Know-how in different areas such as distributed programming, information search and retrieval, collaboration among people, task coordination and many others according to the context. This situation is not ideal because it requires great programming efforts. Fortunately, some CIS application frameworks and toolkits are increasing their popularity since they have a high reusability impact for both developers and researchers, like Coagmento Collaboratory and DrakkarKeel.

Future research directions

Many interesting and important questions remain to be addressed in the field of CIS, including

1. Why do people collaborate? Identifying their motivations can help us design better support for their specific needs.
2. What additional tools are required to enhance existing methods of collaboration, given a specific domain?
3. How to evaluate various aspects of collaborative information seeking, including system and user performance?
4. How to measure the costs and benefits of collaboration?
5. What are the information seeking situations in which collaboration is beneficial? When does it not pay off?
6. How can we measure the performance of a collaborative group?
7. How can we measure the contribution of an individual in a collaborative group?
8. What sorts of retrieval algorithms can be used to combine input from multiple searchers?
9. What kinds of algorithmic mediation can improve team performance?