Monolithic Body Research Articles

Impact simulation in the gravity regime: Exploring the effects of parent body size and internal structure

In this work we extend the systematic investigation of impact outcomes of 100-km-diameter targets started by Durda et al. (2007) and Benavidez et al. (2012) to targets of D = 400km using the same range of impact conditions and two internal structures: monolithic and rubble-pile. We performed a new set of simulations in the gravity regime for targets of 400km in diameter using these same internal structures. This provides a large set of 600 simulations performed in a systematic way that permits a thorough analysis of the impact outcomes and evaluation of the main features of the size frequency distribution due mostly to self-gravity. In addition, we use the impact outcomes to attempt to constrain the impact conditions of the asteroid belt where known asteroid families with a large expected parent body were formed. We have found fairly good matches for the Eunomia and Hygiea families. In addition, we identified a potential acceptable match to the Vesta family from a monolithic parent body of 468km. The impact conditions of the best matches suggest that these families were formed in a dynamically excited belt. The results also suggest that the parent body of the Eunomia family could be a monolithic body of 382km diameter, while the one for Hygiea could have a rubble-pile internal structure of 416km diameter.

Disaggregation of small, cohesive rubble pile asteroids due to YORP

The implication of small amounts of cohesion within relatively small rubble pile asteroids is investigated with regard to their evolution under the persistent presence of the YORP effect. We find that below a characteristic size, which is a function of cohesive strength, density and other properties, rubble pile asteroids can enter a “disaggregation phase” in which they are subject to repeated fissions after which the formation of a stabilizing binary system is not possible. Once this threshold is passed rubble pile asteroids may be disaggregated into their constituent components within a finite time span. These constituent components will have their own spin limits – albeit potentially at a much higher spin rate due to the greater strength of a monolithic body. The implications of this prediction are discussed and include modification of size distributions, prevalence of monolithic bodies among meteoroids and the lifetime of small rubble pile bodies in the solar system. The theory is then used to place constraints on the strength of binary asteroids characterized as a function of their type.

A bio-inspired 3D-printed hybrid finger with integrated ECF (electro-conjugate fluid) micropumps

The paper proposes a novel 3D-printed hybrid finger embedding ECF (electro-conjugate fluid) micropumps inspired from the hydraulic mechanism of spider legs. Two integrated ECF micropumps control two bellows-like joints respectively through fluidic channels built in the finger to realize the compliant motion with 2 DOFs (degree-of-freedom). Instead of the traditional CNC machining, molding and multiple manual assembly, the 3D printing technology of hybrid-material (hard and soft material) is utilized to fabricate our hybrid finger, which consists of (a) one monolithic body with the combination of a finger body base covered with rubber sheets and two bellows-like joints, (b) three finger body covers combined with rubber sheets, solving the annoying problems related to the complicated machining, the elaborate molding, and the delicate assembly and interfacing of soft and hard components. The ECF micropump with TPSEs (triangular prism & slit electrode pairs) was designed and fabricated by the MEMS process based on the micro-molding with thick photoresist and nickel electroplating. Characteristics experiments including output pressure and output flow rate measurement demonstrated that the fabricated ECF micropump had high output power density. The hybrid finger with ECF micropumps was successfully realized and its driving experiments validated the feasibility of our concept.

RESURRECTION OF (3200) PHAETHON IN 2016

ABSTRACT We present a study of the active asteroid (3200) Phaethon in the 2016 apparition using the Solar and Terrestrial Relations Observatory (STEREO) spacecraft and compare the results with data from the previous two perihelia in 2009 and 2012. Once again, Phaethon brightened by ∼2 mag soon after its perihelion passage, contradicting expectations from the phase function of a macroscopic monolithic body. Subsequently, a short antisolar tail of ∼0.°1 in length was formed within ∼1 day and quickly disappeared. No trail was seen. Our syndyne-synchrone analysis indicates that the tail was comprised of submicron to micron particles and can be approximated by a synchrone coinciding with the outburst. We estimate that the outburst has released a mass of ∼104–105 kg, comparable to the two mass ejections in 2009 and 2012, and that the average mass-loss rate is ∼0.1–1 kg s−1. The forward-scattering effect hinted at low level activity of Phaethon prior to the outburst, which increased the effective cross section by merely ≲1 km2. Without the forward-scattering enhancement, detecting such activity at side-scattering phase angles is very difficult. The forward-scattering effect also reinforces the idea that the ejected dust grains rather than gas emissions were responsible for the activity of Phaethon. Despite Phaethon's reactivation, it is highly unlikely that the Geminid meteoroid stream can be sustained by similar perihelion mass-loss events.

Rethinking Mass and Elite: Decision-Making in the Athenian Law-Courts

In the Athenian law-courts, wealthy, educated, and powerful elites fought one another to prevail as leaders and advisors of the masses. Regulated by the masses’ ideals of a good society, elite competition pushed Athens toward stability, prosperity and cultural immortality. Or did it? This article puts pressure on the mass and elite model of Athenian litigation (ME elite litigants seek to win over their opponents as a means to gain honor; and the masses constitute a monolithic body with identical preferences. This model, we suggest, does not adequately explain the dynamics of law- and policy-making in the Athenian courts. Combining findings from two separate bodies of literature in classics and political science, we build a new model of Athenian litigation that modifies the ME and second, litigants want to win, but they also have preferences over policy/legal outcomes. Our model identifies the mechanisms that enabled diverse interests to be advanced and negotiated in ways that fostered both stability and innovation in Athenian law- and policy-making.

Color‐Temperature Tuning and Control of Trichromatic White Light Emission from a Multisegment ZnCdSSe Heterostructure Nanosheet

Tuning and control of color temperature of trichromatic white light emission is demonstrated for the first time from a single ZnCdSSe nanosheet realized by a novel growth method using chemical vapor deposition (CVD). The nanosheets have thicknesses in the range of 60–350 nm and lateral dimensions of tens of micrometers. These nanosheet structures with three or more parallel segments are able to emit the three primary colors of light from a monolithic body and the combination of the emitted light appears as white. Due to temperature dependence of the alloy composition and the spatial profile of the temperature in the CVD chamber, alloy compositions and the widths of individual segments can be controlled by the substrate locations and the growth time, respectively. Such control determines the emission color and relative intensity of each segment, thus resulting in the tuning of the color temperature of the white light, or in the realization of any visible colors. Trichromatic white light emission is demonstrated with the correlated color temperature covering an extensive range from 2700 to 14 400 K using various growth parameters. In addition, a dynamic tuning of colors and color temperature is demonstrated by sweeping a pump beam across a single nanosheet.

Application of Mesoporous Silica Foam for Immobilization of Salen Complexes in Chiral Intermediates Synthesis

A route to synthesize porous materials with a hierarchical micro/meso/macroscopic pore system was investigated. Meso/macroporous monolithic silica foams with a large pore size could be fabricated from a mixture of monodispersed PMMA beads and SBA‐15, ‐16 sol solutions. The size, bulk shape and density of the mesoporous monolithic foam could be controlled by the container and the heat treatment temperature. Drying at temperatures higher than 300 °C resulted in an expansion of the SBA silica sol and its solidification to form the mesoporous foams. In contrast, only a dense silica monolith was obtained after full evaporation of the solvent at room temperature without releasing the foam structure in the monolithic body. A large fraction of macroporosity in three dimensions was formed in the monolith body, and the remaining silica walls exhibited uniform mesoporosity. Hydrolytic and phenolic ring‐opening of epoxides were performed successfully using chiral (salen)Co‐BF3 complex‐immobilized catalysts in the packed bed of a continuous flow system. Very high catalytic activity with desirable enantioselectivity was obtained in asymmetric catalysis.

The "Building Parson" - The role of Reverend David Hall in the solution of Ireland's early twentieth-century housing problems

The analysis of the role of decision makers in the creation of the urban landscape, often Government or local authorities, lends to suggest a powerful, monolithic and impersonal body at work. However, sometimes just one person can be the catalyst for a whole new way of doing things. This paper is concerned with the work and influence of a man whose role in the solution of Ireland's housing problems has been almost forgotten, yet his impact was profound. The work of the first operational public utility society in Ireland is examined, indicating some of its links to the garden city movement. It is argued that the influence of this St Barnabas public utility society, and its founder, the Reverend David Henry Hall, was far greater than might be suggested by the small number of houses which it built. It is also suggested that the role of public utility societies as agents in housing provision throughout Ireland was far greater than has been heretofore recognised.

Christine Jencken’s Großmutters Erzählung (Grandmother’s Story) and the Aspect of Power in Baltic-German Autobiographical Writing

This paper aims to offer a postcolonial reading of an un published autobiography Großmutters Erzählung (Grandmother’s Story, 1869) by Christine Jencken. The author was born into a family of Baltic-German old nobility. The text is rather unusual because of the critical comments on the Baltic-German way of life. It can be stated that Baltic-German life-writing is in its majority forms in many aspects a monolithic body of collective memory which supported the Baltic-German hegemonic identity. It is therefore difficult to find texts which do not follow the usual line of argument which includes the “historical right” of Baltic-Germans to the land and the praise of the traditional family values. However, in every society there are people who do not agree with certain traditions or models of behaviour but they are hardly represented in Baltic-German autobiographical writing. In my search for alternative voices I have found Christine Jencken’s unpublished autobiography, which offers a different insight into the Baltic-German everyday life compared to what we are used to in the autobiographies and literary texts written by the Baltic-Germans from that period.

What Are We Doing When We Do Theology

It may be useful to begin with a number of distinctions. If we can see what theology is not, we are in a better position to see its identity or what it is called to do. to begin with, theology is not a neutral discipline because, unlike “religious studies,” it is grounded in a commitment of faith. Similarly, it is not an individual project only but takes place within an ecclesial community of believers, and hence it is rooted in a rich tradition of reflection. But to insist on these two contexts for theology (faith and a community of faith) should not restrict theology to narrowly religious themes or only to being an ecclesial specialization. although its focus is on god and revelation, theology also deals with all things in relation to god (as thomas aquinas said). although it is grounded in a long history of thinking, it is asked to reinterpret or mediate that tradition for different audiences today—not just for the Church, but also for a pluralist society and for a pluralist intellectual world (as david tracy has argued). although its foundation lies in god’s Word, written and handed on, it is rooted also in the transforming experience of god’s love (as Bernard lonergan insists). although in an older meaning theology claimed to be a science, it differs radically from modern empirical sciences which begin from external data. theology can never claim that kind of evidence about its object which involves the mystery of god. It begins from revelation and faith, and aims at a different and relational kind of truth: in other words, as Vatican I put it beautifully, theology seeks obscure, imperfect and yet fruitful understanding of mysteries, and it does so mainly through analogies. this also means that theology cannot be equated with doctrine alone but also with understanding the spiritual depth and cultural significance of doctrinal truths. Therefore, it is not a question of repeating “a monolithic body of doctrine” as abstract theories, as Pope Francis has said, but ultimately of serving the “freshness” of faith for today, and doing so through discerning dialogue with “human experiences” and cultures.

Development of Ink Jet Printhead Equipped With a Large Monolithic Unimorph Piezoelectric Actuator Unit

Kyocera realized a trapezoidal actuator unit with one inch width approximately, in which 664 portions of individual unimorph piezoelectric actuators are formed in matrix of 16 rows. This actuator unit has been used for its own piezoelectric ink jet printheads known as KJ4 series, in which four units are used to cover 4.25 inch (108.25 mm) print width.Then, Kyocera has developed a larger actuator unit that covers 4.4 inch (112.35 mm) print width with monolithic rectangular body, in which numbers of individual active portions are arranged. And, it has been adopted for development of new ink jet printhead series.As the first model of the new printhead series, 4.4 inch (112.35 mm), 300 npi ink jet printhead for aqueous ink is introduced. It is equipped with nozzles forming a matrix of 16 rows × 166 columns in 4.4 inch × 1 inch (112.35 mm × 25.4 mm) rectangular region. Each group of adjacent eight nozzle rows belongs to individual channel group, in which nozzles are arranged in 300 npi. And, independent driving conditions in voltage and waveform can be applied to each nozzle group. Practically, this printhead is intended to pack two pieces of 300 npi printheads in 200mm × 36mm × 61mm single body for downsizing and simplification in printer design especially for multi-pass printing applications.

Diversity Within Yoruba-Language Video Films

Olu Olowogemo. Bosun Omo Yankee. 2011. Nigeria. Yoruba, with English subtitles. Nigeria. High-Waves Video Mart. 275 min. No price reported. Funke Akindele and Abbey Lanre. Omo Getto. 201 1 . Nigeria. Yoruba, with English subtitles. Olasco Films Nigeria Ltd. 174 min. No price reported. Tunde Kelani. Ma'ami. 201 1 . Nigeria. English, Yoruba, with English subtitles. Mainframe Productions. 92 min. No price reported. After two decades of prolific growth, Nigeria's video film industry, commonly called Nollywood, has garnered significant scholarly attention. The emergence of Nollywood studies is indebted to several seminal surveys, including Jonathan Haynes and Onokome Okome's Nigerian Video Films (2000), Foluke Ogunleye's African Video Film Today (2003), and Mahir Saul and Ralph Austen's Viewing African Cinema in the Twenty-First Century (2010). What is called for today, however, are investigations focused on the great diversity among the myriad titles that appear for sale across West Africa every year. Language has offered a natural means of categorizing these videos. It is true that a Yoruba-language film follows a distinctly different social life from screenplay to first screening compared to, say, one of Kannywood's Hausa-language films. But more important, each film responds to and carries forward a particular cinematic tradition. In the case of contemporary Yoruba-language video film, Wole Ogundele has argued convincingly that we might find its antecedents in the alarinjo traveling folk opera of the recent past. The films reviewed here - Olu Olowogemo 's Bosun Omo Yankee (2011), Funke Akindele and Abbey Lanre 's Omo Getto (2011), and Tunde Kelani's Ma'ami (2011) - complicate the notion that Yoruba video film represents a monolithic body of videos. In the rapidly changing environment of Nigerian video film, what has emerged is a splintering of productions, differing in production value, financial investment, target audience, and aesthetic form. While the films selected here demonstrate the diversity of Yoruba-language video film today, they do share a thematic preoccupation with Nigeria's place amidst the wider global cultural economy. We might ask how each constructs its narrative and positions its viewers around images and ideas of global and local culture, especially popular cultural forms like music and sports. Written, produced, and directed by Olu Olowogemo, Bosun Omo Yankee is the director/ actor's only film to date. Bosun (Olu Olowogemo), once a destitute young artist plucking his guitar by the roadside, now returns from America as an international pop star, bringing with him unimaginable wealth, an American swagger, and an ostentatious sense of pride. He refuses even to perform for his own community and rejects his family's ultimatum to build a home in the village or remove Amubieya, the family name, from his own. Indeed, Bosun gladly renames himself according to his stage persona, Omo Yankee (Yankee Boy) , donning sunglasses, flashy gold necklaces, and an American flag tee-shirt. Meanwhile, Bosun's childhood friend Olanrewaju is deported from America under suspicion of fraudulently appropriating $15 million. With little proof or due process, the Nigerian authorities detain Lanre for the crime and even charge him with tarnishing the nation's image abroad. Lanre 's mother and wife are unable to convince Bosun to post bail for his friend and must enlist the help of a sympathetic detective who fights for Lanre 's release. Bosun's meteoric rise and Lanre 's demise suggest the film's melodramatic aesthetics, whereby reality is recast as a moral struggle between virtue and vice. We learn that Bosun's wealth and fame are the fruits of an occult pact with a sorcerer, whereas Lanre 's faith in prayer only grows with his time in jail. When all hope for Lanre 's freedom seems lost, two representatives of the Harejan Company in America fortuitously arrive to acquit him of all charges, having discovered a phone message between Bosun and Lanre that implicates Bosun in the disappearance of the $15 million. …

Adding to the Mix: Integrating ELSI into a National Nanoscale Science and Technology Center

This paper describes issues associated with integrating the study of Ethical, Legal and Social Issues (ELSI) into ongoing scientific and technical research and describes an approach adopted by the authors for their own work with the center for nanophase materials sciences (CNMS) at the Oak Ridge national laboratory (ORNL). Four key questions are considered: (a) What is ELSI and how should it identify and address topics of interest for the CNMS? (b) What advantages accrue to incorporating ELSI into the CNMS? (c) How should the integration of ELSI into the CNMS take place? (d) How should one judge the effectiveness of the activity? We conclude that ELSI research is not a monolithic body of knowledge, but should be adapted to the question at hand. Our approach focuses on junctures in the R&D continuum at which key decisions occur, avoids topics of a purely ethical nature or advocacy, and seeks to gather data in ways that permit testing the validity of generalization. Integrating ELSI into the CNMS allows dealing with topics firmly grounded in science, offers concrete examples of potential downstream applications and provides access to the scientists using the CNMS and their insights and observations. As well, integration provides the opportunity for R&D managers to benefit from ELSI insights and the potential to modify R&D agendas. Successful integration is dependent on the particular ELSI question set that drives the project. In this case questions sought to identify key choices, information of value to scientists, institutional attributes, key attributes of the CNMS culture, and alternatives for communicating results. The opportunity to consult with scientists on ELSI implications is offered, but not promoted. Finally, ELSI effectiveness is judged by observing the use to which research products are put within the CNMS, ORNL, and the community of external scholars.

Brazing RB-SiC Used in Large Aperture Space Optical System

Because of the sic material’s superior optical characteristic, machine characteristic and hot characteristic, it becomes currently the space big aperture reflector choose firstly1. For larger aperture sic mirror, it is not economical and safe to make the monolithic body directly2,3. The SiC mirror brazed assembly with several segments can solve these problems. In this paper, one Φ600 mm sic plane mirror as demonstration welded with 3 radial segments is roughly grinded to the required figure at first, then the mirror is finely grinded and polished by the technology of CCOS, the mirror figure error is less than 1/20λ (λ = 632.8nm) in RMS finally. The problems of the preferential removal near braze joint are solved. The methods of reducing the residual stress of mirror are discussed. At last, some measurements and experiments are carried on, and the results conclude that the brazed SiC mirror can meet the requirement of large aperture optical systems

Construction and initial evaluation of an apparatus for spatial comprehensive two-dimensional liquid-phase separations

Spatial comprehensive two-dimensional chromatography is discussed as a potentially alternative to the conventional column-based approach. In “spatial” separations each analyte ends up in a specific location, rather than being eluted at a specific time. Ultimately, higher peak-capacity-production rates (peak capacity per unit time) may be attained by spatial two- and three-dimensional separations. While low-pressure planar chromatography is well developed, the high-pressure equivalent is still in its infancy. We discuss the requirements for a device for high-pressure spatial two-dimensional chromatography and we describe a possible design. A prototype instrument has been constructed in-house. The preparation of a polymer monolithic separation body and a valve configuration that allows manual sample injection are described. Initial tests of this study included the investigation of the homogeneity of the monolith and the flow profile through the separation body. Furthermore, in order to evaluate the current chromatographic performance of the device, a mixture of dyes was separated in one dimension within 30 s.

Explosion of a comet nucleus fragment in the earth’s atmosphere

This paper analyzes data on thermal explosions of large meteoroids in the earth’s atmosphere. The cumulative function of flux of space bodies is corrected with regard to the explosion height, which is determined, according to our approach, by maximum braking. As a result, the integral function of flux in the work [Brown, P., Spalding, R.E., ReVelle, D.O., et al., The Flux of Small Near-Earth Objects Colliding with the Earth, Nature, 2002, vol. 420, pp. 314–316] is consistent with the one we derived earlier. It is found that at least one phenomenon of those discussed in the paper by Brown et al. is a result of explosion of a comet nucleus fragment. It is shown that the Tunguska phenomenon cannot be explained within a monolithic body model.

A large crater as a probe of the internal structure of the E-type asteroid Steins

<i>Context. <i/>The detection of a large crater (2 km in diameter) on Steins, a diamond-shape asteroid with a diameter of only about 4.6 km, was a large surprise given the size of the asteroid itself. Steins belongs to the rare class of E-type asteroids, which had not been observed by any spacecraft before the Rosetta mission of the European Space Agency (ESA) in 2008.<i>Aims. <i/>We demonstrate that this large crater places constraints on both the internal structure of Steins and its age based on crater counting.<i>Methods. <i/>Numerical simulations of impacts were performed to reproduce the large crater, assuming four different initial internal structures of the asteroid: monolithic with or without microporosity, and rubble pile with or without microporosity.<i>Results. <i/>To reproduce this crater, Steins must be either a rubble pile, which also contains microporosity, or a monolithic body with or without microporosity. The lack of porosity in meteorite analogues favors a structure without microporosity, which, according to our results, must have been monolothic. Moreover, the asteroid would be transformed into a rubble pile structure as a result of the crater formation, allowing it to be reshaped in its current shape by the YORP spin-up thermal effect.<i>Conclusions. <i/>A combination of modeling and observations of surface features can thus serve as a probe of the internal structure of a small body and constrains its age estimate. Since the surface was totally refreshed when the large crater was formed, crater counting on Steins indicates the time that has passed since this impact event occurred.

The Present Crisis: Should we go ‘beyond economics’?

Economics is not a monolithic body. Therefore, to call for going ‘beyond economics’ requires qualifications and understanding the pluralistic nature of the discipline. Claudio Sardoni briefly looks at the contributions from three non-mainstream economists (Marx, Keynes and Minsky), whose ideas he argues are very important to understanding the present crisis.

TIDAL EVOLUTION OF RUBBLE PILES

Many small bodies in the solar system are believed to be rubble piles, a collection of smaller elements separated by voids.We propose a model for the structure of a self-gravitating rubble pile. Static friction prevents its elements from sliding relative to each other. Stresses are concentrated around points of contact between individual elements. The effective dimensionless rigidity, μ˜ rubble, is related to that of a monolithic body of similar composition and size, μ˜ by μ˜ rubble ∼ μ˜^1/2 eY^−1/2, where eY ∼ 10^−2 is the yield strain. This represents a reduction in effective rigidity below the maximum radius, Rmax ∼ [μeY /(Gρ^2)]^1/2 ∼ 10^3 km, at which a rubble pile can exist. Our model for the rigidity of rubble piles is compatible with laboratory experiments on the speed of shear waves in sand. Densities derived for binary asteroids imply that they are rubble piles. Thus their tidal evolution proceeds faster than it would if they were monoliths. Binary orbit evolution is also driven by torques resulting from the asymmetrical scattering and reradiation of sunlight (YORP and BYORP effects). The tidal torque probably overcomes the radiative (YORP) torque and synchronizes the spins of secondaries in near-Earth binary asteroids and it definitely does so for secondaries of main-belt binary asteroids. Synchronization is a requirement for the radiative (BYORP) torque to act on the binary orbit. This torque clearly dominates the tidal torque for all near-Earth binary asteroids and for some binaries in the main belt. For other main-belt binaries, the tidal torque appears to be at least comparable in strength to the BYORP torque. An exciting possibility is that in these systems the angular momentum added to the orbit by the tidal torque might be removed by the radiative torque.

Evidence of the complex structure of asteroid 21 Lutetia

We discuss the results of the analysis of three sets of observations of asteroid 21 Lutetia—spectrophotometry, simultaneous BVR photometry, and spectrometry—which show that the asteroid is not a monolithic body. The frequency analysis of the B-V and V-R color indices and the V values, which were obtained from simultaneous BVR measurements in 2004 and calculated from the spectrophotometric observations performed in 2000 (the synthetic values and the color indices), allowed us to demonstrate that the known rotation period of 8.h172 of the asteroid does not exist at all. At a rather high confidence level, six new periods were found: 2.h0, 2.h93, 16.h8, 1.d25, 3.d25, and 60d. During spectral observations with a 1.25-m telescope at the southern laboratory of the Sternberg Astronomical Institute in Nauchnyi (Crimea) in 2004, the spectra of two components spaced 2.8″ apart were registered. In the short-wavelength spectral range, quick variations of the reflectance of the components were observed. They show the changes in their spectral types from S to C. The analysis of the synthetic values of the color indices determined from the spectrophotometric observations in 2000 confirmed the presence of quick spectral variations. We conclude that asteroid 21 Lutetia is a complex satellite system. This statement is confirmed by the analysis of data published in different sources.