Evaluation of commercially-available spacecraft-type heat pipes

As part of an effort to develop reliable, cost effective spacecraft thermal control heat pipes, life tests on 30 commercially available heat pipes in 10 groups of different design and material combinations were conducted. Results for seven groups were reported herein. Materials are aluminum and stainless steel, and working fluids are methanol and ammonia. The formation of noncondensible gas was observed for times exceeding 11,000 hours. The heat transport capacities of the pipes were also determined

Accelerated life tests of specimen heat pipe from Communication Technology Satellite (CTS) project

A gas-loaded variable conductance heat pipe of stainless steel with methanol working fluid identical to one now on the CTS satellite was life tested in the laboratory at accelerated conditions for 14 200 hours, equivalent to about 70 000 hours at flight conditions. The noncondensible gas inventory increased about 20 percent over the original charge. The observed gas increase is estimated to increase operating temperature by about 2.2 C, insufficient to harm the electronic gear cooled by the heat pipes in the satellite. Tests of maximum heat input against evaporator elevation agree well with the manufacturer's predictions

Related Party Transactions and Earnings Management

This study examines the association between related party transactions and earnings man-agement, based on a sample of 50 Indonesian publicly listed companies for the periods ending 2004 and 2005. The hypothesis developed in this study draw on past literature and the tenets of agency theory which suggest that the existence of related party transactions represent potential conflict of interest which may results in earnings management and appropriation by controlling shareholder to minority shareholders. The empirical findings of the study suggest that there is no statistically significant evidence of the association between related party transactions and earnings manage-ment attributes. Additional sensitivity analysis conducted with alternative measures of earnings management and related party transactions confirm the initial regression results. The results of this study suggest that the mere presence of related party transactions in Indonesian companies does not necessarily indicate that management engage in greater earnings management. This study pro-vides a valuable starting point for similar research in other developing countries

Intumescent Flame Retardant Polyamide 11 Nanocomposites

Current polyamide 11 and 12 are lacking in fire retardancy and high strength/high heat resistance characteristics for a plethora of fabricated parts that are desired and required for performance driven applications. The introduction of selected nanoparticles such as surface modified montmorillonite (MMT) clay or carbon nanofibers (CNFs), combined with a conventional intumescent flame retardant (FR) additive into the polyamide 11/polyamide 12 (PA11/PA12) by melt processing conditions has resulted in the preparation of a family of intumescent polyamide nanocomposites. These intumescent polyamide 11 and 12 nanocomposites exhibit enhanced polymer performance characteristics, i.e., fire retardancy, high strength and high heat resistance and are expected to expand the market opportunities for polyamide 11 and polyamide 12 polymer manufacturers. The objective of this research is to develop improved polyamide 11 and 12 polymers with enhanced flame retardancy, thermal, and mechanical properties for selective laser sintering (SLS) rapid manufacturing (RM). In the present study, a nanophase was introduced into the polyamide 11 and combining it with a conventional intumescent FR additive via twin screw extrusion. Arkema RILSAN® polyamide 11 molding polymer pellets were examined with two types of nanoparticles: chemically modified montmorillonite (MMT) organoclays, and carbon nanofibers (CNFs); and Clairant’s Exolit® OP 1230 intumescent FR additive were used to create a family of FR intumescent polyamide 11 nanocomposites. Transmission electron microscopy (TEM) was used to determine the degree of nanoparticles dispersion. Injection molded specimens were fabricated for physical, thermal, and flammability measurements. Thermal stability of these intumescent polyamide 11 nanocomposites was examined by TGA. Flammability properties were obtained using the Cone Calorimeter at an external heat flux of 35 kW/m 2 and UL 94 Test Method. Heat deflection temperatures (HDT) were also measured. TEM micrographs, physical, thermal, and flammability properties are presented. FR intumescent polyamide 11 nanocomposites properties are compared with polyamide 11 baseline polymer. Based on flammability and mechanical material performance, selective polymers including polyamide 11 nanocomposites and control polyamide 11 will be cryogenically ground into fine powders for SLS RM processing. SLS specimens will be fabricated for thermal, flammability, and mechanical properties characterization.Mechanical Engineerin

Gettysburg College Sustainability Proposal

In the fall of 2011, the Environmental Studies capstone class led by Professor Rutherford Platt was asked to write Gettysburg College’s first Sustainability Plan. The goal of the plan was to develop specific sustainable practices for the campus that were related to the three pillars of sustainability: economic, social, and environmental, and how integrating diligent sustainable practices into each of these respected pillars will result in a more conscious campus, community, and future. In 2010, Gettysburg College turned to the Sustainability Tracking Assessment and Rating System (STARS) to quantify the institution’s sustainability efforts, providing a self-check mechanism to encourage sustainability applications to all aspects of the College. The American College and University Presidents’ Climate Commitment was signed in 2007 by former Gettysburg College President Katherine Haley Will, declaring that Gettysburg College would become carbon neutral by 2032. Gettysburg College has made large strides in the search for sustainability, and aims to continue its dedication to furthering sustainable practice. The following plan outlines the six priority areas identified by the Capstone class: progress of the American College and University Presidents’ Climate Commitment, Dining Services, campus green space, community outreach, integration of sustainability into the Gettysburg College Curriculum, and the Sustainability Advisory Committee. The first priority area identified was monitoring and upholding the American College and University Presidents’ Climate Commitment (ACUPCC). Though creating new sustainability initiatives on campus is the driving force towards an increasingly sustainable college and community, it is imperative that these goals be carried out in full to maximize beneficial returns. In order to reach carbon neutrality, Gettysburg College hopes to increase energy efficiency in buildings, incorporate renewable energy sources on campus, and mitigate remaining emissions through the purchase of carbon offsets. To further the College’s progress, it is proposed that Gettysburg College continue its energy-efficient appliance purchasing policy, as well as create a policy to offset all greenhouse gas emissions generated by air travel for students study abroad. As stated by the ACUPCC, a Sustainability Committee should take responsibility for the updates and progress reports required to meet the goal of carbon neutrality. The second priority area identified was sustainability in Dining Services. Gettysburg College is home to 2,600 students, all of whom require three full meals a day. Dining Services accounts for a large fraction of Gettysburg College’s sustainability efforts, already implementing sustainability through composting, buying local produce, and using biodegradable products. The proposed on-campus sales cuts of non-reusable to-go items, a change in campus mentality on food waste, and improved composting practices will translate to an increasingly sustainable campus, as well as a well-fed campus body. The third priority was maintaining green space on campus. Ranked as the 23rd most beautiful campus in the United States by The Best Colleges, Gettysburg College utilizes campus green space to create an atmosphere that is conducive to activity as well as tranquility. The plan proposes that Gettysburg College and its grounds facilities continue their exceptional efforts, focusing on increasing the use of the student garden, creating a new rain garden or social area on campus, and converting unnecessary parking lots into green space. As these additions are completed, they must be introduced to the student body and faculty alike to assure these areas are known and utilized. The fourth priority was utilizing community outreach to spread awareness of sustainability initiatives on and off campus. To connect the sustainability-geared changes proposed in this plan, community outreach at Gettysburg College is assessed to estimate how well these initiatives are communicated and promoted to both potential and enrolled students, faculty, and other concerned parties. To evaluate the efficiency of communication at Gettysburg College, a quantitative assessment is presented to measure the ease of finding the sustainability webpage, the quality of sustainability-related topics available on the webpage, and quality of webpage design. The webpage is in need of improved text to image ratios, locations of sustainability topics, and data displays. Despite not having a link to the sustainability webpage on the Gettysburg College homepage, sustainability events should be covered and presented on the rotational news feed found on the homepage to maximize outreach to interested parties or simply to add to the definition of Gettysburg College. The fifth priority was integrating sustainability into the Curriculum to build a culture on campus that values academic rigor, supports students as they cultivate intellectual and civic passions, and promotes the development of healthy social relationships and behaviors. The proposed Sustainability Committee on Sustainability in the Curriculum (SCC) will hold sustainability workshops for faculty with the aim to instill sustainability into all academic disciplines, providing all Gettysburg graduates with a means to approach their professional careers in a fashion that is conscious of sustainability. The sixth and last priority was the Sustainability Advisory Committee. Established in 2007, the Sustainability Advisory Committee is currently under review, but it is recommended that the committee restructure itself in accordance with the new Sustainability Committee Bylaws. These bylaws aim to define the purposes, membership, governance, and involvement with the college. With a clearly defined set of goals and methodology, the Sustainability Advisory Committee will be able to improve the solidarity of the sustainability movement on campus as a whole. By following the propositions laid out in the Gettysburg College Sustainability Plan, the student body, faculty, and community alike will become a part of a multi-faceted progression toward a more sustainable future

The Chagos Islands cases: the empire strikes back

Good governance requires the accommodation of multiple interests in the cause of decision making. However, undue regard for particular sectional interests can take their toll upon public faith in government administration. Historically, broad conceptions of the good of the commonwealth were employed to outweigh the interests of groups that resisted colonisation. In the decision making of the British Empire, the standard approach for justifying the marginalisation of the interests of colonised groups was that they were uncivilised and that particular hardships were the price to be paid for bringing to them the imperial dividend of industrial society. It is widely assumed that with the dismantling of the British Empire, such impulses and their accompanying jurisprudence became a thing of the past. Even as decolonisation proceeded apace after the Second World War, however, the United Kingdom maintained control of strategically important islands with a view towards sustaining its global role. In an infamous example from this twilight period of empire, in the 1960s imperial interests were used to justify the expulsion of the Chagos islanders from the British Indian Ocean Territory (BIOT). Into the twenty-first century, this forced elision of the UK’s interests with the imperial “common good” continues to take centre stage in courtroom battles over the islanders’ rights, being cited before domestic and international tribunals in order to maintain the Chagossians’ exclusion from their homeland. This article considers the new jurisprudence of imperialism which has emerged in a string of decisions which have continued to marginalise the Chagossians’ interests

NGF-p75 signaling coordinates skeletal cell migration during bone repair

: Bone regeneration following injury is initiated by inflammatory signals and occurs in association with infiltration by sensory nerve fibers. Together, these events are believed to coordinate angiogenesis and tissue reprogramming, but the mechanism of coupling immune signals to reinnervation and osteogenesis is unknown. Here, we found that nerve growth factor (NGF) is expressed following cranial bone injury and signals via p75 in resident mesenchymal osteogenic precursors to affect their migration into the damaged tissue. Mice lacking Ngf in myeloid cells demonstrated reduced migration of osteogenic precursors to the injury site with consequently delayed bone healing. These features were phenocopied by mice lacking p75 in Pdgfra+ osteoblast precursors. Single-cell transcriptomics identified mesenchymal subpopulations with potential roles in cell migration and immune response, altered in the context of p75 deletion. Together, these results identify the role of p75 signaling pathway in coordinating skeletal cell migration during early bone repair

Spatial transcriptomics reveals a role for sensory nerves in preserving cranial suture patency through modulation of BMP/TGF-β signaling

: The patterning and ossification of the mammalian skeleton requires the coordinated actions of both intrinsic bone morphogens and extrinsic neurovascular signals, which function in a temporal and spatial fashion to control mesenchymal progenitor cell (MPC) fate. Here, we show the genetic inhibition of tropomyosin receptor kinase A (TrkA) sensory nerve innervation of the developing cranium results in premature calvarial suture closure, associated with a decrease in suture MPC proliferation and increased mineralization. In vitro, axons from peripheral afferent neurons derived from dorsal root ganglions (DRGs) of wild-type mice induce MPC proliferation in a spatially restricted manner via a soluble factor when cocultured in microfluidic chambers. Comparative spatial transcriptomic analysis of the cranial sutures in vivo confirmed a positive association between sensory axons and proliferative MPCs. SpatialTime analysis across the developing suture revealed regional-specific alterations in bone morphogenetic protein (BMP) and TGF-β signaling pathway transcripts in response to TrkA inhibition. RNA sequencing of DRG cell bodies, following direct, axonal coculture with MPCs, confirmed the alterations in BMP/TGF-β signaling pathway transcripts. Among these, the BMP inhibitor follistatin-like 1 (FSTL1) replicated key features of the neural-to-bone influence, including mitogenic and anti-osteogenic effects via the inhibition of BMP/TGF-β signaling. Taken together, our results demonstrate that sensory nerve-derived signals, including FSTL1, function to coordinate cranial bone patterning by regulating MPC proliferation and differentiation in the suture mesenchyme

NGF-TrkA signaling dictates neural ingrowth and aberrant osteochondral differentiation after soft tissue trauma

: Pain is a central feature of soft tissue trauma, which under certain contexts, results in aberrant osteochondral differentiation of tissue-specific stem cells. Here, the role of sensory nerve fibers in this abnormal cell fate decision is investigated using a severe extremity injury model in mice. Soft tissue trauma results in NGF (Nerve growth factor) expression, particularly within perivascular cell types. Consequently, NGF-responsive axonal invasion occurs which precedes osteocartilaginous differentiation. Surgical denervation impedes axonal ingrowth, with significant delays in cartilage and bone formation. Likewise, either deletion of Ngf or two complementary methods to inhibit its receptor TrkA (Tropomyosin receptor kinase A) lead to similar delays in axonal invasion and osteochondral differentiation. Mechanistically, single-cell sequencing suggests a shift from TGFβ to FGF signaling activation among pre-chondrogenic cells after denervation. Finally, analysis of human pathologic specimens and databases confirms the relevance of NGF-TrkA signaling in human disease. In sum, NGF-mediated TrkA-expressing axonal ingrowth drives abnormal osteochondral differentiation after soft tissue trauma. NGF-TrkA signaling inhibition may have dual therapeutic use in soft tissue trauma, both as an analgesic and negative regulator of aberrant stem cell differentiation

Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012