bluuebunny/crossref_metadata_2025 huggingface dataset:
High operating temperature split-off band infrared detectors
Authors: Perera A. G. U. , Matsik S. G. , Jayaweera P. V. V. , Tennakone K. , Liu H. C. , Buchanan M. , Von Winckel G. , Stintz A. , Krishna S.
Published: October 2006

Heterojunction interfacial work function internal photoemission detectors were used to demonstrate infrared response originating from hole transitions between light/heavy hole bands and the split-off (spin-orbit) band. A GaAs∕AlGaAs heterojunction with a threshold wavelength of ∼20μm indicated an operating temperature of 130K for split-off response in the range of 1.5–5μm with a peak D* of 1.0×108 Jones. Analysis suggests that practical devices with optimized parameters are capable of achieving room temperature operation with higher specific detectivity. Possible approaches to tailor the threshold for the split-off response to different wavelength ranges using different materials such as phosphides and nitrides are also discussed.
Quantitative analysis of hysteresis in carbon nanotube field-effect devices
Authors: Kar Swastik , Vijayaraghavan Aravind , Soldano Caterina , Talapatra Saikat , Vajtai Robert , Nalamasu Omkaram , Ajayan Pulickel M.
Published: October 2006

The authors present a model to analyze hysteresis in transfer characteristics (TCs) of single-wall carbon nanotube field-effect transistors, based on capacitive charging of the surrounding dielectric by charges injected out of the nanotube. The model identifies the extent and time scale of the hysteresis and correctly describes the dependence of the magnitude of hysteresis on common experimental parameters. The authors propose and experimentally establish a “time-decay” experiment for obtaining accurate device properties in hysteresis-affected devices without actually measuring TCs. The authors further show that values obtained by this method can be used to precisely predict TCs for the same device under different experimental parameters.
Super-resolution imaging of dielectric objects using a slab of left-handed material
Authors: Zhao Lei , Cui Tie Jun
Published: October 2006

The Born iterative method has been presented to study two-dimensional inverse scattering problems for dielectric objects with the aid of left-handed material (LHM). Super-resolution imaging can be achieved since the LHM slab could amplify evanescent waves emitted from transmitters, which are interacted with the dielectric objects and then captured by receivers. The evanescent waves contain high-frequency spectra of dielectric objects, leading to significant improvement of resolution in imaging. Simulation results are presented to verify the super-resolution imaging.
Ultraviolet photoluminescence from 3C-SiC nanorods
Authors: Zhang Ligong , Yang Weiyou , Jin Hua , Zheng Zhuhong , Xie Zhipeng , Miao Hezhuo , An Linan
Published: October 2006

An intensive sharp photoluminescence at 3.3eV is observed from single-crystal 3C-SiC nanorods. Structural characterization reveals that the nanorods contain a fairly large amount of threefold stacking faults. We tentatively attribute the emission to these stalking faults, which structurally resemble 6H-SiC nano-layers of 1.5nm embedded in a 3C-SiC matrix. The emission mechanism is discussed in terms of spontaneous polarization at the stacking faults.
Electro-optic coefficients of Si0.75Ge0.25∕Si∕Si0.5Ge0.5 asymmetric superlattice measured by polarization-maintaining fiber-optic Mach-Zehnder interferometer
Authors: Zhao L. , Tu X. G. , Zuo Y. H. , Chen S. W. , Wang Q. M.
Published: October 2006

Ten-period 5.5nm Si0.75Ge0.25∕10.3nm Si∕2.5nm Si0.5Ge0.5 trilayer asymmetric superlattice was prepared on Si (001) substrate by ultrahigh vacuum chemical vapor deposition at 500°C. The stability of Mach-Zehnder interferometer was improved by utilizing polarization-maintaining fibers. According to the electro-optic responses of the superlattice with the light polarization along [110] and [−110], respectively, both electro-optic coefficients γ13 and γ63 of such asymmetric superlattice were measured. γ13 and γ63 are 2.4×10−11 and 1.3×10−11cm∕V, respectively, with the incident light wavelength at 1.55μm.
30
-
nm
-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography
Authors: Wang Jian Jim , Chen Lei , Liu Xiaoming , Sciortino Paul , Liu Feng , Walters Frank , Deng Xuegong
Published: October 2006

Both high contrast and high transmittance are preferred for optical polarizers. To achieve high transmittance for aluminum nanowire-grid polarizers, a narrow linewidth is required. In this letter, aluminum nanowire-grid polarizers with 30-nm-wide linewidth and 200nm depth were fabricated by UV-nanoimprint lithography, which leads to ultrahigh transmittance. To achieve a high contrast, the authors fabricated the 30-nm-wide aluminum nanowire structures on both sides of the glass wafers. An extremely high contrast up to 10 000:1 was achieved, in the visible range, along with good transmittance of 83%–87% for the double-side aluminum nanowire-grid polarizers.
Generation of heavy-chain-only antibodies in mice
Authors: Janssens Rick , Dekker Sylvia , Hendriks Rudi W. , Panayotou George , Remoortere Alexandra van , San John Kong-a , Grosveld Frank , Drabek Dubravka
Published: October 2006

We have generated transgenic mice containing hybrid llama/human antibody loci that contain two llama variable regions and the human D, J, and Cμ and/or Cγ constant regions. Such loci rearrange productively and rescue B cell development efficiently without LC rearrangement. Heavy-chain-only antibodies (HCAb) are expressed at high levels, provided that the CH1 domain is deleted from the constant regions. HCAb production does not require an IgM stage for effective pre-B cell signaling. Antigen-specific heavy-chain-only IgM or IgGs are produced upon immunization. The IgG is dimeric, whereas IgM is multimeric. The chimeric HCAb loci are subject to allelic exclusion, but several copies of the transgenic locus can be rearranged and expressed successfully on the same allele in the same cell. Such cells are not subject to negative selection. The mice produce a full antibody repertoire and provide a previously undescribed avenue to produce specific human HCAb in the future.
Slow progressive degeneration of nigral dopaminergic neurons in postnatal
Engrailed
mutant mice
Authors: Sgadò Paola , Albéri Lavinia , Gherbassi Daniel , Galasso Sherri L. , Ramakers Geert M. J. , Alavian Kambiz N. , Smidt Marten P. , Dyck Richard H. , Simon Horst H.
Published: October 2006

The homeobox transcription factors
Engrailed-1
and
Engrailed-2
are required for the survival of mesencephalic dopaminergic neurons in a cell-autonomous and gene-dose-dependent manner. Because of this requirement, the cells die by apoptosis when all four alleles of the
Engrailed
genes are genetically ablated (
En1
−/−;
En2
−/−). In the present study, we show that viable and fertile mice, heterozygous null for
Engrailed-1
and homozygous null for
Engrailed-2
(
En1
+/−;
En2
−/−), have an adult phenotype that resembles key pathological features of Parkinson's disease. Specifically, postnatal mutant mice exhibit a progressive degeneration of dopaminergic neurons in the substantia nigra during the first 3 mo of their lives, leading to diminished storage and release of dopamine in the caudate putamen, motor deficits similar to akinesia and bradykinesia, and a lower body weight. This genetic model may provide access to the molecular etiology for Parkinson's disease and could assist in the development of novel treatments for this neurodegenerative disorder.
Ultrafast infrared spectroscopy reveals a key step for successful entry into the photocycle for photoactive yellow protein
Authors: van Wilderen L. J. G. W. , van der Horst M. A. , van Stokkum I. H. M. , Hellingwerf K. J. , van Grondelle R. , Groot M. L.
Published: October 2006

Photoactive proteins such as PYP (photoactive yellow protein) are generally accepted as model systems for studying protein signal state formation. PYP is a blue-light sensor from the bacterium
Halorhodospira halophila
. The formation of PYP's signaling state is initiated by
trans-cis
isomerization of the
p
-coumaric acid chromophore upon the absorption of light. The quantum yield of signaling state formation is ≈0.3. Using femtosecond visible pump/mid-IR probe spectroscopy, we investigated the structure of the very short-lived ground state intermediate (GSI) that results from an unsuccessful attempt to enter the photocycle. This intermediate and the first stable GSI on pathway into the photocycle, I
0
, both have a mid-IR difference spectrum that is characteristic of a
cis
isomer, but only the I
0
intermediate has a chromophore with a broken hydrogen bond with the backbone N atom of Cys-69. We suggest, therefore, that breaking this hydrogen bond is decisive for a successful entry into the photocycle. The chromophore also engages in a hydrogen-bonding network by means of its phenolate group with residues Tyr-42 and Glu-46. We have investigated the role of this hydrogen bond by exchanging the H bond-donating residue Glu-46 with the weaker H bond-donating glutamine (i.e., Gln-46). We have observed that this mutant exhibits virtually identical kinetics and product yields as WT PYP, even though during the I
0
-to-I
1
transition, on the 800-ps time scale, the hydrogen bond of the chromophore with Gln-46 is broken, whereas this hydrogen bond remains intact with Glu-46.
Interdigital webbing retention in bat wings illustrates genetic changes underlying amniote limb diversification
Authors: Weatherbee Scott D. , Behringer Richard R. , Rasweiler John J. , Niswander Lee A.
Published: October 2006

Developmentally regulated programmed cell death sculpts the limbs and other embryonic organs in vertebrates. One intriguing example of species-specific differences in apoptotic extent is observed in the tissue between the digits. In chicks and mice, bone morphogenetic proteins (Bmps) trigger apoptosis of the interdigital mesenchyme, leading to freed digits, whereas in ducks, Bmp antagonists inhibit the apoptotic program, resulting in webbed feet. Here, we show that the phyllostomid bat
Carollia perspicillata
utilizes a distinct mechanism for maintaining interdigit tissue. We find that bat forelimb and hindlimb interdigital tissues express Bmp signaling components but that only bat hindlimbs undergo interdigital apoptosis. Strikingly, the retention of interdigital webbing in the bat forelimb is correlated with a unique pattern of
Fgf8
expression in addition to the Bmp inhibitor
Gremlin
. By using a functional assay, we show that maintenance of interdigit tissue in the bat wing depends on the combined effects of high levels of Fgf signaling and inhibition of Bmp signaling. Our data also indicate that although there is not a conserved mechanism for maintaining interdigit tissue across amniotes, the expression in the bat forelimb interdigits of
Gremlin
and
Fgf8
suggests that these key molecular changes contributed to the evolution of the bat wing.
Culling and cattle controls influence tuberculosis risk for badgers
Authors: Woodroffe Rosie , Donnelly Christl A. , Jenkins Helen E. , Johnston W. Thomas , Cox David R. , Bourne F. John , Cheeseman Chris L. , Delahay Richard J. , Clifton-Hadley Richard S. , Gettinby George , Gilks Peter , Hewinson R. Glyn , McInerney John P. , Morrison W. Ivan
Published: October 2006

Human and livestock diseases can be difficult to control where infection persists in wildlife populations. In Britain, European badgers (Meles meles) are implicated in transmittingMycobacterium bovis, the causative agent of bovine tuberculosis (TB), to cattle. Badger culling has therefore been a component of British TB control policy for many years. However, large-scale field trials have recently shown that badger culling has the capacity to cause both increases and decreases in cattle TB incidence. Here, we show that repeated badger culling in the same area is associated with increasing prevalence ofM. bovisinfection in badgers, especially where landscape features allow badgers from neighboring land to recolonize culled areas. This impact on prevalence in badgers might reduce the beneficial effects of culling on cattle TB incidence, and could contribute to the detrimental effects that have been observed. Additionally, we show that suspension of cattle TB controls during a nationwide epidemic of foot and mouth disease, which substantially delayed removal of TB-affected cattle, was associated with a widespread increase in the prevalence ofM. bovisinfection in badgers. This pattern suggests that infection may be transmitted from cattle to badgers, as well as vice versa. Clearly, disease control measures aimed at either host species may have unintended consequences for transmission, both within and between species. Our findings highlight the need for policymakers to consider multiple transmission routes when managing multihost pathogens.
Enzyme therapy in mannose receptor-null mucopolysaccharidosis VII mice defines roles for the mannose 6-phosphate and mannose receptors
Authors: Sly William S. , Vogler Carole , Grubb Jeffrey H. , Levy Beth , Galvin Nancy , Tan Yun , Nishioka Tatsuo , Tomatsu Shunji
Published: October 2006

Enzyme replacement therapy (ERT) is available for several lysosomal storage diseases. Except for Gaucher disease, for which an enzyme with exposed mannosyl residues targets mannose receptors (MR) on macrophages, ERT targets primarily the mannose 6-phosphate receptor (MPR). Most recombinant lysosomal enzymes contain oligosaccharides with both terminal mannosyl and mannose 6-phosphate residues. Effective MPR-mediated delivery may be compromised by rapid clearance of infused enzyme by the MR on fixed tissue macrophages, especially Kupffer cells. To evaluate the impact of this obstacle to ERT, we introduced the MR-null mutation onto the mucopolysaccharidosis type VII (MPS VII) background and produced doubly deficient MR
−/−
MPS VII mice. The availability of both MR
+/+
and MR
−/−
mice allowed us to study the effects of eliminating the MR on MR- and MPR-mediated plasma clearance and tissue distribution of infused phosphorylated (P) and nonphosphorylated (NP) forms of human β-glucuronidase (GUS). In MR
+/+
MPS VII mice, the MR clearance system predominated at doses up to 6.4 mg/kg P-GUS. Genetically eliminating the MR slowed plasma clearance of both P- and NP-GUS and enhanced the effectiveness of P-GUS in clearing storage in kidney, bone, and retina. Saturating the MR clearance system by high doses of enzyme also improved targeting to MPR-containing tissues such as muscle, kidney, heart, and hepatocytes. Although ablating the MR clearance system genetically is not practical clinically, blocking the MR-mediated clearance system with high doses of enzyme is feasible. This approach delivers a larger fraction of enzyme to MPR-expressing tissues, thus enhancing the effectiveness of MPR-targeted ERT.
DJ-1, a cancer- and Parkinson's disease-associated protein, stabilizes the antioxidant transcriptional master regulator Nrf2
Authors: Clements Casey M. , McNally Richard S. , Conti Brian J. , Mak Tak W. , Ting Jenny P.-Y.
Published: October 2006

DJ-1/PARK7, a cancer- and Parkinson's disease (PD)-associated protein, protects cells from toxic stresses. However, the functional basis of this protection has remained elusive. We found that loss of DJ-1 leads to deficits in NQO1 [NAD(P)H quinone oxidoreductase 1], a detoxification enzyme. This deficit is attributed to a loss of Nrf2 (nuclear factor erythroid 2-related factor), a master regulator of antioxidant transcriptional responses. DJ-1 stabilizes Nrf2 by preventing association with its inhibitor protein, Keap1, and Nrf2's subsequent ubiquitination. Without intact DJ-1, Nrf2 protein is unstable, and transcriptional responses are thereby decreased both basally and after induction. This effect of DJ-1 on Nrf2 is present in both transformed lines and primary cells across human and mouse species. DJ-1's effect on Nrf2 and subsequent effects on antioxidant responses may explain how DJ-1 affects the etiology of both cancer and PD, which are seemingly disparate disorders. Furthermore, this DJ-1/Nrf2 functional axis presents a therapeutic target in cancer treatment and justifies DJ-1 as a tumor biomarker.
Structural basis for understanding oncogenic p53 mutations and designing rescue drugs
Authors: Joerger Andreas C. , Ang Hwee Ching , Fersht Alan R.
Published: October 2006

The DNA-binding domain of the tumor suppressor p53 is inactivated by mutation in ≈50% of human cancers. We have solved high-resolution crystal structures of several oncogenic mutants to investigate the structural basis of inactivation and provide information for designing drugs that may rescue inactivated mutants. We found a variety of structural consequences upon mutation: (
i
) the removal of an essential contact with DNA, (
ii
) creation of large, water-accessible crevices or hydrophobic internal cavities with no other structural changes but with a large loss of thermodynamic stability, (
iii
) distortion of the DNA-binding surface, and (
iv
) alterations to surfaces not directly involved in DNA binding but involved in domain–domain interactions on binding as a tetramer. These findings explain differences in functional properties and associated phenotypes (e.g., temperature sensitivity). Some mutants have the potential of being rescued by a generic stabilizing drug. In addition, a mutation-induced crevice is a potential target site for a mutant-selective stabilizing drug.
Evolution of sensory complexity recorded in a myxobacterial genome
Authors: Goldman B. S. , Nierman W. C. , Kaiser D. , Slater S. C. , Durkin A. S. , Eisen J. A. , Ronning C. M. , Barbazuk W. B. , Blanchard M. , Field C. , Halling C. , Hinkle G. , Iartchuk O. , Kim H. S. , Mackenzie C. , Madupu R. , Miller N. , Shvartsbeyn A. , Sullivan S. A. , Vaudin M. , Wiegand R. , Kaplan H. B.
Published: October 2006

Myxobacteria are single-celled, but social, eubacterial predators. Upon starvation they build multicellular fruiting bodies using a developmental program that progressively changes the pattern of cell movement and the repertoire of genes expressed. Development terminates with spore differentiation and is coordinated by both diffusible and cell-bound signals. The growth and development of
Myxococcus xanthus
is regulated by the integration of multiple signals from outside the cells with physiological signals from within. A collection of
M. xanthus
cells behaves, in many respects, like a multicellular organism. For these reasons
M. xanthus
offers unparalleled access to a regulatory network that controls development and that organizes cell movement on surfaces. The genome of
M. xanthus
is large (9.14 Mb), considerably larger than the other sequenced δ-proteobacteria. We suggest that gene duplication and divergence were major contributors to genomic expansion from its progenitor. More than 1,500 duplications specific to the myxobacterial lineage were identified, representing >15% of the total genes. Genes were not duplicated at random; rather, genes for cell–cell signaling, small molecule sensing, and integrative transcription control were amplified selectively. Families of genes encoding the production of secondary metabolites are overrepresented in the genome but may have been received by horizontal gene transfer and are likely to be important for predation.
SHP-2 activates signaling of the nuclear factor of activated T cells to promote skeletal muscle growth
Authors: Fornaro Mara , Burch Peter M. , Yang Wentian , Zhang Lei , Hamilton Claire E. , Kim Jung H. , Neel Benjamin G. , Bennett Anton M.
Published: October 2006

The formation of multinucleated myofibers is essential for the growth of skeletal muscle. The nuclear factor of activated T cells (NFAT) promotes skeletal muscle growth. How NFAT responds to changes in extracellular cues to regulate skeletal muscle growth remains to be fully defined. In this study, we demonstrate that mice containing a skeletal muscle–specific deletion of the tyrosine phosphatase SHP-2 (muscle creatine kinase [MCK]–SHP-2 null) exhibited a reduction in both myofiber size and type I slow myofiber number. We found that interleukin-4, an NFAT-regulated cytokine known to stimulate myofiber growth, was reduced in its expression in skeletal muscles of MCK–SHP-2–null mice. When SHP-2 was deleted during the differentiation of primary myoblasts, NFAT transcriptional activity and myotube multinucleation were impaired. Finally, SHP-2 coupled myotube multinucleation to an integrin-dependent pathway and activated NFAT by stimulating c-Src. Thus, SHP-2 transduces extracellular matrix stimuli to intracellular signaling pathways to promote skeletal muscle growth.
Kinesin-13s form rings around microtubules
Authors: Tan Dongyan , Asenjo Ana B. , Mennella Vito , Sharp David J. , Sosa Hernando
Published: October 2006

Kinesin is a superfamily of motor proteins that uses the energy of adenosine triphosphate hydrolysis to move and generate force along microtubules. A notable exception to this general description is found in the kinesin-13 family that actively depolymerizes microtubules rather than actively moving along them. This depolymerization activity is important in mitosis during chromosome segregation. It is still not fully clear by which mechanism kinesin-13s depolymerize microtubules. To address this issue, we used electron microscopy to investigate the interaction of kinesin-13s with microtubules. Surprisingly, we found that proteins of the kinesin-13 family form rings and spirals around microtubules. This is the first report of this type of oligomeric structure for any kinesin protein. These rings may allow kinesin-13s to stay at the ends of microtubules during depolymerization.
MicroRNA-9a ensures the precise specification of sensory organ precursors in Drosophila
Authors: Li Yan , Wang Fay , Lee Jin-A , Gao Fen-Biao
Published: October 2006

MicroRNAs (miRNAs) have been implicated in regulating various aspects of animal development, but their functions in neurogenesis are largely unknown. Here we report that loss of miR-9a function in the Drosophila peripheral nervous system leads to ectopic production of sensory organ precursors (SOPs), whereas overexpression of miR-9a results in a severe loss of SOPs. We further demonstrate a strong genetic interaction between miR-9a and senseless (sens) in controlling the formation of SOPs in the adult wing imaginal disc. Moreover, miR-9a suppresses Sens expression through its 3′ untranslated region. miR-9a is expressed in epithelial cells, including those adjacent to SOPs within proneural clusters, suggesting that miR-9a normally inhibits neuronal fate in non-SOP cells by down-regulating Sens expression. These results indicate that miR-9a ensures the generation of the precise number of neuronal precursor cells during development.
Regions of high differentiation—Worth a check
Authors: Harr Bettina
Published: October 2006

B. Boursot and K. Belkhir in this issue of Genome Research point to an ascertainment bias in my use of SNPs to identify regions of high differentiation between a pair of house mouse subspecies. Here, I discuss additional points to consider and argue that the ultimate test for such regions should be an independent confirmation using unrelated samples. I provide evidence that regions of high differentiation as identified from laboratory strains and potentially biased SNP markers can be confirmed and therefore are worth a deeper investigation.
A reflection on the South African food research environment
Authors: Lues J.F.R. , Lategan L.O.K.
Published: October 2006

Purpose

This paper seeks to cast light on the issues impacting South African food research. During the first decade of democracy the South African research and development sector has experienced many changes and although the aim of these changes was to bring about efficiency, the research and development (R&D) fraternity is still faced with various challenges in its endeavours to meet the demands from commerce and industry. As a result of continuously changing market demands the food and drink industry has become one of the main sectors that are dependant on novel technologies developed by the R&D sector.

Design/methodology/approach

An overview of the broader South African research landscape is given followed by a closer look at the nature and extent of local food‐related research.

Findings

In order to meet the demand of industry a new mindset is required amongst research institutions towards providing an array of scientific services that extend intra‐ and inter‐disciplinary boundaries and where long‐term partnerships between food industries and the R&D sector are forged. However, against this backdrop South Africa's national research priorities are increasingly directed towards poverty alleviation and development. Human resources in science and technology have not been developed adequately, which in turn has resulted in an aging and declining scientific population. Thus, a balancing act is needed in order to address the scant human resources while at the same time effectively bridging the innovation chasm. This predicament extends to food researchers who find themselves amidst a well developed and technologically advanced formal industry while at the same time having to address issues relating to a relatively primitive yet lucrative informal food sector.

Originality/value

The paper presents novel information regarding South African food research and places it in context against the broader research landscape.
NOTES ON THE COLORATION OF GLAZES BY LIGHT*
Authors: PARMELEE C. W. , BADGER A. E.
Published: October 2006

The actinic darkening of the colors of certain glazes and bodies is described.
GLASS: THE BOND IN CERAMICS*
Authors: MOREY GEORGE W.
Published: October 2006

A ceramic industry is one which manufactures products by the application of heat to raw materials containing silica or silicates as essential ingredients, and ceramic chemistry is that branch of Chemistry which deals with the chemistry of silica. The property which makes silica the basis of industries as apparently diverse as water glass and refractories and which is conferred on all mixtures in which it is present in adequate amounts is that of forming glasses. While silica itself forms an ideal glass, its high melting point requires the addition of a flux, and the commonest and most powerful flux is soda. The addition of soda to silica produces a remarkable lowering of the melting point, from 1713 to 793° and glass of this composition is remarkably stable against devitrification. It is dissolved by water and forms the basis for the soluble silicate industry. But insolubility in water and acids is essential for most of the glasses of ceramics, and other oxides must be added to obtain this stability. The commonest and cheapest is lime (CaO), and most of the glass of commerce may be regarded as derived from the sodium‐silicate glass by the addition of several per cent of lime, usually also with the addition of small amounts of other oxides, notably magnesia, boric oxide, and alumina. Boric oxide and alumina are especially characteristic of the glassy base of enamels, which chiefly differ from glasses in containing insoluble materials to render them opaque and often coloring agents soluble in the glassy phase. Glazes, too, are of similar composition. Refractories are bonded by glass; either a lime glass in the silica refractories, or an aluminum glass in the clay refractories. But a siliceous glass is the characteristic feature which is found in all products of the ceramic art, and glass is the bond which unites the divers ceramic industries.
ELECTROLYTIC REACTIONS IN VITREOUS ENAMELS AND THEIR RELATION TO THE ADHERENCE OF ENAMELS TO STEEL*
Authors: STALEY HOMER F.
Published: October 2006

All the metals between iron and copper in the electromotive‐force series of metals are plated out of solution during the firing of sheet‐steel ground coats by the electrolytic action of the hot iron base. Of these plates, cobalt, nickel, and antimony promote adhesion, each of the following factors probably playing a part: (1) The plates of these metals adhere tenaciously to steel while enamel does not. (2) The coefficients of thermal expansion of these metals are intermediate between those of steel and those of commercial ground‐coat and cover‐coat glasses, thus giving a gradation of coefficients found desirable by Danielson and Sweely. (3) The enamel glass is mechanically bonded to the metal plate by dendrites, aided by any jagged projections and holes. (4) These metal plates are insoluble in the molten enamel; thus any structure favorable to adhesion, once formed, remains.
THE THERMAL CONDUCTIVITY OF REFRACTORIES*
Authors: WILKES GORDON B.
Published: October 2006

The thermal conductivity of recrystallized silicon carbide, clay‐bonded silicon carbide, and silica and fireclay brick has been determined from 200 to 2600°F. The results are compared with those of previous investigators and a possible explanation of the peculiar variation of the coefficient of thermal conductivity with temperature for certain brick is given.
A STUDY OF THE EFFECT OF NATURAL GAS AND OF HYDROGEN UPON VARIOUS REFRACTORIES*
Authors: RUPRECHT BERTRAM C. , PIERCE R. H H. , HARVEY FRED A.
Published: October 2006

Natural gas was passed through an electric‐tube furnace where it was partially cracked and then through a second furnace containing the sample of a refractory. The refractories tested were fireclay brick of various types and fired in various manners and brick made of magnesite, high alumina material, and silica. The action on the refractory was similar to that of carbon monoxide. Carbon was deposited in some of the refractory bodies within a critical temperature range. Some of the fireclay bodies were almost completely disintegrated by the growth of the carbon deposits, although others were scarcely affected. Hydrogen gas had no disintegrating action at any temperature studied.
TMECHANICS OF ENAMEL ADHERENCE. X
Authors: KING R. M.
Published: October 2006

The formation and significance of the so‐called “iron oxide layer” have have studied experimentally and are discussed here.
THE EFFECT OF FLUORIDES ON THE PROPERTIES OF WHITE SHEET‐IRON ENAMELS*
Authors: ANDREWS A. I. , HOWE E. E.
Published: October 2006

This investigation deals primarily with determinations of the thermal expansion and fusion properties of white sheet‐iron cover enamels. A comparison of the results of the factor method of calculating the thermal expansions and those obtained experimentally shows considerable disagreement.
VISCOSITY AND ELECTRICAL CONDUCTIVITY OF MOLTEN GLASSES*
Authors: BABCOCK C. L.
Published: October 2006

Using a new type of concentric cylinder viscosimeter, the viscosity, 7, and electrical resistivity, κ of some commercial glasses and the glasses of the soda‐silicate system have been investigated in the region of 700 to 1400 °C corresponding from 3 to 102 poises and from 0.3 to 103ohms. The results in the viscous region show proportionality between log η and log κ in the region investigated. In the two glasses investigated at lower temperatures, it can be seen that the same constants do not hold thronghout the whole region. These results are discussed considering the kinetic picture of liquids (see summary).
PRINCIPLES OF HEAT FLOW IN POROUS INSULATORS*
Authors: Russell H. W.
Published: October 2006

An approximate theory of the thermal conductivity of porous materials is given. The effect of pore size and shape is discussed.
PARTICLE‐SIZE DISTRIBUTION IN SOME GROUND CERAMIC RAW MATERIALS*
Authors: Vibweg Hermann F.
Published: October 2006

A study of the particle‐size distribution in batch and continuous ground commercial flints and feldspars is discussed. A size‐frequency law for batch‐ground materials is proposed. The use of similar investigations in systematic modification of continuous grinding procedure is indicated.
THE ADJUSTMENT OF ENAMELS TO SHEET STEEL*
Authors: Dietzel A. , Meures K. , King R. M.
Published: October 2006

The authors present data on their tests on the expansion coefficient of enamels to sheet steel and give results on their tests for cover enamels, upper and lower ground coats, and sheet steel. They find that the expansion coefficient, 0° to softening temperature, of the fired ground coat is only a little less in the region of the steel surface than the steel itself, and that it decreases within the ground coat toward the cover coat in order to approach the lower coefficient of the ground coat. They state that all previous measurements of the coefficients of sheet‐steel ground coats are not efficient. This study is being continued.
SMALL CAST THORIUM OXIDE CRUCIBLES*
Authors: Richardson H. K.
Published: October 2006

Crucibles were made from thorium oxide by casting from a slip made according to ceramic practice. The presence of cryolite in the slip insured its successful use. These were fired to 1885°C in a gas furnace of special construction. The addition of zirconium oxide makes a crucible easier to manufacture. The finished crucibles were successfully used in vacuum‐induction furnaces to melt pure metals to 2300°C. No contamination of the metals resulted.

Expansion curves indicate a peculiar action of the crucibles made with zirconium oxide in the 700 to 900° region. The mean coefficient of expansion of fused thoria is found to be 93 × from 0 to 600°C.

These crucibles are found to be (a) fairly resistant to chemical reagents, but not enough so for chemical work and (b) resistant to wetting of molten metals of high melting point.
THE SYSTEM Na2O‐B2O, III
Authors: Cole Sandford S. , Taylor Nelson W. , Scholes S. R.
Published: October 2006

The sodium borates with the molecular ratio of Na2O to B2O3 of 1:2, 1:3, and 1:4 have been crystallized. Optical properties, melting points, and X‐ray diffraction data are reported.
COMPARISON OF USED SILICA BRICK FROM INSULATED AND UNINSULATED BASIC OPEN‐HEARTH ROOFS*
Authors: Harvey Fred A.
Published: October 2006

Samples of silica brick from the roofs of two basic open‐hearth furnaces, one of which had been insulated and the other uninsulated, after a full campaign were compared chemically and petrographically. The uninsulated brick was divided into nine distinct color zones, while the insulated brick showed but three. The three zones of the insulated brick were nearly identical zone for zone with the three inner zones of the uninsulated brick. The zone of weakness which normally occurs in open‐hearth roof brick from uninsulated furnaces did not occur in the brick from the insulated roof. Chemical and petrographic analyses are given.
REACTION‐EXPANSION MEASUREMENTS ON CHROMITE AND ALLIED SPINELS*
Authors: Chesters J. H. , Parmelee C. W.
Published: October 2006

The rate of formation of spinel in mixtures of magnesia with alumina or chromic oxide (Cr2O3) was greatly increased by the addition of 2% of boric acid. When the three oxides were heated together in the molecular ratio (2MgO + A12O3+ Cr2O3), reaction‐expansion set in at a temperature much below that observed with the binary mixtures. The product appeared to be a mixture of green magnesium chromite with a pink colored spinel whose lattice edge was greater than that of magnesium aluminate but smaller than that of the chromite.

Test pieces made from unfired Cuban chromite began to shrink at 1300°C, and gave a final shrinkage of 2.2% after two hours at 1500°C. Microscopic examination showed that the serpentine had changed to a glass. The compensation of firing shrinkage by the addition of 20% of coarse Austrian magnesite or 10% of fine electrically fused magnesia was found to be due to the formation of a doubly refracting mineral resembling forsterite. With a 20% alumina addition, a firing expansion of 0.8% was obtained.
STRENGTH AND YOUNG'S MODULUS OF SOME GROUND‐COAT ENAMELS FOR SHEET IRON*
Authors: Harrison W. N. , Shelton S. M. , Wadleigh W. H.
Published: October 2006

Eleven enamel compositions of the sheet‐iron ground‐coat type were studied. For nine compositions, flint and feldspar were substituted one for the other, and boric and sodium oxides one for the other. For the remaining two, a given combination of flint and feldspar and a given combination of boric and sodium oxides were substituted one for the other. Tests were made for Young's modulus of elasticity, tensile strength, and modulus of rupture. The shape of the stress‐strain curve, the effect of the duration of the stress period on apparent strength, and the strength distribution in specimens of the respective enamels were investigated. The changes in modulus of rupture were not large, but this property varied systematically with the composition, as did the scatter in the modulus of rupture and also the extensibility.
TITANIUM COMPOUNDS AND APPLICATION THEREOF IN VITREOUS ENAMELS*
Authors: Kinzie C. J. , Plunkett J. A.
Published: October 2006

A study was made of the effect of titanium oxide, alumina, zirconia, silica, tin oxide, and antimony oxide on the thermal dilatation, melting point, and fusion flow properties of a simple enamel glass.
THE TRANSFORMATION OF ALUMINUM OXIDE FROM THE BETA TO THE ALPHA FORM*
Authors: Gallup John
Published: October 2006

Until recently it had not been known that beta alumina could be converted directly to the alpha form without going through the molten state. This paper is the report on an investigation which shows that beta alumina changes rapidly to the alpha form at temperatures as low as 1300°C when heated in a vacuum. It was also found that the temperature at which rapid conversion starts rises successively in atmospheres of hydrogen, air, and argon. Petrographic identifications were checked by density determinations.
NOTE ON THE INFLUENCE OF ZIRCONIA ON THE ELASTICITY OF SOME SODA‐LIME GLASSES*
Authors: Horak William , Sharp Donald E.
Published: October 2006

Measurements of the moduli of elasticity and of rigidity were made on four soda‐lime glasses containing ZrO2. Both moduli are lowered by the substitution of ZrO2 for CaO
A DISCUSSION RELATING TO THERMAL EXPANSION METHODS FROM THEORETICAL AND PRACTICAL STANDPOINTS*
Authors: Kinzie C. J. , Commons C. H.
Published: October 2006

Calculated factors are compared with coefficients as determined by the interferometer and rod methods, and conclusions are drawn relating to the probable effect upon results obtained.
COLOR STABILITY IN ENAMELS*
Authors: Baldwin William J.
Published: October 2006

A series of frits in which the ratio of boric oxide to sodium oxide was varied was milled with various color oxides and the stability of the color was noted at different temperatures. It was found that a frit having a boric‐oxide content in excess of the sodium‐oxide content was preferable. Colors such as reds and mahoganies were found to be more stable in these frits and the general workability of the enamel was better, There was no trouble from these enamels settling as was the case with frits of a high sodium‐oxide and low boric‐oxide content.

The presence of lime was found to be essential in maintaining color stability in the frits tested and had a marked influence on the viscosity of the enamel.
THE EFFECT OF THE SOLID‐LIQUID RATIO ON GRINDING A CERAMIC NONPLASTIC*
Authors: Schwartzwalder Karl , Herold Paul G.
Published: October 2006

A ceramic nonplastic (specific gravity 3.01) was wet‐ground with solid‐liquid ratios of 2.7 to 1 and 1 to 15 for various lengths of time. Grain‐size distribution and surface area, as measured by the Wagner turbidimeter method, were compared. The material ground with the least water gave a lower percentage retained on a 325‐mesh screen, fewer particles between 10 and 60 microns, and more between 0 and 10 microns.
COMPARISON OF TENSILE STRENGTHS OF SHEET‐IRON GROUND‐COAT ENAMEL GLASSES*
Authors: Andrews A. I. , Coffeen W. W.
Published: October 2006

Abstract

The fiber method developed by Schwalbe, Badger, and Silverman for comparing the tensile strengths of glasses was used to compare the tensile strengths of sheet‐iron ground‐coat enamel glasses whose feldspar, borax, and quartz contents varied within workable limits. For purposes of comparison, this method uses that value of the unit stress at failure which exists in a fiber whose fractured surface shows a smooth portion constituting 1% of the total cross‐section. For the enamels tested, these values of tensile strength ranged from 30.0 to 32.7 kg. per sq. mm. (42,000 to 46,000 lb. per sq. in.). An increase in quartz or feldspar tended to raise the tensile strength slightly, while an increase in borax tended to lower it slightly, although the total variation was small. From these data, it was concluded that insofar as the enamel strength was concerned mechanical failures of the enamel, such as chipping, fishscaling, or crazing, could not be aided by variations of the feldspar, borax, and quartz contents of sheet‐iron ground‐coat enamel glasses within workable limits.
USE OF NEPHELINE SYENITE IN SANITARY PORCELAIN*
Authors: Koenig C. J.
Published: October 2006

Abstract

By introducing nepheline syenite in sanitary porcelain in reduced amounts to replace potash feldspar, a longer vitrification range is afforded which results in less warpage.

Ware fluxed with nepheline syenite has a steel‐like ring, the pitch being higher than the regular ware. An electrical machine for producing pure tones was used to classify the various pitches. An oscillograph was used to determine decrement or tone decay. Nepheline syenite, ground to near pottery‐grade fineness, was air‐separated into coarse, medium, and fine divisions. When used in a porcelain body, the fine division afforded a longer vitrification range, lower warpage, and increased mechanical strength. The sound properties of these bodies are classified. Photomicrographs of body structures are included.
USE OF LITHIUM CARBONATE IN RAW ALKALINE GLAZES*
Authors: Richardson Florence Wood
Published: October 2006

Abstract

The results of using lithium carbonate to replace the more soluble alkalis and their frits in glazes fired between cones 07 and 05 are discussed. Owing to its unusual fluxing properties, the use of from 9 to 12% lithium carbonate permits a marked increase in the amounts of alumina, calcium, and silica which may be used, resulting in a more stable glaze, with sufficient alkalinity to produce vivid copper blues and other typically alkaline colors.
RELATION OF THE COMPOSITION TO THE PROPERTIES OF CLAYS*
Authors: Grim Ralph E.
Published: October 2006

Abstract

Most clays are composed essentially of minute particles of one or more of the clay minerals of which the kaolinite, montmorillonite, and illite groups are most important. The clay minerals occur in flake‐shaped particles, possess base‐exchange capacity, and exist in or are reducible to extremely small grain sizes on working with water. Different clay minerals possess these properties in varying degrees.

The clay mineral component is the chief factor determining the properties of a clay. In general, plasticity and bond strength caused by the clay minerals decrease in the following order: montmorillonite, illite, and kaolinite. In many clays, the plasticity and bond strength mainly result from the presence of the montmorillonite minerals or some members of the illite group, although these constituents may compose only minor amounts of the clay. The influence of the clay minerals on other properties is considered.

The green properties of clays are also related to the character of the exchangeable bases carried by the clay minerals. The fundamental reasons for the differences in properties resulting from different mineral constituents and various exchangeable bases are considered. The properties of clays are related further to the effective size‐grade distribution developed in actual use which frequently differs from the size‐grade obtained by mechanical analyses.
X‐RAY STUDY OF BORIC OXIDE‐SILICA GLASS*
Authors: Biscoe J. , Robinson C. S. , Warren B. E.
Published: October 2006

Abstract

X‐ray diffraction patterns have been made of four samples of boric oxide‐silica glass (15, 30, 45, and 60% SiO2) and of Pyrex‐brand chemical resistant glass. Radial distribution curves for the 5 samples were obtained by the usual Fourier analysis method. The results lead to a picture of boric oxide‐silica glass in which each silicon is tetra‐hedrally surrounded by 4 oxygens, each boron is triangularly surrounded by 3 oxygens, and each oxygen is bonded between 2 cations. In Pyrex‐brand chemical resistant glass, part of the borons are probably in tetrahedral coordination. The softening of silica glass by the addition of boric oxide results from replacing in the random network fourfold coordinated silicon by threefold coordinated boron. The low expansion coefficient of vitreous silica, contrasted with the higher expansion of crystalline silica, is explained by the impossibility of cooperative maneuvers in the random network of glassy silica.
BERYLLIUM OXIDE: I*
Authors: White H. E. , Shremp R. M.
Published: October 2006

Abstract

This interesting and unusual material forms few mineralogical combinations, although many binary and some ternary diagrams have been plotted. The apparent stable crystalline formation at relatively low temperature has been confirmed by specific‐gravity determinations on the oxide fired at different temperatures and on the electrically fused oxide, both by the writers and others. The thermal expansion of the electrically fused beryllium oxide and of bars of the oxide fired at lower temperatures is also very close. The electrical conductivity is higher than that for magnesia and alumina. The thermal conductivity appears to be greater than that of alumina and zircon. The hardness is 9.
EFFECT OF ATMOSPHERIC EXPOSURE ON THE PROPERTIES OF UNFIRED CLAY BODIES*
Authors: EVERHART J. O. , RUSSELL R.
Published: October 2006

Abstract

The effect of storage conditions on the unfired properties of seven representative ceramic bodies is reported. These bodies were dried thoroughly and stored in desiccators, open air, and damp rooms for various periods of time. The effect of this treatment on volume, weight, and transverse and compressive strengths was observed. One surface clay showed complete loss of strength after a few hours of exposure in the open air. Other bodies showed less change, but all were affected to some degree. Bodies with low organic content may be restored approximately to their original condition by redrying; those high in organic content can not be restored.
METHOD OF RECORDING PLASTIC PROPERTIES OF PORCELAIN BODIES*
Authors: Thiess L. E.
Published: October 2006

Abstract

The plastic working properties of a series of high‐tension porcelain bodies have been tested on an apparatus called the Plastograph. An attempt has been made to correlate the data thus obtained with other physical properties, such as grain size, amount of organic (carbonaceous) matter, and dry strength.
STRESSES IN PORCELAIN GLAZES*
Authors: Johnson A. L.
Published: October 2006

Abstract

The stresses developed by five glazes in the field of cone 9 porcelain glazes were determined by the tuning fork method of Blakely. A reaction between the body and glaze at the interface causes a development of stress above the softening point of the glaze. The mat glaze studied showed no crazing even though it was extremely high in tension, whereas a semimat and clear glaze, lower in tension, showed craze marks.
HIGH‐TEMPERATURE VISCOSITIES OF SODA‐SILICA GLASSES*
Authors: Lillie H. R.
Published: October 2006

Abstract

A careful study of the viscosities of glasses composed of silica and between 22 and 40% soda shows that viscosity‐composition isotherms are smooth curves. The sharp minima at about 34% Na2O (and possibly at about 26% Na2O) observed by Preston1 are found to be entirely absent. Neither time nor shearing stress has any effect upon observed viscosities in the region investigated as long as temperature constancy has been established. A study of deviations, i.e., of individual points from the smooth isotherms, shows that these are all within the expected limits of experimental error.