Turnover of15N ammonium sulfate with dicyandiamide under aerobic and anaerobic soil conditions

The influence of the nitrification inhibitor dicyandiamide (DCD) on the turnover of¹⁵N-labelled ammonium sulfate (AS) was investigated in two soils under aerobic and waterlogged conditions. Nitrification of ammonium sulfate was markedly inhibited by addition of DCD in both soils. Up to 45% of the supplied N was transformed into a non-extractable N form, which only slowly released nitrogen over 147 or 264 days. This immobilization was higher in the presence of DCD than without DCD. In all aerobic experiments, the recovery was 100% ± max. 2.4%, indicating that no gaseous losses of N occurred.If aerobic preincubation of 28 or 42 days was followed by water-logging with H₂O or a solution of glucose, considerable N losses occurred only in presence of the carbohydrate. DCD retarded nitrification and thus reduced losses by denitrification from 61 to 15%.DCD application resulted in an increased immobilization of labelled N into the non-exchangeable soil N fraction. This amounted to more than 50% of the applied N, compared to 39% without DCD.The late Dr. Klaus Vilsmeier, a very dedicated and talented young scientist, died before he was able to finish completely the revised version of this article. We will always keep him in our minds and kindly remember his kind personality as well as his sense of humour and justice. Prof. Dr. Heiner Goldbach on behalf of all members of the department.     

What We Learned in 25 Years of Interactive Molecular Design Sessions

We retrace Prof. François Diederich's consultancy work for Roche and its impact over the years he worked with us. François Diederich uniquely shaped our approach to molecular design, and interactions with him and his research group at ETH Zurich have created deep insights into molecular recognition. Herein we share how his style and approach continue to inspire us.     

Colour as vocation: Werner Spillmann's contribution to environmental colour design

Werner Spillmann is known as a colour consultant, influential pedagogue, and passionate promoter of colour as a primary design issue. This article aims to present Spillmann's important contribution to environmental colour design giving special attention to his noteworthy activities in the context of the International Colour Association (AIC). Since 1960, beginning with the period when he became a lecturer and subsequently professor in the Department of Architecture at the Winterthur Polytechnic in Switzerland, Spillmann has successfully introduced colour as a basic element of architectural education and also developed a method for using colour in environmental design. During the initial years of the AIC, Spillmann attended the association's rather sporadic events beginning with its first Congress in 1969. Spillmann's influence on the AIC grew with the association's own consolidation and increasing international importance. He presented his first AIC paper in 1976 and by 1977, when the AIC began to consequently fulfill its constitutional aim of realizing an annual program and had become an internationally renowned organization in the field of colour studies, Spillmann began to play a key role in the leadership of the association. In 1982, Spillmann became a member of the AIC Study Group on Environmental Colour Design. In 1983, he was invited to give a presentation at the AIC Midterm Meeting in Sweden, and, in 1985, he was elected to the AIC Executive Committee for the period 1986–1989. In serving the AIC during this time period, he organized the Interim Meeting on Colour in Environmental Design, which took place in 1988 at the Winterthur Polytechnic. Spillmann's contribution to the AIC represents the crystalization of the theoretical and practical lines of development that he pursued through his own teaching and professional design practice. During this same time period that he was intensely involved in the AIC, his importance and influence as a teacher and design professional increased as well. The intense courses he developed for architects, designers, and planners and taught in Winterthur between 1982 and 1995 were highly successful. As a teacher, Spillmann was acclaimed not only because of his consistent methodological approach and comprehensive content of his courses but especially for his charisma. Spillmann's involvement in the AIC and his teaching and personal professional development demonstrate how his assiduous striving toward a greater appreciation of colour as an imminent element in contemporary architectural design resulted in raising awareness of the psychological, social, and cultural value of colour within the related fields of architectural history and theory, cultural studies, design, and urbanism. Especially Spillmann's special contribution is underscored by his capacity to take up new approaches adapting and testing these through application in architectural education and design practice. Spillmann has published several essays on colour in environmental design and colour order systems. He presently lives in Basel, Switzerland. © 2004 Wiley Periodicals, Inc. Col Res Appl, 30, 53–65, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20075     

John Mercer FRS,FCS, MPhS,JP: the Father of Textile Chemistry

John Mercer (1791–1866) was a pioneering textile and colour chemist with a legacy of achievements. His invention of mercerising that bears his name, treating cellulosics with sodium hydroxide to bring about advantageous changes in fibre and fabric properties, will stand for all time as one of the most important textile chemical treatments ever developed. However, Mercer's contributions to the textiles and coloration industries went far beyond mercerisation. A self‐taught chemical experimentalist par excellence, his keen observations and interest in calico printing led to many novel developments, such as his work on Chrome Yellow and other ‘mineral colours’. Mercer developed new methods for fixing Prussian Blue on calico and wool, developed new mordants for dyeing, improved the extraction of carminic acid from cochineal, and improved the oiling process in Turkey Red dyeing. He saved lives with his research into early antimicrobials, preventing the spread of cholera in textile villages in Lancashire. Mercer was an unsung hero of early photography, and developed light‐sensitive imaging materials and made some of the earliest recorded monochromatic colour photographs. His forward‐looking views on technical education, that workers in the industry should be fully instructed in the nature of the various substances used in their arts, later came to fruition in the establishment of the textile departments in Manchester, Leeds and Glasgow. To this day, Mercer remains the only textile chemist who has ever been elected as a Fellow of the Royal Society since 1852. He is thus quite rightly considered as the Father of Textile Chemistry.     

The Use of SI Units

It is intended that, generally, the SI system of units shall be used in the Society's publications, in accordance with accepted rules. It is important to appreciate that SI units have evolved, that further additions and amendments may be made, and, particularly, that there is still lack of uniformity in interpretation and application of the system. It may be argued that the Society, through its Publications Committee, should take a lead in proposing and adopting one well-considered procedure. On the other hand, it can be maintained that what is required is a clear exposition of the “state of the art”, and that it is this that the Society can and should provide to guide readers of its publications and contributors to them. This paper, sponsored by the Publications Committee, is designed to serve as a guide to SI units and the use of the SI system. It owes its inception to MrR. Murphy of the Department of Industrial Chemistry, The Queen's University, Belfast. It was his “Notes on the Use of SI Units”, submitted to the Committee, which led to the decision that a more general paper on SI units should be produced. A large part of the information regarding SI equivalents for cgs (centimetre-gram-second) and ft-lb-sec (foot-pound-second) units is taken from his paper. The Committee is much indebted to him for this. It is also much obliged to him for the many helpful and instructive comments he made following very thorough reading of the paper in draft.     

Chen Jiayong:Pioneer in hydrometallurgy and chemical engineering disciplines

Dr.Chen Jiayong (Chia-Yung) was born on Feb.17,1922 in a prestigous intellectual clan at Jintang County,Sichuan Province,China.After receiving early education at the Chengdu County Middle School (now Chengdu 7th School),he was admitted as an undergraduate student to the Department of Chemical Engineering,the National Central University at the city of Chongqing from 1939 through 1943 dur-ing the Anti-Japanese War.After gradua-tion,he continued to work as a teaching assistant for both the inorganic and organic chemistry courses.In 1947,he enrolled in the graduate program in the Department of Chemical Engineering on the Urbana-Champaign campus,University of Illinois,USA,and was conferred the MS and PhD degrees in 1949 and 1951 respec-tively.His doctoral thesis topic was on reaction kinetics of carbon with vapor and water in a porous graphite tube.In 1948,he mar-ried Ms.Liu Rong who was also studying at University of Illinois.After graduation in 1951,his intention was to return to China,but his journey was delayed by the US government due to the out-break of the Korean War.During this period,he took positions at Massachusetts Institute of Technology,University of Illinois(Urbana-Champaign),and the Yerkes Institute of the DuPont Film Division at Buffalo,NY.     

TOWARD A NEW VIEWPOINT FOR THE ARTIST

Communication between the artist and the scientific and technological community has been so tenuous during the past 50 years that the artist is not using knowledge and techniques which originate in that world. Conversely, the scientists and technicians have little insight into the problems of artists, making it difficult for the artist to obtain information he knows he needs. Some of the concepts and techniques valuable to artists are outlined in this paper with a special emphasis on those relating to color. Artists' pigments and vehicles are rapidly changing. Channels of information are needed to keep him current and knowledgable. The artist must use both additive and subtractive color simultaneously, since the visual world he utilizes in creating a picture consists largely of additive situations, but the mixture of his paints is a subtractive process. Metamerism is a problem for the artist as it is in color matching for industry. Color systems, although long known, have never been adequately utilized. The Munsell system is the most practical one at the present time for several reasons. Expanding the Munsell notation to include a relative intensity dimension for pigments would add to its usefulness. A color slide rule and a table of approximate chroma loss between pairs of additive colors are proposed to aid the artist in creating depth effects, illumination effects and transparency effects. The artist should be practical in obtaining and using the facts of paint technology, but flexible in the application of systematic color in order to keep his options open. The use of color systems and techniques, while of value to every artist, can be used at many levels for differing purposes. Such concepts must be tailored to the individual artist's needs.     

Characterization of bagasse‐rind particleboard bonded with chitosan

The development of high‐performance non‐wood lignocellulosic board without using synthetic adhesives derived from fossils resources is very important for the future. In this study, the characterization of bagasse particleboard bonded with chitosan was investigated. The 4 wt % chitosan‐acetic acid solution was sprayed onto bagasse rind particles at a 2–10 wt % chitosan solid content based on the dry particles. Particleboards with target densities of 0.75 and 0.9 g/cm³ were manufactured using a steam‐injection press. The steam pressure and total pressing time were 1 MPa (180°C) and 7 min, respectively. The addition of 2–4 wt % of chitosan was the most effective in the bending properties. The high‐density board bonded with a 4 wt % addition of chitosan showed a good result in the internal bond strength test. Furthermore, the board had favorable dimensional stability in dilute acetic acid as well as in a cyclic accelerated aging test. Judging from the analysis of bagasse extract‐added chitosan films, it was suggested that chitosan reacted with extract from bagasse during steam‐injection pressing. The reaction seemed to contribute to the board's good resistance to dilute acid. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Atmospheric Condensation Nuclei P. J. Coulier 1875 and J. Aitken 1880 (Historical Review)

P. J. Coulier in France and J. Aitken in England performed the first basic experiments and made the observations dealing with the role of fine airborne particles in vapor condensation processes. Coulier published his results in 1875 and Aitken published in 1880. They did almost the same experiments, obtained very similar results and provided similar explanations. Vapors condense on solid airborne nuclei. Nevertheless, Coulier had difficulty explaining some of his later results by the ''condensation nuclei hypothesis.'' He thought that this hypothesis was not generally valid. Aitken only saw Coulier's paper in 1881. He repeated some of Coulier's experiments and was then able to explain all of his and Coulier's results by means of the ''condensation nuclei hypothesis,'' which he considered as generally valid. This work has led to the continuing study of heterogeneous nucleation and the development of condensation nuclei counters.     

Keith McLaren —colourist and communicator

Keith McLaren, who died in 1990, was one of this century's most active workers in colour science and technology. His influence in the fields of colour fastness testing and colour measurement was of particular importance. The Society decided to hold a lecture in his memory, to be presented by Roderick McDonald, another well known colour scientist and a friend of Keith McLaren's. The lecture was presented at Dyers' Hall, London, on 19 March 1992. Reproduced below is Dr McDonald's detailed insight into the career of a unique contributor to the world of colour.     

Thoughts and observations on fire‐endurance tests of wood‐frame assemblies protected by gypsum board

Forintek Canada Corp. participated in a series of collaborative research projects with the National Research Council Canada and other organizations to determine fire‐resistance ratings for wood‐frame assemblies used in the construction of Canadian housing and small buildings. Over the course of those studies, Forintek's scientists observed a large number of full‐scale fire‐endurance tests on walls lined on both faces with gypsum board and floor assemblies with gypsum‐board ceilings. Those observations have given Forintek's researchers unique insights into the fire performance of wood‐frame assemblies and fire‐endurance testing. Those insights are the subject of this paper. Copyright © 2002 John Wiley & Sons, Ltd.     

Color difference thresholds in young's theory

In the context of widely accepted trichromatic theory, two colors will differ in appearance unless they produce very nearly equal excitations of all three classes of cones. Ordinarily, for colors that do not match, all three will differ. For the special case of chromaticity differences at equal luminance, Yves Le Grand was the first to propose, without wishing to abandon the trichromatic conception, that there might be only two dimensions of chromatic variation. He assumed that S cones make no contribution to luminance, which is hypothesized instead to depend upon the linear sum of L and M cone activity, so that any increase in the excitation of one of these is exactly mirrored by a decrease in the other. Therefore, only one of them need be specified, such as L. In combination with the level of S-cone excitation, then, that of L will be sufficient to specify any color. MacAdam's 1941 study, which produced his famous ellipses, had been carefully conducted at equal luminance and provided the data to be explained by Le Grand. the CIE chromaticity diagram, upon which MacAdam plotted his results, is not very useful for the representation of Le Grand's dimensions, which lie along oblique axes whose slopes differ continuously throughout the CIE diagram. Working almost a decade before Le Grand published his article, MacAdam, a devotee of strictly mathematical interpretation, did not have a physiological model in mind. Therefore, except occasionally by accident, he did not test discriminations along either of the dimensions that interested Le Grand. Consequently, Le Grand's analysis of MacAdam's data had to be rather indirect. Perhaps for this reason, and possibly also because it was written in French, this article didn't attract much attention among English-speaking researchers until Boynton and colleagues published six articles during the period from 1978 to 1987. the last five of which were heavily based upon it.^3-8 Le Grand's analysis of a MacAdam's ellipse amounted to the following. (1) Determine the slopes of the pair of oblique axes, passing through the center of the ellipse on the CIE diagram, which correspond to the dimensions of pure changes of S- and L-cone excitations, (2) Determine the levels of S- and L-cone excitations represented by a stimulus that plots at the center of the ellipse. (3) Accept the notion that a fitted ellipse constitutes an adequate resentation of MacAdam's data. (4)Determine the magnitude of change along each of the Sand L axes required to achieve a MacAdam discrimination step (the standard deviation of repeated attempts to match the stimulus which plots at the center of the ellipse). (5)Represent that step in terms of changes in S- and L-cone excitations. Le GrandS approach was actually more algebraic and less geometric than what has just been described. Either way, the analysis cannot be done unless S- and L-cone excitations can somehow be calculated. To do this requires knowledge of the spectral sensitivities of the three classes of cones. Arbitrary transformations (of which CIE tristimulus values are a prime example) will not do. Le Grand considers two sets of coneficndamentals thaf were available in 1949, both based on evidence derived from dichromats, but which differed because of unlike assumptions concerning the cause of their reduced form of normal color vision. One set was based on Fick's hypothesis that signals from L and M cones fuse, perhaps arising from cones of a single mixed type. The other set reflected Konig's conception that one of the two cone classes is entirely missing in dichromacy. Le Grand carried out his calculations separately for these two sets of sensitivity curves (fundamentals). Figure 2 shows a derived threshold-vs-intensity curve (log AB vs. log B) for S-cone excitation alone, which passes reasonably close to 25 data points-one for each of MacAdamS ellipses. The data shown are based on Fick's hypothesis, but a change to Konig's would not move the points significantly. The limited scatter ofthe data points around the curve suggests that the level of L-cone excitation, which varies from point to point, would not significantly afect discriminations uniquely mediated by variations of S-cone excitation. The data show that the greater the level of prevailing S-cone excitation, the greater is the increment required for a discriminable difference. This relation is similar to that exhibited in threshold-vs-intensity curves for luminance discrimination. Figure 3 displays calculations of log AR vs. log (R/G); points are plotted that are based on both hypotheses. In each case, the ordinate values are clearly minimal when the L- and M-cone excitations are balanced (R/G = I log R/G = 0), showing that chromatic acuity is best there. Straight lines that intersect at the minimum, one with a negative and the other with a positive slope, describe the Fick data remarkably well. Because such lines (which he does not draw) would apparently not jit the Konig data as accurately, Le Grand takes this as a vindication of the choice of Fick fundamentals, which he accepts in preference to Konig's. Although Le Grand noted the heightened acuity of redgreen chromatic discrimination at the balance point of L-and M-cone excitation, he failed to speculate about why it happens. Opponent-color theory can easily make sense of it. Here, as with S-cone and luminance discriminations, the greater the prevailing level of |L-M| activity in the r-g opponent channel, the greater is the increment required for a discriminable change. By 1957, in his text book Light, Colour and Vision, (without, curiously, any specific text reference to this article) Le Grand reached essentially this position on page 447. There he rewrites Eq. (7) by taking the antilogarithms of both sides. Had he kept the same symbols for R and G (which he did not), the revised formula would read ΔR = .0022(1.26R/G)ⁿ, (where n is either 2/3 or ? 2/3 depending upon whether 1.26RIG is greater or less than unity). Then he writes: … it is just as ifthe fundamentals [R] and [G] acted in close association and neutralized each other's responses so that the difference threshold corresponds to that of much weaker stimuli. As a result of this association, the red and green fundamentals acting together have (especially near the points on the chromaticity diagram where their responses are balanced) a difference sensitivity which is much greater than that of the blue fundamental… A classic approach to the understanding of color differences, which began with Helmholtz, and was later embellished and improved by Stiles, lo involves the notion of the “line element.” It is a receptor-based theory, according to which thresholds depend on the distance between vectors in a three-space in which the L, M, and S receptor outputs dejne three orthogonal dimensions. Le Grand points out that such an analysis by Stiles predicted the orientation of the long axes of MacAdam's ellipses fairly well, but failed completely to account for the short ones. From our point of view, such an approach is bound to fail because of the assumption that signals generated by the L and M cones remain separated at a level of processing where they each can be compared to signals generated by S cones, whereas the weight of the evidence indicates that the L-M difference is computed well before any such comparison can take place. Le Grand makes a similar argument, stating that “…R and G are associated and cannot in any way be considered as independent receptors, and definitely not as Fechnerian receptors.” Indeed, Wyszecki and Stiles show (page 687-689) that a line-element theory, even one that includes a chromatic difference term arising.fiom independent receptors each subject to Weber's Law, falsely predicts an elevation of threshold, rather than the observed reduction, when L- and M-cone excitations are balanced. Most of the time, when two stimuli are compared at equal luminance, dierences bet ween them exist along the L and S dimensions simultaneously. MacAdam's ellipses provide a contour that describes his experimental results for such combined differences, and Le Grand raises the question of why an ellipse should result. He considers three possibilities. Thejirst is that the two components of difference act independently and are then combined in a root-mean-squarefashion [Eq. (8)], as would be expected mathematically for the distances between the each of vectors represented on three orthogonal axes. But he rejects this idea, as well as a suggestion made by Silherstein and MacAdam, who had posited a “two-dimensional normal probability law.” Near the end of his article, Le Grand makes the excellent point that be should definitely not forget that color vision is based on biology and not on geometric analogies. Instead, heproposes (without using the expression) that probability summation ofthresholds mediated by independent receptors could also predict an ellipse, provided that Crozier's law (which states that the variability of threshold estimates is proportional to their mean values) is valid. To do this exactly requires knowledge oflfrequency-of seeing curves. However, these were not obtained with MacAdam's method, so additional assumptions are needed to yield the prediction of an ellipse. It is not clear why this hypothesis is not subject to the same kind of objection as thefirst two. On the basis ofwork in San Diego in which thresholds were tested directly on the L and S axes, as well as those that produced combined changes, the heretical notion was proposed that a hexagon might be the “true” form with which to Jit the data. A tendency toward perfect summation was consistently found when L and S were simultaneously increased or decreased, and something less than probability summation resulted when their signs diflered, suggesting that the combined threshold in this instance was determined exclusively by whichever component ofthe combined change reached its threshold valuejrst. An appeal to color appearance was also made. A pure increase in Sfvom the white point, which could be produced in a very direct fashion with the La Jolla Analytic Calorimeter, produces not a pure blue, but a sensation of increasing saturation that is as much red as blue, suggesting that when more redness is also introduced by simultaneously increasing L-cone excitation, the two rednesses will add. It was also observed that individual diferences are accounted for mostly by the size of threshold steps along the critical dimensions, but when these are normalized the rules just described apply similarly to all subjects-not only those ofthe La Jolla experimen Is, but those ofprevious studies re-analyzed from this point of view.8 A hexagon appears to fit the data about as well as an ellipse. However, given a set of discrimination data obtained along many axes, the diflerences between a best-fitting hexagon and a best-fitting ellipse are far too small, relative to the experimental variability, to allow a choice based on curve-fitting alone. Following the publication of the Jirst La Jolla experiment, Krauskopfand his colleagues l 5 independently discovered, based upon their experimental data alone, the special nature of the L and S dimensions. Many of their experiments were electrophysiological, with nerve impulses recordedfrom cells in the lateral geniculate nuclei of Macaque monkeys, an ideal human surrogate. Stimulation started at a white point, and movedgingerly in various directions in color space. Whereas Boynton termed the L and S axes “critical,” Krauskopfet al. referred to them as “cardinal” instead (which has a nice ring to it). Over the years, there has been considerable argument concerning whether S cones contribute nothing to luminance, as Le Grand assumed (see also the translation qf Schrodinger and Zaidi's commentary), or some very small amount (no one has proposed a contribution any- where near that ofthe other cone types). This is not the place to review the controversy, but it is safe to say that the S-cone contribution (ifany) is so small, and its inclusion would be so destructive to the elegance ofLe Grand's proposed analysis and others that have followedfrom it, that the assumption of zero S-cone contribution to luminance is the one that should befavoredfor an analytic view of chromatic discrimination. There are some remaining puzzles concerning Le Grand's personal reaction to his very clever article. It seems odd that his analysis did not suggest to him (note his title) that behavior along the R-G dimension might somehow relate to opponent-color processing (even though he actually uses the word inhibition at one point in the Conclusions section of his article). Nor was this idea apparently suggested by any ofhisjve distinguished referees, whose comments he discusses in the addendum, except in reverse, fashion by De Vries who wonders “whether the physiological linkage that we find between R and G receptors would not arise from the equal luminance condition … that imposes a mathematical linkage between the R and G responses.” Le Grand replies by stating that “we would only be able to decide this by applying our analysis to the cases where luminance and chromaticity vary simultaneously.” This is a curious exchange, because in the body of the article Le Grand proposes only one kind ofphysiological linkage, namely that luminance is based on the sum ofL- and M-cone excitations. This assumption obviously does produce a mathematical linkage between them, and this is a principal reason why the system works, allowing him to reduce three dimensions to two. If DeVries (who unjortunately died young) were alive today, it seems very likely that he would agree that the physiological opponent-color linkage is very real. Judd felt that Le Grand's analysis of Figure 3 would not allow a choice ofFick's fundamentals in preference to Konig's. From the perspective gained more than 40 years later, one must agree with Judd. Boynton and colleagues have carried out a similar analysis ofMacAdam 's data, as well as those from some other studies, using the Smith-Pokorny fundamentals, and as already noted they have experimentally examined discriminations along the S and L dimensions of variation.^3-7 All of the experimental data make sense in the context of Le Grand's system when the Smith-Pokorny fundamentals are used. The fact is that discrimination data are much too variable to serve as a critical test among fundamentals that difer little from one another; there is so little diference anyway between the Smith-Pokorny fundamentals and other recent candidates that the issue should be considered moot. Of the four other referees (MacAdam, Judd, Wright, and Stiles), all but Judd were strict trichromaticists. (MacAdam, the sole survivor of this quartet, still is.) Judd, on the other hand, was fully aware and very sympathetic to opponent-color concepts, and it is possible that he made mention of them in the critique he sent to Le Grand, but that Le Grand failed to note it. This seems plausible because, in Light, Colour and Vision, Le Grand gives very short shrift to opponent color notions. In his 32-page chapter on “Theories of Color Vision,” there is no such mention until the last two pages where he introduces the subject by saying that (italics ours) “Young's system must now be left (although with reluctance) for a consideration of that proposed by Hering in 1872…” It is also curious that, although Le Grand lists this article among the references in the end matter of his textbook, he doesn't specifically cite it anywhere in the body of the text—almost as if he wanted to have it overlooked. It is, therefore, not surprising that Robert Rodieck, in his textbook, developed similar ideas without apparent knowledge of Le Grand's work, or that Boynton did not know of it either when the first article of the La Jolla series was published in 1978. Nor does it seem likely that Krauskopf and his colleagues were influenced by it. Almost all of the ideas outlined in 1986 in “A system of photometry and colorimetry based on cone excitations,” which had originally been proposed to the CIE in 1979, are evident in Le Grand's article, and the 1979 Mac-Leod-Boynton chromaticity diagram is essentially a representation of Le Grand's two dimensions using orthogonal coordinates and the Smith-Pokorny fundamentals. to the extent that the use of this diagram is gaining favor among basic vision scientists for representing pure chromaticity variations, it is because it clearly represents exactly what Le Grand was writing about, namely the free-floating excitation level of S cones versus the linked tradeoff between the activity levels of the L and M receptors. It has taken the better part of a half-century, but Le Grand's ideas as put forth in this article (despite his tendency to abandon them) are beginning to catch on, Maybe, before another 45 years go by, the CIE will see the light as well. Actually, the situation looks more hopeful at present than in the past. A CIE committee established in 1979 to promote an alternate system of photometry and colorimetry, one heavily based upon Le Grand's trail-blazing insights, was not very productive untilfairly recently—partly because it got bogged down in controversy about choice of fundamentals, and also because of strong differences of opinion concerning whether it is safe to assume no contribution of the S-cones to luminance. Now, under the competent and vigorous leadership of Françoise Viénot, who recently assumed the chairmanship of a reconstituted committee, it appears likely that an alternative system of photometry and colorimetry, one consistent with Le Grand's insights, will be forthcoming without too much further delay beyond the 15 years that have already elapsed since the CIE met in Kyoto. The set of ellipses that represent dierence thresholds at constant luminance in the chromaticity diagram can be readily explained by the Young-Helmholtz theory if one assumes Fick's hypothesis (that dichromacy arises from trichromacy byfusion oftwo,fundamentals) . Wefind that the blue.fundamenta1 functions as an independent receptor of a generalized Fechnerian type, while the red and green fundamentals remain on the contrary closely linked. The existence ofthe ellipses is interpreted, on the other hand, by means ofa simple statistical theory, taking into account Crozier's Law.     

Reverse osmosis in shell and tubes

Reverse osmosis in shell and tubes geometry and in an annulus in both laminar and turbulent flows is considered. Incomplete salt rejection and axial variation of the osmotic pressure are taken into account. For laminar flow it is shown that for a given bundle of tubes, the value of the polarization when the brine flows outside the tube is about half its value for when the brine flows inside the tubes. For reverse osmosis in turbulent flow an expression similar to that proposed by Sherwood et. al. is shown to apply for all geometries. The shape factor enters only through an appropriate definition of the Reynolds number.Yeshaiahu Winograd was born in Tel Aviv on 3rd December, 1938. He graduated from the Technion in 1962, and earned his Master's and Doctor's degrees at Brown University, U.S.A. After a year of postdoctoral work at M.I.T., he returned to the Technion in 1967 as a member of the Faculty of Mechanical Engineering, where he became Head of the Energy Laboratory and was active in research on desalination and fluid mechanics. His published work includes five articles in Desalination. He is survived by his widow Ruth, and three children.Professor Winograd's untimely death was a great loss to the Technion and to the whole desalination community. His work and pleasant personality will long be remembered by all those who knew him.     

Dyers and Finishers – Can You Manage to Survive?

This paper was presented at the Thirteenth George Douglas Memorial Lecture, held at the Post House Hotel, Northenden, Manchester, on 5 May 1981. The proceedings were chaired by the President of the Society, Dr J. V. Butcher.     

A tribute to professor Roger Sargent: Intellectual leader of process systems engineering

This article and this issue of the AIChE Journal, is a tribute to Professor Roger Sargent who, as pioneer and intellectual leader of process systems engineering, has had a profound impact on the discipline of chemical engineering. Spanning more than five decades, his work has provided a strong mathematical foundation to process systems engineering through the development of sophisticated mathematical and computational tools for the simulation, design, control, operation and optimization of chemical processes. In this article we first give a brief overview of his career that included several leadership positions and the establishment of the Centre for Process Systems Engineering (CPSE) at Imperial College London. We next review his research contributions in the areas of process modeling, differential algebraic systems, process dynamics and control, nonlinear optimization and optimal control, design under uncertainty, and process scheduling. We highlight the tremendous impact that he has had through his students, students' students, and his entire academic family tree, which at present contains over 2000 names, probably one of the largest among the academic leaders of chemical engineering. Finally, we provide a brief overview of him as a modest and charming individual with a wonderful sense of humor. He is without doubt a true intellectual giant who has helped to expand the scope of chemical engineering by providing a strong systems component to it, and by establishing strong multidisciplinary links with other fields. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2951–2958, 2016     

A retrospective look at developments in size exclusion chromatography from the early Hamielec research era to the present day

At the start of Archie Hamielec's research career, size exclusion chromatography (SEC) (including gel permeation chromatography [GPC]) was in its infancy as an analytical and preparative laboratory technique in polymer science and engineering. As described below, Archie Hamielec saw its potential early in his academic career and was among the group of pioneers who took it from a developing technique to what it is now. His group's work was instrumental in improving the understanding of the mechanism of separation in SEC and setting up best procedures for sample handling. In addition, much work was done to assess detectors to improve data collection and to obtain consistent/reliable measurements. Importantly, he established it as a key method for obtaining molecular size information to support research in polymer reaction engineering. Nowadays we take it for granted that we can use SEC to obtain molecular weight data rapidly and reliably with user-friendly computer-aided analyses. This ease of routine practicality stems from the base that the early researchers built. Although now it is a well-developed (almost ‘black box’) method there are still areas of novel interest into analysis of complex polymer samples. This has led to modern developments forging ahead in expanding the applicability of SEC as an analytical technique with the exploitation of multi-detector systems and novel detectors.     

Catalytic Aspects of Synthetic Fuels from Coal

It is appropriate that this symposium honoring Dr. Henry H. Storch should focus on catalysis, a field in which he made so many contributions and in which he published widely, most recently posthumously in the comprehensive review with Wu [1]. One of Dr. Storch's greater contribution was in attracting to the Bureau of Mines and training highly competent scientists and engineers who still constitute a research resource of great present national value and who, in a real sense, are continuing his research efforts.     

The AOCS smalley program

This program is named for Frank N. Smalley, a charter member of AOCS. In 1909, he was chief chemist for the Southern Cotton Oil Company, the same year in which AOCS was formed. Smalley checked the proficiency of his firm’s laboratories by distributing weekly meal samples that had been prepared in his Savannah laboratory. Other analytical chemists saw the value of such a program and asked to participate. In 1915, the Uniform Methods Committee, under Dr. Smalley, adopted this program. In 1955, the name was formally shortened to the Smalley Committee. It continues to function largely with the aid of volunteer help. AOCS is greatly indebted to the people and industries who give of their time and talents. In 1981, an ad-hoc committee reviewed the Smalley Committee and each of the series involved and declared the program was functioning well and carrying out its intended purpose.