Bent's Rule Research Articles

Influence of beam polarisation in laser bending process

In this paper, the influence of beam polarisation in the laser bending process was experimentally studied. Based on the laser beam polarisation, the laser absorption of the metallic specimen could be enhanced by increasing the incident angle. The bending angles are achieved in stainless foil specimens without absorptive coatings, and larger bending angles can be produced by single laser scanning with higher incident angles. Multipass laser bending experiments were also carried out on the same material with graphite coatings. The results show that the bending angle per pass is affected obviously by the beam polarisation at lower laser line energy; and the bending angle per pass increases significantly when the total bending angle is large enough. When using polarised light, the laser beam distortion and laser absorption change induced by the variation of the absorptive coatings and laser incident angle are the two main factors that affect the coupled laser energy. The bending rule is the synthesis effect of the two factors.

The impact of the global crisis on transition economies

All forecasts for transition countries - the 29 EBRD countries of operation - since mid-2008 have been repeatedly downgraded. The latest forecasts (May 2009) envisage an average income decline of 5 per cent in 2009 and only a small recovery of 1.4 per cent in 2010; performance is very diverse. In general, transition countries faced two shocks: a sudden stop and reversal of capital inflows, and an exports collapse due to the global slump. More specific factors include: 1) Home made sub-primes (domestic loans to households, enterprises and governments originally denominated in foreign currency); 2) External imbalances; 3) Worsening terms of trade for primary products exporters; 4) Fall or reversal of FDI and portfolio investment inflows; 5) Funds withdrawal by foreign banks; 6) External demand reduction; 7) Differences in initial positions and policy response. Earlier membership of the Euro by the new member states through a relaxation of Maastricht rules might have been beneficial, but the current crisis is no time for changing or bending rules. By comparison with the transition recession of the 1990s, the current recession is much smaller and shorter, it benefits from more generous assistance from the international community, and from the more enlightened fiscal and monetary policies now uncharacteristically recommended by International Financial Organizations.

Nonlinear Buckling of Woven Fabrics Part II: Recovery from Buckling and Experimental Verification

In the first part of this paper, the fabric buckling model proposed by Grosberg and Swani was modified by incorporating Huang's bilinear bending rule. This buckling theory is further extended to model the recovery behavior by incorporating the bilinear bending rule. This model removes the obvious inconsistency of earlier approaches. The recovery behavior computed from the proposed theory appears realistic and consistent with typical experimental results. The experimental validation of both buckling and recovery models is compared with similar models proposed by Grosberg and Swani. The agreement between experimental and theoretical behavior is fairly good and mostly consistent. Possible reasons for certain observed discrepancies are summarized.

Theoretical Study and Comparasion of Bent's Rule with Hardness and Polarizibility for SF4, SF4O, PCl4F, PCl3F2, PCl2F3, PCl2F4 Molecules

Electronic parameters such as HOMO-LUMO energies, Mulliken charges, dipole moments for different isomers of SF4, SF4O, PCl4F, PCl3F2, PCl2F3, PCl2F4 molecules have been carried out at the MP2 level of theory using 6-31G(d), 6-311G(d,p) basis sets by applying Gaussian 03 Revision B-04. Maximum hardness and minimum polarizability have been calculated to see the consistency with the Bent rule. According to Maximum Hardness Principles (MHP) and Minimum Polarizability Principles (MPP) most stable structure can be predicted if they have different isomers. We have investigated how bond orbitals change for studied molecules by natural bond orbital (NBO) analysis, as well. There is agreement between our results and experimentaql results on the dipole moments and structures of the phosphorus chlorofluorides obtained by IR and Raman vibrational data, NMR measurements and 35Cl pure quadrupole resonance frequencies reported earlier by Holmes aand coworkers.

Ethical entrepreneurs: a study of perceptions

This paper presents the results of a survey of early stage incubator sited entrepreneurial technology firms. Firms were asked about their views on ethics and the ethical climate of their organisations. Results indicated that respondents tend to think of themselves as ethical and do not feel they must sacrifice their ethics to succeed in their ventures. The results also show that most early-stage entrepreneurs have a code of ethics that is communicated to employees. Contrary to anecdotal and theoretical suggestions that entrepreneurs are by nature more likely to 'bend rules' and act unethically, these results lend support to studies that have found that entrepreneurs are ethical.

Structural properties and magic structures in hydrogenated finite and infinite silicon nanowires

Unusual effects such as bending and “canting,” related with the stability, have been identified by ab initio real-space calculations for hydrogenated silicon nanowires. We have examined in detail the electronic and structural properties of finite and infinite nanowires as a function of length (and width) and have developed stability and bending rules, demonstrating that “magic” wires do not bend. Reconstructed 2×1 nanowires are practically as stable as the magic ones. Our calculations are in good agreement with the experimental data of Ma et al. [Science 299, 1874 (2003).].

Analysis of bending on the front end of sheet during hot rolling

Abstract The analysis of bending in finishing rolling was performed. An asymmetrical rolling force model was established, and the upper and lower neutral points were determined. The bending which resulted from the asymmetrical rolling force at the roll gap was studied and related flexibility equations were proposed according to elastic mechanics. Moreover, material mechanics was used to analyze the effects of temperature difference and self-weight on the bending out of the roll gap, and the flexibility equations were constructed. The main factors on bending were summed up, and the bending rule in the rolling could be obtained. In addition practical calculation was made with the production data of ribbon steel from Laiwu Iron & Steel Group Co. Ltd.

Nonlinear Buckling of Woven Fabrics Part I: Elastic and Nonelastic Cases

The fabric buckling model proposed by Grosberg and Swani has been modified by incorporating Huang’s bilinear bending rule. The proposed model is an extension of the present model and also covers the special cases. The numerical results appear realistic and conform to the trend observed by other researchers. The effects of fabric bending parameters on the buckling behavior of woven fabrics were explored by numerical computations. The second part of this paper includes the recovery from large-scale buckling of woven fabric.

Computation of quantum mechanical hybridization and dipole correlation of the electronic structure of the F3B–NH3supermolecule

AbstractA valence bond description of the electronic structure and the process of the formation of the adduct supermolecule, F3B–NH3by charge transfer interactions between a Lewis acid, BF3, and a Lewis base, NH3, is computed in terms of the quantum mechanical localized molecular orbital (LMO) method. A dipole correlation of electronic structure is also reported. The valence bond description in terms of bond pair and lone pair is transparent in the generated LMOs of the donor, acceptor, and adduct supermolecule. It is transparent in the computed LMOs that the lone pair of N in NH3is actually involved in forming a new dative bond between B and N atoms. The present work reports the evaluated hybridization status of the boron, nitrogen, and fluorine atoms in the interesting donor–acceptor compound, F3B–NH3. It is transparent in the computed results that the quantum mechanical hybridization automatically incorporates the effect of change of environment in the pattern of hybridization perfectly in accordance with Bent's rule. The calculated dipole moment of the supermolecule is high; it is partitioned into contributions resulting from bond moments and atomic dipoles, as contributions from hybrid orbitals accommodating lone pairs of electrons. The magnitude of atomic dipole is small compared with the bond dipole component. A rationale of the bond moment of the molecule is attempted in terms of the charge density distribution on atomic sites and the atomic dipole is correlated in terms of the pattern of hybridization of lone pairs on the F atoms. The generated LMOs reveal that only one lone pair on each F atom is in a hybrid orbital, and the remaining two lone pairs are in pureporbitals. The small lone pair contribution to molecular dipole is thus transparent in computed quantum mechanical hybridization that shows that, out of three, only one lone pair on the F atoms can set in atomic dipole. This study demonstrates that atomic dipole can be used as a descriptor of the hybridization status of lone pairs on atoms in the molecules. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005

The maximum hardness and minimum polarizability principles in accordance with the Bent rule

Abstract Energies, hardness values and polarizabilities for different isomers of SF4, SF4O molecules and a family of PClxF5−x, (x=1,2,3,4) compounds are calculated at the density functional level of theory (B3LYP) using different basis sets (6-31G**, 6-311G**, 6-31++G and 6-311++G). For all molecules and in all cases the Bent rule is confirmed with the stability orders, which is obtained from the calculated energies. It is also found that for each molecule the isomer in which the more electronegative atom occupies the axial position has maximum hardness; and therefore according to the Maximum Hardness Principle (MHP), it must be the most stable isomer. This result is consistent with the Bent rule, but for some cases in which there are more than two isomers, the obtained trends for the stability are not in accordance with this rule. On the other hand, since the calculation of dipole polarizability is very sensitive to the quality of the selected basis set, only for those calculations in which diffuse basis sets are used the obtained trends of stability from the Minimum Polarizability Principle (MPP) are the same as those which are predicted from the Bent rule. It seems that when there are more than two isomers for a molecule both the MHP and MPP can only predict the most stable isomer and cannot predict the correct trend for the stability of the isomers.

Goodnight Desdemona (Good Morning Juliet) : From Shakespearean Tragedy to Postmodern Satyr Play

Northrop Frye followed in the footsteps of Aristotle and the author of the Tractatus Coislinianus in his attempt to define and describe the main aspects of the literary genres in the monumental Anatomy of Criticism. For centuries Aristotle's theory of poetics had been understood as prescriptive instead of descriptive; thus any effort to establish a schematic approach to literary theory in the twentieth century--the age of experimentation, rule bending, and wholesale rule breaking--was likely to encounter strong opposition. While there are certain limitations to Frye's schematic system in dealing with many modern and postmodern works that defy classification into any genre, it is precisely the clear delineation of subcategories and elements within the genres that promotes his theory as the most useful in a study of works that either are based upon a prescriptive view of poetics or are contemporary revisions of such works. I am not suggesting that Shakespeare's notions about dramatic genres were shaped by Aristotle's Poetics, or that he would have necessarily understood them as prescriptive; equally, I am not suggesting that AnnMarie MacDonald necessarily relied on Frye's theory to write her play. I am merely taking Aristotle as an example of a generic theory which, while it may not have directly influenced English Renaissance playwrights or Shakespeare himself, certainly resonates with Horace's much-read Art of Poetry and is exemplified in the much-imitated tragedies of Seneca--two crucial literary forces whose authority during the early modern period became the foundation of the future prescriptive and rigid understanding of genre theory. In a similar fashion, Frye's work is the best twentieth-century example of a schematic approach to literary theory that many understood as prescriptive, and it is, because of his appropriation of Aristotelian terminology, a perfect complement to Aristotle's Poetics in my comparative analysis of dramatic texts from two eras. For this reason, the full virtuosity and complexity of a postmodern work such as Ann-Marie MacDonald's play Goodnight Desdemona (Good Morning Juliet)--which not only revisits two Renaissance narratives, but appropriates them, revises them, and subverts their original genres by defusing the tragic elements and substituting them with comical ones--can be fully appreciated only through an approach based on a literary theory that clearly delineates the characteristics of and boundaries between the genres. Indeed, as Frye himself points out, the boundaries between the genres are anything but rigid. Rather, these hazy frontier areas where genres are fluid and merge into one another often become the inspirational playground of versatile artists like MacDonald who appear to enjoy thumbing their noses at form. Othello and Romeo and Juliet are both tragedies, and because much of the humor of MacDonald's play depends on the audience's acquaintance with the source narratives, and in particular on our understanding of the stories as tragic;' it is necessary first to identify briefly the generic paradigms in the narratives that define them as such. As both Aristotle and Frye point out, tragedy needs primarily a hero or heroine who is superior in degree to other men and women, but not to his/her environment. The destruction of the hero is typically a product of hamartia, a Greek term that has been traditionally translated either as a flaw in character or an error in judgment. Without getting trapped in the debate about the theoretical fallacies bred from the possible mistranslations of hamartia, we can generally accept that tragedy properly deals with an individual and the tragic hero's fall as an individual act, an inevitable outcome of the confrontation with an overwhelming and inscrutable force--be it Fate, the will of the gods, the laws of a society, or one's own psyche. Frye explains: Tragedy in the central or high mimetic sense, the fiction of the fall of a leader (he has to fall because that is the only way in which a leader can be isolated from his society), mingles the heroic with the ironic. …

Social Criticism as Moral Criticism

Sports at all levels have been racked by one moral controversy after another. It is almost a truism that socialization into sports nowadays has as much to do with becoming adept at breaking and bending rules, not to mention other forms of cheating and violence, as it does with the furtherance of athletic excellence. Surprisingly, although critical social theorists of sports have had plenty to say about these and other shortcomings of contemporary sports, little of what they say touches on their specifically moral character. Habermas’s critical theory of society is a notable exception, claiming, as it does, that if one wants to understand contemporary social practices such as sports, one cannot turn their back on the moral ideals and values that drive them. The author puts Habermas’s theory to the test here, examining how successful it is in shedding light on the moral dilemmas that presently plague sports.

Directing power of cyclobutenoid annelations on the double bonds of planar cyclooctatetraenes.

Ab initio and hybrid density functional quantum mechanical computations are applied to the structure and energetics of a series of two-atom-bridge annelated cyclooctatetraenes. The contribution of each annelation to the exo/endo relative energy is estimated. Key directing factors for a given type of annelation, such as strain, electronegativity, or cyclic electron count, can be sorted out by comparison of various bridge compositions. Overall, electron count and the essential components of the Clar/Robinson rule work well to predict the exo/endo preferences. Specifically, three 4-e(-) Hückel systems (CH-CH, NH-BH and NH-C(O)) display dominant exo forms whereas the three 4n + 2 Hückel counterparts (C(O)-C(O), BH-BH, and planar NH-NH) display a common preference for endo. These endo systems act like four independent four-membered "aromatic" rings linked by "single" bonds. An analysis based on the effective hybridization of carbon atoms in the annulene (Bent's rule) provides a rationale for subtle trends in their specific annulene geometry.

The Human Side: Mike Receives a “Present”

THE HUMAN SIDE The following hypothetical human resources problem has, like so many of its ilk, no correct answer. In order to help your colleagues deal with such a situation, please tell us how you would handle it. We'll print as many as space permits. The Editor. Boss, here's a present for you! exclaimed Crane, as he tossed a bundle of computer paper on Hubbard's desk. Mike was manager of mechanical engineering research for XYZ Corporation, and Todd was a recent college graduate and new hire who was assigned to Mike's department. Brilliant, superbly confident, brash, very much inclined to bend rules, and unconventional in much of his behavior, Todd had impressed everyone with his knowledge of the computer and the engineering computer applications he had developed. As Todd left his office, Mike took a look at the computer output he had just been handed. He was shocked to discover he was looking at material from one of XYZ's competitors. Looking further, he recognized the plans for introducing a product with a new feature-one that XYZ was desperately hurrying to get to the market ahead of this competitor. At this point, Mike realized that his possession of this material was very likely illegal and certainly unethical. He knew full well he should have nothing to do with the documents, but his curiosity got the better of him. As he scanned the documents he could tell that the competitor was clearly ahead of XYZ in the race to introduce this new feature, that it had solved a design problem troubling XYZ, and that it planned an aggressive pricing strategy for the new model. In short, the documents were a gold mine of information, and certainly information Mike had no right to possess. The Amateur Hacker Early the next day, Mike asked Todd to come to his office and immediately asked, How did you get the computer runoff that you gave me yesterday? Todd replied sheepishly, always been an amateur computer 'hacker'-- had a lot of fun with it in college. Once I got the final exam for one of my classes from my prof's computer and shared it with my friends, of course. Certainly helped our grades! Todd went on, One of my friends-a classmate-went to work in a competitor's lab. He told me how to get into their computer. He's doing materials testing and he was interested in my looking over his reports to see if I spotted any flaws in his work. But once I got into their computer I got curious and discovered their security was extremely poor and that I could look at about anything I wanted. What I gave you yesterday was fairly easy to get. Thought you'd like to see it. What else would you like me to get? I'm sure I could tell you how much salary your counterpart in their company is getting! A shocked Mike recognized that receiving competitive information in this way could change the whole culture of how R&D at XYZ operated. He scolded, Todd, what you are doing is certainly illegal. I admit I scanned the stuff you gave me but have since shredded it. I've got to check with Legal, but what you did is probably grounds for dismissal. I insist that you confine your computer activities to our system! The Legal Counsel Listens XYZ's legal cousel listened carefully to Mike and explained, This situation has never come up. We really don't have a company policy or procedure to cover a situation like this-just felt it was never needed. But if you are knowingly using proprietary and confidential information-even if you found it on an airplane seat-I believe you have crossed the line into illegal territory. Intellectual property law defines trade secret broadly as almost any type of business information that derives economic value from not being generally known and whose confidentiality has been protected by reasonable measures. Illegal use of a trade secret is not without penalty. However, since you've shredded the material and don't plan to use it-I assume you don't-maybe we should just put a reprimand in Todd's personnel file and tell him no more of this hacking into our competitor's system. …

New synthetic and structural aspects in the chemistry of alkylaluminum fluorides. The mutual influence of hard and soft ligands and the hybridization as rigorous structural criterion.

A general synthetic strategy starting from metal alkyls is reported based on the hydrogen difluoride anion as a suitable reagent for obtaining organometallic fluorides. The newly prepared compounds are [Me(4)N][(i-Bu)(2)AlF(2)] (1), [Ph(4)P][(i-Bu)(2)AlF(2)] (2), and [Ph(4)P][AlF(4)] (3), containing the tetrahedral anions [(i-Bu)(2)AlF(2)](-) and [AlF(4)](-). The actual structures are prototypes that allowed a comparison of inorganic and organometallic fluorides in the frame of the hard and soft acid and base principle, by means of ab initio calculations. A new theoretical model is designed to put in equation form the qualitative statements of the Bent rule. The model allows the rationalization of the tendencies of bond angle variation in [R(2)MX(2)] systems containing a main group metal (M), in terms of hybridization of the central atom and the reciprocal influence of hard and soft ligands.

Partially bridge-fluorinated dimethyl bicyclo[1.1.1]pentane-1,3-dicarboxylates: preparation and NMR spectra.

Direct fluorination of dimethyl bicyclo[1.1.1]pentane-1,3-dicarboxylate, obtained from [1.1.1]propellane prepared by an improved synthetic procedure, furnished esters of 14 of the 15 possible bridge-fluorinated bicyclo[1.1.1]pentane-1,3-dicarboxylic acids, isolated by preparative GC. Calculated geometries reflect the substitution pattern in a regular fashion compatible with Bent's rules. Considerable additional strain is introduced into the bicyclo[1.1.1]pentane cage by polyfluorination; it is calculated to be as high as 33-35 kcal/mol for hexasubstitution. Three arrangements of the fluorine substituents are especially strain-rich: geminal, proximate, and W-related. The (1)H, (13)C, and (19)F NMR spectra exhibit a striking variety of chemical shifts and long-range coupling constants. These are in good agreement with results calculated with neglect of the bridgehead substituents for all of the chemical shifts by the GIAO-RHF/6-31G//RHF/6-31G and GIAO-RHF/6-31G//MP2/6-31G methods and for many of the coupling constants by the EOM-CCSD/6-311G//MP2/6-311G method. The proximate (4)J(FF) constants are particularly large (50-100 Hz) and show an inverse linear dependence on the calculated F-F distance in the range 2.43-2.58 A.

Dimensions of psychological masculinity-femininity in adult twins from opposite-sex and same-sex pairs.

Male and female twins with opposite-sex co-twins were compared to twins with same-sex co-twins on three independent dimensions of masculinity-femininity, in order to examine the hypothesis that the hormones of the co-twin might have an effect on prenatal masculinization. The analysis was originally carried out for an older cohort from the Australian Twin Registry (2647 pairs, mean age 41.2), and then repeated in a younger cohort (1503 pairs, mean age 23.2). For women, the results on two of the three scales support and extend that of an earlier large study in Finland by Rose et al. (1994), who found no effect of sex of co-twin on feminine interests. One of the two scales contrasted worried and calm individuals, the other, confiding and reserved ones. The third scale, willingness to break or bend rules, showed a small effect of shared environmental influence, and it lay in the expected direction for a prenatal hormonal effect--females with a male co-twin scored higher (more like males). Most previous studies have not looked at the effect of sex of co-twin on males. The present study detected several such effects, although all were small in magnitude. The pattern was complex: sometimes the effect was in the masculine direction, sometimes in the feminine direction; sometimes there was agreement between the older and younger cohorts, sometimes not. Overall, the results suggest that no simple masculinization hypothesis--prenatal or postnatal--will adequately account for all the evidence. Age, sex, and aspect of masculinity-femininity must be taken into account.

On the Relation between π Bonding, Electronegativity, and Bond Angles in High-Valent Transition Metal Complexes

Bonding modelsfor d0complexes are invariably more complicated than for main group compounds due to the complicated dependence of in-plane and out-of-plane π-components on bond angles in the former. The figure shows the “inverse Bent's rule structure” of TiCl2(CH3)2, (compared with the “regular structure” for SiCl2(CH3)2). In contrast to previous work, this is found to be largely due to improved π bonding at larger Cl-Ti-Cl angles. Detailed computational analyses are given for various d0 complexes (e. g. ScF2+, ZrO2, TiCl2Y2, CrO2Y2, and related species).

Perceptions of Farm Hazards and Personal Safety Behavior among Adolescent Farmworkers

This qualitative study was performed to investigate the perceptions of safety,behavior, and hazards of children working on farms. Thirty-six adolescents, ages 14-18,were interviewed in four focus groups. All participants were living in eastern Coloradoand were members of the Future Farmers of America. They were asked questionsregarding work they do on the farm, how they learned, and what safety rules they doand do not follow. Emergent themes include Age Started Chores, Safety Behavior,Attitude Toward Injury, and Attitude Toward Prev ention. These themes provideinformation on learning safety information, why injuries occur, the inevitability ofinjury, injuries sustained during farmwork and play, and attitudes of participantsregarding injuries and injury prevention. The results indicate that these adolescentshave been and are at risk of injury on the farm while working, playing, and playing inthe context of work. They recognize the importance of safety rules, but bend or breakthose rules based on a personal assessment of risk. They take more risks while playingthan while working, but playing often occurs in the context of work, and involves someof the same equipment or machinery (i.e., ATVs). Finally, many of the studentsreported modeling the unsafe practices of parents, grandparents, and other authorityfigures as opposed to performing chores the way those individuals taught them.

Deviations from idealised geometries part 4: approximately tetrahedral molecules of form MX 2Y 2 studied by SCF and MP2 localised orbital calculations

Using the delocalised wavefunctions from Part 3, for a series of molecules of type MX 2Y 2 where M is tetravalent, and X, Y are either H, Me or halogen, with a triple-zeta plus polarisation basis and either SCF of MP2 methods, the wavefunctions were converted to localised orbitals by the Foster-Boys method. This enabled the LMO to be subject to population analysis for changes in hybridisation in the individual total density of the MX and MY bonds, and some quantitative discussion of the role of hybridisation in Bent's Rule.