139 Sentences With "unsymmetrical" | Random Sentence Generator

Its hypergolic propellants — nitrogen tetroxide and unsymmetrical dimethyl hydrazine — ignited only when they combined, creating a fast and reliable detonation.

Although they all seem to cry, their highly unsymmetrical faces portray a range of emotions, from a compatible jarring sadness to a severely off-putting morbid happiness, in seeming opposition to the tears.

The Knoevenagel–Fries modification allows for the synthesis of unsymmetrical pyridine compounds.

Symmetrical disulfides are compounds of the formula R2S2. Most disulfides encountered in organo sulfur chemistry are symmetrical disulfides. Unsymmetrical disulfides (also called heterodisulfides) are compounds of the formula RSSR'. They are less common in organic chemistry, but most disulfides in nature are unsymmetrical.

Unsymmetrical sulfides are prochiral, thus their oxidation gives chiral sulfoxides. This process can be performed enantioselectively.

By observing the binding of a hydroxide to one of the manganese, an unsymmetrical dimer is created.

After fertilization, an unsymmetrical ovoid capsule forms, filled with brown seeds, each with a circular "wing" around it.

As another possibility, one may condene a substituted pyrroles with a 2-acylpyrrole; this route allows the synthesis of unsymmetrical dipyrromethenes.

In unsymmetrical ethylated compounds, the methylene protons in the ethyl substituent are diastereotopic. Chiral reagents are known to stereoselectively modify such substituents.

All stages used UDMH (unsymmetrical Dimethylhydrazine) as fuel and dinitrogen tetroxide as oxidiser. The Strela is a similar rocket, also based on the SS-19.

"Organic Chemistry" Fifth Edition, by Paula Yurkanis Bruice. Pearson Prentice Hall, Upper Saddle River, NJ, 2007 The regioselectivity also differs: The halogenation of an unsymmetrical ketone in acid results in the more substituted alkyl group being halogenated. A second equivalent of halogen results in the halogenation of the other alkyl substituent (without the halogen). In contrast, in base, an unsymmetrical ketone halogenates at the less substituted alkyl group.

The chemical weapon tabun is derived from dimethylamine. The surfactant lauryl dimethylamine oxide is found in soaps and cleaning compounds. Unsymmetrical dimethylhydrazine, a rocket fuel, is prepared from dimethylamine.

Unsymmetrical dimethylhydrazine, a rocket fuel, is a highly effective precursor to NDMA: :(CH3)2NNH2 \+ 2 O → (CH3)2NNO + H2O Groundwater near rocket launch sites often has high levels of NDMA.

1- On the Appearance of Unsymmetrical Components in the Stark Effect (Phil. Mag. Vol. 43, p. 943) - (1922) 2- On the Stark Effect for Strong Electric Fields (Phil. Mag. Vol. 44, p.

The larger saturated hexahydrobenzodipyran ring derivatives have been referred to as "butterfly" compounds. The 8-bromo group can also be replaced by other groups to give compounds such as TFMFly. A large number of symmetrical and unsymmetrical derivatives can be produced by using different combinations of ring systems. Because the 2- and 5- positions (using phenethylamine numbering scheme, 1,5-positions if numbered as benzodifuran) are not equivalent, all unsymmetrical combinations also have two possible positional isomers, with different potencies at the various 5-HT2 subtypes.

IPDI exists in two stereoisomers, cis and trans. Their reactivities are similar. Each stereoisomer is an unsymmetrical molecule, and thus has isocyanate groups with different reactivities. The primary isocyanate group is more reactive than the secondary isocyanate group.

During his time at Merck he has continued to explore the limits of detection for low level samples by heteronuclear 2D NMR using newly developed 1.7 mm Micro CryoProbe™ technology. He has developed, in collaboration with ACD/Labs, and Bruker, unsymmetrical indirect covariance NMR spectroscopy, exploring the calculation of hyphenated heteronuclear 2D correlation spectra. He has also continued collaborative investigations in the area of Computer-Assisted Structure Elucidation (CASE) with ACD/Labs. He has also explored the use of unsymmetrical indirect covariance NMR processing methods to define 13C-15N and 13C-13C heteronuclear connectivity networks.

6, pp. 544-53. They are also used to generate unsymmetrical disulfides: :Na[O3S2R] + NaSR' → RSSR' + Na2SO3 According to X-ray crystallography, they adopt the expected structure with tetrahedral S(VI), an S-S single bond, and three S=O double bonds.

Hydyne is a mixture of 60% unsymmetrical dimethylhydrazine (UDMH) and 40% diethylenetriamine (DETA), developed in 1957 at Rocketdyne for use in liquid- fuel rockets.Morgan, George. It was created by Mary Sherman Morgan. America's First Lady of Rocketry, Caltech News, California Institute of Technology, Vol.

R. B. Woodward and H. Bickel, (1979); Chem. Abstr., 91, 74633J (1979). This undergoes fragmentation when treated with benzothiazole-2-thiol to give 2. Ozonolysis (reductive work-up) cleaves the olefinic linkage and the unsymmetrical disulfide moiety is converted to a tosyl thioester (3).

The Kleinspehn synthesis was extended under David Dolphin by the use of unsymmetrical β-diketones (such as 3-alkyl substituted 2,4-hexanediones), which preferentially reacted initially at the less hindered acetyl group and afforded the corresponding 5-methylpyrrole-2-carboxylate esters. N,N-Dialkyl 2-oximinoacetoacetamides also were found to give pyrroles when reacted under Knorr conditions with 3-substituted-2,4-pentanediones, in yields comparable to the corresponding esters (around 45%). However, when unsymmetrical diketones were used, it was found that the acetyl group from the acetoacetamide was retained in the product, and one of the acyl groups from the diketone had been lost.

General structure of 1,2-, 1,3-, and 1,4-dicarbonyls A dicarbonyl is a molecule containing two carbonyl (C=O) groups. Although this term could refer to any organic compound containing two carbonyl groups, it is used more specifically to describe molecules in which both carbonyls are in close enough proximity that their reactivity is changed, such as 1,2-, 1,3-, and 1,4-dicarbonyls. Their properties often differ from those of monocarbonyls, and so they are usually considered functional groups of their own. These compounds can have symmetrical or unsymmetrical substituents on each carbonyl, and may also be functionally symmetrical (dialdehydes, diketones, diesters, etc.) or unsymmetrical (keto-esters, keto-acids, etc.).

Under such conditions, they exist in low concentrations, but they still undergo reactions with electrophiles. Many factors affect the behavior of enolates, especially the solvent, additives (e.g. diamines), and the countercation (Li+ vs Na+, etc.). For unsymmetrical ketones, methods exist to control the regiochemistry of the deprotonation.

CN, CO2Me) stabilize reduced and anionic complexes. Derivatives are known where the substituents are the same, symmetrical dithiolenes (R = R') are more common than unsymmetrical. Due to their delocalized electronic structure, metal dithiolenes undergo reversible redox reaction. When oxidized, dithiolene complexes have greater 1,2-dithioketone character.

Phosgenation entails the reaction of amines with phosgene, proceeding via the isocyanate (or carbamoyl chloride) as an intermediate: :COCl2 \+ R2NH → R2NC(O)Cl + HCl :COCl2 \+ RNH2 → RNCO + 2 HCl Overall reaction: :COCl2 \+ 2 R2NH → (R2N)2CO + 2 HCl Tetramethylurea is prepared in this way and in general secondary amines give reliable results. Reactions using primary amines must be carefully controlled as the isocyanate intermediate can react with the urea to form a biuret: :R2NC(O)N(H)R' + R"NCO → R2NC(O)NR'C(O)NHR" Unsymmetrical ureas are generated by condensation of isocyanates with amines: :RNCO + R'2NH → (R'2N)(R(H)N)CO Analogously, unsymmetrical primary ureas are generated by condensation of ammonium salts and alkali metal cyanates: :Na+NCO− \+ [R2NH2]Cl → (R’2N)(H2N)CO + KCl The artificial sweetener dulcin is produced by the condensation of ethoxyaniline with potassium cyanate. Si(NCO)4 is also used as a precursor to such unsymmetrical ureas. bis(hydroxymethyl)urea and related compounds are additives for permanent press clothing. Isobutylidenediurea.

The tree was described by Nilsson as columnar, having a rounded elongate-ovoid crown, and dense sub-erect branches. The relatively elongated leaves are widest above the middle, quite tapered towards a long tip, and tapering to an unsymmetrical base. The margin is triple-toothed. New shoots are downy.

1,2-Dimethyldiborane is an easily condensed, colorless gas that ignites spontaneously in air. An isomer of 1,2-dimethyldiborane is 1,1-dimethyldiborane, known as unsymmetrical dimethyldiborane, which has two methyl groups on one boron atom. Other methylated versions of diborane including methyldiborane, trimethyldiborane, tetramethyldiborane. Trimethylborane exists as a monomer.

The narrator discusses the case of Gottfried Plattner, a schoolteacher in the south of England. He establishes the known facts: the unsymmetrical parts of his body are opposite from the usual way round, and his unsymmetrical facial features are the reverse of what are seen on his portrayal in an old photograph. "The curious inversion of Plattner's right and left sides is proof that he has moved out of our space into what is called the Fourth Dimension, and that he has returned again to our world." Plattner disappeared when he experimented in a chemistry class with green powder found by a boy, which caused an explosion; he re- appeared nine days later.

Ryabenko wore none and received a high dose of radiation. On 24 October 1960 he got exposed to the toxic chemical unsymmetrical dimethylhydrazine, shortly after the Nedelin catastrophe, in which a ballistic rocket exploded on the launch pad. As a result, Ryabenko was hospitalized for two months with a heart attack.

Additions involving higher-order cuprates must be quenched with a silyl halide before alkylation.F.-T. Luo, E. Negishi, J. Org. Chem. 1985, 50, 4762. (5)File:VDScope2.png When unsymmetrical cuprates are employed, the group whose carbon-copper bond contains less s character is almost always transferred to the β-position.

Pinacolone (3,3-dimethyl-2-butanone) is an important ketone in organic chemistry. It is a colorless liquid and has a slight peppermint- or camphor- odor. It is a precursor to triazolylpinacolone in the synthesis of the fungicide triadimefon and in synthesis of the herbicide metribuzin. The molecule is an unsymmetrical ketone.

Two examples of pinacol coupling used in total synthesis are the Mukaiyama Taxol total synthesis and the Nicolaou Taxol total synthesis. p-Hydroxypropiophenone is used as the substrate in the synthesis of diethylstilbestrol. An unsymmetrical pinacol coupling reaction between para- chloro-acetophenone and acetone was employed to give phenaglycodol in a 40% yield.

Catalysts for cyclotrimerisation are selective for triple bonds, which gives the reaction a fairly wide substrate scope. Many functional groups are tolerated. Regioselective intermolecular trimerization of unsymmetrical alkynes remains an unsolved problem. Perhaps the most useful development in this area, at least from the commercial perspective is the cotrimerization of nitriles and alkynes.

Larock indole synthesis mechanism. The carbopalladation step is regioselective when unsymmetrical alkynes are used. Although it was previously believed that the alkyne is inserted with the less sterically-hindering R-group adjacent to the arylpalladium, Larock et al. observed that the larger more sterically- hindering R-group is inserted next to the arylpalladium.

Letting go is a hard lesson and one the artist explores with the unsymmetrical placement within a perfectly etched box. Trusting in simplicity and in nature are equally challenging in today's society. Musco joins an impressive list of artist such as Jeff Koons, Damien Hirst and Richard Prince who have also personalized the Fendi Baguette.

The cathedral façade is dominated by two polygonal unsymmetrical towers with a height nearing 50 metres. Above the central door is a terrace which enabled the bishop to address a crowd and give blessings and under the right-hand tower is a small door used in the Middle Ages as an entrance for lepers.

3,5-Dimethylpyrazole is an organic compound with the formula (CH3C)2CHN2H. It is one of several isomeric derivatives of pyrazole that contain two methyl substituents. The compound is unsymmetrical but the corresponding conjugate acid (pyrazolium) and conjugate base (pyrazolide) have C2v symmetry. It is a white solid that dissolves well in polar organic solvents.

Hatiora and the most broadly circumscribed Schlumbergera both branch from the tip and have short segments (less than 7 cm long). Hatiora has stems that are round in cross-section and radially symmetrical (actinomorphic) flowers, whereas Schlumbergera has flattened or otherwise angular stems and its flowers may be radially symmetrical or radially unsymmetrical (zygomorphic).

However, the method is unsymmetrical and still lacks explicit theoretical foundation. By using the Green second identity, the modified Kansa method W. Chen, "New RBF Collocation Methods and Kernel RBF with Applications: Meshfree Methods for Partial Differential Equations." vol. 26, M. Griebel and M. A. Schweitzer, Eds., ed: Springer Berlin Heidelberg, 2002, pp. 75–86.

Somewhat like the parent amines, imines are mildly basic and reversibly protonate to give iminium salts. Iminium derivatives are particularly susceptible to reduction to the amines using transfer hydrogenation or by the stoichiometric action of sodium cyanoborohydride. Since imines derived from unsymmetrical ketones are prochiral, their reduction is a useful method for the synthesis of chiral amines.

Theodore Samuel DuBose added another story to the house in 1827, which made it a -story house. Peter Gaillard Stoney expanded the house by building an unsymmetrical wing toward the west in 1855. The house was expanded again by adding two rooms toward the east prior to 1875. The house was damaged in the 1886 Charleston earthquake.

The pectus carinatum can be easily diagnosed by certain tests like a CT scan (2D and 3D). It may then be found out that the rib cage is in normal structure. If there is more than average growth of sternum than pectus carinatum protrudes. Also it is of two types, as pectus carinatum is symmetrical or unsymmetrical.

In multinuclear cases (compounds containing more than one metal), more complicated and more varied coordination geometries are observed. One example is the unsymmetrical compound containing four rhenium centres, [(CO)5ReCO2Re(CO)4]2. Carbon dioxide can also bind to ligands on a metal complex (vs just the metal), e.g. by converting hydroxy ligands to carbonato ligands.

There are four symmetrical isomers of DBT which can be made, or ten isomers in total if unsymmetrical substitution is used. Of these only the n-butyl analogue DBT is known to be active in humans; the isobutyl, sec-butyl, and tert-butyl isomers DIBT, DSBT and DTBT have never been tested and only DBT and DIBT were made by Shulgin. 400px The unsymmetrical isomers BIBT, BSBT, BTBT, IBSBT, IBTBT and SBTBT are also possible but have never been made and no predictions have been made about their activity. Shulgin speculates that the s-butyl isomer DSBT may be more potent than the straight chain compound DBT, but that the more highly branched DIBT and DTBT would probably be inactive due to the bulk of the substituent group.

The diene is known to react with amines, aldehydes, alkenes and alkynes. Reactions with imines and nitro-olefins have been reported. It was first synthesized by the reaction of trimethylsilyl chloride with 4-methoxy-3-buten-2-one and zinc chloride: Danishefsky’s diene The diene has two features of interest: the substituents promote regiospecific addition to unsymmetrical dienophiles and the resulting adduct is amenable to further functional group manipulations after the addition reaction. High regioselectivity is obtained with unsymmetrical alkenes with a preference for a 1,2-relation of the ether group with the electron-deficient alkene-carbon. All this is exemplified in this aza Diels-Alder reaction: Danishefsky’s diene in Aza-Diels_Alder In the cycloaddition product, the silyl ether is a synthon for a carbonyl group through the enol.

The complex is used as a pre-catalyst for a variety of coupling reactions. One-pot Procedure for the Synthesis of Unsymmetrical Diarylalkynes. The Suzuki reaction was once limited by high levels of catalyst and the limited availability of boronic acids. Replacements for halides were also found, increasing the number of coupling partners for the halide or pseudohalide as well.

After 1263 it was restored and rebuilt. As a settlement, Kaptol's shape was an unsymmetrical rectangle, which had a southern entrance in Bakačeva Street, and ended at its north end near the present day Kaptol School (Miroslav Krleža Elementary School). In the Middle Ages, Kaptol had no fortifications. It was merely enclosed with wooden fences or palisades, which were repeatedly destroyed and rebuilt.

Unsymmetrical dimethylhydrazine (UDMH; 1,1-dimethylhydrazine ; heptyl) is a chemical compound with the formula H2NN(CH3)2 that is used as a rocket propellant. It is a colorless liquid, with a sharp, fishy, ammonia-like smell typical for organic amines. Samples turn yellowish on exposure to air and absorb oxygen and carbon dioxide. It is miscible with water, ethanol, and kerosene.

Trimerisation of unsymmetrical alkynes gives two isomeric benzenes. For example, phenylacetylene affords both 1,3,5- and 1,2,4-C6R3H3. The substitution pattern about the product arene is determined in two steps: formation of the metallocyclopentadiene intermediate and incorporation of the third equivalent of alkyne. Steric bulk on the alkyne coupling partners and catalyst have been invoked as the controlling elements of regioselectivity.

Stereoregularity is relevant for unsymmetrical alkenes such as propylene. The coordination sphere of the metal ligands sterically influences which end of the propylene attaches to the growing polymer chain and the relative stereochemistry of the methyl groups on the polymer. The stereoregularity is influenced by the ligands. For the metallocene catalysts, the cyclopentadienyl ligands (or their surrogates) fulfill this role.

Oxygen is more electronegative than carbon, thus the hydrogens alpha to ethers are more acidic than in simple hydrocarbons. They are far less acidic than hydrogens alpha to carbonyl groups (such as in ketones or aldehydes), however. Ethers can be symmetrical of the type ROR or unsymmetrical of the type ROR'. Examples of the former are diethyl ether, dimethyl ether, dipropyl ether etc.

The most common hypergolic fuels, hydrazine, monomethylhydrazine and unsymmetrical dimethylhydrazine, and oxidizer, nitrogen tetroxide, are all liquid at ordinary temperatures and pressures. They are therefore sometimes called storable liquid propellants. They are suitable for use in spacecraft missions lasting many years. The cryogenity of liquid hydrogen and liquid oxygen limits their practical use to space launch vehicles where they need to be stored only briefly.

The antlers of the opposite sides are unsymmetrical with respect to each other. The beams are unbranched initially whereas curvature increases as length increases and they get forked also. The sexes are moderately dimorphic in body size and weight. The height and weight of a fully grown stag may be approximately 115–125 cm at shoulder and 95 to 110 kg (210 to 230 lb) respectively.

Redstone was capable of flights from . It consisted of a thrust unit for powered flight and a missile body for overall missile control and payload delivery on target. During powered flight, Redstone burned a fuel mixture of 25 percent water–75 percent ethyl alcohol with liquid oxygen (LOX) used as the oxidizer. Later Redstones used Hydyne, 60% unsymmetrical dimethylhydrazine (UDMH) and 40% diethylenetriamine (DETA), as the fuel.

A linear tetradentate ligand has the four donor atoms in a line, each subsequent donor is connected by one of three bridges. A linear tetradetate ligand bound to a metal in tetrahedral coordination can only connect in one way. If the ligand is unsymmetrical then there are two chiral arrangements. A linear tetradetate ligand bound to a metal in square planar coordination in one way.

K3PO4 Tripotassium phosphate has few industrial applications except as a reagent in organic synthesis, where it has been used as a catalyst. Some of the reactions catalysed by K3PO4are listed below: # The hydrate (K3PO4\cdot H2O) has been used to catalyze deprotection of BOC amines. Microwave radiation is used to aid the reaction. # As a catalyst for the synthesis of unsymmetrical diaryl ethers using [Bmim]BF4 as the solvent.

C3S2 was discovered by Béla Lengyel, who assigned it an unsymmetrical structure. Later, infrared and Raman spectroscopy showed that the structure is symmetrical with a D∞h point group symmetry, i.e. S=C=C=C=S. This compound is analogous to carbon suboxide whose structure is O=C=C=C=O. Lengyel first synthesized this compound by passing carbon disulfide (CS2) vapor through an electric arc with carbon electrodes.

Hydrogen thioperoxide molecules have a gauche conformation. They are unsymmetrical, but have a low barrier to convert from left-hand to right-hand forms, so that the molecule can tunnel between the forms. The measurements of the bond-lengths in hydrogen thioperoxide are H-S 1.3420 Å, S-O 1.6616 Å, O-H 0.9606 Å. The bond angles are ∠HSO 98.57°, ∠SOH 107.19°. The two -H bonds are twisted at 90.41°.

Hydrogen ditelluride has been investigated theoretically, with various properties predicted. The molecule is twisted with a C2 symmetry. There are two enantiomers. Hydrogen ditelluride is one of the simplest possible unsymmetrical molecules; any simpler molecule will not have the required low symmetry. The equilibrium geometry (not counting zero point energy or vibrational energy) has bond lengths of 2.879 Å between the tellurium atoms and 1.678 Å between hydrogen and tellurium.

Symmetrical naphthalene diimides are synthesized by the condensation reaction of primary amines and the dianhydride. Unsymmetrical derivatives, i.e. those derived from two different amines, are obtained by hydrolysis of one of the two anhydride groups prior to the condensation with the first amine. These diimides are members of a broader class of compounds called rylenes, oligomers of naphthalene with bonds between the 1 and 1' and 8 and 8' positions.

The dehydration of alcohols affords ethers: : 2 R–OH → R–O–R + H2O at high temperature center This direct nucleophilic substitution reaction requires elevated temperatures (about 125 °C). The reaction is catalyzed by acids, usually sulfuric acid. The method is effective for generating symmetrical ethers, but not unsymmetrical ethers, since either OH can be protonated, which would give a mixture of products. Diethyl ether is produced from ethanol by this method.

Spectroscopic evidence indicates that the two carbonyl groups may be unsymmetrical, in which case the idealized C2v symmetry is reduced to C2. In solution Fe3(CO)12 is fluxional, resulting in equivalencing all 12 CO groups. Overall, it can be appreciated that these three clusters formally arise from condensation of three 16-electron M(CO)4 fragments, akin to the theoretical condensation of three methylene (:CH2) molecules into cyclopropane.

The Vilsmeier–Haack reaction (also called the Vilsmeier reaction) is the chemical reaction of a substituted amide (1) with phosphorus oxychloride and an electron-rich arene (3) to produce an aryl aldehyde or ketone (5). The reaction is named after Anton Vilsmeier and Albrecht Haack. For example, benzanilide and dimethylaniline react with phosphorus oxychloride to produce an unsymmetrical diaryl ketone. Similarly, anthracene is formylated at the 9-position.

Ullmann synthesis of biaryl compounds can be used to generate chiral products from chiral reactants. Nelson and collaborators worked on the synthesis of asymmetric biaryl compounds and obtained the thermodynamically controlled product. Ullman Asymmetric reaction The diastereometric ratio of the products is enhanced with bulkier R groups in the auxiliary oxazoline group. Unsymmetrical Ullmann reactions are rarely pursued but have been achieved when one of the two coupling components is in excess.

Either a second fender panel must be contacted or the fender cannot compress to much in an unsymmetrical fashion. The structural elements of a fender system must be analyzed ensure equilibrium and stability of each unit at all times. Chains are installed to keep the panel from putting unnecessary shear due to vessel action or weight of the panel. Also, anchors are installed into the wharf to anchor the fender to the wharf face.

Its robustness makes it suitable for identifying outliers in adjusted boxplots. Ordinary box plots do not fare well with skew distributions, since they label the longer unsymmetrical tails as outliers. Using the medcouple, the whiskers of a boxplot can be adjusted for skew distributions and thus have a more accurate identification of outliers for non-symmetrical distributions. As a kind of order statistic, the medcouple belongs to the class of incomplete generalised L-statistics.

If an unsymmetrical ketone is subjected to base, it has the potential to form two regioisomeric enolates (ignoring enolate geometry). For example: Kinetic and thermodynamic enolates The trisubstituted enolate is considered the kinetic enolate, while the tetrasubstituted enolate is considered the thermodynamic enolate. The alpha hydrogen deprotonated to form the kinetic enolate is less hindered, and therefore deprotonated more quickly. In general, tetrasubstituted olefins are more stable than trisubstituted olefins due to hyperconjugative stabilization.

The Jupiter-C and Juno I rockets used the same first-stage engines as the missile, but needed more thrust due to the increased size of the payload. With the use of the newly developed Hydyne, composed of a blend of 60% unsymmetrical dimethylhydrazine (UDMH) and 40% diethylenetriamine (DETA),NASA. The Mercury- Redstone Project, p. 2-2. the Jupiter-C and Juno I engines gained a 12% increase in thrust and higher specific impulse.

Simple scheme of an R-27 missile The R-27 Zyb was a submarine-launched ballistic missile developed by the Soviet Union and employed by the Soviet Navy from 1968 through 1988. NATO assigned the missile the reporting name SS-N-6 Serb. In the USSR, it was given the GRAU index 4K10. It was a liquid fuel rocket using a hypergolic combination of unsymmetrical dimethylhydrazine (UDMH) as fuel, and nitrogen tetroxide (NTO) as oxidizer.

The reaction is catalyzed by bases and also by transition metal complexes.Alonso, F., Beletskaya, I. P., Yus, M., "Transition-Metal-Catalyzed Addition of Heteroatom-Hydrogen Bonds to Alkynes", Chemical Reviews 2004, volume 104, 3079. Usually symmetrical ethers are prepared by dehydration of alcohols and unsymmetrical ethers by the Williamson ether synthesis from alkyl halides and alkali metal alkoxides.Wilhelm Heitmann, Günther Strehlke, Dieter Mayer "Ethers, Aliphatic" Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim.

Mallory created Recurring Chapters in the Book of Inevitable Outcomes when she got selected to be in the Eiteljorg Fellowship exhibition in 2015. The dark unsymmetrical tall shapes scattered around but yet again joined together by wires, surrounded by colorful geometric spike-shaped forms placed on the floor and the wall. Mallory's inspiration of this piece of art was from the history of the Cherokee culture. Mallory has always felt disconnected from her culture.

Materials are only ferroelectric below their corresponding transition temperature . Ferroelectric materials are all pyroelectric and therefore have a spontaneous electric polarisation as the structures are unsymmetrical. Ferroelectric materials' polarization is subject to hysteresis (Figure 4); that is they are dependent on their past state as well as their current state. As an electric field is applied the dipoles are forced to align and polarisation is created, when the electric field is removed polarisation remains.

The vapour pressure for the symmetrical isomer is given by Log P = 7.523−(1290/T). Gas chromatography can be used to determine the amounts of the methyl boranes in a mixture. The order of elution are: diborane, monomethyldiborane, trimethylborane, 1,1-dimethyldiborane, 1,2-dimethyldiborane, trimethyldiborane, and last tetramethyldiborane. The nuclear resonance shift for the bridge hydrogen is 9.55 ppm for the unsymmetrical isomer and 9.73 ppm for the symmetrical isomers, compared to 10.49 for diborane.

This compound is cap sensitive with an explosive velocity of around 6200 m/s and is discussed in patent #3,713,915. Mixed with unsymmetrical dimethylhydrazine it was used as Hydyne, a propellent for liquid-fuel rockets. DETA has been evaluated for use in the Countermine System under development by the U.S. Office of Naval Research, where it would be used to ignite and consume the explosive fill of land mines in beach and surf zones.

The main advantages of hypergolic propellants are that they can be stored as liquids at room temperature and that engines which are powered by them are easy to ignite reliably and repeatedly. Although commonly used, hypergolic propellants are difficult to handle due to their extreme toxicity and/or corrosiveness. In contemporary usage, the terms "hypergol" or "hypergolic propellant" usually mean the most common such propellant combination, dinitrogen tetroxide plus hydrazine and/or its relatives monomethylhydrazine and unsymmetrical dimethylhydrazine.

943 in the translation of I.B. Cohen and A. Whitman Newton defined the force acting on a planet to be the product of its mass and the acceleration (see Newton's laws of motion). So: # Every planet is attracted towards the Sun. # The force acting on a planet is directly proportional to the mass of the planet and is inversely proportional to the square of its distance from the Sun. The Sun plays an unsymmetrical part, which is unjustified.

The possible bonding modes of phosphinimide ligands include: bridging - linear (A) or bent (B), μ2-N-bridging – unsymmetrical (C) or symmetrical (D), and μ3-N-bridging (E). Transition metal phosphinimide complexes are metal complexes that contain phosphinimide ligands of the general formula NPR3− (R = organic substituent). Several coordination modes have been observed, including terminal and various bridging geometries. In the terminal bonding mode the M-N=P core is usually linear but some are quite bent.

Earlier, Compton Wynyates (begun c. 1481, greatly extended 1515–1525) was a resolutely unsymmetrical jumble of essentially medieval styles, including prominent half-timbering on the gables of the facade.Airs, 42–43 It also nestles in a hollow, as medieval houses often did, avoiding the worst of the wind. In contrast, prodigy houses, like castles before them, often deliberately chose exposed sites where they could command the landscape (Wollaton, Hardwick); their owners mostly did not anticipate being there in winter.

Recognizing the importance of linear anti-Markovnikov products, Goldberg's research focuses on discovery of transition metal catalysts which helps in catalysis of anti-Markovnikov hydroamination of alkenes. In one of her publications, she introduces a method to catalyze the hydroarylation of unactivated alkenes using Pt(II) complexes with unsymmetrical pyrrolide ligands. Selectivity was provided by using benzene and 1-hexene and an optimized catalyst. The result was production of high olefin concentration using propylene as the substrate.

This parameter is commonly expressed as the epoxide number, which is the number of epoxide equivalents in 1 kg of resin (Eq./kg), or as the equivalent weight, which is the weight in grams of resin containing 1 mole equivalent of epoxide (g/mol). Since unsymmetrical epoxides are chiral, the bis epoxide consists of three stereoisomers, although these are not separated. Bisphenol A diglycidyl ether slowly hydrolyzes to 2,2-bis[4(2,3-hydroxypropoxy)phenyl)propane (bis-HPPP).

RD-270 (, Rocket Engine 270, 8D420) was a single-chamber liquid-bipropellant rocket engine designed by Energomash (USSR) in 1960–1970. It was to be used on the first stages of proposed heavy-lift UR-700 and UR-900 rocket families, as well as on the N1. It has the highest thrust among single-chamber engines of the USSR, 640 metric tons at the surface of Earth. The propellants used are unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide (N2O4).

When an alkyl halide is used, the reaction is called a dehydrohalogenation. For unsymmetrical products, the more substituted alkenes (those with fewer hydrogens attached to the C=C) tend to predominate (see Zaitsev's rule). Two common methods of elimination reactions are dehydrohalogenation of alkyl halides and dehydration of alcohols. A typical example is shown below; note that if possible, the H is anti to the leaving group, even though this leads to the less stable Z-isomer.

When Pharmacia was acquired by Pfizer, he served as the senior scientific consultant working on new methods development. He led the development of applications of unsymmetrical indirect covariance NMR, initially in an effort to eliminate artifacts and subsequently in the investigation of the mathematical combination of discretely-acquired 2D NMR data. The time savings for the latter was nearly a factor of 16 in time, with a 10-fold improvement in signal-to-noise ratios vs.

The principal reaction of interest involves the addition of the acetylene to a ketone or aldehyde: :RCOR' + HC≡CR" → RR'C(OH)C≡CR" The reaction proceeds with retention of the triple bond. For aldehydes and unsymmetrical ketones, the product is chiral, hence there is interest in asymmetric variants. These reactions invariably involve metal-acetylide intermediates. This reaction was discovered by chemist John Ulric Nef in 1899 while experimenting with reactions of elemental sodium, phenylacetylene, and acetophenone.

In contrast to disulfate (), disulfite ion () has an unsymmetrical structure with an S-S bond. The oxidation state of the sulfur atom bonded to 3 oxygen atoms is +5 while oxidation number of other sulfur atom is +3. The anion consists of an SO2 group linked to an SO3 group, with the negative charge more localized on the SO3 end. The S–S bond length is 2.22 Å, and the "thionate" and "thionite" S–O distances are 1.46 and 1.50 Å respectively.

The missile used a hypergolic bipropellant combination of unsymmetrical dimethylhydrazine (UDMH) fuel in combination with red fuming nitric acid (RFNA) oxidiser. The Soviets initially deployed it at soft sites which were not shielded from nuclear attack. On normal duty the missiles were stored in hangars, and it took one to three hours to roll them out, fuel them, and reach launch readiness. The missiles could remain fueled for only a few days due to the corrosive nature of the nitric acid.

The SS-1e Scud-D variant developed in the 1980s can deliver a terminally guided warhead capable of greater precision. All models are long (except Scud-A, which is shorter) and in diameter. They are propelled by a single liquid-fuel rocket engine burning kerosene and corrosion-inhibited red fuming nitric acid (IRFNA) with unsymmetrical dimethylhydrazine (UDMH, Russian TG-02 like German Tonka 250) as liquid igniter (self-ignition with IRFNA) in all models. The missile reaches a maximum speed of Mach 5.

In polyphase electrical systems, generally phase-to-phase, phase-to-ground (earth), and phase-to-neutral faults are examined, as well as a case where all three phases are short-circuited. Because impedances of cables or devices varies between phases, the prospective short-circuit current varies depending on the type of fault. Protection devices in the system must respond to all three cases. The method of symmetrical components is used to simplify analysis of unsymmetrical faults in three-phase systems.

The Mortreux system consists of molybdenum hexacarbonyl resorcinol catalyst system. The phenyl and p-methylphenyl substituents on the alkyne group are scrambled Metal-catalyzed alkyne metathesis was first described in 1968 by Bailey, et al. The Bailey system utilized a mixture of tungsten and silicon oxides at temperatures as high as 450 °C. In 1974 Mortreux reported the use of a homogeneous catalyst—molybdenum hexacarbonyl at 160 °C—to observe an alkyne scrambling phenomenon, in which an unsymmetrical alkyne equilibrates with its two symmetrical derivatives.

The problem of "control" in the aldol addition is best demonstrated by an example. Consider the outcome of this hypothetical reaction: Hypothetical aldol reaction In this reaction, two unsymmetrical ketones are being condensed using sodium ethoxide. The basicity of sodium ethoxide is such that it cannot fully deprotonate either of the ketones, but can produce small amounts of the sodium enolate of both ketones. This means that, in addition to being potential aldol electrophiles, both ketones may also act as nucleophiles via their sodium enolate.

The first stage of the three-stage Vanguard Test vehicle was powered by a General Electric GE X-405 liquid rocket engine, of of thrust, propelled by of kerosene (RP-1) and LOX, with helium pressurant. It also held of hydrogen peroxide. It was finless, tall, in diameter, and had a launch mass of approximately . The second stage was a high, diameter Aerojet General AJ-10 liquid engine burning Unsymmetrical Dimethylhydrazine (UDMH) and White Inhibited Fuming Nitric Acid (WIFNA) with a helium pressurant tank.

Aside from deactivating radicals and reactive oxidants, glutathione participates in thiol protection and redox regulation of cellular thiol proteins under oxidative stress by protein S-glutathionylation, a redox- regulated post-translational thiol modification. The general reaction involves formation of an unsymmetrical disulfide from the protectable protein (RSH) and GSH: :RSH + GSH + [O] → GSSR + H2O Glutathione is also employed for the detoxification of methylglyoxal and formaldehyde, toxic metabolites produced under oxidative stress. This detoxification reaction is carried out by the glyoxalase system. Glyoxalase I (EC 4.4.

Similarly lactones reduce to diols. α,β-Enones undergo 1,4-addition to give lithium enolates. Disulfides reduce to thiols (via thiolates). LiBHEt3 deprotonates carboxylic acids, but does not reduce the resulting lithium carboxylates. For similar reasons, epoxides undergo ring-opening upon treatment with LiBHEt3 to give the alcohol. With unsymmetrical epoxides, the reaction can proceed with high regio- and stereo- selectivity, favoring attack at the least hindered position:[2] :Image:Reduction of epoxide.png Acetals and ketals are not reduced by LiBHEt3. It can be used in the reductive cleavage of mesylates and tosylates.

The Agena was 5.0 feet (1.5 m) in diameter, three-axis stabilized (for the benefit of the reconnaissance system cameras) and its Bell Aircraft XLR81 engine produced 16,000 lbs (71 kN) of thrust using unsymmetrical dimethylhydrazine (UDMH) as the fuel, and inhibited red fuming nitric acid (IRFNA) as the oxidizer. This is a hypergolic fuel/oxidizer combination, and as such, it does not need an ignition system. This rocket engine could be restarted multiple times in orbit, by radio command, and it frequently was. The engine was notable for its unusual aluminum construction.

Hick believed that eschatological verification is "unsymmetrical" because while it could be verified if it is true, it cannot be falsified if not. This is in contrast to ordinary "symmetrical" statements, which can be verified or falsified. In his biography of Hick, David Cheetham notes a criticism of Hick's theory: waiting for eschatological verification could make religious belief provisional, preventing total commitment to faith. Cheetham argues that such criticism is misapplied because Hick's theory was not directed to religious believers but to philosophers, who argued that religion is unverifiable and therefore meaningless.

Grayish- white nepheline crystals with dark 204x204px Nepheline crystals are rare and belong to the hexagonal system, usually having the form of a short, six-sided prism terminated by the basal plane. The unsymmetrical etched figures produced artificially on the prism faces indicate, however, that the crystals are hemimorphic and tetartohedral, the only element of symmetry being a polar hexad axis. It is found in compact, granular aggregates, and can be white, yellow, gray, green, or even reddish (in the eleolite variety). The hardness is 5.5 – 6, and the specific gravity 2.56 – 2.66.

As Hydyne-LOX (liquid oxygen) was the fuel combination used for the Redstone rocket, Morgan whimsically suggested naming her new fuel formulation Bagel, since the rocket's propellant combination would then be called Bagel and LOX. Her suggested name for the new fuel was not accepted, and Hydyne was chosen instead by the U.S. Army. The standard Redstone was fueled with a 75% ethyl alcohol solution, but the Jupiter-C first stage had used Hydyne fuel, a blend of 60% unsymmetrical dimethylhydrazine (UDMH) and 40% diethylenetriamine (DETA).The Mercury-Redstone Project, p. 2-2.

On the other hand, scramjets spend more time in the atmosphere and require more hydrogen fuel to deal with aerodynamic drag. Whereas liquid oxygen is quite a dense fluid (1141 kg/m³), liquid hydrogen has much lower density (70.85 kg/m³) and takes up more volume. This means that the vehicle using this fuel becomes much bigger and gives more drag. Other fuels have more comparable density, such as RP-1 (464 kg/m³) JP-7 (density at 15 °C 779–806 kg/m³) and unsymmetrical dimethylhydrazine (UDMH) (793.00 kg/m³).

The windows on the south side have the appearance of later additions and are unsymmetrical. All traces of doors have vanished, but the opes, which have been arched and protected by the Board of Works, seem to indicate the position of a west door and an entrance on the north side to the cloister. An upper chamber exists and when perfect, covered the Chapter-house sacristy, and the east cloister, the internal walls of the lower apartments forming intermediate supports for the flooring. The interior walls of the church were once plastered.

Journal of Colloid and Interface Science (2009), 336(2), 766-772. CODEN: JCISA5 . AN 2009:776584 Yin, Shouchun; Wang, Chao; Song, Bo; Chen, Senlin; Wang, Zhiqiang. Self-Organization of a Polymerizable Bolaamphiphile Bearing a Diacetylene Group and L-Aspartic Acid Group. Langmuir (2009), 25(16), 8968-8973. CODEN: LANGD5 . CAN 151:173915 AN 2009:383258 Wang, H.; Li, M.; Xu, Z.; Qiao, W.; Li, Z. Interfacial tension of unsymmetrical bolaamphiphile surfactant in surfactant/alkali/crude oil systems. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects (2008), 30(16), 1442-1450.

He sends out Miss Lemon to make particular enquiries and then interviews Katrina who confirms that she ate separately from the family, as she always did, but had the same food as them. Poirot, after consulting with Miss Lemon, calls at Rosebank and sees Mrs Delafontaine. At the front door, he points to the unfinished row of shells – the only unsymmetrical item in that well-maintained and symmetrical garden – and points out they are oyster shells. Miss Lemon found the fishmonger who sold the oysters to the Delafontaines.

This atom could be nitrogen, phosphorus, or arsenic. Molecules containing phosphorus, or arsenic donor atoms remain stiff at the P or As and can hold their shape, unlike nitrogen compounds which rapidly racemize. If all the feet of the tripod are symmetrical and identical to each other, there will be only one way to attach in an octahedral coordination. However, there are two non-equivalent positions left on the central atom, so if two different monodentate, or an unsymmetrical bidentate ligand attaches there will be two possible isomers.

The catalyst structure affects the proportion of the NH3 that is dissociated in reaction 3; a higher temperature is desirable for rocket thrusters, while more molecules are desirable when the reactions are intended to produce greater quantities of gas. Other variants of hydrazine that are used as rocket fuel are monomethylhydrazine, (CH3)NH(NH2) (also known as MMH), and unsymmetrical dimethylhydrazine, (CH3)2N(NH2) (also known as UDMH). These derivatives are used in two-component rocket fuels, often together with dinitrogen tetroxide, N2O4. These reactions are extremely exothermic, and the burning is also hypergolic (it starts burning without any external ignition).

As chemists continued to probe this reaction with more and more advanced technology and methods, other factors began to be tabled as possibilities for what was controlling product formation of unsymmetrical amino alcohols. In 1963, Jones and Price of the University of Toronto demonstrated how remote substituents in steroids play a role in product distribution . In 1968, Carlson and Behn of the University of Kansas discovered that experimental conditions also play a role. These latter scientists established that in ring extension via the TDR, initial temperature and concentration of reagents all played a role in eventual product distribution .

The Pauson–Khand reaction (or PKR or PK-type reaction) is a chemical reaction described as a [2+2+1] cycloaddition between an alkyne, an alkene and carbon monoxide to form a α,β-cyclopentenone. The reaction was discovered by Ihsan Ullah Khand (1935-1980), who was working as a postdoctoral associate with Peter Ludwig Pauson (1925-2013) at the University of Strathclyde in Glasgow. This reaction was originally mediated by stoichiometric amounts of dicobalt octacarbonyl, but newer versions are both more efficient and catalytic. PK reaction With unsymmetrical alkenes or alkynes, regioselectivity can be problematic, but less so with intramolecular reactions.

Cyanuric triazide is planar and has three-fold axis symmetry consisting of alternating carbon and nitrogen atoms, whose centers alternate 1.38 Å and 1.31 Å apart. The distance between the center of the ring and carbon atoms of each of the nitrogens is 1.30 Å and 1.39 Å. This fixing of the position of the bonds in the cyanuric ring is mainly due to the unsymmetrical positions of the azide chains. Azide groups are linked to the carbon atoms on the cyanuric ring by single bonds with an interatomic distance of 1.38 Å, similar to the cyanuric ring itself.

The parent compound can be prepared by heating urea above the melting point at which temperature ammonia is expelled: : 2 CO(NH2)2 → H2N-CO-NH-CO-NH2 \+ NH3 Under related conditions, pyrolysis of urea affords triuret ((H2N-CO-NH)2CO). In general, organic biurets (those with alkyl or aryl groups in place of one or more H atoms) are prepared by trimerization of isocyanates. For example, the trimer of 1,6-hexamethylene diisocyanate is also known as HDI-biuret. In the anhydrous material, the molecule is planar and unsymmetrical in the solid state owing to intramolecular hydrogen bonding.

Critics claim that Proton rocket fuel (unsymmetrical dimethylhydrazine (UDMH)) and debris created by Russia's space programme is poisoning areas of Russia and Kazakhstan. Residents claim that acid rain falls after some launches. Anatoly Kuzin, deputy director of the Khrunichev State Research and Production Space Center, has however denied these claims, saying: "We did special research into the issue. The level of acidity in the atmosphere is not affected by the rocket launches [and] there is no data to prove any link between the illnesses, in Altai town and the influence of rocket fuel components or space activity of any kind".

They have the general formula R–O–R′, where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.

Propellant combinations based on IRFNA or pure as oxidizer and kerosene or hypergolic (self igniting) aniline, hydrazine or unsymmetrical dimethylhydrazine (UDMH) as fuel were then adopted in the United States and the Soviet Union for use in strategic and tactical missiles. The self-igniting storeable liquid bi-propellants have somewhat lower specific impulse than LOX/kerosene but have higher density so a greater mass of propellant can be placed in the same sized tanks. Gasoline was replaced by different hydrocarbon fuels, for example RP-1 - a highly refined grade of kerosene. This combination is quite practical for rockets that need not be stored.

Nitrite is an ambidentate ligand and can form a wide variety of coordination complexes by binding to metal ions in several ways: #When donation is from the nitrogen atom to a metal center, the complex is known as a nitro- complex. #When donation is from one oxygen atom to a metal center, the complex is known as a nitrito- complex. #Both oxygen atoms may donate to a metal center, forming a chelate complex. #A nitrite ion can form an unsymmetrical bridge between two metal centers, donating through nitrogen to one metal, and through oxygen to the other.

Additionally, the warhead was reduced from a three-warhead MIRV to a single warhead. The actual rocket design is a liquid fuel rocket, generally believed to use a hypergolic combination of unsymmetrical dimethylhydrazine (UDMH) as fuel, and nitrogen tetroxide (NTO) as oxidizer. Once the fuel/oxidizer combination are fed into the missile, it could maintain a 'ready to launch' condition for several days, or even weeks, like the R-27 SLBM, in moderate ambient temperatures. A fueled Hwasong-10 would not have the structural strength to be safely land transported, so would have to be fueled at the launch site.

Although chemists at the time knew very well what the product of a symmetrical 1-aminomethylcycloalcohol would be when exposed to nitrous acid, there was significant debate on the reaction's mechanism that lasted up until the 1980s. Scientists were puzzled over the array of products they would obtain when the reaction was performed on an unsymmetrical 1-aminomethylcycloalcohols and bridged cyclo-systems. Even today, experiments continue that are designed to shed light into the more subtle mechanistic features of this reaction and increase yields of desired expanded products. In 1960, Peter A.S. Smith and Donald R. Baer, both of the University of Michigan, published a treatise on the TDR.

This chemical is toxic and carcinogenic in small amounts, but it is easily stored in orbit providing moderate performance for very low fuel tank system weight. MMH and its chemical relative unsymmetrical dimethylhydrazine (UDMH) have a key advantage that they are stable enough to be used in regeneratively cooled rocket engines. The European Space Agency (ESA) has attempted to seek new options in terms of bipropellant rocket combinations to avoid poisonous chemicals such as MMH and its relatives.International Conference on Green Propellant for Space Propulsion, European Space Agency MMH is believed to be the main cause of the toxicity of mushrooms of genus Gyromitra, especially the false morel (Gyromitra esculenta).

The Dong Feng 4 () or DF-4 (also known as the CSS-3) is a first-generation two-stage Chinese intercontinental ballistic missile with liquid fuel (Nitric acid/Unsymmetrical dimethylhydrazine). It was thought to be deployed in limited numbers in underground silos beginning in the late 1970s and early 1980s. The Dong Feng 4 has a takeoff thrust of 1,224.00 kN, a takeoff weight of 82000 kg, a diameter of 2.25 m, a length of 28.05 m and a fin span of 2.74 m. The range of the Dong Feng 4, which is equipped with a 2,190 kg nuclear warhead with 3.3 Megaton yield, with a nominal range of 5,500 km.

This eliminates the need for the spacecraft to include a liquid apogee engine or an apogee kick motor. Yuanzheng has a thrust of with a specific impulse of 315.5 seconds. It uses the storable hypergolic propellants unsymmetrical dimethylhydrazine (UDMH) and dinitrogen tetroxide (), and can perform at least two burns within its rated life of 6.5 hours, sufficient to reach the transfer orbit apogee, and perform the circularization burn from there. Operational variants are designated YZ-1 for Long March 3B and 3C, YZ-1A for Long March 7, YZ-1S for Long March 2C, YZ-2 for Long March 5, and YZ-3 for Long March 2D.

In 1890, , a 28-year-old assistant in Berlin, published instructions for folding a piece of paper to represent two forms of cyclohexane he called symmetrical and unsymmetrical (what we would now call chair and boat). He clearly understood that these forms had two positions for the hydrogen atoms (again, to use modern terminology, axial and equatorial), that two chairs would probably interconvert, and even how certain substituents might favor one of the chair forms (). Because he expressed all this in mathematical language, few chemists of the time understood his arguments. He had several attempts at publishing these ideas, but none succeeded in capturing the imagination of chemists.

The Martin company received a contract for the new missile, designated SM-68B Titan II, in June 1960. The Titan II was 50% heavier than the Titan I, with a longer first stage and a larger diameter second stage. The Titan II also used storable propellants: Aerozine 50, which is a 1:1 mixture of hydrazine and unsymmetrical dimethylhydrazine (UDMH), and dinitrogen tetroxide. The Titan I, whose liquid oxygen oxidizer must be loaded immediately before launching, had to be raised from its silo and fueled before launch. The use of storable propellants enabled the Titan II to be launched within 60 seconds directly from within its silo.

Critics claim that Proton rocket fuel (unsymmetrical dimethylhydrazine, UDMH) and debris created by Russia's space programme is poisoning areas of Russia and Kazakhstan. Clusters of cancers have been found in the Republic of Altai and residents claim that acid rain falls after some launches. Anatoly Kuzin, deputy director of the Khrunichev State Research and Production Space Center, has denied these claims, saying: "We did special research into the issue. The level of acidity in the atmosphere is not affected by the rocket launches [and] there is no data to prove any link between the illnesses [in Altai] and the influence of rocket fuel components or space activity of any kind".

Heat of vapourisation at the boiling point is 3.85 kcal/mol. The F3NO molecule has C3V symmetry, with all the N-F bonds being equivalent. The shape is almost a tetrahedron as N-O bond is similar to the N-F bonds in nature. The nuclear magnetic resonance (NMR) spectrum of 19F has a triplet line around −363 ppm. JNF is 136 Hz. The infra red spectrum N-O stretch at 1687 cm−1, N-F stretch at 743 cm−1, unsymmetrical N-F stretch 887 cm−1 ∠ONF bend 528 cm−1, wither other bands at 558, 528, 801, 929, 1055, 1410, 1622, 1772, 2435, and 3345 cm−1.

243 cluster compounds of up to five iron atoms have been isolated.S.Jeannin, Y.Jeannin, F.Robert, C.Rosenberger, « Reaction of unsymmetrical thioalkynes RCCSC2H5 with iron carbonyl : cluster nuclearity has been increased from two to five iron atoms by utilizing CS cleavage », J.Organomet.Chem., 480, (1994), p. 111 He has also been interested in the coordination chemistry of copperJ.Gouteron, S.Jeannin, Y.Jeannin, J.Livage, C.Sanchez, « X-ray, ESR, and optical absorption studies of tetrakis(cyclohexylamine)copper(II)) nitrate : an example of a flattened tetrahedral copper(II) complex », Inorg.Chem., 23, (1984), p. 3394 and molybdenum.V.Chilou, P.Gouzerh, Y.Jeannin, C.Knobler, « Oxygen transfer from amidoximes to Mo(II) centers : synthesis and X-ray crystallographic characterization of [CH3C(NH2)2]2[Mo4O12{CH3C(NH2)NO}2] », Inorg.Chim.

In the protonation of an enolate ion, the kinetic product is the enol and the thermodynamic product is a ketone or aldehyde. Carbonyl compounds and their enols interchange rapidly by proton transfers catalyzed by acids or bases, even in trace amounts, in this case mediated by the enolate or the proton source. In the deprotonation of an unsymmetrical ketone, the kinetic product is the enolate resulting from removal of the most accessible α-H while the thermodynamic product has the more highly substituted enolate moiety.Thermodynamic Product vs Kinetic ProductJean d'Angelo, Tetrahedron report number 25 : Ketone enolates: regiospecific preparation and synthetic uses, Tetrahedron, Volume 32, Issue 24, 1976, Pages 2979-2990, , The Chemistry of Carbanions.

The Proton-M launch vehicle consists of three stages; all of them powered by liquid rocket engines using the hypergolic propellant combination of dinitrogen tetroxide as the oxidizer, and unsymmetrical dimethylhydrazine for fuel. The first stage is unique in that it consists of a central cylindrical oxidizer tank with the same diameter as the other two stages with six fuel tanks attached to its circumference, each carrying an engine. The engines in this stage can swivel tangentially up to 7.0° from the neutral position, providing full thrust vector control. The rationale for this design is logistics: the diameter of the oxidizer tanks and the two following stages is the maximum that can be delivered by railroad to Baikonur.

Indeed, two of the five violin makers of the Guarneri family, the two Pietros—of different generations—left Cremona, the first for Mantua, the second for Venice, apparently because business prospects in Cremona were so stunted by the presence of Stradivari. From the 1720s until about 1737, Guarneri's work is quick and accurate, although he was not obsessed with quality of finish. However, from the late 1730s until his death, his work shows increasing haste and lack of patience with the time needed to achieve a high quality finish. Some of his late violins from circa 1742 to 1744 have scrolls that can be crudely carved, the purfling hastily inserted, the f-holes unsymmetrical and jagged.

Chemie Int. Ed. 2006, 45, 3484. This increases the rate of productive reaction and thus subdues unwanted decomposition pathways such as protodeboronation. Cross- coupling reactions have also been accelerated with metal additives such as silverChen, J.; Cammers-Goodwin, A. "2-(Fluorophenyl)pyridines by the Suzuki- Miyaura method: Ag2O accelerates coupling over undesired ipso substitution (SNAr) of fluorine" Tetrahedron Lett. 2003, 44, 1503.Nishihara, Y.; Onodera, H.; Osakada, K. "Synthesis and structural characterization of the first unsymmetrical from transmetallation between 2,4,6-trifluorophenylboronic acid and trans-Pd(C6F5)I(PEt3)2" Chem. Commun. 2004, 192. Korenaga, T.; Kosaki, T.; Fukumura, R.; Ema, T.; Sakai, T. "Suzuki-Miyaura coupling reaction using pentafluorophenylboronic acid". Org. Lett. 2005, 7, 4915.

Valentin Glushko, who then held a near-monopoly on rocket engine design in the Soviet Union, proposed the RD-270 engine using unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide (N2O4) propellants to power the newly enlarged N1 design. These hypergolic propellants ignite on contact, reducing the complexity of the engine, and were widely used in Glushko's existing engines on various ICBMs. The full flow staged combustion cycle RD-270 was in testing before program cancellation, achieving a higher specific impulse than the gas-generator cycle Rocketdyne F-1 despite the use of UDMH/N2O4 propellants with lower potential impulse. The F-1 engine was five years into its development at the time and still experiencing combustion stability problems.

A custom-tuned insulator was developed for the front and rear mounts to help control both idle vibration and acceleration shock. For the Mitsubishi Outlander PHEV, a modified variant of the 4B11 is adopted. The MIVEC VVT system is only applied on the intake side, a balancer shaft derived from the 4B12 is adopted (in place of the standard oil pump), a linear Air/Fuel sensor fitted in place of the Oxygen sensor of front intake, unsymmetrical piston skirts, different pattern piston skirt resin coating & a unique resin coating crank shaft bearing is used. The PHEV 4B11 is restricted to a maximum operating speed of 4500 rpm to prevent damage to the electrical motors & generator from overspeeding.

The (GRAU index) 8K82K version is now usually called "Proton K". It is fuelled by very toxic unsymmetrical dimethyl hydrazine and nitrogen tetroxide. These are hypergolic fuels which ignite on contact, avoiding the need for an ignition system, and can be stored at ambient temperatures. This avoids the need for components that are tolerant of low temperatures, and allows the rocket to remain on the pad indefinitely (other launchers with such capability include the U.S. Titan II GLV, Titan III, and Titan IV, the Chinese Long March 2 and Long March 4, the Soviet/Ukrainian Tsyklon launchers, the Soviet/Russian Kosmos-3 and Kosmos-3M launchers and the European Ariane 1 to Ariane 4 launchers). In contrast, cryogenic fuels need periodic replenishment as they boil off.

The baseline Proton-K was a three-stage rocket. Thirty were launched in this configuration, with payloads including all of the Soviet Union's Salyut space stations, all Mir modules with the exception of the Docking Module, which was launched on the United States Space Shuttle, and the Zarya and Zvezda modules of the International Space Station. It was intended to launch Chelomey's crewed TKS spacecraft, and succeeded in launching four uncrewed tests flights prior to the program's cancellation. It was also intended for Chelomey's 20-ton LKS spaceplane that was never realised. The early Proton-K launch configurations from 1965 to 1971 Like other members of the Universal Rocket family, the Proton-K was fuelled by Unsymmetrical dimethylhydrazine and nitrogen tetroxide.

Long March 1's 1st and 2nd stage used nitric acid and Unsymmetrical dimethylhydrazine (UDMH) propellants, and its upper stage used a spin-stabilized solid rocket engine. Long March 2, Long March 3, Long March 4, the main stages and associated liquid rocket boosters use dinitrogen tetroxide (N2O4) as the oxidizing agent and UDMH as the fuel. The upper stages (third stage) of Long March 3 rockets use YF-73 and YF-75 engines, using Liquid hydrogen (LH2) as the fuel and Liquid oxygen (LOX) as the oxidizer. The new generation of Long March rocket family, Long March 5, and its derivations Long March 6, Long March 7 use LOX and kerosene as core stage and liquid booster propellant, with LOX and LH2 in upper stages.

This type of benzannulation involves a [4+2] cycloaddition followed by a 1,3-hydrogen shift. In dichloromethane, the symmetrical benzannulation products are yielded but in tetrahydrofuran (THF), unsymmetrical benzannulation products were obtained with good regioselectivity. These reactions utilize 1,3-bis(diphenylphosphino)propane (dppp) substituted cobalt catalyst in the presence of powdered zinc and zinc iodide for a solvent dependent benzannulation reaction (Scheme 11). In dichloromethane the ratio of A:B is 78:22 with an overall combined yield of 90% and in THF the ratio has switched to 7:93 (A:B) with a combined yield of 85%.Pünner, F., Hilt, G. “Regioselective Solvent-dependent Benzannulation of Conjugated Enynes.” Chem. Commun. 2012, 48, 3617–3619. center Palladium- catalyzed benzannulations have been developed using allylic compounds and alkynes.

By opening the stop wider, similar deviations arise for lateral points as have been already discussed for axial points; but in this case they are much more complicated. The course of the rays in the meridional section is no longer symmetrical to the principal ray of the pencil; and on an intercepting plane there appears, instead of a luminous point, a patch of light, not symmetrical about a point, and often exhibiting a resemblance to a comet having its tail directed towards or away from the axis. From this appearance it takes its name. The unsymmetrical form of the meridional pencil—formerly the only one considered—is coma in the narrower sense only; other errors of coma have been treated by Arthur König and Moritz von Rohr, and later by Allvar Gullstrand.

Geological section from north to south of the Wealden Anticline, note the unsymmetrical lower Cretaceous/Jurassic sediments in the core of the anticline. The diagram has undergone extensive vertical exaggeration As a result of the Alpine orogeny the basin was squeezed between the basement to the north and the south, this resulted in the reactivation of the formerly normal faults into minor thrusts (as they had been during the Variscan Orogeny) and the formation of the Wealden Anticline. The region's two surface structural highs (areas of crust and rocks which are uplifted), the Wealden Anticline and the Channel High, are superimposed upon earlier, Mesozoic basins, (the Weald and Channel basins). This nearly exact superimposition of compressional features upon underlying formerly extensional features exemplifies perfectly the principles of structural inversion across a large and well defined geologic feature.

It is part of developing barrier-free and smart furniture that can be used with peace of mind from young people to the elderly and those requiring nursing care. 200x200px DABLIU COAT HUNGER Coat Hanger (Desiree_Italy) 2014 A sculptural coat hanger design that weaves various shapes depending on the viewing angle due to the geometric structure of the metal wire. 200x200px MERIT PYUAN Shampoo, Treatment Series Packaging Design (Kao_Japan) 2015 While following the traditional shape of shampoo, it expresses a new feeling of dynamism and an unsymmetrical silence that flows down quietly. This design combines the historical value and new value of a product. JPC Japan Package Design Award, Cosmetic Goods Award (2016, Japan) 200x200px ILY-I Interactive Armchair (Aisin_Japan) 2015 Developed a sofa-type personal mobility design that can be moved smartly from the elderly to young people in outdoor public facilities.

These freighters, which brought supplies and extra equipment to keep the station replenished, helped ensure that the crew were always able to carry out useful scientific work aboard the station. In all, twelve Progress flights delivered over 20 tonnes of equipment, supplies and fuel. The addition of the extra docking port caused the adoption of the Almaz-derived twin-chamber propulsion system first used on Salyut 3 and 5, with the two engine nozzles – each producing 2.9 kilonewtons of thrust – mounted peripherally on either side of the aft port. Salyut 6 introduced a Unified Propulsion System, with both the engines and the station's control thrusters running on unsymmetrical dimethylhydrazine and nitrogen tetroxide, drawn from a common set of pressurized tanks, allowing the refueling capabilities of the visiting Progress tankers to be exploited to the maximal effect.

The simplest halonium ions are of the structure (X = F, Cl, Br, I). Many halonium ions have a three-atom cyclic structure, similar to that of an epoxide, resulting from the formal addition of a halogenium ion X+ to a C=C double bond, as when a halogen is added to an alkene. The propensity to form bridging halonium ions is in the order I > Br > Cl > F. Whereas iodine and bromine readily form bridged iodonium and bromonium ions, fluoronium ions have only recently been characterized in designed systems that force close encounter of the fluorine lone pair and a carbocationic center. In practice, structurally, there is a continuum between a symmetrically bridged halonium, to an unsymmetrical halonium with a long weak bond to one of the carbon centers, to a true β-halocarbocation with no halonium character. The equilibrium structure depends on the ability of the carbon atoms and the halogen to accommodate positive charge.

E. Martin, M. Solntseva, and A. J. Williams "Applications of 15N NMR in Alkaloid Chemistry" Modern Alkaloids, E. Fattorusso and O. Taglialatela-Scafati, Wiley- VCH, New York, 2007, pp. 411-476 More recently, his research interests have also led to the development of unsymmetrical indirect covariance NMR processing methods that have the potential for significant spectrometer time savings when experimental access to hyphenated 2D NMR. These methods also provide access to 13C-15N Heteronuclear Single Quantum Coherence-Heteronuclear Multiple Bond Coherence (HSQC-HMBC) correlation data that are experimentally inaccessible at natural abundance, and to HSQC-ADEQUATE correlation plots that allow carbon-carbon connectivity networks of molecules to be mapped without having to resort to the highly insensitive 13C-13C INADEQUATE experiment. In recent years Martin has extended his work into the application of residual dipolar couplings, residual chemical shift anisotropy and DFT calculations to demonstrate that, in combination, some of the most complex chemical structures could be elucidated and making unambiguous assignment essentially difficult or impossible.

The R-17 featured important improvements over the R-11. The Isayev RD-21 engine used a combination of inhibited red fuming nitric acid (IRFNA) oxidiser and unsymmetrical dimethylhydrazine (UDMH) fuel, fed into the combustion chamber by fuel pumps that ensured a more consistent thrust. The guidance system, active only during the boosted phase, uses three gyroscopes, that give it a Circular error probable (CEP) of 450 m (900 m according to western sources.) A nuclear warhead was designed for the R-17, with a selectable yield, from 5 to 70 kilotons. However it could also carry a chemical warhead, containing 555 kg of viscous VX; a conventional weapon, with a single high explosive warhead; or a series of fragmentation payloads, using either high explosive, anti-tank or anti-runway munitions. MAZ-543 Uragan carrying SS-1с Scud B (9K72 Elbrus) At first, the R-17 was carried on a tracked TEL similar to that of the R-11, designated 2P19, but this was not very successful, as the vibration of the tracks had a tendency to interfere with the launch electronics.

They are popular camera perspectives among 2D video games, most commonly those released for 16-bit or earlier and handheld consoles, as well as in later strategy and role-playing video games. The advantage of these perspectives is that they combine the visibility and mobility of a top-down game with the character recognizability of a side-scrolling game. Thus the player can be presented an overview of the game world in the ability to see it from above, more or less, and with additional details in artwork made possible by using an angle: Instead of showing a humanoid in top-down perspective, as a head and shoulders seen from above, the entire body can be drawn when using a slanted angle; Turning a character around would reveal how it looks from the sides, the front and the back, while the top-down perspective will display the same head and shoulders regardless. There are three main divisions of axonometric projection: isometric (equal measure), dimetric (symmetrical and unsymmetrical), and trimetric (single-view or only two sides).