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In this paper, following the Backus (in J. Geophys. Res. 67(11):4427–4440, 1962) approach, we examine expressions for elasticity parameters of a homogeneous generally anisotropic medium that is long-wave-equivalent to a stack of thin generally anisotropic layers. These expressions reduce to the results of Backus (1962) for the case of isotropic and transversely isotropic layers. In the over half-a-century since the publications of Backus (1962) there have been numerous publications applying and extending that formulation. However, neither George Backus nor the authors of the present paper are aware of further examinations of the mathematical underpinnings of the original formulation; hence this paper. We prove that—within the long-wave approximation—if the thin layers obey stability conditions, then so does the equivalent medium. We examine—within the Backus-average context—the approximation of the average of a product as the product of averages, which underlies the averaging process. In the presented examination we use the expression of Hooke’s law as a tensor equation; in other words, we use Kelvin’s—as opposed to Voigt’s—notation. In general, the tensorial notation allows us to conveniently examine effects due to rotations of coordinate systems.

We study the Backus (1962) average of a stack of layers overlying a halfspace to examine its applicability for the quasi-Rayleigh and Love wave dispersion curves. We choose these waves since both propagate in the same model. We compare these curves to values obtained for the stack of layers using the propagator matrix. In contrast to the propagator matrix, the Backus (1962) average is applicable only for thin layers or low frequencies. This is true for both a weakly inhomogeneous stack of layers resulting in a weakly anisotropic medium and a strongly inhomogeneous stack of alternating layers resulting in a strongly anisotropic medium. We also compare the strongly anisotropic and weakly anisotropic media , given by the Backus (1962) averages, to results obtained by the isotropic Voigt (1910) averages of these media. As expected, we find only a small difference between these results for weak anisotropy and a large difference for strong anisotropy. We perform the Backus (1962) average for a stack of alternating transversely isotropic layers that is strongly inhomogeneous to evaluate the dispersion relations for the resulting medium. We compare the resulting dispersion curves to values obtained using a propagator matrix for that stack of layers. Again, there is a good match only for thin layers or low frequencies. Finally, we perform the Backus (1962) average for a stack of nonalternating transversely isotropic layers that is strongly inhomogeneous, and evaluate the quasi-Rayleigh wave dispersion relations for the resulting transversely isotropic medium . We compare the resulting curves to values obtained using the propagator matrix for the stack of layers. In this case, the Backus (1962) average performs less well, but—for the fundamental mode—remains adequate for low frequencies or thin layers.

Generally, grape vines produce extraneous shoots (“suckers”) on the plant in addition to those growing beyond the few desired on the cordon wanted for proper vine growth. Generally, again, suckers are less fertile than the primary shoots, they crowd the canopy of the vine, and their growth utilizes resources required for proper growth of the primary shoots. Further, the chaotic growth makes it difficult to manage the harvest. A crowded canopy (as will be discussed subsequently) is not a healthy one for grape growth. As shown in Figures 12.1 and 12.2 and noted earlier, buds (the small part of the vine that lies between the vine’s stem and the leaf stem or petiole) can start alongside the beginning of leaves at the base of the apical meristem. The buds swell and eventually produce shoots. As the shoot grows the flowers appear on a stem from the node, from where leaves have also sprung. That is, grape nodes hold buds that grow into leaves and inflorescences or “clusters of flowers” (i.e., the reproductive portion of a plant) arranged on a smaller stem growing from the node. It is not yet clear, despite recognizing the flow of nutrients and auxins as well as changes in proteins, how, after vernalization (i.e., the ability to flower so that fruit can be set—but only after exposure cold), the plant decides which, leaf or stem bearing flowers, should sprout from the node. The fundamentals of the coming forth of the buds are often outlined as a three-step process. First there is the formation of uncommitted primordia (primordia refer to tissues in their earliest recognizable stages of development) called “anlagen” (from German, in English, “assets” or “facilities”) at the apices of lateral buds. Second, differentiation of anlagen to form inflorescence primordia or tendril primordia occurs. Finally, flowers form from the inflorescence primordia when activated by phytohormones, nutrients, and growth regulators and when the external conditions of light and temperature are correct.

As noted earlier in the general description of the plant cell, there is a site at which photosynthesis, the process which allows plants to capture sunlight and convert it into energy, occurs. It is this process which has produced oxygen on the planet, food for herbivores, and the cool green hills of Earth we enjoy today. The capture of sunlight allows the grape vine to grow and produce fruit. Of course, while the discussion of the “light reactions” (capture of sunlight) and the subsequent so-called “dark reactions” (producing carbohydrates) is necessarily brief here, it is, nonetheless, an exciting story. We are only now beginning to understand a little of it. The earlier picture (Figure 7.1) of the plant cell is repeated here (Figure 9.1) so that the position of the chloroplast is seen. Refer to page 24 for a discussion of the numbered items. As the leaves begin to develop alongside the apical meristem, proplastids, which are present in the meristematic regions of the plant, are formed. Proplastids grow into plas¬tids (such as amyloplasts and chloroplasts) as they mature in different ways dictated by the plant’s DNA. Some plastids (e.g., chloroplasts) carry pigments, discussed more fully below, that allow them to carry out photosynthesis. Others are used for storage of fat, starch (amyloplasts) or specialized proteins. Still other plastids are used to synthesize specialized compounds needed to form different tissues or to produce compounds for protection (e.g., tannins). Each plastid builds multiple copies of its DNA as it grows. If it is growing rapidly, it makes more genome copies than if it is growing slowly. The genes, ignoring epigenetic (literally “above the gene”) and postgenetic (literally “after the gene”) modifications, about which we still have much to learn, encode plastid proteins, the regulation of whose expression controls differentiation and thus which plastid is eventually formed. However, despite the differentiation of plastids, it appears that many plastids remain connected to each other by tubes called stromules through which proteins can be exchanged.

The yeast, Saccharomyces cerevisiae, is a fungus, one of the group of eukaryotes (organisms with membrane- enclosed organelles and nuclei in their cells) that lie on that branch of the tree of life that, as shown in Figure 18.1, includes plants and animals. Many years of debate preceded their notation as a separate branch on the tree while advocates forcing them into either plant or animal families battled. Thus, although the cell walls of yeast are strikingly similar to plants (save that yeasts utilize N-acetylglucosamine and related nitrogenous carbohydrate polymers [chitin-like] in place of polyphenols [lignin] for cross linking), it is clear that chloroplasts, common to plants, are missing. Similarly, while their organization and food disposition is similar to animals, the very presence of a cell wall, rather than a simple membrane, forces their exclusion from the family of animals. Of course, all life utilizes the same set of purine and pyrimidine bases bonded to a ribose or deoxyribose carbohydrate and amino acids. So while classifications are necessary, they may also be specious. A generic eukaryotic cell and a plant cell (seen before in Figure 7.1) are shown in Figure 18.2. Hundreds of yeasts and strains of those yeasts are available for use in the wine industry for fermenting the must obtained on crushing the grapes. Some of the yeasts are referred to as “wild” and are brought in with the grapes from the vineyard. Others, originally “wild,” have been isolated and maintained because it is held that their use adds value to the vintage. Indeed, it is here that a great deal of experience is required. Generally, the vintner has a good idea of the amount of sugar (measured as glucose) in the grapes harvested. However, different strains of yeast (some 1500 yeast species, including S. cerevisiae are a subgroup of 700,000 or so fungi), while probably processing glucose in the same way, will also process other sugars too and, in that vein, there are other issues to be faced.

The widespread practices of viniculture (the study of production of grapes for wine) and oenology (the study of winemaking) affirm the generalization that grapevines have fewer problems with mineral deficiency than many other crops. Only occasionally is the addition of iron (Fe), phosphorus (P), magnesium (Mg), and manganese (Mn) supplements to the soil needed. Addition of potassium (K), zinc (Zn), and boron (B) to the soil is more common. And, of course, nitrogen (N) is critical for the production of proteins. Over the years, various transition metals (metals in groups three through twelve [3– 12] of the periodic table, Appendix 1) have been shown to be generally important. These groups include iron (Fe), magnesium (Mg), manganese (Mn), zinc (Zn), and copper (Cu). Many metals are bound to organic molecules that are important for life. Some of the metals, such as copper (Cu) and iron (Fe), are important in electron transport while others, including manganese (Mn) and iron (Fe), inhibit reactive oxygen (O) species (ROSs) that can destroy cells. Metals serve both to cause some reactions to speed up, called positive catalysis while caus¬ing others (e.g., unwanted oxidation) to slow down (negative catalysis). It is not uncommon to add nitrogen (N), in the form of ammonium salts such as ammonium nitrate (NH4NO3), as fertilizer to the soil in which the vines are growing. It is also common to increase the nitrogen (N) content in the soil by planting legumes (legumes have roots that are frequently colonized by nitrogen-fixing bacteria). Nitrogen- fixing bacteria convert atmospheric nitrogen (N2), which plants cannot use, to forms, such as ammonia (NH3) or its equivalent, capable of absorption by plants. Nitrogen, used in plant proteins, tends to remain in the soil after harvest or decomposition. With sufficient nitrogen present in the soil the growth cycle can begin again in the following season without adding too much fertilizer. In a more general sense, however, it is clear (as mentioned earlier) that the soil must be capable of good drainage so the sub-soil parts of the plant do not rot and it must be loose enough to permit oxygen to be available to the growing roots.

Aside from grafting onto already established rootstock or the development of roots from a planted cane (vide supra), root systems develop from the radicle in the plant’s seed. Both as roots begin to form from the cane, and as the sprouting seed coat opens in response to soil temperature, moisture, and genetic programming left in place when the seed formed, the roots begin to grow and interact with the rhizosphere. Similarly, signals received by rootstock where grafting has been effected also occur. The roots begin to bring moisture and food to produce and support the stem and, eventually, the leaves, flowers, and fruit. Heavily fruited plants such as grapes require additional support for the stems. In the roots, epidermal (surface) cells elongate and develop into root hairs. Beneath the epidermal cells it appears that the phloem cells which bring the starch bodies (amyloplasts) to the root tips and help direct which way “down” is, develop first. Then xylem elements develop in order to move the minerals into the system. Most of the minerals are absorbed through channels developing in the walls of the growing undifferentiated cells (the meristems). Because of concentration gradients (i.e., there is less on one side of a cell membrane than on the other), some minerals appear to be actively transported into the cells of the xylem (presumably through similar channels) in response to signals emanating from the plant. From the xylem cells, the minerals and water move upward into the apical meristem and get distributed to other regions. Interestingly, although most of the cells are derived from the same group of meristems which thus might be considered true stem cells, it is genetic programming which permits that differentiation. Thus, the derivatives of the meristems undergo transformation and develop into various cell types that perform the different functions (Figure 6.1). Relatively recently there has been an increased interest in what has been the largely unexplored biology of roots.

This undistinguished, productive, drought resistant, vigorous white grape, Airén, from the La Mancha region of Spain, was said to be the most widely planted grape in the world. In part the justification for this claim relies upon the observation that it is planted at a very low density! Except for its use in blending to make other wines “lighter,” it has not found wide accep¬tance. In part, it appears that its lack of popularity is the result of what is reported to be a mild, neutral flavor, and advertising has not pushed wines produced from it to the fore. Although it is now common to attempt to analyze the headspace (or ullage) in bottled wine (as well as the wine itself ) by chromatographic and mass spectrometric techniques it is less common to find that the grapes (skin, must, and seeds) are also subjected to such analysis. Nonetheless, the phenolic composition of V. vinifera var Airén was subjected to just such analysis during ripening from véraison to “technological” maturity (i.e., maturity which might actually be earlier than harvest, the latter being the decision of the viticulturist and vintner). The analysis of the ethyl ether extract of macerated skins, seeds, and accumulated solids (the pomace) was undertaken. Procyanidins and anthocyanins which would (the authors claim) interfere with subsequent analysis would not move into the ether phase. It was also found (using controls) that other highly polar materials (e.g., carboxylic acids) were only poorly extracted from the macerated skins and seeds. The isolated compounds and some information about their sources are provided in Figures 14.1 and 14.2. The analysis of the seeds, skin, and must did lead to the conclusion that “the maximum concentrations of benzoic and cinnamic acids and aldehydes and flavonol aglycones and glycosides at the end of the ripening period did not coincide with the minimum concentrations of the flavan-3-ols and hydroxycinnamic tartaric esters.” Depending upon what was sought, this information might thus affect decisions concerning the harvest date.

The bottled beverage before you is to be opened. This work has already described the bottle (colorless or not), the closure (screw cap, synthetic cork and cork), and the contents (the wine). If the wine is not a table wine (vin ordinaire or vin de pays) which is simply enjoyed in a family or informal surrounding where the details of the container into which it is poured are less important, then it is generally found that: (a) clear colorless glass or crystal is used so that the visual appeal of the beverage can be enjoyed; (b) the bowls of wine glasses (except for sparkling wines and dessert wines) will be tapered upward from the stem into a bulbous shape which diminishes again at the top; and (c) the rim of the glass will be thin enough to allow it to be unnoticed when the wine is sipped. It is held that these are important, and in particular, the shape of the glass helps retain the more volatile constituents for the consumer’s enjoyment. Bowls used in glasses for red wines are more rounded so that when half full, the surface area is large. For white wines, this is considered less important, and of course, for Champagne and other sparkling wines, where conical flutes are used, a small surface area is avoided to enhance the flow of bubbles. As the wine briefly stands, perhaps having been swirled, it is often found that “legs” or “tears” of wine are seen to form on the wall above the surface. Their appearance is, in part, a function of temperature as well as the alcohol content of the wine and the resulting surface tension of the liquid. Then, using capillary action, the liquid climbs the side of the glass. Both alcohol and water evaporate, but the alcohol evaporates faster, so more liquid is drawn up from the bulk. The wine thus moves up the side of the glass and forms droplets that run back down the glass.

Poets extol the burst of aroma when the bottle is opened, the wine poured, the flavor on the palate as it combines with the olfactory expression detected and the resulting glow realized. But what is the chemistry behind it? What are the compounds involved and how do they work their wonder? What do we know? Distinct and measurable differences in terroir, coupled with the plasticity of the grape berry genome and the metabolic products, as well as the work of the vintner, are critical to the production of the symphony of flavors found in the final bottled product. Analytical chemistry can inform us about the chemical differences and similarities in the grape berry constituents with which we start and what is happening to those and other constituents as the grape matures. The details of the grape and its treatment produce substantive detectable differences in each wine. While there are clear generalities - all wine is mostly water, ethanol is usually between 10% - 20% of the volume, etc - it is the details, shown to us by Analytical Chemistry and structural analysis accompanying it, that clearly allow one wine to be distinguished from another.

Products of reactions are separated from reactants by a barrier or barriers. if this were not so we could not have any reactants—everything would already be products! In order for the grapevine to grow beyond the materials provided in the seed, the rootstock, or the cutting, it is necessary for the reactants obtained from the environment (i.e., nutrients in the soil and air) to be converted to plant material. The energy for this conversion comes from the sun, and it is the chloroplasts that take the light and, using the aforementioned materials, convert it to useful energy in the plant. So, overall, for processes to occur within the plant, a high energy species must be formed and then used. Subsequent regeneration of the high energy species can use more sunlight. The currency of energy is adenosine triphosphate (ATP). When it is used, it is converted to adenosine diphosphate (ADP) and inorganic phosphate (Pi), and in that conversion (or those conversions as more than one can be used to accomplish the same end) the barrier between reactant and product can be overcome (Figure 10.1). Additionally, for moving electrons and protons around where simple solvation (the use of—and interactions with—solvents) will not work, a cofactor (a “factor” that needs to be present in addition to an enzyme to enable the catalyzed reaction to occur) is often needed. These movements of electrons and protons are simply oxidations and reductions (see Appendix 1), and it is common to find oxidation and reduction being effected by using, as cofactors, either the oxidized or reduced forms of the phosphate ester of nicotinamide adenine dinucleotide (NADP+) to/ from (NADPH) and/ or the related conversion of the oxidized/ reduced forms of flavin adenine dinucleotide (FAD)/ (FADH2) (Figure 10.2). A cartoon representation of the chloroplast wall, with the stroma (the colorless fluid filling the chloroplast through which materials move) shown on the top and the lumen of the thylakoid body (where the light- dependent photochemistry occurs) on the bottom is provided in Figure 10.3. The working agents in the membrane are shown.

The judicious use of sulfur dioxide (SO2) will inhibit the growth of microorganisms (e.g., bacteria) present on the grape skins as the berries come from the vineyard. Its early use presumes the vintner has decided that the adventitious wild yeasts which might be destroyed or inhibited by sulfur dioxide will not contribute to the vintage. It appears that Saccharomyces cerevisiae might be less susceptible to the action of sulfur dioxide than other yeasts that may be present. So, if the particular strain of S. cerevisiae used can cope, it may be able to function unimpeded. Regardless, sulfur dioxide might still be used because, in addition to suppression of deleterious microorganisms, it appears to reduce oxidation of particularly fragile white wine components. In industrial settings, both gaseous sulfur dioxide and sulfur dioxide as a liquefied gas (boiling point – 10 °C [14 °F]) are used. In either form it is a dangerous tool. It is dangerous first because it is toxic and second because an excess of it will ruin the wine. In many cases, because its value is recognized as beneficial, sulfur dioxide is replaced by addition of either sodium metabisulfite (Na2S2O5) or potassium metabisulfite (K2S2O5) with the latter generally preferred. Indeed, while it is best to look at the MSDS. (Manufacturer’s Safety Data Sheet) before use, the solubility of the two salts is the same and given as 450 grams/ liter (g/ L) at 68 °F (20 °C) and the pH on dissolution as between 3.5 and 4.5. The potassium (K) salt appears, at this writing, to be more readily available in food quality (as opposed to chemical quality) grade. So, with regard to sulfur dioxide (SO2), and as shown in Figure 17.1, its structure is much more similar to water and to ozone than it is to carbon dioxide (CO2); sulfur lies beneath oxygen (O2) in the periodic table (silicon, Si, lies beneath carbon). Nonetheless, sulfur dioxide (SO2) reacts with water much the same way that carbon dioxide (CO2) does.

Three turns of the Calvin cycle (Figure 11.1), allow the conversion of three (3) equivalents of carbon dioxide (CO2) (i.e., 3 C1 units) along with three (3) equivalents of the five-carbon carbohydrate derivative, ribulose-1,5-bisphosphate (i.e., 3 C5 units) to yield three (3) not yet isolated six-carbon adducts, 2-carboxy-3-ketoribitol-1,5-bisphosphate (3 C1 + 3 C5 = 3 C6) to form. The three (3) C6 species then undergo fragmentation to yield six (6) equivalents of the three (3) carbon dihydroxy monocarboxylate, 3-phosphoglycerate (i.e., 3 C6 = 6 C3). A cartoon representation of this process is shown in Scheme 11.1 for one of the three CO2 units. Of the six (6) three-carbon unit equivalents, five (5) are used to regenerate three (3) equiv¬alents of ribulose-1,5-bisphosphate (i.e., 5 C3 = 3 C5), while the sixth three- carbon fragment is now available to combine with another to make a six (6) carbon sugar (2 C3 = 1 C6) such as glucose (C6H12O6) (Figure 11.2). Additionally, as shown in Figure 11.3, 3-phosphoglycerate can be used to make other small compound building blocks such as glyceric acid, lactic acid, pyruvic acid and even acetic acid (after decarboxylation). Ribulose- 1,5-bisphosphate (often abbreviated as RuBP), using the enzyme ribulose- 1,5- bisphosphate carboxylase (EC 4.1.1.39, carboxydismutase, rubisco), catalyzes the Mg2+- dependent conversion of the 1,5- bisphosphate ester of the carbohydrate ribulose with carbon dioxide (CO2) to produce two (2) equivalents of 3- phosphoglycerate (PGA). As shown in the Schemes 11.1 and 11.2. A hypothetical the six carbon intermediate, 2- carboxy- 3- ketoribitol- 1,5- bisphosphate, is often written. It is important to keep in mind that we want the 3- phosphoglycerate for purposes of construction of other important compounds. But, as noted above, three turns of the cycle are necessary to produce six (6) equivalents of 3- phosphoglycerate, and five (5) of them are reused in making the three (3) ribulose- 1,5- bisphosphates necessary to turn the cycle three (3) times.

It is widely claimed that growing the vines that will produce good wine grapes starting from seed is difficult. In part, as noted above, this is apparently due to the presence of different alleles expressed differently as a function of environmental factors. As a consequence, most wine is produced from grapes arising from a graft of a vine that already produces desirable product. However, it is possible to plant seeds to generate vines— although the product is not always what is expected! The fact that parent varieties (the flower of one parent and pollen of another) will generally produce a variety different from either parent is generally sought to be avoided in com¬mercial enterprise. However, since grape flowers (as will be discussed in Chapter 12) are often found as tight clusters, hermaphroditic reproduction either naturally or by intervention can be effective. Adventures in crossing, such as with the Vitis vinifera varieties Cabernet franc and Sauvignon blanc can be profitable. They are reported to have led to the formation of Cabernet Sauvignon. The grape seed needs to germinate. Germination is evidenced by the forming of the plant within the seed and the opening of the seed coat to produce a seedling (Figure 2.1). The plant embryo responds, as dictated by the genome, to the warmth of the soil and the availability of water, and continues to grow from the first cell division until the plant sprouts. It is not uncommon for seeds of many species to have set a genetically dictated timer. The setting of the timer may, for example, require that the ground be frozen and subsequently thawed (a process called vernalization). Once moistened, by a thaw or rain, the dry seed takes up water that passes through channels in cell walls and membranes (the inside of the cell being drier than the outside) that apparently open in response to the “timer” and in response to soil constituents. Ions found in the soil are washed in with the water. The water and nutrients in the soil are now available to put the enzymes and their cofactors, previously lying fallow in the seed, to work.

The history of cutting deeply into the vascular tissues of one growing, strong, host plant and then inserting a part of another plant in such a way that they join together is called grafting (originally from the Greek, “graphion” referring to the sharpened end of piece to be inserted, the scion). The original cut into the host plant, the rootstock, is made into the vascular cambium of the plant (i.e., that part of the plant stem that contains the meristem, which is the plant tissue made up of undifferentiated cells where growth can take place). The piece to be grafted, the scion, is also cut to its vascular tissue. The vascular joining is called inosculation, and the process can be traced back to the early cultivation of fruit trees. Healthy, fruit- bearing crops from the stock of the scion rather than that of the rootstock are known to result. That is, the meristem adapts. The vascular cambium itself consists of cells that are already partially specialized (e.g., the “xylem” for the woody tissue that carries water and some water soluble mineral nutrients and the “phloem” for carrying carbohydrates and other similar nutrients). The plan is that the undifferentiated cells, as well as those partially differentiated, will accommodate the scion to the rootstock, and the phloem from the root-stock will learn to feed the growing scion graft. Should the graft “take,” the matured scion will, with the advent of photosynthesis (vide infra), return the favor to the rootstock. Both will profit. One story of the grafting process and the interaction between plants and the insects that feed on the plants as applied to the wine industry has been told often. A family of plant par¬asitic insects which are native to North America, the Phylloxeridae (Genus: Daktulosphaira; Species: vitifolia, Fitch, 1855, commonly called “phylloxera”) were involved. Grapevines in North America had built resistance to some members of the Phylloxeridae family and had, apparently, been able to match genetic changes in the insect with their own changes over the years.

Viticulture, it will be recalled, is the art and science of vine-growing and grape-harvesting, and it was the subject of Sections I–IV (Chapters 1–14). Enology, the subject of this Section (Chapters 15– 20), is the art and science of winemaking. Much of what follows in this brief Chapter on General Comments is expanded upon in other Chapters in this Section. In making the wine, it appears to be generally agreed that where possible it is best to follow the traditional methods to produce the best results. However, it should be clearly understood that work is underway to engineer yeast to make it more alcohol tolerant and to use the yeast to produce specific compounds recognized as being particularly flavorful. Additionally, as the number of vintners has grown, finding the proper oak for casks is becoming ever harder. Therefore, the art of reworking old oak casks or even avoiding them altogether (e.g., by aging wine in the presence of oak chips) may be used. In the same vein, it is widely recognized that stoppers other than cork may be used, so that the day may come when the cork stopper will be a thing of the past. Traditionally, grapes are taken directly from the vineyard to be crushed, and it is still the case in many of the oldest and most respected vineyards that this practice will continue. However, as the use of pesticides and fungicides has increased, methods for rapid washing and then drying of grapes before crushing may be employed. The arguments against these extra steps are mainly two. First, lingering water would dilute the grape juice. Second, the adventitious yeasts that might be removed by washing or deactivated by drying are often desired for the production of the vintage. Indeed, it has been argued that unique fungi, which might be exclusive to the most prestigious vineyards, are important to the production of the best wines. The issue of washing versus not washing has been investigated, and it was concluded for the case examined that only minor changes are effected by washing.

It has been suggested that containers made of clay (e.g., the amphora of the bronze age) were adopted for use during the thousands of years of winemaking that preceded the ability to produce suitable glass vessels. Sealing the amphora, as reported by archeologists and historians, was accomplished with clay or leaves covered with clay, rags, wax, pine resin (producing retsina), and even today’s popular choice, cork. With the exception of the latter, where only a small amount of air can leak in, it appears that too much air would enter and the flavor of the wine would change. In part, the effort to seal the amphora was futile, as the clay amphora would leak too. But waxes and resins helped seal out air and, in the process, often changed the flavor of the beverage. Again, historically, it appears from analysis of the contents remaining in the old vessels that various flavoring agents, such as berries, fruits, leaves, flowers, and even metals such as lead were intentionally added to wines to suit the tastes of the consumer. Nonetheless, oxidation and bacteria (e.g., Acetobacter aceti, known to convert ethanol [CH3CH2OH] to acetaldehyde [CH3CHO] and thence to acetic acid [CH3CH2OH]) would often make the beverage unpalatable (by today’s tastes). So, tastes were adjusted to fit the beverage available! It was also found that wines that had additional ethanol present were resistant to bacterial action, so tastes (even into the twentieth century) were developed for “fortified” wines (vide infra, Chapter 21) such as Port, Sherry, and Madeira that were to be shipped in casks. More recently shipment of the latter in glass bottles (since late in the nineteenth century) along with cork stoppers have become common. Most recently, synthetic (i.e., polymer) stoppers and aluminum screw caps have been used for all of these beverages because most wine is produced to be consumed within a few years of its bottling. This fairly recent change has arisen as an accommodation to large-scale production, long-distance shipping, and storage in commercial sales facilities, none of which encourage saving wine for aging.

Rooted plants can often be obtained and transferred from one environment into another either in order to increase the number of vines producing a specific grape in a vineyard or to introduce a new variety or propagate a new cultivar. It has been found that some vines can be grown from hardwood cuttings. The technique of hardwood cutting involves removing a cane (Figure 4.1, a and b) from a successful vine once the vine has gone dormant for the winter, trimming it appropriately, and then planting it in well-fertilized soil either with or without growth stimulants (i.e., phytohormones, vide supra). It is clear that the conditions of planting, reported by various sources, are a function of variety and terroir. Interestingly, it appears that the cutting, which may have been grown on a rootstock different from the variety of grape produced, will produce roots that are true to the variety of grape. Once the vine, from seed, grafting, or cane begins to grow, it must be “trained” so that its growth can be monitored and successful grape crops harvested. The training includes proper spacing of vines and the establishment of a trellis system or posts for each vine. Trellis systems are set up during the first or second year of the growth of the vine since harvesting of grape crops before the third year is rare. The trellis, which will need to bear the weight of the vine and grapes, is built much like a fence. Thus, the row of grape vines is held up by end posts at the end of the row and line posts about 20 feet apart between the ends. Usually, there is a line post for every two or three vines with some species needing more space than others. Generally the end posts are thick treated wood, concrete, or steel and are strongly anchored. The line posts are thinner, and the trellis itself is made of twelve (12) gauge or heavier wire with the number of wires a function of the weight to be supported and the height to which the grapes are to be grown.

The grape berry is composed of skin, flesh (pulp) and seeds. After destemming (Chapter 13), the grapes are sent on for crushing. On crushing, the thick walls of the skin, including the waxy cuticle, are broken. Crushing the grapes (Figure 16.1) is a question of quantity. Small quantities are handled differently than large. The skins, including the contaminants thereon, as well as the majority of the materials discussed above for the individual grapes (i.e., phenols, anthocyanins, tanins, some acids, terpenes, pyrazines, and some carbohydrates including those attached to the anthocyanidins, forming anthocyanins) therein, are released. The cells of the pulp are also broken and released into the juice on crushing. This berry cell juice is mainly water (70–80% by weight) which contains the mixture of sugars (mostly glucose and fructose, but small concentrations of many other carbohydrates are also present), carboxylic acids (mostly tartaric and malic, but additional members of the tricarboxylic acid cycle, oxalic, glucuronic, etc. are also present), complex cross-linked polysaccharides from cell walls (pectins), some phenols and proteins (as well as the peptides and simple amino acids from which they are constructed), and minerals, including oxides of iron (Fe), phosphorus (P), and sulfur (S), as well as salts of potassium (K) and sodium (Na) brought up in the xylem to the growing berry. The seeds have their cellulose carbohydrate-based exterior coatings, which are also rich in complexed polyphenols (tannins). Additionally, amino acids, generally found as constituents of peptides, proteins, and enzymes, and their cofactors needed for all life, nucleic acids and their attached sugars needed for the next generation, are all present too. Thus, overall, the result of crushing the berries is a mixture consisting of skins, seeds, and fruit juice (the must = Latin vinum mustum = young wine). This mixture may, if the grapes were “white,” be cooled and the cap on the must—sometimes called the pomace (the solid portion of the must) removed early or late (usually between 12 and 24 hours) by the vintner. Most of the flavoring constituents are quickly extracted, and brightly colored phenols, tannins, anthocyanins, etc.

Grape leaves are thin and flat. As is common among leaves in general, they are composed of different sets of specialized cells. Today, on average, sunlight reaching their surface is about 4% ultraviolet (UV) (750 nm) and 44% visible (VIS) radiation. Little of the UV and IR are used by plants. As with other leaves that are green, only the red and blue ends of the visible part of the electromagnetic spectrum are absorbed, thus leaving green available by reflection and transmission. On the surface of the leaf (Figure 8.1), the cells of the outermost layer (the epidermis) are designed to protect the inner cells where the workings needed for gathering the sunlight used for photosynthesis and other chemistry necessary to the life of the plant are found. That is, the more delicate cells, beneath the epidermis, are involved in production of carbohydrates as well as the movement of nutrients in and products out of the leaf. The epidermis, exposed to the atmosphere, has cells that are usually thicker and are covered by a waxy layer made up of long- chain carboxylic acids that have hydroxyl groups (–OH) at or near their termini. These so-called omega hydroxy acids can then form esters using the hydroxyl group of one and the carboxylic acid of the next. This yields long-chain polyester polymers called “cutin.” As indicated in the earlier discussion of cells and, in particular, regarding the fatty acids of cell walls, the fatty acids found in the epidermis generally consist of an even number of carbon atoms, and for cutin, the sixteen carbon (palmitic acid) family (Figure 8.2) and the eighteen carbon family (oleic acid bearing a double bond or the saturated analogue stearic acid) are common. While one terminal hydroxyl group is usual (e.g., 16-hydroxypalmitic acid, 18-hydroxyoleic acid, or its saturated analogue 18-hydroxystearic acid) more than one (allowing for cross-linking) is not uncommon (e.g., 10,16-dihydroxypalmitic and 9,10,18-trihydroxystearic acid).

Beginning with fruit set (generally the grape berry is now between 1.5 and 3.0 mm, i.e., less than 1/ 8 of an inch in diameter) the grape berry growth is divided into three stages. Stages I and III correspond to periods of rapid growth, and the intervening slow growth phase is called Stage II. Generally the slow growth stage (Stage II) corresponds to the slowing of Stage I and the acceleration of Stage III, but it is clear that different grape cultivars have stages of different lengths even under ostensibly identical conditions. In the first stage of fruit set (also called “nouaison”) the actual development of the flower ovary into the grape berry begins. The seeds in the two seed cavities (the locules) and the flesh (the pericarp) begin to take form. The pericarp separates into the exocarp (the skin with its cuticle—a thin wax coating) and the mesocarp. The mesocarp, as it grows and divides, will eventually (by the end of Stage III) account for more than 90% of the grape’s weight. The exocarp, significantly thinner than the mesocarp, may be only five or six cells thick, and the cuticle only several layers of lipids (waxy, fatty acid esters, and compounds similar to those of cell walls and the chloroplast envelope, see pages 30 and 31). It is in this stage that the as yet undeveloped berries are green and hard (it has been sug¬gested that this is because chlorophyll is present and photosynthesis in the berry—as well as in leaves—is occurring). The berries are low in sugar (sucrose) but high in carboxylic acids, predominately malic acid and tartaric acid along with, generally, a lesser amount of ascorbic acid (vitamin C), hydroxycinnamic acid, and some acidic tannins (Figures 13.1 and 13.2). The grape berry structure is generally divided into three types of tissue: skin, flesh, and seed (Figure 13.3). The first, skin, as already mentioned is also known as exocarp.

Specialized wines will have often have passed through similar sequences of grape maturation, harvest, and fermentation (which may or may not be carried to completion) typical of more normal wines but are, nonetheless, treated somewhat differently. Wines developed for shipment, such as Port, Madeira, and Sherry, discussed here, and wines developed from grapes infected with the fungal ascomycete known as Botrytis cinerea (aka the Noble Rot), wines produced from frozen grapes (Ice wine), and wines produced from grapes similar to those grown in the Champagne region of France and destined to become “sparkling wines,” to be discussed subsequently, are all slightly different from the general types already described. And yet, because the compounds initially found in the grapes enjoy the same precursors and are doubtlessly very similar save for their terroir and their individual genomic and epig¬enomic differences, all but the final treatments they undergo are somewhat similar. Indeed, in that vein, Port and Madeira wines apparently originated in Portugal and Sherry in Spain, and the preferred grapes from which the preferred beverages are made continue to grow in and or near the initial locations. Other growing regions do try, with greater or lesser success, to create similar beverages. Port, Sherry, and Madeira wines are all called “fortified” beverages. They are generally higher in alcohol content and other flavorings than those produced by typical fermentation processes and have one or two additional steps that are associated with their processing. The first step involves producing a “distilled beverage.” In this process a portion of the wine produced in the usual way by fermentation is subjected to the process of distillation in the presence of air. In that process the wine is heated above the temperature at which it vaporizes (different components vaporizing at different temperatures) and then the vapors produced are removed, condensed, and separated from the residue. Low- boiling materials such as water (H2O, the major constituent of wine), methyl alcohol (methanol [CH3OH] of which there are traces), acetaldehyde (ethanal [CH3CHO] produced by oxidation of ethanol), and perhaps surprisingly, ethyl alcohol (ethanol [CH3CH2OH]), as well as other low-boiling components (e.g., some esters) are removed.

The end of fermentation, signaled by density measurements, the alcohol-driven death of the Saccharomyces cerevisiae strain that was used, the cessation of evolution of carbon dioxide, and the generally accepted passage of the several weeks over which time the fermentation has been permitted to extend, is followed by the previously discussed (Chapter 16) process of racking. The racking, as noted earlier, will separate most of the precipitated solids that are present or have developed during the fermentation process (e.g., accumulated seed and twig pieces not previously removed, insoluble carboxylic acid salts, dead yeast cells, and other solids [the lees]) from the fermented juice. But the wine may not yet be clear. Indeed, the wine may need racking once or twice more for clarification before a final filtration to produce the appropriate bright and clear beverage-quality wine. The last, or even a penultimate racking, might be done into an oaken vessel and should be done into oak if a red wine is being finished (European or American oaks are commonly used, but with different results, vide infra). However, it is important that regardless of the color of the wine each racking operation be done as carefully as possible to exclude transfer of solids and oxygen. At this stage of finishing, the oxygen will probably not be utilized in biochemical processes, barring the presence of microbial life, and normal oxidation of phenols and alcohols in the wine will have been inhibited by the presence of carbon dioxide (which replaced the oxygen in the solution during fermentation). Thus, if oxygen is introduced, it is likely that unwanted oxidation products might form. The final racking for white wines (excluding Champagne, other “sparkling” wines, and some specialty beverages to be considered later) is generally carried out so that the beverage can rest for a few months (often with cooling to inhibit deleterious processes occurring as a result of aging) before filtering and bottling.

We show that, in general, the translational average over a spatial variable---discussed by Backus \cite{backus}, and referred to as the equivalent-medium average---and the rotational average over a symmetry group at a point---discussed by Gazis et al. \cite{gazis}, and referred to as the effective-medium average---do not commute. However, they do commute in special cases of particular symmetry classes, which correspond to special relations among the elasticity parameters. We also show that this noncommutativity is a function of the strength of anisotropy. Surprisingly, a perturbation of the elasticity parameters about a point of weak anisotropy results in the commutator of the two types of averaging being of the order of the {\it square\/} of this perturbation. Thus, these averages nearly commute in the case of weak anisotropy, which is of interest in such disciplines as quantitative seismology, where the weak-anisotropy assumption results in empirically adequate models., 16 pages, 1 figure. arXiv admin note: text overlap with arXiv:1601.02969

We examine the sensitivity of the Love and the quasi-Rayleigh waves to model parameters. Both waves are guided waves that propagate in the same model of an elastic layer above an elastic halfspace. We study their dispersion curves without any simplifying assumptions, beyond the standard approach of elasticity theory in isotropic media. We examine the sensitivity of both waves to elasticity parameters, frequency and layer thickness, for varying frequency and different modes. In the case of Love waves, we derive and plot the absolute value of a dimensionless sensitivity coefficient in terms of partial derivatives, and perform an analysis to find the optimum frequency for determining the layer thickness. For a coherency of the background information, we briefly review the Love-wave dispersion relation and provide details of the less common derivation of the quasi-Rayleigh relation in an appendix. We compare that derivation to past results in the literature, finding certain discrepancies among them.

Gaseous mixtures of HCl and vinylacetylene were permitted to react in Pyrex IR cells (NaCl windows). Gaseous 4-chloro-1,2-butadiene and 2-chloro-1,3-butadiene (chloroprene) were the major products. Kinetic data (FTIR) generated a rate expression in concert with surface catalysis. Computational studies involving surface associated water provide a view that accounts for the experimentally determined orders and a bifurcated pathway producing both products. The results are in accord with wall-adsorbed reactant(s) as well as previously reported computational studies on the reactants.

Improved protocols for the preparation of 1-bromodihydrocodeinone (1-bromohydrocodone) and 1-bromo-14-hydroxydihydrocodeinone (1-bromooxycodone) and synthesis of the corresponding 1-chloro and 1-iodo derivatives have been achieved using the corresponding N-halosuccinimides in acidic milieu. The corresponding 1-carboethoxy derivative of 14-hydroxydihydrocodeinone (1-carboethoxyoxycodone) has been prepared by Pd-catalyzed reaction with carbon monoxide in ethanol. The ester was hydrolyzed to the corresponding zwitterionic amino acid.

The Diels–Alder reaction between (R)-(−)-methyl (Z)-3-(4,5-dihydro-2-phenyl-4-oxazolyl)-2-propenoate (1) and cyclopentadiene in the presence of one equivalent of Et2AlCl gave stereochemical results opposite to those obtained with one equivalent of EtAlCl2. Energy minimizations of proposed complexes of these Lewis acids with the chiral dienophile at the RHF/3–21G level suggest that the aluminum is tetrahedrally complexed with Et2AlCl, but bound in a trigonal bipyramid with EtAlCl2. These complexes expose the diastereotopic faces of the dienophile to reaction with diene.

Beginning with (+)-serine or (-)-serine, as appropriate, convenient, high-yield, enantioselective synthesis of all eight stereoisomeric 2-hydroxymethyl-3,4-dihydroxypyrrolidines (the enantiomeric pairs of iminoribitol, -arabinitol, -xylitol, and -lyxitol) can be effected. The absolute configuration of the starting amino acid defines the set of azasugars produced.

A series of pyridine-2-carbaldoximes, all of which are substituted at the 4- or 5-position with derivatives of the corresponding carboxylic acids, have been prepared via the corresponding pyridine-2-carbaldehydes.

Mixtures of gaseous hydrogen chloride and gaseous 2-butyne at total initial pressures less than 500 Torr, and at temperatures between 296 and 336 K, react in Pyrex IR cells (NaCl windows) to yield only (Z)-2-chloro-2-butene, i.e., the product of net trans (or anti or antarafacial) addition. Kinetic measurements have been made by observing the reaction throughout its course utilizing FT-IR spectroscopy. It is concluded that surface catalysis is required for product formation and that the reaction is occurring at the walls

A single N-chloromethylcodinium iodide has been isolated from the reaction of chloroiodomethane with codeine. Complete proton and carbon nmr and X-ray analyses dictate that this stable material bears the chloromethyl group axial. It is identical (except for the anion) to one of the salts obtained on long term storage of codeine in dichloromethane

A series of 2-pyridinecarbaldoximes and salts derived from them by methylation of the pyridine nitrogen, all of which are substituted at the 3-position with carbon (i.e., derivatives of nicotinic acid and its homologues) or oxygen, have been prepared.

The rates of disappearance of gaseous hydrogen chloride (-d[HCl]/dt) and 1,3-butadiene and appearance of the gaseous products 3-chloro-l-butene and (E)- and (Z)-1-chloro-2-butene (+d[products]/dt) in Pyrex IR cells at 295 K and total initial pressures of about 450 torr are found to be proportional to the surface-to-volume ratio (S/V) of the reaction vessel.

A series of 2-pyridinecarbaldoximes and salts derived from them by methylation of the pyridine nitrogen, all of which are substituted at the 3-position with carbon (i.e., derivatives of nicotinic acid and its homologues) or oxygen, have been prepared.

The rates of disappearance of gaseous hydrogen chloride (-d[HCl]/dt) and 1,3-butadiene and appearance of the gaseous products 3-chloro-l-butene and (E)- and (Z)-1-chloro-2-butene (+d[products]/dt) in Pyrex IR cells at 295 K and total initial pressures of about 450 torr are found to be proportional to the surface-to-volume ratio (S/V) of the reaction vessel.