bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyethylene, High Density
Authors: Benham Elizabeth , McDaniel Max 
Published: May 2005

AbstractPolyethylene (PE) is the most widely used plastic throughout the world, and high density polyethylene (HDPE) is the most widely used type of polyethylene. It was invented independently in the early 1950s in three different laboratories across the world. Commercial catalytic processes were quickly developed based on three different transition metals: Cr, Mo, and Ti. Today, hundreds of different grades of HDPE are manufactured by dozens of different commercial processes worldwide to meet the demands of applications too numerous to describe completely. The properties of HDPE can be made to vary widely for these specialized applications by varying its molecular structure, such as the molecular weight (MW); the MW distribution; the amount; type, and placement of short‐chain branching; the end group composition; and the degree of long‐chain branching. These affect the stiffness of the polymer; the gloss or clarity; the impact, puncture, and tear resistance; chemical resistance; electrical insulation properties; molding characteristics; and tensile properties. Common uses for HDPE include food packaging, bottles, bags, medical applications, drums, fuel tanks and other automotive parts, pipe, film, geomembranes, toys, film, and filament.
Maintenance
Authors: Levitt Joel D. 
Published: May 2005

Abstract
One of the goals of good management is to operate with a predictive and preventive maintenance program that prevents unscheduled utility service interruptions and machine breakdowns. A reasonable cost of such a program contributes to the profitability of manufacturing plants and results in reduction of operating costs and increased productivity. This all can be accomplished by organizing, managing, and controlling maintenance.
A good maintenance program should include designing, laying out, and constructing facilities with maintenance in mind; providing for reliable utilities and their uses; developing a maintenance organization and program while the facility is under construction; developing a simple, practical, predictive, and preventative maintenance program; supplementing an in‐house maintenance organization with contract maintenance; motivating the maintenance workers; organizing safety as an important function of any maintenance program; including environmental care and appreciation in any maintenance program; developing an energy conservation program as part of the maintenance program; creating a partnership with suppliers and equipment manufacturers; cooperating with other service groups of the facility; and controlling costs and assuring budget responsibility.
Malts and Malting
Authors: Mulder Chris J. 
Published: May 2005

Abstract
The malting process consists of three key steps: steeping, whereby barley is moistened to about 45% moisture; germination, wherein rootlets (sprouts) and a stem (acrospire) emerge while enzymes are formed that alter the cellular structure and composition; and kilning, where barley is dried to preserve enzyme activity and to impart flavor. Nearly all of the malt produced is used to make beer. Barley is grown in Minnesota, North and South Dakota, Montana, and other western States. Barley varieties are developed specifically for good malting and brewing traits. Less than 50% of the U.S. barley crop is converted into malt. World malt production in 2003 was ∼12 million metric tons. The 2003 U.S. production was 2.6 million tons, with stagnant growth during the last few years. Large United States and Canadian producers are Busch Agricultural Resources, Inc., Cargill Malt, Conagra Malt, Rahr Malting Co., and International Malting Co. There is excess malting capacity, resulting in low margin commodity pricing. Production and raw material costs are ∼$230/t.
Nitric Acid
Authors: Clarke Stephen I. , Mazzafro William J. ,   Updated by Staff
Published: May 2005

AbstractNitric acid is a strong acid, a powerful oxidizing compound, and a nitrating agent. These properties make it an important basic chemical compound that is used in the production of many important chemicals such as fertilizers, polyurethanes, organic chemical intermediates, pharmaceuticals, synthetic fibers, dyes, insecticides, fungicides, and explosives. Nitric acid is produced through the oxidation of ammonia to nitrogen oxides, which are then absorbed by water to produce nitric acid. Weak nitric acid processes produce nitric acid in the concentration range of 50–65 wt %. The two main types of weak acid process are the monopressure process and the dual‐pressure process. The monopressure process operates at either moderate (0.3–0.6 MPa) or high pressure (0.7–1.2 MPa). The dual‐pressure process performs the conversion of ammonia at atmospheric or moderate pressures (0.3–0.6 MPa) and the absorption of nitrogen oxides at high pressure (1.1–1.5 MPa). Nitrogen oxides in the tail gas leaving the process are reduced to below environmental regulatory limits by either extended absorption or catalytic abatement. Strong nitric acid of 98–99 wt % is produced by either extractive distillation or direct strong nitric acid process. The extractive distillation process uses either magnesium nitrate or sulfuric acid as a dehydrating agent to surpass the maximum boiling azeotrope of nitric acid. The direct strong nitric acid process is similar to the weak nitric acid process, but has additional processing steps that bypass the azeotrope to produce strong nitric acid. Information on the chemical and physical properties, manufacturing processes, materials of construction, uses, safety and health, analytical methods, and producers of nitric acid is included.
Nitrogen
Authors: Hardenburger Thomas L. , Ennis Matthew ,   Updated by Staff
Published: May 2005

Abstract
Nitrogen is an important industrial gas and an element that is essential to all life. Most naturally occurring, noncombined nitrogen exists as a diatomic gas sometimes referred to as dinitrogen. Dinitrogen is an extremely stable, relatively inert molecule. High temperatures are generally required to coax its reactivity. Due to its inert nature, gaseous nitrogen finds wide application in many industrial processes as a blanketing and purging agent. Dinitrogen liquifies at −196°C to a colorless liquid. Liquid nitrogen is used in many applications as an inert, expendable refrigerant. All commercial nitrogen uses atmospheric air as the feedstock. The principal manufacturing processes include cryogenic distillation, pressure swing adsorption, membrane permeation, and combustion‐based processes. At the present time, cryogenic distillation is the most significant. Commercial nitrogen is distributed in very large volumes by pipeline or in smaller volumes in liquified form for use or vaporization at the use point or in compressed gaseous form in steel cylinders. Nitrogen is nontoxic but does not support life, therefore care is required before entering areas suspected of being nitrogen‐enriched.
Recycling, Oil
Authors: Brinkman Dennis W. , Parry Barbara J. 
Published: May 2005

AbstractThis article discusses the recycling of used petroleum oils, especially those employed as lubricants. The term oil includes a variety of liquid or easily liquefiable, unctuous, combustible substances that are soluble in ether, but not in water, and that leave a greasy stain on paper or cloth. These substances can include animal, vegetable, and synthetic oils, but usually the word oil refers to a mineral oil produced from petroleum. An oil that has been used or contaminated, or both, but not consumed, can often be recycled to regain a useful material regardless of its origin. In the past, used or contaminated oil was often considered a waste and was disposed of in a variety of ways, including incineration, road oiling, landspreading, municipal landfills, and dumping on the ground or into storm sewers. However, growing public awareness of the societal costs of pollution, the advent of periodic petroleum shortages, and increased prices for most kinds of oils and oil products have combined to generate a strong interest in developing ways to conserve the valuable energy and resource content of these products.
Perchloric Acid and Perchlorates
Authors: Mendiratta Sudhir K. , Dotson Ronald L. , Brooker Robert T. ,   Updated by Staff
Published: May 2005

AbstractPerchlorates are chlorine oxyanions in which the chlorine is present in its highest oxidation state (+7). The most outstanding property of the perchlorates, which are more stable than other chlorine oxyanions, is their oxidizing ability. Most cations form perchlorate compounds. Commercially, one of the most important compounds of this class is ammonium perchlorate, used as an oxidizer in propellant formulations for solid rocket fuel. Perchlorates are also used in explosives and pyrotechnics, in dry batteries, and in oxygen‐generation systems. Commercial perchlorates are prepared by electrochemical oxidation. Perchloric acid, commercially available as a 72% aqueous solution, is one of the strongest of the mineral acids. Properties, manufacturing, and uses of these compounds are described.
Phenol
Authors: Wallace Jim ,   Updated by Staff
Published: May 2005

AbstractPhenol (hydroxybenzene) is a commercially important derivative of benzene. It is the primary feedstock for the production of epoxy resins and polycarbonates, phenolic resins and molding compounds, caprolactam, aniline, and other chemical derivatives.More than 95% of the phenol consumed is produced by the cumene peroxidation process. Phenol is a white, crystalline mass at room temperature. Its freezing point is 40.91°C. It is a protoplasmic poison that is corrosive to living tissue and is readily absorbed through the skin.Phenol’s consumption growth rate is based primarily on its use in engineering plastics such as bisphenol A, polycarbonates, polyetherimide and poly(phenylene oxide), and epoxy resins for the electronics industry. Due to the nature of its end markets, phenol consumption is highly cyclic. Future production processes for phenol will be affected by the disparity in growth rate between phenol and its coproduct, acetone.
Pyrolysis, Flash Vacuum
Authors: McNab Hamish 
Published: May 2005

Abstract
The use of the technique of flash vacuum pyrolysis (FVP) in mechanistic and synthetic organic chemistry is reviewed. The design of typical apparatus and typical reactions used in FVP experiments are discussed. Examples of protocols for mechanistic studies and the investigation of reactive intermediates (use of isotopic labeling, gas‐phase analytical methods, and matrix isolation) are given. The synthetic applications of FVP are considered with respect to the new bond(s) generated in the pyrolysis step, namely, alkanes, alkenes, alkynes, aromatics, heteroatom‐containing functional groups, and heterocycles.
High Pressure Chemistry
Authors: Hubbard Colin D. , van Eldik Rudi 
Published: May 2005

AbstractThe technology associated with application of hydrostatic pressure in chemistry is presented. Apparatus and equipment range from a straightforward autoclave‐type arrangement to more sophisticated techniques of subjecting materials or chemical reactions in solution to pressure, and monitoring events caused by pressure application while the system is under pressure (ie,in situ). Spectroscopic detection is the principal monitoring technique inin situmethods. The wide span of time ranges of changes taking place during a pressure cycle requires different types of technologies and these are described. The type of system under investigation directs the choice of method and the range of pressure applied. For synthetic and preparative solution chemistry, pressures up to a few thousand megapascals (MPa) have been used. For processing of materials to bring about a change in properties, pressures up to 600 MPa are usually adequate, whereas for most mechanistic studies pressures > 200 MPa are rarely used (1 atm = 1.01325 × 105Pa; 1 Pa = 1 N/m2). Examples of systems studied from organic chemistry, inorganic chemistry, bioinorganic chemistry, and colloid chemistry are provided. These clearly illustrate the value of applying hydrostatic pressure and demonstrate insight into understanding physicochemical and chemical changes that occur. Such insight is not normally achievable by other experimental approaches and highlights the unique value and success of high pressure technology in chemistry.
Pharmaceuticals, Large‐Scale Synthesis
Authors: Gupton B. Frank , Grozinger Karl 
Published: May 2005

Abstract
The capability to fulfill drug substance requirements in support of the various elements of pharmaceutical development is an essential component of the overall drug development process. The preparation of bulk materials for toxicology, formulation development, and clinical supplies can represent a significant challenge, depending on such factors as the molecular complexity of the drug candidate, the quantities of materials required, and the state of development of the synthetic process. As a drug candidate proceeds through the various stages of drug development and into commercial launch, the challenge of process development is to ensure the uninterrupted supply of drug substance without compromising the ability to ultimately supply a commercially viable chemical process. This chapter serves to provide a general overview of the issues and requirements associated with the development and scale‐up of chemical processes for bulk active drug substances. An account of the nevirapine process development efforts at Boehringer Ingelheim is also provided as an example of the evolution of a chemical process from the initial efforts in medicinal chemistry through to commercial‐scale operations.
Ethnic expansions and between‐group differences in children's health: A case study from the Rukwa Valley, Tanzania
Authors: Hadley Craig 
Published: May 2005

AbstractThe Sukuma ethnic group appears to be expanding across Tanzania at a rate far greater than other ethnic groups in the area. In this paper, the household‐level dynamics that may be fueling this expansion are explored by comparing measures of infant mortality and child health with another Tanzanian ethnic group, the Pimbwe. Consistent with expectations, the Sukuma appear to have comparable levels of fertility but lower child mortality. As predicted, compared to the Pimbwe, Sukuma children are also heavier and taller for their age, suggesting better nutritional status. Four hypotheses about why the Sukuma are so successful in this area are addressed. Surprisingly, the results show that household food security and wealth are not related to children's nutritional status, nor can maternal effects account for the observed health differences. Several lines of evidence suggest that different patterns of infant feeding practices may underlie the differences in children's nutritional status. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Growth and nutritional status of male adolescent laborers in Ankara, Turkey
Authors: Duyar İzzet , Özener Barış 
Published: May 2005

AbstractUndernutrition, pathogenic agents, and poor living conditions are of primary importance in the evaluation of adverse environmental conditions' effects on human growth; but child labor (an equally significant factor, especially in underdeveloped countries) is generally overlooked or ignored. The aim of this study is to focus on this subject and clarify the effects of labor on the physical growth and nutritional status of child and adolescent laborers. In this study, the height and weight of 532 male adolescent laborers aged 13.5–18.5 years and their nonlaboring peers (n = 451) (the control group) were measured by standard anthropometric techniques and equipment. The individuals of both groups come from lower socioeconomic strata and share similar living conditions. Data were transformed to z‐scores, using the US Center for Disease Control and Prevention's 2000 growth charts. The analyses show that the z‐scores for height‐for‐age, weight‐for‐age, and body mass index (BMI)‐for‐age were negative in both groups. The z‐scores of laborers' height‐for‐age and weight‐for‐age values lie below the controls', but there is no significant difference between the two groups' BMI‐for‐age scores. In the laboring group, the percentages of stunting (−2 SD of height‐for‐age), underweight (−2 SD of weight‐for‐age), and wasting (−2 SD of BMI‐for‐age) were 14.3, 2.6, and 0.2, respectively. These values suggest that malnutrition is not a common problem among adolescent laborers living in Ankara; but laboring is an important cause of faltering in growth, particularly in linear growth, in less or underdeveloped economic environments. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Dental caries among the prehispanic population from Gran Canaria
Authors: Delgado‐Darias T. , Velasco‐Vázquez J. , Arnay‐de‐la‐Rosa M. , Martín‐Rodríguez E. , González‐Reimers E. 
Published: May 2005

AbstractThe island of Gran Canaria was inhabited in pre‐Hispanic times by people of North African origin who arrived on the island towards the second half of the first millennium BC. In previous studies, we reported that there are some differences between the coastal inhabitants from Gran Canaria, mainly buried in tumuli, and those from the central mountains, mainly buried in caves. For example, the prevalence of auricular exostoses is higher among the population interred in coastal tumuli when compared with the inland population. This finding may be explained by the practice of marine activities, as supported by chroniclers' reports, by archaeological data, and by bone trace‐element analysis, which point to a more intense consumption of marine products by the inhabitants of the coastal regions. Dental caries epidemiology is one of the most important ways in which the diet of past populations can be reconstructed. The purpose of this study is to assess the prevalence and intensity of caries among the pre‐Hispanic population of Gran Canaria, in order to increase our knowledge about the dietary habits of these people, and to search for differences among the population buried in caves and that buried in tumuli. We studied a total of 791 individuals. Sex was estimated in 561 cases, and age at death, following Brothwell's criteria, in 549. We found that 66.95% of individuals buried in caves and 58.91% of those buried in tumuli showed at least one carious lesion. The proportion of carious teeth was significantlty higher among the population buried in caves (median = 15.71%, interquartile range (IR) = 0–33.33%) than among the population buried in tumuli (median = 6.25%, IR = 0–20%, P = 0.001). Type of burial is the main factor associated with the proportion of carious teeth.These data suggest that the population buried in caves had a different dietary pattern from that of those buried in tumuli. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Population continuity vs. discontinuity revisited: Dental affinities among late Paleolithic through Christian‐era Nubians
Authors: Irish Dr. Joel D. 
Published: May 2005

AbstractThe present study revisits a subject that has been a source of long‐standing bioarchaeological contention, namely, estimation of Nubian population origins and affinities. Using the Arizona State University dental anthropology system, frequencies of 36 crown, root, and intraoral osseous discrete traits in 12 late Pleistocene through early historic Nubian samples were recorded and analyzed. Specifically, intersample phenetic affinities, and an indication of which traits are most important in driving this variation, were determined through the application of correspondence analysis and the mean measure of divergence distance statistic. The results support previous work by the author and others indicating that population discontinuity, in the form of replacement or significant gene flow into an existing gene pool, occurred sometime after the Pleistocene. This analysis now suggests that the break occurred before the Final Neolithic. Samples from the latter through Christian periods exhibit relative homogeneity, which implies overall post‐Pleistocene diachronic and regional population continuity. Yet there are several perceptible trends among these latter samples that: 1) are consistent with documented Nubian population history, 2) enable the testing of several existing peopling hypotheses, and 3) allow the formulation of new hypotheses, including a suggestion of two post‐Pleistocene subgroups predicated on an age‐based sample dichotomy. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Body proportions in ancient Andeans from high and low altitudes
Authors: Weinstein Karen J. 
Published: May 2005

AbstractLiving human populations from high altitudes in the Andes exhibit relatively short limbs compared with neighboring groups from lower elevations as adaptations to cold climates characteristic of high‐altitude environments. This study compares relative limb lengths and proportions in pre‐Contact human skeletons from different altitudes to test whether ecogeographic variation also existed in Andean prehistory. Maximum lengths of the humerus, radius, femur, and tibia, and femoral head breadth are measured in sex‐specific groups of adult human skeletons (N = 346) from the central (n = 80) and the south‐central (n = 123) Andean coasts, the Atacama Desert at 2,500 m (n = 102), and the southern Peruvian highlands at 2,000–3,800 m (n = 41). To test whether limb lengths vary with altitude, comparisons are made of intralimb proportions, limb lengths against body mass estimates derived from published equations, limb lengths against the geometric mean of all measurements, and principal component analysis. Intralimb proportions do not statistically differ between coastal groups and those from the Atacama Desert, whereas intralimb proportions are significantly shorter in the Peruvian highland sample. Overall body size and limb lengths relative to body size vary along an altitudinal gradient, with larger individuals from coastal environments and smaller individuals with relatively longer limbs for their size from higher elevations. Ecogeographic variation in relation to climate explains the variation in intralimb proportions, and dietary variation may explain the altitudinal cline in body size and limb lengths relative to body size. The potential effects of gene flow on variation in body proportions in Andean prehistory are also explored. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Brief communication: mtDNA variation in North Cameroon: Lack of asian lineages and implications for back migration from Asia to sub‐Saharan Africa
Authors: Coia Valentina , Destro‐Bisol Giovanni , Verginelli Fabio , Battaggia Cinzia , Boschi Ilaria , Cruciani Fulvio , Spedini Gabriella , Comas David , Calafell Francesc 
Published: May 2005

AbstractThe hypervariable region‐1 and four nucleotide positions (10400, 10873, 12308, and 12705) of the coding region of mitochondrial DNA (mtDNA) were analyzed in 441 individuals belonging to eight populations (Daba, Fali, Fulbe, Mandara, Uldeme, Podokwo, Tali, and Tupuri) from North Cameroon and four populations (Bakaka, Bassa, Bamileke, and Ewondo) from South Cameroon. All mtDNAs were assigned to five haplogroups: three sub‐Saharan (L1, L2, and L3), one northern African (U6), and one European (U5). Our results contrast with the observed high frequencies of a Y‐chromosome haplogroup of probable Asian origin (R1*‐M173) in North Cameroon. As a first step toward a better understanding of the evident discrepancy between mtDNA and Y‐chromosome data, we propose two contrasting scenarios. The first one, here termed “migration and asymmetric admixture,” implies a back migration from Asia to North Cameroon of a population group carrying the haplotype R1*‐M173 at high frequency, and an admixture process restricted to migrant males. The second scenario, on the other hand, temed “divergent drift,” implies that modern populations of North Cameroon originated from a small population group which migrated from Asia to Africa and in which, through genetic drift, Y‐chromosome haplotype R1*‐M173 became predominant, whereas the Asian mtDNA haplogroups were lost. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.