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The critical pH for passivation of steel balls during wet grinding of hematite ore was found to be 10.5. With slurry pH below this critical value, corrosion played a significant role in the total wear of steel and the wear was temperature dependent. Above this critical value, corrosion was prevented and wear of steel, mainly due to abrasion, was independent of grinding temperature. Potential measurements also indicated that steel balls were passive at pH 10.5. In the region of passivation, protection of steel by lime additions was 24–26 per cent and by silicate additions was 30–32 per cent over the temperature range 25°–65°C. Neither grinding temperature nor slurry pH had a significant effect on work done on ore as measured by the increase of minus 200 mesh ore during grinding.

Empirical studies reveal Black male student-athletes have both positive and negative experiences on predominantly White college and university campuses. Mindful also of race-based stereotypic beliefs about Black male student-athletes in collegiate sports, these phenomena warrant further discourse and scrutiny. Critical race theory is a race-centered theoretical and analytical framework that has shaped discourse on race and racism in intercollegiate athletics in recent years. Discourse in this chapter is therefore grounded in the narrative of critical race theory and focuses primarily on the academic and athletic plight of Black male student-athletes matriculating at predominantly White colleges and universities with National Collegiate Athletic Association affiliation.

Historically Black Colleges and Universities (HBCUs) were established during an era of legal segregation in the United States and, by providing access to higher education, added considerably to the progress of millions of Black Americans. Moreover, to the benefit of their students, faculties, staffs, alumni, and local communities, most HBCUs sponsor intercollegiate athletic teams. No doubt on these campuses, student-athletes are under pressure to meet academic and athletic demands. In this chapter, the central narrative is on the academic and athletic experiences of Black male student-athletes matriculating at HBCUs with National Collegiate Athletic Association affiliation. This chapter adds to the extant literature on the athletic status and academic plight of Black male student-athletes at HBCUs.

Equipment and typical results from cathodic protection surveying systems. In the simplest form, cathodic protection surveying of fixed offshore platforms is achieved by the so called ‘dipping’ technique, dipping a reference electrode into the sea and measuring a steel/sea potential with respect to it via an indicating voltmeter and a metallic connection to the topside steelwork. This procedure is allowed in NACE RP‐01–76 REF 36 but the standard does address the importance of placing the electrode close to platform members, distant from anodes and into areas of greatest shielding. The conventionally undertaken dip survey, particularly in geographic regions with substantial sea currents which cany the electrode away from structure members, is nothing better than a general indication of the overall level of protection. The probability is of errors indicating better levels than actually exist, due to the IR related voltage drops in the sea between the electrode location and the platform member.

GERMANY Corrosion protection by means of flame‐sprayed coal‐tar pitch. An unusual method has been employed to ensure the corrosion protection in hydro‐electric plant of the steel tunnel lining, penstocks and surge tank. This method is known as the Colarit flame spraying method and consists in applying coal‐tar pitch by means of a spray gun heated with propane gas. It has been developed by two German firms (Roos & Liebscher, Weiden, and Colarit‐Korro‐sionsschutzgesellschaft Düsseldorf).

Unlike conventional aircraft, birds can glide without a vertical tail. The purpose of this paper is to analyse the influence of dihedral angle spanwise distribution on lateral-directional dynamic stability by the simulation, calculation in the development of the bird-inspired aircraft and the flight testing.

The gliding magnificent frigatebird (Fregata magnificens) was selected as the study object. The geometric and mass model of the study object were developed. Stability derivatives and moments of inertia were obtained. The lateral-directional stability was assessed under different spanwise distributions of dihedral angle. A bird-inspired aircraft was developed, and a flight test was carried out to verify the analysed results.

The results show that spanwise distribution changing of dihedral angle has influence on the lateral-directional mode stability. All of the analysed configurations have convergent Dutch roll mode and rolling mode. The key role of dihedral angle changing is to achieve a convergent spiral mode. Flight test results show that the bird-inspired aircraft has a well-convergent Dutch roll mode.

The theory that birds can achieve its lateral-directional stability by changing its dihedral angle spanwise distribution may explain the stability mechanism of gliding birds.

This paper helps to improve the understanding of bird gliding stability mechanism and provides bio-inspired solutions in aircraft designing.

Important reserves of oil and gas, which are left to be discovered and produced, are mainly concentrated in challenging locations and under severe conditions such as high pressure (HP)/high temperature (HT). The presence of aggressive environments including H₂S, CO₂ and chlorides plus HP/HT causes a series of corrosion problems, which cost the oil industry billions of dollars a year. Thus, there is an increasing challenge for tubes (i.e. oil country tubular goods, for short, OCTG) used in producing oil and gas. The purpose of this study is to summarize different kinds of corrosion problems and their mitigation, to more efficiently protect OCTG from corrosion.

To effectively select proper mitigation methods, the mechanism of corrosion must be understood, which can be classified into four categories: sweet corrosion, sour corrosion, galvanic corrosion and microbiologically induced corrosion. Also, the effects of environmental and material factors on the corrosion rate are presented. Subsequently, current technology of mitigating these corrosion problems has been discussed, including the development of materials, application of chemical inhibitors and application of protective layers.

It is stressed that limits exist for each individual mitigation method; therefore, a careful balance between economic life of OCTG and safety in operation is required.

The main purpose of this essay is to give a brief review and detailed introduction and analysis about those technologies.

PAINTING is required on Service aircraft to protect the structure from corrosion under world wide operating conditions. It is also required for camouflage, purposes and marking.

Purpose: We examine how one's occupational class affects emotional experience. To do this, we look at both general affective outcomes (job satisfaction, respect at work, and life happiness) and the experience of specific positive emotions (overjoyed, proud, and excited) during the week.

Methodology/Approach: Using affect control theory simulations, we find the characteristic emotions of four occupational classes, derived from Maloney's (2020) block model analysis: everyday specialists, service-to-society occupations, the disagreeably powerful, and the actively revered. Using these characteristic emotions, we make predictions about how likely it is that individuals in these occupational classes will report workplace affective experiences: job satisfaction and respect at work, and broader affective experience: general happiness in the prior year. Lastly, we generate and test predictions about everyday emotional experience of positive emotions.

Findings: We find mixed results for our hypotheses. In general, our predictions regarding the actively revered as the highest status block in Maloney (2020) are supported for general happiness, job satisfaction, and daily emotional experience. However, we find higher probabilities of happiness and job satisfaction for the disagreeably powerful, a lower evaluation but higher power block, than were expected.

Research Limitations: The current analysis uses only 268 occupations out of the 650 occupational titles in the US Census three-digit occupational codes. An analysis that includes the entire occupational structure would be more definitive. Additionally, it would be preferable to have emotion-dependent variables that were specifically tied to work, rather than broader emotional experience, to have a cleaner test of our hypotheses about occupational identities.

Practical and Social Implications: Prior research has shown how the emotional experiences associated with different identity labels can explain mental health outcomes, workplace anger, and broader patterns of inequality (Foy, Freeland, Miles, Rogers, & Smith-Lovin, 2014; Kroska & Harkness, 2008, 2016; Lively & Powell, 2016). Understanding how occupational class elicits certain types of emotions in everyday interactions may help scholars explain differences in health and overall life satisfaction across occupations that are not explained by material resource differentiation.