ABSTRACT This paper investigates the drivers of long term real interest rates in Brazil. It is shown that long term yield on inflation linked bonds are driven by yields on 10 year interest rates of United States (US) government bonds and 10 year risk premium, as measured by the Credit Default Swap (CDS). Long term interest rates in Brazil were on a downward trend, following US real rates and stable risk premium, until the taper tantrum in the first half of 2013. From then onwards, real interest rates rose due to the increase in US real rates in anticipation of the beginning of monetary policy normalization and, more recently, due to a sharp increase in Brazilian risk premium. Policy interest rates do not significantly affect long term real interest rates.

Tapers in group 1–4 were manufactured from TiAl6V4 ELI, tapers in group 5–7 were manufactured from CoCr28Mo6 (shaded in grey).

IntroductionModular hip implants enables a more precise adaptation of the prosthesis to the patient’s anatomy. However, they also carry the risk of increased revision rates due to micromotion at the taper junction. In order to minimize this risk, one potential solution is to establish an adhesive bond between the metal taper junctions. Load-stable bonding techniques, already successfully employed in dentistry for connecting materials such as metals and ceramics or different alloys, offer a promising approach. Nevertheless, the bond strength of tapered adhesive bonds in modular hip implants has not been investigated to date.Materials and methodsTwenty-eight tapered junctions, consisting of a taper (female taper) and a trunnion (male taper) were turned using TiAl6V4 ELI (n = 16) and CoCr28Mo6 (n = 12). The process parameters cutting speed (vc = 50 m/min or 100 m/min) and feed (f = 0.1 mm, 0.05 mm or 0.2 mm) were varied for the trunnions. For each set of process parameters, one trunnion and one taper were additionally subjected to sandblasting. To investigate the effect of geometry, angular mismatch in the samples were measured. The taper pairs were bonded with a biocompatible adhesive, and push-out tests were subsequently performed.ResultsThe push-out forces generated from the taper connections where both tapers were sandblasted showed a mean push-out force of 5.70 kN. For the samples with only the trunnion sandblasted, the mean force was 0.58 kN, while for the samples with only taper sandblasted the mean push-out force was 1.32 kN. When neither of the tapers was sandblasted the mean push-out force was 0.91 kN. No significant effect of the process parameters on the push-out force was observed. Only the reduced valley depth Svk showed a slight correlation for the CoCr28Mo6 samples (R2 = 0.54). The taper pairs with taper mismatch (between trunnion and taper) greater than |0.1°| did not show lower push-out forces than the specimens with lower taper mismatch.ConclusionsSandblasted and adhesive-bonded tapered connections represent a viable suitable alternative for modular hip implant connections. Slight differences in taper geometry do not result in reduced push-out forces and are compensated by the adhesive. In mechanically joined tapers these differences can lead to higher wear rates. Further investigation under realistic test conditions is necessary to assess long-term suitability.

Vitrified Bond Wheel Market Outlook

In 2023, the global vitrified bond wheel market size was estimated at USD 1.2 billion, with projections suggesting it will reach USD 2.6 billion by 2032, growing at a compound annual growth rate (CAGR) of 8.2% over the forecast period. This growth is driven by multiple factors, including advancements in manufacturing technologies and increasing demand across various industries such as automotive, aerospace, and electronics.

The rapid growth of industrialization, particularly in emerging economies, is a significant factor propelling the vitrified bond wheel market. Expanding manufacturing activities necessitate efficient grinding and cutting tools, thereby boosting the demand for vitrified bond wheels. Technological advancements in the production of these wheels, which enhance their durability and performance, are further fueling market growth. Additionally, the shift towards automation in manufacturing processes increases the need for high-precision grinding tools, creating more opportunities for market expansion.

Furthermore, the rising demand for high-quality surface finishes in metalworking and machining operations significantly contributes to market growth. Vitrified bond wheels are known for their superior grinding capabilities and longer service life, making them ideal for achieving fine surface finishes. The automotive industry's continuous evolution, driven by the need for lightweight and high-strength components, also plays a crucial role. Vitrified bond wheels are extensively used in the production of automotive parts, including engine components and transmission systems, thereby driving market demand.

Another critical growth factor is the increased focus on sustainability and environmental regulations. Vitrified bond wheels, which are less prone to wear and tear, offer a sustainable solution by reducing waste and operational costs. Additionally, their ability to work at higher speeds with minimal environmental impact aligns with stringent regulations, further propelling their adoption across various industries. The ongoing research and development activities aimed at enhancing the efficiency and effectiveness of vitrified bond wheels are expected to create new growth avenues in the market.

Regionally, Asia Pacific dominates the vitrified bond wheel market due to its robust manufacturing sector and substantial investments in industrial development. Countries like China, India, and Japan are key contributors, driven by the growing automotive and electronics industries. North America and Europe also present significant market opportunities, supported by advanced technological infrastructure and high adoption rates of precision grinding tools. Latin America and the Middle East & Africa, although smaller in market share, are expected to witness steady growth due to increasing industrial activities and investments in manufacturing capabilities.

Product Type Analysis

The vitrified bond wheel market is segmented by product type into straight wheels, tapered wheels, cylindrical wheels, and others. Straight wheels hold a significant market share due to their extensive use in precision grinding applications. They are particularly favored in the automotive and aerospace industries for their ability to deliver high-quality surface finishes. The demand for straight wheels is expected to remain robust, driven by continuous advancements in the automotive sector and increasing production of complex aerospace components.

Tapered wheels are another essential segment, known for their versatility and efficiency in grinding operations that require a tapered profile. These wheels are extensively used in metalworking and tool sharpening applications. The growing need for precision tools in various industries, including metalworking and machinery, is driving the demand for tapered wheels. Additionally, the increasing focus on achieving high precision and accuracy in manufacturing processes further bolsters the market for tapered wheels.

Cylindrical wheels, characterized by their cylindrical shape, are predominantly used for cylindrical grinding operations. These wheels are crucial in the production of cylindrical components, such as shafts and rods, across various industries. The demand for cylindrical wheels is driven by the growing need for high-precision and high-tolerance components in sectors like automotive, aerospace, and industrial machinery. Continuous innovations in grinding technologies and the development of advanced cylindrical wheels with enhanced performance characteristics are