Innovation in Homebuilding and the Future of Housing

Problem: The future of housing depends in part on innovation by homebuilders. Planners should know how to influence innovation in homebuilding in order to promote innovative practices that conserve the environment, improve quality, and reduce costs.

Purpose: This article explains challenges involved in innovation in home building, as well as providing planners with strategies to influence innovation in the industry.

Methods: I review the literature and identify sources of resistance to or acceptance of innovation in home building. I also report the results of two national surveys of innovation adoption and use regression analysis to test variables likely to inhibit or promote innovation.

Results and conclusions: Small builders receptive to innovation are likely to be led by a technology champion and to build custom homes for a relatively affluent and informed clientele. These firms provide a likely audience for technology innovations that require more upfront investment, as with some green building products, but can be marketed as highly innovative to homebuyers interested in higher performance in energy efficiency, sustainability or durability. In order to impact a larger portion of the housing market, large production builders should be the target for innovations that contribute to affordability in entry-level homes or to energy efficiency, sustainability and durability in higher priced houses.

Takeaway for practice: Planners aiming to encourage innovation in homebuilding should craft strategies that recognize the opportunities, the structure of the industry, and the factors influencing innovation adoption. Local builders with owners who champion innovation are good targets for demonstration programs that involve custom homes. Larger production builders will want strategies that can be replicated in multiple market areas, and are likely to avoid localities whose codes and regulations would require them to change their production models.

Research support: This research was partially funded by the U. S. Department of Housing and Urban Development under the Partnership to Advance Technology in Housing (PATH) program.     

Directional neighbor discovery in mmWave wireless networks

The directional neighbor discovery problem, i.e., spatial rendezvous, is a fundamental problem in millimeter wave (mmWave) wireless networks, where directional transmissions are used to overcome the high attenuation. The challenge is how to let the transmitter and the receiver beams meet in space under deafness caused by directional transmission and reception, where no control channel, prior information, and coordination are available. In this paper, we present a Hunting-based Directional Neighbor Discovery (HDND) scheme for ad hoc mmWave networks, where a node follows a unique sequence to determine its transmission or reception mode, and continuously rotates its directional beam to scan the neighborhood for other mmWave nodes. Through a rigorous analysis, we derive the conditions for ensured neighbor discovery, as well as a bound for the worst-case discovery time and the impact of sidelobes. We validate the analysis with extensive simulations and demonstrate the superior performance of the proposed scheme over several baseline schemes.     

Static fatigue of Hi-Nicalon™-S fiber at elevated temperature in air,steam, and silicic acid-saturated steam

A facility for testing SiC fiber tows in static fatigue and creep at elevated temperatures in air and steam was developed. Static fatigue of Hi-Nicalon™-S fibers was investigated at 800°C-1100°C at applied stresses between 115 and 1250 MPa in air, in Si(OH)₄(g)-saturated steam, and in unsaturated steam. Fibers tested in Si(OH)₄(g)-saturated steam and in air had silica scales throughout the test sections, but those tested in unsaturated steam did not develop scales near the steam injection point. Fiber lifetimes in static fatigue were shortest in unsaturated steam, intermediate in Si(OH)₄(g)-saturated steam, and longest in air. Failure strains did not exceed 0.3%. Steady-state strain rates and static fatigue lifetimes are modelled empirically by the Monkman-Grant relationship. Failure mechanisms are discussed.     

Detection of warfare agents in liquid foods using the brine shrimp lethality assay

The brine shrimp lethality assay (BSLA) was used for rapid and non-specific detection of biological and chemical warfare agents at concentrations considerably below that which will cause harm to humans. Warfare agents detected include T-2 toxin, trimethylsilyl cyanide, and commercially available pesticides such as dichlorvos, diazinon, dursban, malathion, and parathion. The assay was performed by introducing 50 μL of milk or orange juice contaminated with each analyte into vials containing 10 freshly hatched brine shrimp nauplii in seawater. This was incubated at 28 °C for 24 h, after which mortality was determined. Mortality was converted to probits and the LC(50) was determined for each analyte by plotting probits of mortality against analyte concentration (log(10)). Our findings were the following: (1) the lethal effects of toxins dissolved in milk were observed, with T-2 toxin being the most lethal and malathion being the least, (2) except for parathion, the dosage (based on LC(50)) of analyte in a cup of milk (200 mL) consumed by a 6-y-old (20 kg) was less than the respective published rat LD(50) values, and (3) the BSLA was only suitable for detecting toxins dissolved in orange juice if incubation time was reduced to 6 h. Our results support the application of the BSLA for routine, rapid, and non-specific prescreening of liquid foods for possible sabotage by an employee or an intentional bioterrorist act. Practical Application: The findings of this study strongly indicate that the brine shrimp lethality assay can be adapted for nonspecific detection of warfare agents or toxins in food at any point during food production and distribution.     

Length to diameter ratio of extrudates in catalyst technology I. Modeling catalyst breakage by impulsive forces

Natural or forced catalyst extrudate breakage is an important phenomenon during catalyst manufacture. Here, a two‐parameter model for predicting the reduction in the length to diameter ratio of catalyst extrudates due to breakage by impulsive forces as experienced in a laboratory drop test is developed. Part II will show how both parameters can be correlated with the strength of the extrudates and the severity of the drop test. For breakage by impulsive forces, the model reveals that extrudates are reduced in length to diameter ratio according to a pseudosecond‐order break law. Also, a tie‐in exists with the well‐known Golden Ratio that is famous for its inherent esthetic value. Applying the model to cases of “severity sequencing” and “severity conditioning” reveals the nonlinear behavior of the length to diameter ratio and yields results that are often nonintuitive and hard to get without this engineering analysis. © 2015 American Institute of Chemical Engineers AIChE J, 62: 639–647, 2016     

N‐Arylsulfonyl Indolines as Retinoic Acid Receptor‐Related Orphan Receptor γ (RORγ) Agonists

The nuclear retinoic acid receptor‐related orphan receptor γ (RORγ; NR1F3) is a key regulator of inflammatory gene programs involved in T helper 17 (T_H17) cell proliferation. As such, synthetic small‐molecule repressors (inverse agonists) targeting RORγ have been extensively studied for their potential as therapeutic agents for various autoimmune diseases. Alternatively, enhancing T_H17 cell proliferation through activation (agonism) of RORγ may boost an immune response, thereby offering a potentially new approach in cancer immunotherapy. Herein we describe the development of N‐arylsulfonyl indolines as RORγ agonists. Structure–activity studies reveal a critical linker region in these molecules as the major determinant for agonism. Hydrogen/deuterium exchange coupled to mass spectrometry (HDX‐MS) analysis of RORγ–ligand complexes help rationalize the observed results.     

Estimating design reliability of composite rotor blades under ultimate loading

A probabilistic stress analysis tool predicting reliability of composite wind turbine rotor blades was developed and validated by comparing with results from a three‐dimensional shell finite element model of a blade. Stress analysis was based on thin wall multicellular Euler–Bernoulli beam theory using as input section stress resultants directly from aeroelastic simulations; a finite strip method was implemented for elastic stability calculations. Reliability analysis was performed at the ply level of the multidirectional laminates implementing various methods such as the response surface method, β‐index and crude Monte Carlo simulation. Physical and statistical uncertainties of the basic variables was taken into account while several model uncertainties related to the material properties were further introduced and quantified in the light of appropriate test results. To prove the efficiency of the code as a design tool, the effect of various probabilistic assumptions concerning the material properties was directly investigated on the estimated reliability β‐index values for two rotor blade design cases typical of stall‐regulated and pitch‐regulated wind turbines. Copyright © 2014 John Wiley & Sons, Ltd.     

Production of hydrogen for fuel cells by steam reforming of ethanol over supported noble metal catalysts

The catalytic performance of supported noble metal catalysts for the steam reforming (SR) of ethanol has been investigated in the temperature range of 600–850 °C with respect to the nature of the active metallic phase (Rh, Ru, Pt, Pd), the nature of the support (Al₂O₃, MgO, TiO₂) and the metal loading (0–5 wt.%). It is found that for low-loaded catalysts, Rh is significantly more active and selective toward hydrogen formation compared to Ru, Pt and Pd, which show a similar behavior. The catalytic performance of Rh and, particularly, Ru is significantly improved with increasing metal loading, leading to higher ethanol conversions and hydrogen selectivities at given reaction temperatures. The catalytic activity and selectivity of high-loaded Ru catalysts is comparable to that of Rh and, therefore, ruthenium was further investigated as a less costly alternative. It was found that, under certain reaction conditions, the 5% Ru/Al₂O₃ catalyst is able to completely convert ethanol with selectivities toward hydrogen above 95%, the only byproduct being methane. Long-term tests conducted under severe conditions showed that the catalyst is acceptably stable and could be a good candidate for the production of hydrogen by steam reforming of ethanol for fuel cell applications.