Energy conservation in edible oil processing (US view)

Energy conservation procedures starting with crude edible oil and following through the various process steps are described. Each step illustrates the necessary operating conditions and energy conservation measures now in use or proposed for US edible oil refineries.     

Decrease in Electricity Intensity From Increased Efficiency and Changed Product Mix

In this article, we examine the determinants of improvements in US manufacturing electricity intensity 1998–2010, via decomposition and regression analysis. Decomposition analysis finds both structural change and efficiency improvements played important roles in intensity improvements, with results varying by region. One implication is that improvements in electricity intensity should not be assumed to come only from efficiency improvements: it is important to attempt to understand what drives efficiency improvements and structural change.     

Fast gas chromatography combustion isotope ratio mass spectrometry

We report here the first coupling of fast GC to IRMS, in a system capable of 250 ms peak widths (fwhm) at 1 mL/min flow rates, one-fifth as narrow as any previously reported GCC-IRMS system. We developed an optimized postcolumn interface that results in minimal peak broadening, using a programmable temperature vaporization injector in place of a rotary valve or backflush system to divert solvent, a narrow capillary combustion reactor followed by a cryogenic water trap with narrow-bore (<0.20 mm i.d.) transfer lines, and a narrow i.d. open split to the IRMS directly inserted into the column effluent. Quantitative combustion was demonstrated with CH4 injections. A comparison of CO2 injections with different fwhm peak widths (250, 2500, and 7500 ms) showed similar precisions, SD(delta13C)=0.2-0.3 per thousand, for injections of >600 pmol C on column; precision for the narrow peaks (250 ms) was considerably better for injections<150 pmol C on column. SD(delta13C)<1 per thousand was achievable for injections of 5-15 pmol on column for 250 ms wide peaks, 10-fold better precision than 2500 ms wide peaks, and within a factor of 3 of the counting statistics limit. For a mixture of 15 fatty acid methyl esters (FAME), 1.5 nmol C of each on column yielded typical SD(delta13Cpdb)=0.4 per thousand for fast GC and 0.5 per thousand for conventional GC. For 14 of the 15 FAME, delta13C values between the two systems were within+/-1.5 per thousand and not significantly different. Fast GCC-IRMS required one-third the run time (450 s vs 1400 s) to achieve comparable resolution. Mean peak widths for fast GCC-IRMS of the FAME were 720 ms, compared to 650 ms by fast GC with flame ionization detection. At a 15-fold dilution (100 pmol C on column for each FAME), fast GCC-IRMS achieved approximately 2-fold better precision and accuracy than similar injections on conventional GCC-IRMS. Finally, a mixture of 10 steroids (approximately 7 nmol C (100 ng) each on column) was analyzed with mean precision of SD(delta13C)=0.2 per thousand in 620 s by fast GCC-IRMS, while conventional GCC-IRMS required 1200 s and achieved poorer resolution. delta13C values for the two system were similar (Deltadelta13C1 nmol C) and achieves modest precision (approximately 1 per thousand) near the counting statistics limit on low level components.     

Evaluation of engineering properties for the use of leached brown coal ash in soil covers

The need to engineer cover systems for the successful rehabilitation or remediation of a wide variety of solid wastes is increasing. Some common applications include landfills, hazardous waste repositories, or mine tailings dams and waste rock/overburden dumps. The brown coal industry of the Latrobe Valley region of Victoria, Australia, produces significant quantities of coal ash and overburden annually. There are some site-specific acid mine drainage (AMD) issues associated with overburden material. This needs to be addressed both during the operational phase of a project and during rehabilitation. An innovative approach was taken to investigate the potential to use leached brown coal ash in engineered soil covers on this overburden dump. The basis for this is two-fold: first, the ash has favourable physical characteristics for use in cover systems (such as high storage capacity/porosity, moderately low permeability, and an ability to act as a capillary break layer generating minimal leachate or seepage); and second, the leachate from the ash is mildly alkaline (which can help to mitigate and reduce the risk of AMD). This paper will review the engineering issues involved in using leached brown coal ash in designing soil covers for potentially acid-forming overburden dumps. It presents the results of laboratory work investigating the technical feasibility of using leached brown coal ash in engineered solid waste cover systems.     

Aromatization of propane over Ga/H-ZSM-5: An explanation of the synergy observed between Ga3+ and H+

The aromatization of propane is investigated for Ga₂O₃, H-ZSM-5 and Ga₂O₃/H-ZSM-5 catalysts, and the results are discussed for a series of ZSM-5 catalysts containing varying SiO₂/Al₂O₃ ratios. It is apparent that on addition of a gallium phase to H-ZSM-5, the yield of methane is significantly decreased. These results are discussed with respect to the mechanism of formation of the initial reaction product from propane. It is proposed that the synergy observed between the gallium compound and the zeolite can be explained in terms of a mechanism in which the role of the gallium phase is to induce C-H bond polarization in the propane, which leads to attack via the Bronsted acid sites of the zeolite, which leads to initial C-H bond cleavage occurring.     

基于移相控制的多路输出降压变换器提升EMI性能的PCB布局优化

本文对移相控制下的双路输出降压变换器的两种不同PCB布局进行比较。     

Occupant Tenability in Single Family Homes: Part I—Impact of Structure Type,Fire Location and Interior Doors Prior to Fire Department Arrival

This paper describes an experimental investigation of the impact of structure geometry, fire location, and closed interior doors on occupant tenability in typical single family house geometries using common fuels from twenty-first century fires. Two houses were constructed inside a large fire facility; a one-story, 112 m², 3-bedroom, 1-bathroom house with 8 total rooms, and a two-story 297 m², 4-bedroom, 2.5-bathroom house with 12 total rooms. Seventeen experiments were conducted with varying fire locations. In all scenarios, two bedrooms had doors remaining open while the door remained closed in a third bedroom immediately adjacent to the open door bedrooms. Temperature and gas measurement at the approximate location of a crawling or crouching trapped occupant (0.9 m from the floor) were utilized with the ISO 13571 fractional effective dose (FED) methodology to characterize occupant tenability up to the point of firefighter intervention. The FED values for the fire room were higher for heat exposure than for toxic gases, while target rooms reached highest FED due to CO/CO₂ exposure. The closed interior door decreased FED significantly, with the worst case scenario resulting in a 2% probability of receiving an incapacitating dose compared to the worst case scenario for an open bedroom of 93% probability of receiving an incapacitating dose. In fact, in 7 of the 17 experiments, the closed interior door resulted in a less than 0.1% chance of an occupant receiving an incapacitating dose prior to firefighter ‘intervention.’     

Egress Efficacy of Persons with Multiple Sclerosis During Simulated Evacuations

Expedited evacuation of commercial and residential structures in the event of an emergency may be more difficult for persons with physical movement disorders. There is a need to better characterize the impact of such disorders and provide movement data to improve evacuee and responder safety. We undertook a pilot, feasibility study that investigated the ability of persons with multiple sclerosis (MS) and controls without MS to walk along a 48 m long path that included five different door configurations with various opening hardware and closure mechanisms, both before and after a six-minute walk, simulating a long evacuation path. Persons with MS took longer to complete the evacuation circuit (102 vs. 31 s) and to pass through each door (average 4.8 vs. 1.4 s) compared to controls. During the six-minute walk, persons with MS had decreased walking speed (0.7 vs. 1.9 m/s). The MS population demonstrated more conservative gait biomechanics throughout the simulation, i.e., wider, shorter and slower steps. Timing and biomechanical differences between populations and the potential fatigue induced through an extended evacuation can be used to improve understanding of movement in populations with disabilities, and incorporate these data into estimation of flow rates during evacuation.     

Promoting the supply of low income rental housing

There is disturbing evidence of a contraction in the stock of low income private rental housing. In this paper we offer evidence indicating that federal government tax preferences, economies of scope and higher operating costs are part of the explanation for this contraction. The Australian Bureau of Statistics Rental Investors' Survey is used to gauge whether low income housing tax credits and tax-free capital gains thresholds can be used to promote the supply of low income rental housing.     

A Light-Scattering Apparatus for the Study of Cellular Suspensions

A system is described which uses scattered laser light to study the kinetics of cellular suspensions. The scattered light is collected by optical fibers placed at 10°increments around the cuvette. With a novel normalization scheme all outputs are made proportional to the percentage changes relative to the values measured upon insertion of the sample. The system includes a noise level detector to give an output proportional to the relative amplitude of fluctuation of the light intensity.