Benchmarking in municipal solid waste recycling

The paper presents an analysis of the factors influencing the recycling potential of municipalities in Israel, including population size and density, geographic location, current waste levels, and current waste management system. We employ a standard regression analysis in order to develop an econometric model to predict where potential for economically efficient recycling is highest. By applying this model to readily available data, it is possible to predict with close to 90% accuracy whether or not recycling will be economically efficient in any given municipality. Government agencies working to promote advanced waste management solutions have at their disposal only limited resources and budget, and so must concentrate their efforts where they will be most effective. The paper thus provides policy-makers with a powerful tool to help direct their efforts to promote recycling at those municipalities where it is indeed optimal.     

The effect of recycling price uncertainty on municipal waste management choices

This paper analyzes the effect of price uncertainty and irreversible investment on the decision of municipalities to switch from landfill waste disposal to recycling by developing a model to predict recycling adoption behavior and applying it to empirical data. It is shown that uncertainty regarding the price of recycled materials may induce a risk neutral municipality to prefer landfill disposal, even when recycling is less expensive. A model is developed to describe the switching process and estimate its parameters using empirical data from 79 municipalities in Israel. The model is then used to predict municipalities' recycling adoption decisions under various assumptions regarding price uncertainty. The results support the hypothesis that price uncertainty is a major obstacle for recycling. Finally, several options for price stabilization are sketched and it is argued that these policies may be effective in establishing viable recycling markets.     

A cost-benefit analysis of a deposit–refund program for beverage containers in Israel

The paper presents a full cost-benefit analysis of a deposit–refund program for beverage containers in Israel. We examine all cost elements of the program – storage, collection, and treatment costs of empty containers, and all potential benefits – savings in alternative treatment costs (waste collection and landfill disposal), cleaner public spaces, reduction of landfill volumes, energy-savings externalities associated with use of recycled materials, and creation of new workplaces. A wide variety of data resources is employed, and some of the critical issues are examined via several approaches. The main finding of the paper is that the deposit–refund program is clearly economically worthwhile. The paper contributes to the growing body of literature on deposit–refund programs by its complete and detailed analysis of all relevant factors of such a program, and also specifically in its analysis of the savings in alternative waste management costs. This analysis reveals greater savings than are usually assumed, and thus shows the deposit–refund program to be highly efficient.     

Development of a Computationally Efficient Full Human Body Finite Element Model

Introduction: A simplified and computationally efficient human body finite element model is presented. The model complements the Global Human Body Models Consortium (GHBMC) detailed 50th percentile occupant (M50-O) by providing kinematic and kinetic data with a significantly reduced run time using the same body habitus.

Methods: The simplified occupant model (M50-OS) was developed using the same source geometry as the M50-O. Though some meshed components were preserved, the total element count was reduced by remeshing, homogenizing, or in some cases omitting structures that are explicitly contained in the M50-O. Bones are included as rigid bodies, with the exception of the ribs, which are deformable but were remeshed to a coarser element density than the M50-O. Material models for all deformable components were drawn from the biomechanics literature. Kinematic joints were implemented at major articulations (shoulder, elbow, wrist, hip, knee, and ankle) with moment vs. angle relationships from the literature included for the knee and ankle. The brain of the detailed model was inserted within the skull of the simplified model, and kinematics and strain patterns are compared.

Results: The M50-OS model has 11 contacts and 354,000 elements; in contrast, the M50-O model has 447 contacts and 2.2 million elements. The model can be repositioned without requiring simulation. Thirteen validation and robustness simulations were completed. This included denuded rib compression at 7 discrete sites, 5 rigid body impacts, and one sled simulation. Denuded tests showed a good match to the experimental data of force vs. deflection slopes. The frontal rigid chest impact simulation produced a peak force and deflection within the corridor of 4.63 kN and 31.2%, respectively. Similar results vs. experimental data (peak forces of 5.19 and 8.71 kN) were found for an abdominal bar impact and lateral sled test, respectively. A lateral plate impact at 12 m/s exhibited a peak of roughly 20 kN (due to stiff foam used around the shoulder) but a more biofidelic response immediately afterward, plateauing at 9 kN at 12 ms. Results from a frontal sled simulation showed that reaction forces and kinematic trends matched experimental results well. The robustness test demonstrated that peak femur loads were nearly identical to the M50-O model. Use of the detailed model brain within the simplified model demonstrated a paradigm for using the M50-OS to leverage aspects of the M50-O. Strain patterns for the 2 models showed consistent patterns but greater strains in the detailed model, with deviations thought to be the result of slightly different kinematics between models. The M50-OS with the deformable skull and brain exhibited a run time 4.75 faster than the M50-O on the same hardware.

Conclusions: The simplified GHBMC model is intended to complement rather than replace the detailed M50-O model. It exhibited, on average, a 35-fold reduction in run time for a set of rigid impacts. The model can be used in a modular fashion with the M50-O and more broadly can be used as a platform for parametric studies or studies focused on specific body regions.     

Is Municipal Solid Waste Recycling Economically Efficient?

It has traditionally been argued that recycling municipal solid waste (MSW) is usually not economically viable and that only when externalities, long-term dynamic considerations, and/or the entire product life cycle are taken into account, recycling becomes worthwhile from a social point of view. This article explores the results of a wide study conducted in Israel in the years 2000–2004. Our results reveal that recycling is optimal more often than usually claimed, even when externality considerations are ignored. The study is unique in the tools it uses to explore the efficiency of recycling: a computer-based simulation applied to an extensive database. We developed a simulation for assessing the costs of handling and treating MSW under different waste-management systems and used this simulation to explore possible cost reductions obtained by designating some of the waste (otherwise sent to landfill) to recycling. We ran the simulation on data from 79 municipalities in Israel that produce over 60% of MSW in Israel. For each municipality, we were able to arrive at an optimal method of waste management and compare the costs associated with 100% landfilling to the costs born by the municipality when some of the waste is recycled. Our results indicate that for 51% of the municipalities, it would be efficient to adopt recycling, even without accounting for externality costs. We found that by adopting recycling, municipalities would be able to reduce direct costs by an average of 11%. Through interviews conducted with representatives of municipalities, we were also able to identify obstacles to the utilization of recycling, answering in part the question of why actual recycling levels in Israel are lower than our model predicts they should be.     

A cost evaluation method for transferring municipalities to solid waste source-separated system

Most of Israel’s waste is disposed in landfills, threatening scarce land resources and posing environmental and health risks. The aim of this study is to estimate the expected costs of transferring municipalities to solid waste source separation in Israel, aimed at reducing the amount of waste directed to landfills and increasing the efficiency and amount of recycled waste. Information on the expected costs of operating a solid waste source separation system was gathered from 47 municipalities and compiled onto a database, taking into consideration various factors such as costs of equipment, construction adjustments and waste collection and disposal. This database may serve as a model for estimating the costs of entering the waste source separation system for any municipality in Israel, while taking into consideration its specific characteristics, such as size and region. The model was used in Israel for determining municipalities’ eligibility to receive a governmental grant for entering an accelerated process of solid waste source separation. This study displays a user-friendly and simple operational tool for assessing municipalities’ costs of entering a process of waste source separation, providing policy makers a powerful tool for diverting funds effectively in promoting solid waste source separation.     

The cave resonator and the Parker Turner cave collapse problem

The Parker Turner cave diving accident was unique. Out of several hundred cave diving fatalities that occurred in Florida during the past 50 years, it is the only one that occurred due to a partial collapse of the cave. Here, we propose a natural physical process that might explain this unique accident.While it is possible that the presence of the divers in the cave while the cave collapsed just happened to occur simultaneously, this is unlikely. It is suggested here that resonance in the air pockets in the cavern (or cave), created by breathing (open circuit) divers, may have contributed to the collapse. We propose that divers present in the cavern during the dive may have (unknowingly) caused the collapse through the pressurized air that they release with each breath. When the breathing period of the diver(s) matches the natural oscillations period of our new “cave oscillator”, the ensuing resonance causes the air pressure in the pockets to increase uncontrollably.We model the system as a non-uniform U-tube filled with water on the bottom and compressed air on top. The top of the tube is sealed on both sides so that the compressed air is trapped in the chambers above the water. The bottom part of the tube represents the water filled cavern (or cave) whereas the vertical tubes represent the air cavities. We show analytically that such a system is subject to natural oscillations with a period of roughly the same as the breathing rate of the typical diver.     

The Benefits and Costs of Noise Reduction

This paper attempts to measure, in a cost-benefit analysis, a stricter noise abatement programme for noise originating from roads in Israel. Using the hedonic price method for three large cities and rural area transactions, a benefit from noise reduction was found. In order to perform a social cost-benefit analysis, a measure of benefit has been derived for 1 km of road and has been compared with the cost of noise reduction under different types of road structure. The results indicate that even though benefits have largely increased when compared to past decades (e.g. 1.2% of an average urban property value per 1 decibel reduction), the decision to insulate a given road is dependent on location and road structure. This raises the normative question of a national vs. regional standard that decision makers should be aware of and such studies could be of help in this respect.     

Cost-benefit analysis of an accelerated vehicle-retirement programme

High taxes on new cars in Israel provide an incentive for car owners to defer the purchase of new vehicles. The result is a vehicle fleet of older, more polluting vehicles, with air pollution costs estimated at up to $530 million annually. The purpose of this paper is to conduct a cost benefit analysis (CBA) of an accelerated vehicle-retirement (AVR) programme. The analysis considers the private car fleet as well as trucks and buses. The study develops an economic model to identify the optimal payment level that will maximise the net benefit of the programme, and then apply the model to three different vehicle categories. It finds that an AVR programme for private cars may indeed yield significant net benefits, while a similar programme for trucks and buses fails to meet the cost-benefit test. For private cars, the study finds that even according to a conservative estimate, the programme will result in the voluntary retirement of approximately 98,000 private cars, with a present value net benefit of more than $50 million. This is equal to a 17% reduction in total annual private car air pollution costs for the five-year time span of the proposed programme.     

Cost-benefit analysis of implementing policy measures for reducing PM and O3 concentrations: the case of Israel

This paper aims to identify the most suitable and economically feasible policy measures to reduce concentrations of particulate matter (PM) and ozone (O₃) in Israel. It describes a comprehensive methodology that takes into account the effects of PM and O₃ and describes the overall costs and benefits expected from their reduction. Cost-benefit analysis of a series of proposed policy measures allows us to identify and recommend those that are most feasible and effective. These policy measures have a significant impact on reducing air pollution on one hand, while constituting the highest net benefit to the economy on the other.