Models for predicting impact sensitivity of energetic materials based on the trigger linkage hypothesis and Arrhenius kinetics.

In order to predict the impact sensitivity of high explosives, we designed and evaluated several models based on the trigger linkage hypothesis and the Arrhenius equation. To this effect, we calculated the heat of detonation, temperature of detonation, and bond dissociation energy for 70 energetic molecules. The bond dissociation energy divided by the temperature of detonation proved to be a good predictor of the impact sensitivity of nitroaromatics, with a coefficient of determination (R) of 0.

The crystal density of nitrogen cubane and other polynitrogen species.

The elusive N species remain hypothetical at the time of writing. However, they have long captured the imaginations of researchers in the field of energetic materials due to their high detonation velocity and detonation pressure. Solid nitrogen cubane N is one candidate material that has been much studied theoretically.

A computational study of ANTA and NTO derivatives.

This work is a study of 5-amino-3-nitro-1,2,4-triazole (ANTA), 3-nitro-1,2,4-triazol-5-one (NTO), and nitrated derivatives of ANTA and NTO. RDX and TNT were studied for comparison. ANTA and NTO are low-sensitive high explosives with detonation properties comparable to 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX).

Studying the time trend of Methicillin-resistant Staphylococcus aureus (MRSA) in Norway by use of non-stationary γ-Poisson distributions.

Objectives: Study the time development of methicillin-resistant Staphylococcus aureus (MRSA) and forecast future behaviour. The major question: Is the number of MRSA isolates in Norway increasing and will it continue to increase?

Design: Time trend analysis using non-stationary γ-Poisson distributions.

Setting: Two data sets were analysed.

Mathematical simulation of energy expenditure and recovery during sprint cross-country skiing.

Purpose: A cross-country sprint competition relies on maximal effort durations of 3-4 minutes. Significant anaerobic energy contribution is expected. Anaerobic energy contribution has been estimated in different sports to date from the accumulated O2 deficit.

Using the power balance model to simulate cross-country skiing on varying terrain.

The current study adapts the power balance model to simulate cross-country skiing on varying terrain. We assumed that the skier's locomotive power at a self-chosen pace is a function of speed, which is impacted by friction, incline, air drag, and mass. An elite male skier's position along the track during ski skating was simulated and compared with his experimental data.

A simulation of cross-country skiing on varying terrain by using a mathematical power balance model.

The current study simulated cross-country skiing on varying terrain by using a power balance model. By applying the hypothetical inductive deductive method, we compared the simulated position along the track with actual skiing on snow, and calculated the theoretical effect of friction and air drag on skiing performance. As input values in the model, air drag and friction were estimated from the literature, whereas the model included relationships between heart rate, metabolic rate, and work rate based on the treadmill roller-ski testing of an elite cross-country skier.

Methicillin-resistant Staphylococcus aureus (MRSA) is increasing in Norway: a time series analysis of reported MRSA and methicillin-sensitive S. aureus cases, 1997-2010.

Background: Accurate estimates of the incidence and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infections are needed to inform public health policies. In Norway, where both MRSA infection and carriage are notifiable conditions, the reported incidence of MRSA is slowly increasing. However, the proportion of MRSA in relation to all S.

On the kinetics of anaerobic power.

Background: This study investigated two different mathematical models for the kinetics of anaerobic power. Model 1 assumes that the work power is linear with the work rate, while Model 2 assumes a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. In order to test these models, a cross country skier ran with poles on a treadmill at different exercise intensities.

The kinetics of lactate production and removal during whole-body exercise.

Background: Based on a literature review, the current study aimed to construct mathematical models of lactate production and removal in both muscles and blood during steady state and at varying intensities during whole-body exercise. In order to experimentally test the models in dynamic situations, a cross-country skier performed laboratory tests while treadmill roller skiing, from where work rate, aerobic power and blood lactate concentration were measured. A two-compartment simulation model for blood lactate production and removal was constructed.

Systematization of a set of closure techniques.

Approximations in population dynamics are gaining popularity since stochastic models in large populations are time consuming even on a computer. Stochastic modeling causes an infinite set of ordinary differential equations for the moments. Closure models are useful since they recast this infinite set into a finite set of ordinary differential equations.

A dynamic model of Nordic diagonal stride skiing, with a literature review of cross country skiing.

The forces during the kicking phase in Nordic diagonal stride skiing are described by differential equations and the results are compared with experiments. The difference between static and dynamic friction, interacting with characteristics of the skier such as weight, velocity and the kicking force's angle with the terrain, are essential for high-velocity diagonal striding. Analytical results for relationships between glide length, friction and kicking force are shown.

A mathematical model for the proliferation of bacteria in the urinary bladder due to enlarged prostate.

Urinary retention due to enlargement of the prostate (prostate hypertrophy) leads to increased proliferation of bacteria in the bladder. This in turn increases the infection rate. The reason is that the enlarged prostate presses on the urine channel and tends to close it.

The dynamics of cell proliferation.

The article provides a mathematical description based on the theory of differential equations, for the proliferation of malignant cells (cancer). A model is developed which enables us to describe and predict the dynamics of cell proliferation much better than by using ordinary curve fitting procedures. By using differential equations the ability to foresee the dynamics of cell proliferation is in general much better than by using polynomial extrapolations.

Predicting the concentration level of an anti-cancer drug during treatment of a living organism.

For many drugs used in chemotherapy the difference between the therapeutic concentration and the toxic concentration is small. During treatment of a living organism from cancer by using chemotherapy, it is therefore important to foresee the therapeutic concentration in the organism as a function of the injected therapeutic drug dose. This article provides a mathematical dynamic description of the interaction between the organism and the drug, and analyses the dynamics by using ordinary differential equations.

Behaviorist stochastic modeling of instrumental learning.

A mathematical model is presented descriptive of instrumental learning, i.e. operant conditioning.