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For $\Phi (R,\varphi -\Omega t,z)$ with constant pattern angular velocity $\Omega$, ordinary specific energy satisfies $\dot{E}={\partial }_t\Phi =-\Omega {\partial }_{\varphi }\Phi$ and specific axial angular momentum satisfies ${\dot{L}}_z=-{\partial }_{\varphi }\Phi$. Their combination $E_J$ is conserved. This is the rotating-frame integral of motion; in the circular restricted three-body problem, the usual Jacobi constant is an affine rescaling of it. Thus time dependence in an inertial frame does not alone imply the absence of all integrals.

James B. Pollack led numerical models of gas giant formation that calculated solid and gaseous accretion together. The simulations combined capture of planetesimals, evolution of the planetary gas envelope and dissolution of incoming solid material within that envelope.

The coupling matters because accreting solids both increase the central mass and deposit energy, changing the envelope's subsequent ability to collect gas. The resulting evolutionary phases include rapid solid growth, slower growth of both components and eventually rapid gas accumulation. This gave a physical account of how an initially modest solid core could become a giant planet within the available disk lifetime.^[ref]

James Franck and Gustav Ludwig Hertz measured the transfer of kinetic energy from free electrons into atomic excitation. In Mercury vapor, the collected electric current changes repeatedly as the accelerating voltage rises. Below an excitation threshold, an electron cannot excite the relevant atomic quantum state; above it, an inelastic collision can remove a characteristic energy. Repeated acceleration and energy loss produce the successive features, linking the Franck-Hertz experiment to quantized atomic structure.^[ref][ref]

Physics.^[ref]

James L. Kirtley Jr. is an electrical engineer whose work concerns electric machines and electric power systems. MIT's departmental profile identifies him as a professor emeritus of electrical engineering, with energy and robotics among his research areas.^[ref]

The engineering problem is to match a motor's behaviour to its application. MIT reported in 2016 that Kirtley worked on customized electric motors for the MIT Cheetah robot, where brief peaks of torque serve running and jumping. The same interview describes his interest in electric motors interacting with microgrids, particularly their dynamic behaviour during supply disturbances.^[ref] A short burst and sustained operation place different demands on the system; the largest instantaneous output alone does not describe its operating role.

His AC Power Flow in Linear Networks by James L. Kirtley Jr. connects the phasor representation of electric potential difference and electric current to physical energy transfer. In its peak-amplitude convention, complex electrical power is $S=V_{\mathrm{pk}}{I}_{\mathrm{pk}}^{\ast }/2$. With RMS phasors $V=V_{\mathrm{pk}}/\sqrt{2}$ and $I=I_{\mathrm{pk}}/\sqrt{2}$, this becomes $S=V{I}^{\ast }$. The complex conjugate ensures that the relative phase enters the active power.^[ref]

For an original load example in sinusoidal steady state, take $V=20\mathrm{V}$ and electrical impedance $Z=(3+4i)\Omega$, using RMS phasors and the passive sign convention: electric current enters the positive-potential terminal. A series resistor and inductor realize this model at the specified angular frequency when $R=3\Omega$ and $\omega L=4\Omega$. ThenThus active power is 48 watts, reactive power is 64 vars, apparent power is 80 volt-amperes, and power factor is $48/80=0.6$. Write $\varphi =\arctan (4/3)$ and $x=\omega t$. The corresponding electric potential difference and electric current areMultiplying and applying a trigonometric identity gives instantaneous powerIts cycle average is 48 watts, while its range is $[-32,128]$ watts. The negative portions represent temporary return of stored energy from this ideal load; the electrical resistance still dissipates a positive average. A synchronized product of the two waveforms reveals this behaviour, whereas multiplying their root mean square magnitudes gives only the apparent power.

James Prescott Joule was an English physicist whose private experiments connected electricity, heat and mechanical work. His family ran a brewery in Salford; he developed an experimental laboratory while working in the family business.^[ref] The Royal Society's archive identifies his occupation as physicist and records his life as 1818–1889.^[ref]

His electrical heating experiments placed metal coils in water and measured the temperature change. Later, he used the brewery cellar to reduce ambient temperature fluctuations during friction experiments and took particular care over thermometer calibration.^[ref] These practical choices address a central difficulty of calorimetry: a small temperature rise can reflect both the intended input of energy and unwanted heat transfer to the surroundings. A quiet baseline and a known heat capacity are part of the measurement, not decoration around the formula.

The contrast between Joule heating and Joule's paddle-wheel experiment makes the connection especially clear. One supplies electrical work; the other supplies mechanical work. In each case, calorimetry tracks the resulting change of internal energy. Comparing quantitatively controlled inputs with thermal changes gives an experimental test of conservation of energy, rather than merely showing that stirring or an electric current can warm water. The paddle-wheel account describes the descending weights, vanes, thermal controls and corrections needed for that comparison.

Joule's free-expansion experiment asks a different question: how does a gas's temperature change during expansion without external work? The Joule-Thomson effect instead concerns flow through a restriction and a balance involving enthalpy. Keeping the two experiments distinct prevents a shared historical name from hiding different system boundaries and different conserved quantities.

James R. Melcher was an electrical engineer whose work helped define continuum electromechanics: the interaction of electromagnetic fields with deformable materials and flowing fluids. His applications included energy conversion, flow measurement and the control of industrial processes.^[ref]

With Hermann Anton Haus, he wrote Electromagnetic Fields and Energy by Hermann A. Haus and James R. Melcher. A central engineering theme is the relation between a full field description and a justified approximation. In a magnetic circuit, for example, geometry and permeability assumptions determine when a small set of circuit-like variables can represent the spatial fields.^[ref]

Jan C. Willems was an electrical engineer and systems theorist whose work helped make dissipativity a general tool for studying dynamical systems. His university-hosted curriculum records an electrical-engineering doctorate at MIT in1968, a systems-and-control professorship at Groningen from1973, and later work as a guest professor at KU Leuven. It records his death on31August2013.^[ref]

His1972general theory expresses a system's balance using a storage function and supply rate. The formulation compares a change in stored quantity with integrated input supply, allowing physical energy accounting and input–output performance bounds to share one mathematical language.^[ref]

An original example illustrates the scientific idea. A2kilogram mass with viscous coefficient3newton-seconds per metre obeys $2\dot{v}=u-3v$. Its kinetic energy is $S=v^2$ joules when $v$ is expressed in metres per second, andAt constant velocity1metre per second, a3newton force supplies3watts, all dissipated while the stored kinetic energy stays1joule. The dissipativity article develops the general inequality; this simple case shows why its supply and storage terms must be distinguished.

Willems also developed behavioral systems theory, which describes a dynamical system by a family of admissible time histories. His curriculum explains the motivation: an interconnected system need not come with a uniquely privileged division into control inputs and plant outputs. Interconnection can instead impose shared variables and compatibility between trajectories.^[ref] The two contributions address complementary questions: which histories are possible, and what balance law must each history obey?

A researcher who coauthored quantitative measurements of electron-beam damage in graphene. Counting displaced carbon atoms as beam energy and dose changed gave a displacement cross section. Comparing carbon isotopes helped distinguish nuclear collisions from other damage mechanisms. Including lattice motion was necessary to explain the results, making the microscope itself a controlled scattering experiment.^[ref]

Jean Dalibard developed, with Claude Cohen-Tannoudji, models explaining laser cooling below the simple Doppler cooling limit. Spatially changing wave polarization makes the light shifts of atomic sublevels vary with position.

In Sisyphus cooling, moving chemical atoms climb a light-shift potential and are optically pumped into a lower-energy sublevel. Repeating that sequence removes kinetic energy. The mechanism depends on internal-state structure and optical pumping, explaining why a two-level Doppler model misses the additional cooling.^[ref]

The Jeans escape parameter compares a particle's gravitational binding energy with its thermal energy at a specified atmospheric level. For particle mass $m$, planetary mass $M_p$, radius $r$ and local temperature $T$,Here the second speed uses the factor-two thermal speed convention. For a locally hydrostatic ideal gas, $H=k_{B}T/(mg)$ and $g=G{M}_p/r^2$ also give $\lambda =r/H$; a large parameter is therefore consistent with a thin atmospheric scale height.

In the Maxwellian Jeans escape model at the exobase, the outward Jeans escape flux contains $(1+\lambda )e^{-\lambda }$. Large $\lambda$ suppresses this high-speed tail exponentially, but no finite positive temperature makes it vanish exactly.

A small $\lambda$ warns that a static, thin-atmosphere tail calculation can fail. It does not by itself prove a particular hydrodynamic escape rate: the collision environment, heating and cooling must support the bulk outflow. The parameter uses the upper-atmosphere temperature, which need not equal the planetary equilibrium temperature.

Coauthored the discovery of the J/psi meson in electron-positron annihilation. Scanning the collision energy revealed a sharp enhancement in production of hadrons and electron-Positron pairs near $3.105\mathrm{GeV}$, with a reported full-width upper limit of $1.3\mathrm{MeV}$.^[ref]

Jeffrey Goldstone established a central consequence of spontaneous symmetry breaking: under the usual relativistic assumptions, breaking a continuous global symmetry produces massless Goldstone bosons. Moving along equivalent vacuum states costs no restoring potential energy, giving a low-energy collective mode. His work also developed diagrammatic methods for interacting many-fermion systems. These contributions connect the symmetries of an underlying theory with the physical excitations that an experiment can detect.^[ref]

A physicist working on spontaneous symmetry breaking.^[ref]

Jerome Isaac Friedman helped establish the constituent structure of hadrons through deep inelastic scattering. In the electron–proton measurements, changes in the outgoing electron's energy and angle mapped the target's response at different momentum transfers. Approximate scaling suggested that the probe was interacting with smaller, nearly pointlike constituents. Interpreting that response connected an accelerator measurement with the developing quark model.^[ref]

A physicist.^[ref]

A physicist who applied radiobiology to the comparison of radiation therapy schedules. His work on the linear-quadratic radiobiology model explains why equal total absorbed doses can produce different biological effects when delivered in different-sized fractions. The model separates contributions linear and quadratic in the dose per fraction, while a comparison of schedules must also consider tissue recovery and proliferation over time. This work helped turn a statement of delivered energy into a model of biological response.^[ref]

John Hasbrouck Van Vleck developed the quantum theory of magnetic response in atoms and solids. magnetic susceptibility depends on the spectrum and magnetic matrix elements of the system, not only on a classical picture of permanent dipoles. An applied field can admix excited states into the ground state and thereby change its energy and magnetic moment. His treatment connected atomic quantum mechanics, crystal fields and measured magnetism, explaining effects that a purely classical thermal average misses.^[ref]

A physicist.^[ref]

A radiation physicist who coauthored NIST tables of mass attenuation coefficients and mass energy-absorption coefficients with Stephen M. Seltzer. The tables connect X-ray and gamma ray photon energy to interactions in elements and mixtures. They distinguish removal of photons from a beam from absorption of their energy, a difference needed when calculating shielding or deposited radiation energy.^[ref]

Researcher in structural biology. Rubinstein coauthored studies of bacterial ATP synthase, connecting cryo-electron microscopy structures with the mechanics and regulation of a rotary energy-converting complex.^[ref]

John McGreevy develops quantum field theory through connections with many-particle physics. His authored lectures construct coherent-state path integrals for both bosons and fermions, relating the choice of integration variables to their different quantum statistics. The same treatment derives low-energy phase dynamics for a superfluid. This gives a concrete route from microscopic quantum degrees of freedom to a collective field description, explaining why similar field-theory methods recur in particle and condensed-matter physics.^[ref]

Author of Physics 215C: Quantum Field Theory, Part 3 by John McGreevy. Course record: mcgreevy.physics.ucsd.edu/s22/lecture-notes.html

John P. Grotzinger is a geologist whose work uses sedimentary rocks to reconstruct past planetary environments. His team's 2014 study of Yellowknife Bay in Gale Crater on Mars interpreted fine-grained sedimentary rocks as ancient lacustrine deposits. The combination of sedimentology and chemical measurements addressed both how the sedimentary deposits formed and whether the former environment could have supported microbial life.^[ref]

The inferred water had approximately neutral pH, low salinity and variable redox conditions involving iron and sulfur. Such properties constrain habitability more specifically than the presence of liquid water alone: they bear on chemical conditions and possible sources of metabolic energy. The study's conclusion was that the environment could have supported suitable microorganisms; the interpretation of lacustrine deposits and favourable chemistry is not itself a detection of ancient life.^[ref]

John Robert Schrieffer coauthored the microscopic BCS theory of conventional superconductivity. Its many-electron ground state coherently combines configurations in which states of opposite spin and momentum are paired. An attractive interaction mediated by lattice vibrations can lower the energy of this collective state, while its excitations have a gap. The theory relates that construction to a phase transition, specific heat, magnetic-field penetration and other measurable properties of a superconductor.^[ref]

A physicist.^[ref]