Copper Box Research Articles

Pulsating Heat Pipe Experiments for Microgravity Sounding Rocket Tests

Two flat plate diffusion-bonded pulsating heat pipes (PHPs) for the thermal management and heat dissipation of concentrated heat flux in electronics applications, such as aboard satellites and spacecraft, were specially developed for future tests aboard a sounding rocket in microgravity conditions. Both devices contain 26 channels with round cross sections, one with ultrasharp lateral grooves in the evaporator. Two heat sinks were tested: a water-cooling bath for the thermal characterization of the PHPs, and a copper box with a phase change material (dodecahydrate bibasic sodium phosphate) to be qualified as the heat storage for future microgravity tests. Water was used as the working fluid. The best filling ratio (relative to the total internal volume of the PHPs) was experimentally determined to be 50%, for which the devices presented the earliest startup and the lowest thermal resistance, around 0.033°C/W for the grooved PHP. This research proposes an efficient and alternative cooling method, the phase change material storage, to be used as a heat sink in future microgravity tests. Also, the microgravity effect on the thermal performance of such PHPs can be assessed by comparing the present results with future microgravity data obtained in an experimental module aboard a sounding rocket.

Design and implementation of a temperature-compensated corrector magnet power supply for the Taiwan Photon Source

The Taiwan Photon Source (TPS) is a widely recognised 3 GeV synchrotron light source. It has demonstrated exceptional performance in average beam downtime and meeting international standards over its successful ten-year operation. Regular equipment updates are conducted for all subsystems to ensure continuous improvement and maintain an optimal research facility environment. This study focuses on designing and implementing a temperature-compensated corrector magnet power supply for the TPS. The power supply incorporates a high-bandwidth, compact, cost-effective, bipolar, and highly precise shunt resistor as the current feedback component. A temperature control copper box and temperature compensation circuit are employed to improve the thermal equilibrium time of the output current. A laboratory-developed TPS-corrected magnet power supply with temperature compensation control has been successfully developed through these measures. The prototype exhibits a maximum output current of 10 A and operates at a voltage of 40 V. Metal-oxide-semiconductor field-effect transistors (MOSFETs) are utilised as the power switch in a full-bridge (H-bridge) configuration with a driving frequency of 40 kHz. The output current ripple is effectively maintained at 100 μA for a 10 A output, and the stabilisation time is achieved within 5 minutes. The control loop design of the prototype has been verified to achieve fast and stable output current performance. The completed prototype demonstrated a -3 dB bandwidth of 2.57 kHz when tested with an input reference signal of 0.1 V. Finally, a hardware prototype circuit was constructed in the power supply laboratory, featuring an input voltage of 48 V, an output current of 10 A, and a maximum power capacity of 400 W.

The Secret of the Copper Box: public experiments and the prospects of living archives of Swedish nuclear waste

Abstract. This paper approaches the question of nuclear safety in relation to the prospects of living archives, and in particular, it explores two public events where sociocultural aspects of nuclear waste management in Sweden were enacted. Drawing on an ongoing research collaboration with the Swedish Nuclear Fuel and Waste Management Company (SKB), the paper examines (1) a grass-roots play entitled Kopparkistans hemlighet (or The Secret of the Copper Box), and (2) a drawing competition hosted by schools located near a nuclear waste storage facility in the Östhammar municipality, considering how these events help reproduce certain kinds of social and cultural responsibility. Contributing to critical debates in the social sciences and humanities intersecting questions of memory preservation, nuclear waste, and post-nuclear natures, we consider how the forms of responsibility produced through these public experiments inform important, albeit unconventional, modes of nuclear waste management insofar as they suggest how long-lived nuclear waste sites might become living archives without assuming a narrow notion of heritage and human memory preservation for all time and space. To conclude, we evaluate how the legacy of the two events might be incorporated into wider strategies of nuclear waste management.

Перенос “темного водорода” атомарным веществом. Методы диагностики “темного водорода”

This work experimentally shown that traces found on track detectors during the study of low-energy nuclear reactions are also formed in the course of many widely used technical processes (combustion of hydrocarbons, operation of internal combustion engines, physicochemical processes accompanying the process of charging smartphone batteries). This coincidence of the track pattern allows us to consider low-energy nuclear reactions as a significant environmental factor, and indicates the important role of “dark hydrogen” in nature. The paper shows the convective transfer of “dark hydrogen” from the discharge zone along the path of the air-water mixture. Using the theoretical model of “dark hydrogen”, fundamentally new, less laborious, in comparison with track, methods of its registration have been developed and described: 1) measurement of the charge of a copper box with its irradiation with “dark hydrogen”, 2) measurement of pressure in a closed volume when irradiated with “dark hydrogen”, 3) the use of a torsion balance with a nickel plate with magnets when irradiated with “dark hydrogen”.

Ground-penetrating radar-based underground environmental perception radar for robotic system

In recent years, the environmental perception technology for robotic system has attracted a lot of attention from researchers, but only a little of studies on environmental perception technology are focused on the space underground. Meanwhile, in the field of mobile robotic systems, with the development of research on underground emergency hedging and buried targets’ high-resolution fault imaging, more and more attention has also been paid to underground environmental detection and perception. This article proposes a ground-penetrating radar-based underground environmental perception radar (UEPR) for mobile robotic system indoors. The underground environmental perception radar can achieve noncontact and real-time perception, which helps people detect buried targets and get the image of targets more conveniently and precisely. Major contributions of this work are threefold. Firstly, a stepped frequency continuous wave modulation and demodulation scheme is proposed; secondly, a switch device for a six-channel antenna array is designed and contributed; thirdly, based on a linear antenna array and a signal processing platform, the underground environmental perception radar is supposed to achieve three-dimensional imaging in underground space indoors with its low power consumption. For the experiment of three-dimensional imaging on the copper box and underground environment indoors, the process of imaging is successful, although the size of them is a little bigger than the real size. In addition, the comparison experiment shows that the resolution of underground environmental perception radar system is similar with that of sound wave methods, and the working range of underground environmental perception radar system is deeper than the others. It can be concluded that the underground environmental perception radar can detect the copper box underground and perceive something special within 1.5 m depth.

Experimental Observation of Convective Cell Formation due to a Fast Wave Antenna in the Large Plasma Device.

An experiment in a linear device, the Large Plasma Device, is used to study sheaths caused by an actively powered radio frequency (rf) antenna. The rf antenna used in the experiment consists of a single current strap recessed inside a copper box enclosure without a Faraday screen. A large increase in the plasma potential was observed along magnetic field lines that connect to the antenna limiter. The electric field from the spatial variation of the rectified plasma potential generated E[over →]×B[over →]_{0} flows, often referred to as convective cells. The presence of the flows generated by these potentials is confirmed by Mach probes. The observed convective cell flows are seen to cause the plasma in front of the antenna to flow away and cause a density modification near the antenna edge. These can cause hot spots and damage to the antenna and can result in a decrease in the ion cyclotron range of frequencies antenna coupling.

Development of a PET Insert for simultaneously small animal PET/MRI.

PET/MR is a new multi-modality imaging system which provide both structural and functional information with good soft tissue imaging ability and no ionizing radiation. In recent years, PET/MR is under major progress because of the development of silicon photomultipliers (SiPM). The goal of this study is to develop a MRI compatible PET insert based on SiPM and LYSO scintillator. The PET system was constituted by the detector ring, electronics and software. The detector ring consists of 16 detector module. The inner diameter of the ring was 151 mm, the external diameter was 216 mm, which was big enough for small animal research, e.g. rat, rabbit and tupaia. The sensor of each module was 2*2 SensL SPMArraySL, coupled with an array of 14 x 14 LYSO crystals, each crystal measuring 2 mm x 2 mm 10 mm. The detector was encapsulated in a copper box for light and magnetic shielding. Resister charge multiplexing circuit was used in the front end electronics. Each detector output 8X and 8Y position signals. One summed timing signal was extracted from the common cathode of all 64 channels. All these signals were transmitted to digital electronic board by a 3 m long coaxial cable from inside of the MR to the outside. Each digital electronic board handled 8 detector modules based on FPGA to obtain the timing, position and energy information of a single event. And then these single events were sent to the coincidence processing board to produce coincidence packets which are prepared for further processing. A 0.2mCi 68Ge line source was used to do the preliminary imaging test. The image was reconstructed by 3D-OSEM algorithm. The initial result proved the system to be feasible as a PET. FDG phantom imaging and simultaneous PET/MR imaging are in progress.

A robust and well shielded thermal conductivity device for low temperature measurements.

We present a compact mechanically robust thermal conductivity measurement apparatus for measurements at low temperatures (<1 K) and high magnetic fields on small high-purity single crystal samples. A high-conductivity copper box is used to enclose the sample and all the components. The box provides protection for the thermometers, heater, and most importantly the sample increasing the portability of the mount. In addition to physical protection, the copper box is also effective at shielding radio frequency electromagnetic interference and thermal radiation, which is essential for low temperature measurements. A printed circuit board in conjunction with a braided ribbon cable is used to organize the delicate wiring and provide mechanical robustness.

ChemInform Abstract: Copper(II)‐ and Palladium(II)‐Catalyzed Enantioselective Claisen Rearrangement of Allyloxy‐ and Propargyloxy‐Indoles to Quaternary Oxindoles and Spirocyclic Lactones.

In this Article, a strategy to obtain highly enantioselective catalysts for the Claisen rearrangement of allyloxy- and propargyloxy-indoles is outlined. Ultimately, copper BOX and palladium BINAP or PHOX catalysts were discovered as superior in catalyzing Claisen rearrangements of allyloxy- or proparyloxy-substituted indoles to generate oxindoles bearing allyl- or allenyl-substituted quaternary centers. This method proved to be tolerant of a broad range of functional groups. Tandem reactions of the silyl-allene products provide rapid access to a variety of spirocyclic oxindoles in one operation.

Copper(II)- and palladium(II)-catalyzed enantioselective Claisen rearrangement of allyloxy- and propargyloxy-indoles to quaternary oxindoles and spirocyclic lactones.

In this Article, a strategy to obtain highly enantioselective catalysts for the Claisen rearrangement of allyloxy- and propargyloxy-indoles is outlined. Ultimately, copper BOX and palladium BINAP or PHOX catalysts were discovered as superior in catalyzing Claisen rearrangements of allyloxy- or proparyloxy-substituted indoles to generate oxindoles bearing allyl- or allenyl-substituted quaternary centers. This method proved to be tolerant of a broad range of functional groups. Tandem reactions of the silyl-allene products provide rapid access to a variety of spirocyclic oxindoles in one operation.

Enhancement of post-thaw viability of cells in suspension via pulsed laser heating prior to immersion in liquid nitrogen

In the present study, we compared the structure of ice formation in cryobiologically relevant solutions immersed in liquid nitrogen with solutions that were laser heated prior to immersion in a liquid-nitrogen bath. The results suggest that there is a distinct and observable difference in the type of ice formed. Furthermore, we also present data that suggest pulsed laser heating prior to immersion in liquid nitrogen enhances post-thaw survival of cells in suspension. The laser used in our experimental approach was a Q-switched Quanta-Ray DCR-3 laser (Nd:yttrium aluminum garnet laser) operating in the second harmonic at 532nm. The laser irradiance consisted of pulses with a pulse width of 5–7ns and a pulse energy stability of 3%. The pulse energy at a pulse repetition rate of 1Hz was about 360mJ and the peak power delivered was about 60MW. The samples were held in a copper- (sheet thickness of 0.5mm) molded rectangular box of 5mm thick, 25mm wide, and 15mm long. Preliminary experiments were carried out using adipose-tissue-derived adult stem cells. The pre- and postfreeze∕thaw viability of ADAS cells was assessed using membrane-excluded fluorescent dyes. ADAS cells enclosed in a copper box, laser irradiated, and exposed to liquid nitrogen had a viability of 69%±5%. Similarly, when the cells were exposed directly to liquid nitrogen (note that as before the cell suspension was enclosed and sealed in the copper box), the viability reduced significantly to 9%±10%. These results are very encouraging and demonstrate the feasibility of using lasers and liquid nitrogen to cryopreserve cells in suspension.

Statistical Properties of Fracture Precursors

We present the data of a mode-I fracture experiment. The samples are broken under imposed pressure. The acoustic emission of microfractures before the breakup of the sample is registered. From the acoustic signals, the position of microfractures and the energy released are calculated. A measure of the clustering of microfractures yields information about the critical load. The statistics from energy measurements strongly suggest that the fracture can be viewed as a critical phenomenon; energy events are distributed in magnitude as a power law, and a critical exponent is found for the energy near fracture.

Copper-inducible transcriptional regulation at two promoters in the Escherichia coli copper resistance determinant pco

The pco determinant of Escherichia coli plasmid pRI1004 encodes inducible resistance to the trace element copper. The identification of two copper-dependent transcriptional initiation regions within pco that each contain a similar upstream hyphenated dyad motif is described. Deletion constructs showed that this 'copper box' motif was essential for copper-inducible activity at both pco promoters, PpcoA and PpcoE. The placement of the motif differs in the two promoters, and PpcoA contains an extended -10 nonamer typical of promoters for which RNA polymerase does not bind specifically to -35 sequences. PpcoE does not contain this motif and is the more strongly expressed promoter. The transcript from PpcoA contains the pcoABCDRS genes, while PpcoE expresses only pcoE. The induction profiles for PpcoA- and PpcoE-IacZ fusions were flattened sigmoidal curves with a gradual response to increasing copper concentration. On high-copy-number plasmids, zinc was found also to induce transcription from both promoters in vivo. Both promoters showed inducible activity in the absence of pcoRS, the plasmid-borne two-component regulatory system, indicating that a second trans-acting regulatory system is present on the chromosome. The pcoR product showed repressor action in the absence of pcoS, while still allowing induction, suggesting the chromosome encoded a similar two-component system to pco. TnphoA insertion mutagenesis identified chromosomal genes which affected promoter expression, including ptsH, ptsI (sugar phosphotransferase system) and cya (adenylate cyclase). The results support that idea that pco-encoded copper resistance is an auxiliary mechanism for handling copper, the regulation of which is integrated with the chromosomal regulation of cellular copper metabolism.

Force-cooled current leads for the force-cooled superconducting magnets of the Nuclotron

Force-cooled current leads for force-cooled superconducting magnets have been constructed and tested. The current leads were designed for nominal currents of 6 and 9 kA. The current-carrying element consists of a copper box with welded shields and its cooling surface is 0.9 m 3. The specific heat influx at nominal current is 1 W kA −1, the hydraulic resistance 10 kPa and the electrical insulation strength 2–20 kV. The 6–9 kA current leads have now been operating in the test arrangement of the Nuclotron over a long period of time.

Mass Spectra Stimulated by O+ and Ar+ Interacting with a Surface

Beams of O(+) and Ar(+) in the energy range from 100 to 300 eV were directed into an aperture in one face of a copper box. The mass spectrum from a similar aperture in an adjacent face was observed with the aid of a commercial RF quadrupole spectrometer. On the basis of the results obtained it is reported that O(+) beams at about 200 eV may be essentially lost after a few collisions with a surface, in agreement with similar conclusions about atomic oxygen at thermal energies.

Discrete Flow Rates of the Helium Film

Measurements of the helium-film flow rates over a stainless steel substrate have been made using the heat-transport method of Bowers, Brewer, and Mendelssohn. The moving film from a reservoir is vaporized inside a copper box at the top of the stainless steel capillary in a closed system, by electrical heating. The vapor recondenses in the isothermal reservoir. On any day's run, the rate was constant and reproducible to within 1%. The complete range of flow rates observed at 1.2\ifmmode^\circ\else\textdegree\fi{}K on separate days was about 50%. Seven discrete rates were in fact observed in 18 runs nearly equally spaced at intervals of 0.83\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}5}$ ${\mathrm{cm}}^{2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$. At present, no theory predicts discrete flow rates.

Dynamic nuclear polarization in crystals

We shall be concerned with a system of nuclear spins in coupling with electron spins in a solid, and the possibility of polarizing appreciably the nuclear spins through excitation of the magnetic resonances of the system. This is another example of a dynamic polarization method, but in contrast to the cases just discussed by Professor Abragam and Professor Richards, the nuclei are polarized directly by inducing certain forbidden microwave transitions (Jeffries 1957, 1960). After a rather general description of the phenomena, directed toward those unfamiliar with these methods, details will be given with applications to polarized proton targets. To fix ideas, think of a single crystal of the double nitrate La 2 Mg 3 (NO 3 ) 12 . 24H 2 O, in which, say 1% of the La 3+ ions have been replaced by paramagnetic Nd 3+ ions, which are our electron spin system. The nuclear spins may be either the Nd nuclei; or the nuclei H, La, N, etc., in neighbouring diamagnetic atoms. We consider these cases separately below. Imagine the crystal to be enclosed in a copper box, i. e. a microwave cavity, immersed in liquid helium at T ~ 1 °K and in a magnetic field H ~ 10 4 G. Figure 32 shows the experimental arrangement to keep in mind. An r. f. coil wound around the crystal may be used for measuring the nuclear magnetic resonance absorption, which is just proportional to the nuclear polarization.

The Technique of High Intensity Bombardment with Fast Particles

Recent improvements in cyclotron technique have led, in the case of the 37″ cyclotron at the University of California, to the utilization of beams of such intensity that nearly a kilowatt of power must be dissipated in the target. To maintain high operating efficiency it is desirable that targets should be bombarded in elementary form rather than as compounds, and that the cyclotron vacuum chamber should be protected from the debris of bombardment at all times. The former requirement puts a severe limitation on the designer because many elements are neither refractory nor are they good heat conductors. The second requirement necessitates that a thin metal window be used to isolate the target from the vacuum chamber, because most elements sublime or spatter in one way or another no matter how well cooled they may be. To meet this situation a bombarding chamber has been developed (a ``bell-jar window''). It consists of a rectangular copper box with one end closed by a water-cooled copper plate carrying the target and the other by a thin metal window. The window end is bolted to the cyclotron's target orifice and the interior of the box is filled with hydrogen or helium at a pressure of a few centimeters. The presence of the gas serves to keep the window cool, to keep the target from being damaged by the beam and to protect the cyclotron in the event of a sudden failure of the window. The metal windows are supported on a grid of elongated holes which has a geometrical aperture of about 93 percent. The target plate is heavily knurled and the element being bombarded may either be fused on it or pressed into the knurlings with a spatula. The surface of the target can further be protected by covering it with thin gold foil. With this arrangement it has been found possible to bombard red phosphorus, sodium metal, lithium metal and many other difficult targets with the full intensity of the cyclotron.

Studies in the heat-production associated with muscular work. (Preliminary communication: section A.—Methods; section B.—Results.)

The calorimeter with which the included data have been obtained was built upon the plan described by Benedict, omitting, however, such parts as were essential rather to a study of the respiratory gases than to measurements of heat-production. The general principles of its construction are well known, exceedingly ingenious, were developed by Atwater and Benedict, and are briefly as follows: The body of the calorimeter is of sheet copper built upon an external wooden framework, on which again is built externally an outer zinc box enclosing, but nowhere in contact with, the calorimeter box proper. Between the two metal boxes, sets of thermocouples arranged in groups are utilised to discover any differences of temperature likely to lead to a radiation of heat from one box to the other across the intervening air space partially occupied by the wooden framework. In the walls of a still more external wooden shell are placed means by which heat may be added to or subtracted from the zinc box in a graduated fashion so as to annul any such observed differences in temperature. Thus the zinc box is kept in each of its several zones, each zone corresponding to a group of thermocouples, at the same temperature as the copper box, and the thermal insulation of the calorimeter is thus insured. The subject of the experiment enters the calorimeter by a window space left in the walls of this nest of boxes, and is then sealed in by glass and wax. The heat produced in his body, as well as the heat into which all his mechanical work is finally converted, raises the temperature (1) of an insulated radiator system through which a steady stream of water is maintained; (2) of the calorimeter box; (3) causes some evaporation of water from his respiratory passages and skin, and (4) tends to raise his own temperature. Each one of these four stores of heat is observed in suitable ways, and the summed account of their alterations provides a measure of the heat-production of, or total transformation of energy in, the subject.

The Radio-Balance. A Thermoelectric Balance for the Absolute Measurement of Radiation, with Applications to Radium and its Emanation

In this apparatus, which was first constructed in 1905, heat supplied by radiation is directly compensated by the peltier absorption of heat in a thermo-junction through which a measured electric current is passed. In the simplest form of the instrument, radiation admitted through a measured aperture 2 mm. diameter falls on a small copper disc 3 mm. diameter by 0.5 mm. thick, to which two thermo-junctions are attached, forming a peltier cross. One couple is connected to a sensitive galvanometer for indicating changes of temperature. The other is connected to a battery and rheostat in series with a milliammeter or potentiometer for measuring the current required to reduce the deflection of the galvanometer to zero. If A is the area of the aperture in square centimetres, H the intensity of the radiation in watts per square centimetre, a the absorption coefficient of the surface of the disc, P the peltier coefficient in volts, C the balancing current in amperes, and R the effective resistance of the couple, the equation giving the value of the radiation in absolute measure is aAH = PC - C2R. The absolute value of P is the product of the absolute temperature by the thermoelectric power. The value of R, in the small correction term for the joule effect, is readily determined by observing the neutral current, C0 = P/R, for which the joule effect balances the peltier effect. In practice two similar discs with similar connections are mounted side by side in a thick copper box, and are balanced against each other in order to avoid changes of zero due to exposure to sunshine, or rapid variations of temperature. The advantages of the disc radio-balance are that it is very simple to construct and easy to reproduce without material variation in the reduction constants. It is very suitable for measurements of solar radiation, or strong sources, but is insufficiently sensitive for weak sources; and the absorption coefficient a must be determined by comparison with a standard. In the cup radio-balance the radiation is received in a copper cup 3 mm. diameter by 10 mm. deep, so that the absorption coefficient is practically equal to unity. Greater sensitiveness is secured by employing a pile of several couples, insulated from the cup, in place of the single balancing couple. External disturbances are eliminated by employing a pair of cups, similarly mounted but oppositely connected, enclosed in a thick copper cylinder. The joule effect, represented by the C2R term in the equation, is automatically eliminated by passing the same current in series through the opposing peltier junctions soldered to the bottoms of the cups. The cup exposed to radiation is cooled, and the cup screened from radiation is heated by the peltier effect, while both are equally heated by the joule effect. A complete observation involves reversing the current and switching over the radiation screen, in order to eliminate any difference of sensitiveness of the two piles. By observing the neutral current, each cup can be used separately, as with the disc balance; but the disc balance cannot be used with the peltier couples connected in opposition, unless the balancing couples are insulated from the discs. The cup radio-balance is sensitive to less than a tenth of a microwatt, and is very suitable for measuring the heat evolved by small quantities of radio-active substances. It was applied to radium at Prof. Strutt's suggestion, and Prof. Rutherford very kindly supplied samples of emanation, and determined the value of the radium sample employed by comparison with his own standards. The second sample of emanation had only just come to hand, and the absolute values had not been finally reduced at the time the paper was read; but it appeared from the preliminary reductions that the heat evolution of radium in terms of Prof. Rutherford's standards was somewhat greater than that given by previous observers. The instruments exhibited at the meeting included (1) a disc radio-balance equatorially mounted for solar radiation; (2) a laboratory pattern, with water or steam jackets for determining the temperature coefficients and for investigating the theory of the instrument; (3) a cup radio-balance, with which the heat production of radium and its emanation were demonstrated. The latter intrument is capable of measuring the heat evolved from 1 milligram of radium to about one part in 1,000.