Offset Temperature Research Articles

Thermal properties, triglycerides and crystal morphology of bambangan (Mangifera pajang) kernel fat and palm stearin blends as cocoa butter alternatives

The aim of this study was to investigate the thermal properties of bambangan kernel fat (BKF) and palm stearin (PS) blends and their possibility as cocoa butter alternatives. The triglycerides, thermal behaviors, and crystal morphology of the BKF and PS blends were determined using high performance liquid chromatography (HPLC), differential scanning calorimetry (DSC), and polarized light microscope (PLM). All the blends had three main triglycerides; namely, 1,3-dipalmitoyl-2-oleoyl-glycerol, 1-palmitoyl-2-oleoyl-3-stearoyl-glycerol, and 1,3-distearoyl-2-oleoyl-glycerol. The melting onset temperatures decreased for both non-stabilized (−8.81 to −16.80 °C) and stabilized fat blends (−14.04 to −22.16 °C), whereas the melting offset temperatures shifted toward high temperatures for both non-stabilized (35.94–50.21 °C) and stabilized fat blends (48.35–53.16 °C) with PS. The crystallization onset temperatures increased for both non-stabilized (14.66–23.78 °C) and stabilized fat blends (15.46–26.89 °C), whereas the offset temperatures decreased with the addition of PS for non-stabilized (−15.68 to −22.02 °C) and stabilized fat blends (−15.73 to −22.38 °C). The stabilized fat blends showed higher melting and crystallization peak temperatures than non-stabilized fat blends. In the study of crystal morphology, the fat blends showed small spherulites with the diameter of 10–100 μm.

The Thermodynamics of Ligand Binding to the Aminoglycoside O-Nucleotidyltransferase(4') and Variants Yields Clues about Thermophilic Properties.

The aminoglycoside nucleotidyltransferase(4') is an enzyme with high substrate promiscuity and catalyzes the transfer of the AMP group from ATP to the 4'-OH site of many structurally diverse aminoglycosides, which results in the elimination of their effectiveness as antibiotics. Two thermostable variants carrying single-site mutations are used to determine the molecular properties associated with thermophilicity. The thermodynamics of enzyme-ligand interactions showed that one variant (T130K) has properties identical to those of the mesophilic wild type (WT) while the other (D80Y) behaved differently. Differences between D80Y and the T130K/WT pair include the change in heat capacity (Δ Cp), which is dependent on temperature for D80Y but not for WT or T130K. The change in Δ Cp with temperature (ΔΔ Cp) with D80Y is dependent on aminoglycoside only in H2O and remains the same with all aminoglycosides in D2O. Furthermore, the offset temperature ( Toff), the temperature difference that yields identical enthalpies in H2O and D2O, becomes larger with an increase in temperature for WT and T130K but remains mostly unchanged for D80Y. Studies in H2O and D2O revealed that solvent reorganization becomes the major contributor to ligand binding with an increase in temperature for WT and T130K, but changes in low-frequency vibrational modes are the main contributors with D80Y. Data presented in this paper suggest that global properties associated with the enzyme-ligand interactions, such as the thermodynamics of ligand binding, may yield clues about thermophilicity and permit us to distinguish those variants that are simply a more thermostable version of the mesophilic protein.

The Magnitude of Offset Analgesia as a Measure of Endogenous Pain Modulation in Healthy Participants and Patients With Chronic Pain: A Systematic Review and Meta-Analysis.

Offset analgesia (OA) is a test paradigm increasingly used to estimate endogenous pain modulation characterized by a disproportionally profound analgesia after a small decrease of a heat stimulus. This systematic review and meta-analysis examined the magnitude and difference of OA in healthy participants and chronic pain patients. Controlled trials, case-control studies, cross-sectional studies, case-series or other observational studies evaluating the effect of a ±1°C offset trial in healthy controls and patients with chronic pain were searched in PubMed, Web of Science, CINAHL, PEDro, PsycINFO, and Cochrane CENTRAL. An additional hand search was conducted. Studies fulfilling the eligibility criteria were independently assessed for methodological quality with the Downs and Black scale by 2 reviewers. Twenty-six studies (healthy participants n=758; chronic pain patients n=134) were included in the qualitative synthesis and 12 in meta-analyses (healthy participants n=366; chronic pain patients n=73). A significant difference between offset and constant temperature trials was found for continuous pain intensity rating immediately after a 1°C decrease in temperature (-0.46 [visual analogue scale, 0 to 10]; 95% confidence interval, -0.75 to -0.17; P=0.002), but not after a fixed time period of 5 seconds. Furthermore, a significant difference of the magnitude of OA between chronic pain patients and healthy controls was calculated (-29.9%; 95% confidence interval, -40.3 to -19.5; P<0.00001). Results indicate that pain-free participants show a larger OA response when rating pain continuously compared with individuals with chronic pain.

Towards reduced heating duration in the transient thermal dissipation system of sap flow measurements

The TTD10 method is an empirical evolution of the constant heat dissipation method of Granier (1985). By contrast to Granier, it uses a transient heating of 10 minutes, and it can be applied to a single-needle probe (Do et al., 2011). This system saves energy and cost and reduces thermal interference due to heat storage and passive thermal gradients. However, the heating duration increases the time resolution of measurement, i.e., 20 min with cooling, and assumes a relative stability of the flow rate over 10 min. Hence the objective was to reduce the heating time and measurement cycle. Previous multi-media laboratory data with both dual-needle and single-needle probes were used to test a generic calibration with the maximum temperature taken at 5 min. A calibration with similar sensitivity and accuracy to TTD10 was obtained under two conditions. The first condition used the difference between the maximum temperature and an offset temperature taken at 30 s. The second defined a new thermal index called K2. This new TTD5 system with single-needle probe enhances the previous advantages of low energy, low cost and simplicity of TTD method, well adapted to large sampling experiments.

Superconductivity in nano- and micro-patterned high quality single crystalline boron-doped diamond films

We demonstrate nano- and micro-size patterning processes for high quality single crystal superconducting boron-doped diamond films with low damage using selective microwave plasma chemical vapour deposition and selective oxygen plasma etching. The offset critical temperature Tc(offset) of the micro strip is 10.2 K even if the strip width is 1 μm. However, we show that the critical temperature at zero resistivity Tc(zero) of several narrow strips is decreased owing to the unexpected defects induced by polishing damage and natural nanoscale scratch injury. These defects will induce a two-step superconducting transition. The probability of this tendency increases with decreasing the strip width. We also reveal that the critical current density Jc increases with decreasing the strip width, especially below 30 μm. By using a transport measurement, the maximum Jc is estimated to be 917,000 A/cm2 at 2.0 K with a strip width of 2 μm, which is the highest value reported for a superconducting diamond film. The upper critical field is estimated to be 11.5 T by the WHH approximation and 9.3 T by BCS fitting. Such high values mean superconducting diamond wiring can be used under a high magnetic field. We also attempt to fabricate nano-patterning and reveal that the transition temperature suddenly decreases below 400 nm, and superconductivity is not observed below 300 nm. This work contributes to the future development of superconducting nano- and micro-electro mechanical systems by exploiting the excellent properties of robustness, processability, high transition temperature, critical current density, and critical field associated with diamond.

Performance Analysis of Air Cooled Heat Pump Coupled with Horizontal Air Ground Heat Exchanger in the Mediterranean Climate

A concept of Air-Cooled Heat Pump (ACHP) coupled with a Horizontal Air-Ground Heat Exchanger (HAGHE), also called Horizontal Earth-To-Air Heat Exchanger (EAHX), has been proposed. The Air-Cooled Heat Pump is a system which transfers heat from outside source (air) to inside sink (water) and vice versa in summertime. The innovation is to provide a geothermal treatment of pre-heating/cooling of air before meeting the evaporator in winter or the condenser in summer of the heat pump. Besides, it is known that the variations of the ground temperature, respect to the external air one, are mitigated already in the first layers of the ground throughout the year, due to the high thermal inertia of the ground, letting the heat pump work with more mitigated conditions, improving the performances. The behaviour of HAGHE has been investigated by varying the length and the installation depth of the probes, the air flow rate and the ground thermal properties. All the combinations have been implemented using TRNSYS 17 software (Transient System Simulation Program) to obtain the outlet temperatures from HAGHE, resulting from the 54 configurations. The results are compared in terms of Coefficient of Performance (COP) in wintertime and Energy Efficiency Ratio (EER) in summertime between configurations with and without the coupling with HAGHE. In addition, two seasonal performance SCOP and SEER coefficients have been calculated considering, not only the inlet air temperatures into the Air-Cooled Heat Pump, but also their frequency of occurrence, the off-set external temperature (16 °C), the nominal external temperature and heating and cooling loads.

A detailed research for determination of Bi/Ga partial substitution effect in Bi-2212 superconducting matrix on crucial characteristic features

This multidisciplinary study paves way to investigate the crucial of fundamental characteristic properties including the bulk density, electrical, superconducting, flux pinning mechanism, crystal structure quality and strength quality of interaction between the superconducting grains in the Bi2.1Sr2.0Ca1.1Cu2.0Oy (Bi-2212) superconducting materials with the partial replacement of gallium foreign impurity by bismuth nanoparticles in the crystal structure. Characterizations of polycrystalline ceramic materials prepared by standard ceramic route in the atmospheric air are performed by means of conventional experimental measurement methods such as powder X-ray diffraction, Archimedes water displacement, dc electrical resistivity versus temperature and critical current density examinations. All the bulk Bi-site Ga partial replaced materials exhibit the Bi-2212 superconducting phase within the different fraction levels (%73.1–94.8), moderate self-field critical current densities 54–96 A/cm2 and wide-ranging offset and onset critical transition temperature range of 45.65 K–84.52 K and 70.06 K-85.00 K. As for the experimental findings of bulk density and related degrees of granularity (porosity) parameters, the bulk density parameter is found to be between 5.76 g/cm3 and 6.12 g/cm3 when the corresponding residual porosity value is also obtained to be in a range of 8.57 %–2.86%. Moreover, the mobile hole carrier concentrations in the short-range-ordered antiferromagnetic CuO2 layers are found to be in the range from 0.085 until 0.152. Additionally, the role of Ga/Bi partial substitution in the crystal lattice on the normal state resistivity, residual resistivity, residual resistivity ratio, vibrational mode intensities, texturing, superconducting volume fractions, mobile hole carrier concentrations, average crystallite sizes, Lotgering indices and cell parameters are discussed in details. All the experimental results and theoretical approaches show that the characteristic properties tend to improve regularly with the increment in the Ga foreign impurity level until x = 0.05 due to the increment in the crystal structure quality and interaction between the superconducting grains. After the critical Ga/Bi substitution level of x = 0.05, every feature degrades considerably.

Thermoplastic processing and debinding behavior of NbC-M2 high speed steel cemented carbide

The aim of this study is to evaluate the thermoplastic processing on a new generation of hard metals based on NbC bonded with high speed steel. The conventional technique in producing cemented carbide parts is dry pressing with paraffin binder and post production. To overcome shape restriction in pressing and post production, thermoplastic shaping processes can be used. For this purpose, a previously known binder system for ceramic feedstocks containing paraffin wax and ethylene vinyl acetate was selected and used for the first time with cemented carbides. The stated organic binders were mixed with NbC-12 wt.% M2 high speed steel powder and feedstocks with solid loading content from 50 to 60 vol.% were obtained. The rheological behavior of the feedstocks as well as the critical solid loading content were assessed using a capillary rheometer. A model fitting approach was used for the first time in hardmetal feedstocks to estimate the critical solid loading. Experimental values were fitted to a model from Chong (1971) which is based on bimodally disperse powder mixtures and a critical powder loading of 70 vol.% could be calculated. However, based on the abrasion problems during mixing at high filler content, feedstock with 57.5 vol.% powder loading had the optimum processability characteristics, and was therefore selected for further shaping processes. Thermo gravimetric analysis on green samples was performed after shaping in order to develop an optimum thermal debinding profile. The thermal debinding program was adjusted with special attention on decomposition onset, maximum mass loss rate and decomposition offset temperatures. Initial trials using decomposition offset temperature as holding steps, resulted in fragmented samples after debinding. The final designed heating profile resulted in a consistent mass loss rate according to thermo gravimetric analysis which limited crack formation during debinding. Debinding under a forming gas (95N2-5H2) atmosphere using optimized heating cycles resulted in sound sintered bodies only when green parts were embedded in a powder bed during debinding.

Investigation on the melting and freezing behaviours of pure Si cell for thermocouple calibration

The melting and freezing behaviours of pure Si contained in alumina crucible were investigated using a monitoring Pt/Pd thermocouple. To induce melting and freezing, furnace temperatures were controlled from ± 3 °C to ± 10 °C. The melting and freezing temperatures coincided within 10 mK at the offset temperature of ± 3 °C, showing a good consistency. The melting and freezing plateau temperature varied with offset temperature, and melting had much smaller offset temperature dependence. The freezing temperature showed a good reproducibility of about 20 mK (1 σ) regardless of the offset temperature. After repeated 9 phase transitions at high temperature, it turned out that it was not mechanically broken. One drawback of pure Si cell is the formation of white and finite powders inside. This is probably due to evaporation of molten Si and deposition on the surface of alumina components. Finally it is recommended to calibrate high temperature noble metal thermocouples of about 1412 ° C using the freezing point of a pure Si cell made of alumina crucibles.

Thermal stability of ARMCO iron processed by ECAP

The thermal stability of ARMCO iron processed by equal-channel angular pressing (ECAP) up to a true strain of 16 was investigated by differential scanning calorimetry (DSC). Particularly, the analysis was focused on deriving the recrystallization behavior (onset, peak, and offset temperatures) at three different heating rates (10, 20, and 40 °C/min). Additionally, the stored and activation energies were calculated. As well, the microstructure and the tensile response were evaluated at different numbers of passes before and after annealing heat treatment to assess any significant grain growth and its influence on the material ductility. The different energy contributions (dislocations, grain boundaries, and vacancies) were calculated, being verified that the main contribution came from vacancies.

Seasonal temperature variation influences climate suitability for dengue, chikungunya, and Zika transmission.

Dengue, chikungunya, and Zika virus epidemics transmitted by Aedes aegypti mosquitoes have recently (re)emerged and spread throughout the Americas, Southeast Asia, the Pacific Islands, and elsewhere. Understanding how environmental conditions affect epidemic dynamics is critical for predicting and responding to the geographic and seasonal spread of disease. Specifically, we lack a mechanistic understanding of how seasonal variation in temperature affects epidemic magnitude and duration. Here, we develop a dynamic disease transmission model for dengue virus and Aedes aegypti mosquitoes that integrates mechanistic, empirically parameterized, and independently validated mosquito and virus trait thermal responses under seasonally varying temperatures. We examine the influence of seasonal temperature mean, variation, and temperature at the start of the epidemic on disease dynamics. We find that at both constant and seasonally varying temperatures, warmer temperatures at the start of epidemics promote more rapid epidemics due to faster burnout of the susceptible population. By contrast, intermediate temperatures (24–25°C) at epidemic onset produced the largest epidemics in both constant and seasonally varying temperature regimes. When seasonal temperature variation was low, 25–35°C annual average temperatures produced the largest epidemics, but this range shifted to cooler temperatures as seasonal temperature variation increased (analogous to previous results for diurnal temperature variation). Tropical and sub-tropical cities such as Rio de Janeiro, Fortaleza, and Salvador, Brazil; Cali, Cartagena, and Barranquilla, Colombia; Delhi, India; Guangzhou, China; and Manila, Philippines have mean annual temperatures and seasonal temperature ranges that produced the largest epidemics. However, more temperate cities like Shanghai, China had high epidemic suitability because large seasonal variation offset moderate annual average temperatures. By accounting for seasonal variation in temperature, the model provides a baseline for mechanistically understanding environmental suitability for virus transmission by Aedes aegypti. Overlaying the impact of human activities and socioeconomic factors onto this mechanistic temperature-dependent framework is critical for understanding likelihood and magnitude of outbreaks.

Influence of iron oxide on thermal decomposition behavior and burning characteristics of ammonium nitrate/ammonium perchlorate-based composite propellants

The thermal decomposition behavior and burning characteristics of ammonium nitrate(AN)/ammonium perchlorate(AP) propellants supplemented with Fe2O3 were investigated. Based on these data, the performance differences between the propellants with Fe2O3 and those without Fe2O3 were investigated to reveal the influence of Fe2O3 on the thermal decomposition behavior and burning characteristics of AN/AP-based composite propellants. TG-DTA showed the peak temperature and temperature range of thermal decomposition due to AN decomposition to be independent of the presence of Fe2O3. The peak and the offset temperature of thermal decomposition due to AP decomposition decreased owing to the addition of Fe2O3, while the onset temperature did not vary. The burning rate of the AN/AP propellant was increased by the addition of Fe2O3; the effect of Fe2O3 on increasing the burning rate was influenced by the type of oxidizer, AP content in the oxidizer (ξ), and AP size. Furthermore, Fe2O3 allowed the suppression of the remarkable heterogeneity of the combustion wave of the AN/AP propellant without Fe2O3. The ignitability of the AN/AP propellant was improved by the addition of Fe2O3, except for the propellant with a ξ of 0.4. The cause of depressed ignitability by the addition of Fe2O3 for the propellant with a ξ of 0.4 is discussed based on thermogravimetry-differential thermal analysis, the visual observations of the unignited propellant surfaces, and the decomposition phenomena of the propellants using a high-temperature observation equipment. A large quantity of AN remained on the surface of the unignited propellant at 0.5 MPa. The cause of the depressed ignitability is that AN, AP, and HTPB do not simultaneously decompose and as a result AN remains on the burning surface. Thus, the burning surface of AN did not regress simultaneously with the burning surface of the AP-filled region, the matrix of AP, and HTPB.

Impact of carbon nanotubes addition on transport and superconducting properties of YBa2Cu3O7−δ ceramics

YBa2Cu3O7−δ (Y-123) ceramics added with small amounts (0.0 – 0.8 wt%) of carbon nanotubes (CNTs) were synthesized using co-precipitation process. The effects of CNTs addition on the critical temperature (Tc), critical current density (Jc) measured at 30 K in self-field, phase formation and microstructure properties including elemental compositional analysis were studied. The onset (Tc-onset) and offset critical temperatures (Tc-offset) reduced with increasing CNTs concentration up to x = 0.6 wt% and then increased for sample x = 0.8 wt%. The metallic behaviour of Y-123 changes to semiconducting behaviour with the addition of CNTs. Introduction of CNTs improved Jc significantly. The Jc for pure sample, with volume fraction of 96.2% of Y-123, is 11 A/cm2. The highest value of Jc, 477 A/cm2, is observed for sample x = 0.2 wt%. Sample x = 0.8 wt% shows the highest Tc with good crystallinity and orthorhombicity factor among the added samples. The result suggests the enhancement of Jc may be caused by flux pinning phenomena with the introduction of CNT’s in Y-123 host system.

Plantwide control for optimal operation of industrial-scale crude distillation unit processes

ABSTRACTIn this article, a combination of the wavelet neural network framework and the line-up competition algorithm is used to solve the economic optimization algorithm for an industrial-scale atmospheric distillation column (ADC) process. Compared to the relevant measuring data from Sinopec Wuhan Petroleum Group Company, China, the first optimal operating conditions show that the increments of the duties of furnace and pump-arounds of the ADC can effectively improve oil production. In our approach, the preflash column (PFC) coupled with ADC is denoted as an industrial-scale crude distillation unit (CDU) process. Since the PFC can produce light naphtha and reduce the furnace duty and steam consumption of ADC, it is verified that the CDU process provides the higher economic potential than ADC. Based on the second optimal operating conditions, the plantwide control strategy is employed to operate the system safely as well as regulate the outputs of the plant in the presence of inlet perturbations. Within the plantwide control framework, the inventory control aims to keep the controlled variables close to the desired operating condition and the quality control loops use a combination of inferential predictions and feedforward ratios to effectively suppress the temperature spikes of trays and furnaces. Finally, the simulations show that the product quality is guaranteed due to no offset ASTM D86 distillation temperature responses.

The Effect of Inhomogeneous Phase on the Critical Temperature of Smart Meta-superconductor MgB2

The critical temperature (TC) of MgB2, one of the key factors limiting its application, is highly desired to be improved. On the basis of the meta-material structure, we prepared a smart meta-superconductor structure consisting of MgB2 micro-particles and inhomogeneous phases by an ex situ process. The effect of inhomogeneous phase on the TC of smart meta-superconductor MgB2 was investigated. Results showed that the onset temperature ( $T_{\mathrm {C}}^{\text {on}}$ ) of doping samples was lower than those of pure MgB2. However, the offset temperature ( ${T}_{\mathrm {C}}^{\text {off}}$ ) of the sample doped with Y2O3:Eu3+ nanosheets with a thickness of 2 ∼ 3 nm which is much less than the coherence length of MgB2 is 1.2 K higher than that of pure MgB2. The effect of the applied electric field on the TC of the sample was also studied. Results indicated that with the increase of current, ${T}_{\mathrm {C}}^{\text {on}}$ is slightly increased in the samples doping with different inhomogeneous phases. With increasing current, the ${T}_{\mathrm {C}}^{\text {off}}$ of the samples doped with nonluminous inhomogeneous phases was decreased. However, the ${T}_{\mathrm {C}}^{\text {off}}$ of the luminescent inhomogeneous phase doping samples increased and then decreased with increasing current.

Phase Curves of WASP-33b and HD 149026b and a New Correlation between Phase Curve Offset and Irradiation Temperature

Abstract We present new 3.6 and 4.5 μm Spitzer phase curves for the highly irradiated hot Jupiter WASP-33b and the unusually dense Saturn-mass planet HD 149026b. As part of this analysis, we develop a new variant of pixel-level decorrelation that is effective at removing intrapixel sensitivity variations for long observations (&gt;10 hr) where the position of the star can vary by a significant fraction of a pixel. Using this algorithm, we measure eclipse depths, phase amplitudes, and phase offsets for both planets at 3.6 and 4.5 μm. We use a simple toy model to show that WASP-33b’s phase offset, albedo, and heat recirculation efficiency are largely similar to those of other hot Jupiters despite its very high irradiation. On the other hand, our fits for HD 149026b prefer a very high albedo. We also compare our results to predictions from general circulation models, and we find that while neither planet matches the models well, the discrepancies for HD 149026b are especially large. We speculate that this may be related to its high bulk metallicity, which could lead to enhanced atmospheric opacities and the formation of reflective cloud layers in localized regions of the atmosphere. We then place these two planets in a broader context by exploring relationships between the temperatures, albedos, heat transport efficiencies, and phase offsets of all planets with published thermal phase curves. We find a striking relationship between phase offset and irradiation temperature: the former drops with increasing temperature until around 3400 K and rises thereafter. Although some aspects of this trend are mirrored in the circulation models, there are notable differences that provide important clues for future modeling efforts.

Far infrared cavity of a post C-rich AGB star under IRAS survey

In this paper, we discuss about the physical properties of the dusty environment around the mass losing carbon rich post AGB star located at R.A. (J2000) =06 h 53m 01s and Dec (J2000) =-02o 16’ 00”, in the far infrared IRAS maps. A cavity like structure (major diameter ∼ 103.3 pc &amp; minor diameter ∼33.1 pc) is found to lie at R.A. (J2000)= 06 h 51 m 54.02 s and DEC (J2000) = -01o 35’ 43”, located at a distance ∼ 6.11 kpc from the star. We studied the distribution of flux density, dust color temperature, dust mass in the cavity. The dust color temperature is found to lie in the range 18.7 K to 20.5 K which shows the cavity is isolated and independently evolved. Such a low offset temperature variation shows that there is symmetric outflow or symmetric distribution of density and temperature. It further suggests that our structure is bigger in size and is far away from the far infrared loops(kk loops). The cavity may be in thermally pulsating phase. A possible explanation of the results will be discussed.BIBECHANA 90 (2018) 96

Enzymatic synthesis of structured lipids with behenic acid at the sn-1, 3 positions of triacylglycerols.

A long chain saturated fatty acid (SFA), behenic acid, is incorporated into the sn-1, 3 positions of triacylglycerols in palm olein (POo) and high-oleic sunflower oil (HOS) by solvent-free interesterification catalyzed by Lipozyme RM IM. The enzymatic interesterified HOS (EIE-HOS) yielded 76.5% of BOO and BOB as compared to 45.6% in POo (EIE-POo). The sn-2 position of EIE-HOS displayed 5.3mol% of SFA which is significantly lower compared to 13.5mol% in EIE-POo (P<0.001). The sn-1, 3 positions of EIE-POo exhibited greater amount of behenic acid (82.0mol%) in relation to EIE-HOS (64.0mol%) (P<0.001). Due to the greater variety of constitutive triacylglycerol, EIE-POo showed greater differences between onset (To) and offset temperature (Tf) in the melting endotherms (76.99°C) as compared to EIE-HOS (68.65°C), and may offer more intensive cooling sensation and flavor release.

A 4 mm² Double Differential Torsional MEMS Accelerometer Based on a Double-Beam Configuration.

This paper reports the design and simulation of a 4 mm2 double differential torsional MEMS accelerometer based on a double-beam configuration. Based on the structure of conventional torsional accelerometers, normally composed of one pair of proof masses and one torsional beam, this work explores the double differential configuration: a torsional accelerometer with two pairs of unbalanced proof masses rotating in reverse. Also, the torsional beam is designed as a double-beam structure, which is a symmetrical structure formed by two torsional beams separated by a certain distance. The device area of the novel accelerometer is more than 50 times smaller than that of a traditional double differential torsional MEMS accelerometer. The FEM simulation results demonstrate that the smaller device does not sacrifice other specifications, such as mechanical sensitivity, nonlinearity and temperature robustness. The mechanical sensitivity and nonlinearity of a ±15 g measuring range is 59.4 fF/g and 0.88%, respectively. Compared with traditional single-beam silicon structures, the novel structure can achieve lower maximum principle stress in critical regions and reduce the possibility of failure when high-g acceleration loading is applied along all three axes. The mechanical noise equivalent acceleration is about in the theoretical calculations and the offset temperature coefficient is 0.25 mg/ in the full temperature range of to .

A STUDY OF A PULSAR WIND DRIVEN STRUCTURE IN FAR-INFRARED IRAS MAP AT LATTITUDE -10º

A systematic search of dust structure in the far infrared (100 μm and 60 μm) IRAS (Infrared Astronomical Satellite) survey was performed using Sky View Observatory. In order to find the possible candidate, we used SIMBAD database to locate discrete sources in the region. A deep cavity-like isolated far infrared dust structure (size ~ 4.46 pc × 2.23 pc) at galactic longitude: 284.360o, galactic latitude: -9.549o was found at the distance of about 375 pc. We have studied the flux density variation and then calculated temperature and mass profile of the dust and excess mass using data reduction software ALADIN 7.5 within this region. The dust color temperature was found to lie in the range 23.40 K to 29.28 K. An offset temperature of about 6.0 K was found. The total mass of the dust structure was found to be about 2.55×1027 kg and the excess mass per pixel was 2.52×1024 kg. We also studied the rate of mass loading around the structure. The energy of the pulsar required to create that in homogeneity in the structure was calculated to be 5.04×1036 J. Possible explanations of results will be presented.Journal of Institute of Science and Technology, 2017, 22 (1): 1-9