Relationship between pulse amplitude and thermal exchange in the finger: the effect of smoking

Summary. In 24 healthy volunteers finger pulse amplitude and heart rate (HR) were monitored by pulse plethysmography and thermal exchange from the finger and were compared before and after the smoking of a single cigarette. Thermal exchange was measured using a direct calorimeter consisting of a recording bath and a reference bath, both of which were filled with water at 18°C. The subject immersed the two distal phalanx of a finger into the recording bath. The water thermal gradient between both baths after 4 min of finger immersion and the maximal value of heat loss from the finger to the water were recorded. Decreases in the water thermal gradient (from 6·06 to 5·33°C, P < 0·05) in maximal value of heat loss (from 22·5 to 18·75 w.m^-2, P < 0·01) and in plethysmographic wave amplitude (from 25·8 to 14·6 mm, P < 0·01) and increased HR (from 72 to 83 beats min^-1) were observed in smokers. These changes were not statistically significant in non-smokers. Water thermal gradient and maximal value of heat loss correlated with plethysmographic wave amplitude before and after smoking but not with HR in the 24 subjects studied. The present study shows a good relationship between vascular phenomena and thermal exchange in the fingers. The variations of finger pulse amplitude provide an adequate and sensitive adjustment of thermal exchange since the effects of smoking a single cigarette can be detected by both PWA and calorimetric measurements in the finger.     

Techno-economic analysis of wind power integrated with both compressed air energy storage (CAES) and biomass gasification energy storage (BGES) for power generation

A techno-economic analysis of excess wind electricity powered adiabatic compressed air energy storage (A-CAES) and biomass gasification energy storage (BGES) for electricity generation is implemented to determine the performance of the system and the potential profitability of developing such a facility for distributed power generation in the UK by an investor, given the customer''s demand for heat and electricity. The customers are considered to be about 1600 households in the Humber region, UK, who use heat generally for space heating and domestic hot water applications. The system is modelled using a developed Matlab computer code and its performance evaluated using total system efficiency (TSE), net present value (NPV) and cost of electricity (COE) as metrics. TSE of 36.8% is obtained for the system while the COE is found to be about £0.19 per kW h. In terms of profitability, the system returned a negative NPV of £2 144 062 signalling the non-profitability of the system in the proposed location. However, if 70% of total investment cost (TIC) of the system is provided for by means of a subsidy, the system becomes economically viable with positive NPV of £132 475 and COE of £0.10 per kW h respectively. The sensitivity study shows that the most significant factors swaying the NPV of the A-CAES-BMGES are TIC, O&M cost, excess wind electricity cost, electricity tariff and cost of diesel fuel.

Wind power was integrated with both compressed air energy storage and biomass gasification energy storage for power generation.     

Differential effects of lidocaine on nerve growth factor (NGF)‐evoked heat‐ and mechanical hyperalgesia in humans

We investigated the effects of a non‐specific sodium channel blocker (lidocaine) on heat pain thresholds and mechanical impact pain at day 7 and 21 after intradermal injection of 1 μg NGF. Measurements were performed in 12 healthy male subjects prior to and 5 min after intradermal injection of 150 μl lidocaine administered at concentrations of 0.01% (～0.4 mM) and 0.1% (～4 mM) to both NGF and control skin sites. NGF caused a maximum reduction of heat pain thresholds at day 7 (NGF 42.6 ± 0.6 vs. 49.4 ± 0.3 °C in control skin). Lidocaine sensitized normal skin for heat pain, but reduced heat hyperalgesia after NGF at day 7 (44.3 ± 0.8 °C, lidocaine 0.1%; p < 0.005). Pain upon supra‐threshold mechanical impact stimulation was increased after NGF at day 7 (VAS 29 + 5) and massively enhanced at day 21 (VAS 64 + 5, p < 0.001). Lidocaine dose‐dependently attenuated mechanically‐induced pain at both control and NGF‐treated sites. Maximum lidocaine effects on mechanical hyperalgesia were recorded at day 21 in NGF skin (pain reduction to VAS 37 ± 4, p < 0.00001). Repetitive impact stimuli caused increasingly more pain at the NGF sites at day 21 and this pain increase was efficiently suppressed by lidocaine 0.1%. Lidocaine differentially affects NGF‐induced mechanical hyperalgesia (analgesic effect) and heat sensitivity of nociceptors (sensitizing effect). These opposing responses may be attributed to block of sodium channels vs. sensitization of TRPV1. NGF‐evoked extreme mechanical impact pain indicates high action potential discharge frequencies, which might be more susceptible to lidocaine block.     

Study by Direct Calorimetry of Thermal Balance on the First Day of Life

Abstract. Using a gradient layer direct calorimeter, total heat losses were measured in 69 full term new-borns at 5 different ambient temperatures (T_A): 28, 30, 32, 34 and 36° C. The relative humidity of the air was kept constant at 50%. Oesophageal temperature (T_eg) and mean skin temperature (T?_s) were continuously recorded. All experiments lasted at least one hour. The mean total heat loss was at 28° C: 3.55 W/kg; at 30° C: 2.97 W/kg; at 32° C: 2.35 W/kg; at 34° C: 1.92 W/kg and at 36° C: 2.05 W/kg. Dry heat loss was proportional to the external temperature gradient. Evaporative heat loss was constant when new-borns were not subjected to heat or cold stress, with a mean of 0.39 W/kg. This value is a measurement of insensible perspiration. Sweating was elicited at a T_A of 36° C when the internal temperature gradient reached a mean value of 0.68° C. Heat storage (S). was calculated and was found to be negative at a T_A of 28 and 30° C, and positive at 34 and 36° C. A regression analysis between heat storage and total heat loss showed a mean heat loss of 2.61 W/kg when the new-borns were in thermal equilibrium (S= 0). This occured in most babies at a T_A slightly below 32° C. A minimal metabolic rate of about 6.0 ml kg^-1 min^-1, determined by direct calorimetry and calculation of S, was found at a T_A of 34 and 36° C. The cutaneous thermal conductance, which is an index of cutaneous blood flow was minimal at a T_A of 30° C. It increased sharply when T?_s reached 36.3° C. These data indicate that the range of thermal comfort on the first day of life in normal full-term new-borns is very narrow and that there is a perfect thermal balance at a T_A slightly below 32° C. However, at this T_A, the metabolic rate is not at a minimal level.     

Removal of toluene as a toxic VOC from methane gas using a non-thermal plasma dielectric barrier discharge reactor

Methane is the main component of biogas, which could be used as a renewable energy source for electricity, source of heat, and biofuel production after upgrading from biogas. It also contains toxic compounds which cause environmental and human health problems. Therefore, in this work, the removal of a toxic compound (toluene) from methane gas was studied using a dielectric barrier discharge (DBD) reactor. It was observed that the removal of the toxic compound could be achieved from methane carrier gas using a dielectric barrier discharge reactor, and it depends on plasma input power. The maximum removal of the toxic compound was 85.9% at 40 W and 2.86 s. The major gaseous products were H₂ and lower hydrocarbons (LHC) and the yield of these products also increases with input power. In the current study, the yield of gaseous products depends on the decomposition of toxic compounds and methane, because the decomposition of methane also produces H₂ and lower hydrocarbons. The percentage yield of H₂ increases from 0.43–4.74%. Similarly, the yield of LHC increases from 0.56–7.54% under the same reaction conditions. Hence, input power promoted the decomposition of the toxic compound and enhanced the yield of gaseous products.

The removal of toluene as a toxic volatile organic compound from methane gas, which is the major component of biogas, is carried out using a non-thermal plasma dielectric barrier discharge reactor.     

Linking heat and electricity supply for domestic users: an example of power-to-gas integration in a building

A novel power-to-X system, coupling electricity and gas grid in a building, is presented. This system operates a retrofit of the existing photovoltaic system, consuming the electricity overproduction in the local synthesis of methane instead of injecting it into the electricity grid. Methane can be stored in the gas grid and used in winter in the existing gas burners, providing the required heat to keep the building at a comfortable temperature. Additionally, the methanation system provides waste heat that is used to warm up the sanitary water, eliminating the need for an electric boiler. The system, fed by 800 m² of solar panels, was optimized according to the weather conditions and the dimensions of the main pieces of equipment were determined. This allows the production of ca. 17 MW h of methane for seasonal storage. By retrofitting the building with the power-to-X unit, the energetic independence of the house is maximized, thanks to the synchronous production of electricity, gas, and heat, including energy storage. Therefore, the profitability of the photovoltaic system is ensured independently from the electricity feed-in tariffs. The system performance was evaluated in a case study in the north of Switzerland. When considering the purchase of renewable natural gas (i.e., from biogas), it was calculated that the system would be profitable for an electricity price below 0.05 € per kW h.

A power-to-gas system is integrated in a building to store the excess self-produced solar energy and reduce the heating expenses. This is possible by recovering waste heat from the reaction and using the gas grid as energy storage infrastructure.     

Insights into the specific heat capacity enhancement of ternary carbonate nanofluids with SiO2 nanoparticles: the effect of change in the composition ratio

Ternary carbonate nanofluids have proven to be a promising high temperature thermal energy storage and transfer medium for solar thermal power. For the ternary carbonate K₂CO₃–Li₂CO₃–Na₂CO₃ (4 : 4 : 2, mass ratio) with SiO₂ nanoparticles prepared using a two-step solution method, the enhancement of the specific heat capacity was up to 113.7% at 540 °C compared to the ternary carbonate prepared by a direct mixing method. The present work aims to give insights into the marked enhancement of specific heat capacity. The effect of evaporation temperature on the nanostructures formed in ternary carbonate nanofluids is discussed for the enhancement of specific heat capacity. More importantly, based on an analysis of inductively coupled plasma atomic emission spectrometry, it is revealed that the composition ratio of the ternary carbonate, which can influence its specific heat capacity, was changed during the evaporation process in an electrothermal drier. Besides a difference in the solubility of the carbonates in water, it is demonstrated that the heating mode can affect the composition ratio of mixed molten salts.

The specific heat capacity of a ternary carbonate-SiO₂ nanofluid is enhanced by 113.7% at 540 °C.     

Assessing water quality in the northern Adriatic Sea from HICO™ data

This letter focuses on water-quality estimation in the northern Adriatic Sea using physically-based methods applied to image obtained with the Hyperspectral Imager for the Coastal Ocean (HICO?). Optical properties of atmosphere and water were synchronously measured to parameterise such methods. HICO?-derived maps of chlorophyll-a (chl-a) and suspended particulate matter (SPM) indicated low values, in the range of 0–3 mg m^?3 and 0–4 g m^?3, respectively, correlating significantly with field data (R² = 0.71 for chl-a and R² = 0.85 for SPM). The results, on analysis, identify clear waters in the open sea and moderately turbid waters near the coast due to river sediment discharge and organic matter from coastal lagoons. These findings support the use of HICO? data to assess water-quality parameters in coastal zones and suggest the feasibility of integrating them with future-generation space-borne hyperspectral images.     

Systematic investigation of CO2 : NH3 ice mixtures using mid-IR and VUV spectroscopy – part 2: electron irradiation and thermal processing

Many experimental parameters determine the chemical and physical properties of interstellar ice analogues, each of which may influence the molecular synthesis that occurs in such ices. In part 1, James et al., RSC Adv., 2020, 10, 37517, we demonstrated the effects that the stoichiometric mixing ratio had on the chemical and physical properties of CO₂ : NH₃ mixtures and the impact on molecular synthesis induced by thermal processing. Here, in part 2, we extend this to include 1 keV electron irradiation at 20 K of several stoichiometric mixing ratios of CO₂ : NH₃ ices followed by thermal processing. We demonstrate that not all stoichiometric mixing ratios of CO₂ : NH₃ ice form the same products. Not only did the 4 : 1 ratio form a different residue after thermal processing, but O₃ was observed after electron irradiation at 20 K, which was not observed in the other ratios. For the other ratios, the residue formed from a thermal reaction similar to the work shown in Part 1. However, conversion of ammonium carbamate to carbamic acid was hindered due to electron irradiation at 20 K. Our results demonstrate the need to systematically investigate stoichiometric mixing ratios to better characterise the chemical and physical properties of interstellar ice analogues to further our understanding of the routes of molecular synthesis under different astrochemical conditions.

The stoichiometric mixing ratio of CO₂ : NH₃ ice mixtures determines the electron irradiation products at 20 K and the composition of residue material formed after thermal processing.     

Surface modification of carbon nanotubes with copper oxide nanoparticles for heat transfer enhancement of nanofluids

Over the last few years, nanoparticles have been used as thermal enhancement agents in many heat transfer based fluids to improve the thermal conductivity of the fluids. Recently, many experiments have been carried out to prepare different types of nanofluids (NFs) showing a tremendous increase in thermal conductivity of the base fluids with the addition of a small amount of nanoparticles. However, little experimental work has been proposed to calculate the flow behaviour and heat transfer of nanofluids and the exact mechanism for the increase in effective thermal conductivity in heat exchangers. This study mainly focuses on the development of nanomaterial composites by incorporating copper oxide nanoparticles (CuO) onto the surfaces of carbon nanotubes (CNTs). The CNT–CuO nanocomposite was used to prepare water-based heat transfer NFs. The morphological surfaces and loading contents of the CNT–CuO nanocomposite were characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) while the physical and thermal properties of the water-based nanofluids were characterized using differential scanning calorimetry (DSC), the Mathis TCi system and a viscosity meter for measuring the heat capacity, thermal conductivity and viscosity of the synthesized NFs, respectively. The heat transfer and the pressure drop studies of the NFs were conducted by a horizontal steel tube counter-flow heat exchanger under turbulent flow conditions. The experimental results showed that the developed NFs with different concentrations of modified CNTs (0.01, 0.05 and 0.1 wt%) have yielded a significant increase in specific heat capacity (102% higher than pure water) and thermal conductivity (26% higher than pure water) even at low concentration. The results also revealed that the heat rate of the NF was higher than that of the base liquid (water) and increased with increasing the concentration of nanoparticles. Furthermore, no significant effect of the nanoparticles on the pressure drop of the system was observed.

Over the last few years, nanoparticles have been used as thermal enhancement agents in many heat transfer based fluids to improve the thermal conductivity of the fluids.     

Combined Effect of Heat Shock and Chlorine Fails to Elicit Acquired Thermal Tolerance in <Emphasis Type="Italic">Labeo rohita</Emphasis> Spawns

An experiment was conducted to delineate the effect of heat shock and chlorine on the biochemical responses of Labeo rohita spawns for evaluating acquired thermal tolerance. Spawns were equally distributed in three different groups i.e., group 1 heat shock (37 °C) without chlorine, group 2 heat shock (37 °C) in chlorinated water and group 3 control in ambient water (28 °C). Following 1-h stress, the animal was transferred to ambient water conditions to study the recovery from stress at different sampling hours i.e., 0, 2, 4, 8, 14, 24 and 48 h. Stress parameters viz., glucose, lactate dehydrogenase, malate dehydrogenase and adenosine triphosphatase were measured for both the experimental groups and compared with the control. At the end of 48 h, the recovering spawns in the respective experimental groups were subjected to temperature higher than 37 °C in order to check for thermal tolerance and induction of cross protection. Their survivability rates were checked after exposure to 38, 39, 40, 41 and 42 °C. The result indicated that the spawns in group 1 recovered within 24 h wherein heat shock alone imparted higher thermal tolerance in them leading to 100 % survival at 40 °C; however the fishes in group 2 did not recover even after 48 h and demonstrated only 30 % survival at 40 °C. In both experimental groups, none of the fish survived the exposure to 42 °C. The results indicate that the combined effect of heat shock and chlorine has more pronounced effect on L. rohita spawns and fails to develop acquired thermal tolerance.     

Influence of recovery strategies upon performance and perceptions following fatiguing exercise: a randomized controlled trial

Background

Despite debate regarding their effectiveness, many different post-exercise recovery strategies are used by athletes. This study compared five post-exercise recovery strategies (cold water immersion, contrast water immersion, active recovery, a combined cold water immersion and active recovery and a control condition) to determine which is most effective for subsequent short-term performance and perceived recovery.

Methods

Thirty-four recreationally active males undertook a simulated team-game fatiguing circuit followed by the above recovery strategies (randomized, 1 per week). Prior to the fatiguing exercise, and at 1, 24 and 48 h post-exercise, perceptual, flexibility and performance measures were assessed.

Results

Contrast water immersion significantly enhanced perceptual recovery 1 h after fatiguing exercise in comparison to active and control recovery strategies. Cold water immersion and the combined recovery produced detrimental jump power performance at 1 h compared to the control and active recovery strategies. No recovery strategy was different to the control at 24 and 48 h for either perceptual or performance variables.

Conclusion

For short term perceptual recovery, contrast water therapy should be implemented and for short-term countermovement power performance an active or control recovery is desirable. At 24 and 48 h, no superior recovery strategy was detected.

Trial registration

Retrospectively registered; ISRCTN14415088; 5/11/2017.

     

Thermal management for a tube–shell Li-ion battery pack using water evaporation coupled with forced air cooling

A novel battery thermal management system (BTMS) based on water evaporation (WE) and air-cooling (AC) for a tube–shell Li-ion battery (LIB) pack is designed. A sodium alginate (SA) film with a higher water content above 99% is fortified by adding polyethylene (PE) fibers. The air flow and PE-fiber composite sodium alginate (PECSA) film are both used to control the temperature of the battery pack. Results show that the maximum temperature of the battery pack can be controlled below 32 °C, when WE coupled with AC is used at a discharge rate of 1.8C within a discharge time of 1000 s. This method yields the highest performance of thermal management. The experimental results validate the numerical data, confirming that the design of WE combined with AC helps prevent overheating of a battery pack. This work also provides an automatic refilling system to solve the dehydration problem of the PECSA film.

A novel battery thermal management system (BTMS) based on water evaporation (WE) and air-cooling (AC) for a tube–shell Li-ion battery (LIB) pack is designed.     

Postdischarge support for elective hip arthroplasty patients

This longitudinal study. n 29/ investigated the nature of provision of support available to postoperative discharge patients experiencing elective primary hip arthroplasty. Patients' expectations of support were investigated prior to discharge and at six weeks and three months postdischarge. The assessment tools used were the SF-36 Health Survey ( UK Acute Version) to measure health concepts, and an open ended qualitative questionnaire to investigate the nature of support provision. Patients were assessed between 5 -7 days while in the hospital and six weeks and three months postsurgical procedure. Results indicated a significant improvement in physical activity. p &lt; 0:01/, pain. p &lt; 0:1/, and social activity. p &lt; 0:01/ over time for both groups; however, the pattern of change was different. Patients without partners or close family demonstrated slower patterns of recovery and different levels of physical and emotional factors affecting social function. Reported levels of pain interfering with daily life were greater at six weeks in patients without partners. p &lt; 0:01/. Levels of perceived support were significantly different between the groups. p &lt; 0:0004/ and levels of actual support were also signifi cantly different. p &lt; 0:025/. This study, although small, suggests that patients without support may be more vulnerable in the early postoperative discharge period.     

Older people with hip fracture: depression in the postoperative first year

Title. Older people with hip fracture: depression in the postoperative first year. Aim. This paper is a report of a study conducted to describe changes in risk of depressive symptoms and their predictors for older people with hip fracture during the first year following hospital discharge. Background. The prevalence of depression in older people with hip fracture has been reported as 9–47%. However, the longitudinal changes in prevalence rate following hip fracture have not been well‐studied, particularly in Asian countries. Methods. The study was conducted in Taiwan in 2001–2003. A sample of 147 older people with hip fracture was assessed for depressive symptoms before discharge, and at 1, 3, 6 and 12 months after discharge using the Chinese version of the Geriatric Depression Scale. Longitudinal data were analysed by the generalized estimating equation approach. Findings. The majority of participants were at risk for depressive symptoms before discharge (n = 147, 57·8%) and 35·6% (n = 118) 12 months after discharge. These numbers decreased statistically significantly from before discharge to the 1st month after discharge (57·8% vs. 42·6%, P = 0·008), and from the 1st to the 6th month (42·6% vs. 31·3%, P = 0·03), and then remained stable until the 12th month after discharge. Lower emotional‐social support predicted persistent depressive symptoms after discharge (P < 0·01). Conclusion. Timely psychological interventions are suggested within the first 6 months after discharge, especially the first 3 months. Healthcare professionals need to pay attention to older patients with hip fracture who are female, with poorer prefracture functioning and particularly those with lower emotional‐social support.     

Satellite-derived heat content in the tropical Indian Ocean

Upper layer heat content (HC) in the tropical Indian Ocean (TIO) extending from 40°E to 120°E and 20°S to 30°N was estimated from satellite observations of sea surface temperature and sea level anomaly (SLA). For this estimation, a regression relation was developed from long-period observations of subsurface temperature profiles derived by Argo floats. It was assumed that a reduced gravity approximation is appropriate for representing the oceanic upper layer. Satellite-based HC was computed on a monthly basis and was validated with various independent in situ observations in the TIO. The correlation between satellite and in situ estimates was found to be reasonably good. It was also found that signatures of several dipole events during the study period were well reflected in the estimates. Propagating features such as Kelvin and Rossby waves were also quite clearly visible in the corresponding Hovmoller diagrams.     

Temperature measurement and control system for transtibial prostheses: Single subject clinical evaluation

The snug fit of a prosthetic socket over the residual limb can disturb thermal balance and put skin integrity in jeopardy by providing an unpleasant and infectious environment. The prototype of a temperature measurement and control (TM&C) system was previously introduced to resolve thermal problems related to prostheses. This study evaluates its clinical application in a setting with reversal, single subject design. The TM&C system was installed on a fabricated prosthetic socket of a man with unilateral transtibial amputation. Skin temperature of the residual limb without prosthesis at baseline and with prosthesis during rest and walking was evaluated. The thermal sense and thermal comfort of the participant were also evaluated. The results showed different skin temperature around the residual limb with a temperature decrease tendency from proximal to distal. The TM&C system decreased skin temperature rise after prosthesis wearing. The same situation occurred during walking, but the thermal power of the TM&C system was insufficient to overcome heat build-up in some regions of the residual limb. The participant reported no significant change of thermal sense and thermal comfort. Further investigations are warranted to examine thermography pattern of the residual limb, thermal sense, and thermal comfort in people with amputation.     

Cutaneous afferent C‐fibers regenerating along the distal nerve stump after crush lesion show two types of cold sensitivity

Cutaneous C‐fiber afferents show two distinct types of cold sensitivity corresponding to non‐noxious and noxious cold sensations. Here, responses to cold stimulation of afferent fibers regenerating in the rat sural nerve were studied in vivo 7–14 days after nerve crush and compared with responses to mechanical and heat stimulation. The physiological stimuli were applied to the sural nerve at or distal to the lesion site. Ectopic activity was evoked in 43% of 98 A‐fibers (all mechanosensitive; a few additionally weakly thermosensitive). Ectopic activity was evoked in 127 (49.2%) of 258 electrically identified C‐fibers by the physiological stimuli. Eight C‐fibers were spontaneously active only. Of the 127 C‐fibers, 46% had one of two distinct response patterns to cooling: (1) type 1 cold‐sensitive C‐fibers (n=29) had a high rate of activity at 28°C on the nerve surface and showed graded responses to cooling with maximal discharge rates of 11.5±1.1imp/s. This activity was completely inhibited by heating, while 12/29 fibers were also excited at high threshold (median 48°C) by heating. Only one type 1 cold‐sensitive C‐fiber was mechanosensitive. (2) Type 2 cold‐sensitive C‐fibers (n=29) were silent or showed a low rate of activity at 28°C, had a high threshold (median 5°C) and low maximal discharge rates (2.4±0.4imp/s) to cooling. They were also heat‐sensitive (n=25) and/or mechanosensitive (n=20). These C‐fibers were, apart from their cold sensitivity, functionally indistinguishable from C‐fibers with mechano‐ and/or heat sensitivity only. Thus regenerating cutaneous C‐fibers show two types of cold sensitivity similar to those observed in intact skin: fibers of one group are predominantly sensitive to cooling, whereas the others are polymodal.