Thermoelectric Heat Pump Clothes Dryer using Secondary Loop Heat Exchangers: Experimental Evaluation and System Modeling

Past work has shown that thermoelectric clothes dryers are capable of much higher efficiency than electric resistance clothes dryers. In an effort to improve performance and reduce material utilization, this work explores a new secondary loop system configuration. In this configuration, heat is transferred between air and the thermoelectric heat pumps via two water loops and two water-to-air fin-tube type heat exchangers. Performance is investigated and analyzed using both experimental and thermodynamic simulation methods

DETERMINATION OF S-METHYL L-CYSTEINE BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC METHOD

Objective: A simple, reproducible and sensitive high-performance liquid chromatography method has been developed for determination of S-Methyl L-Cysteine. S-Methyl L-Cysteine is widely observed and most common amino acid in plants, including many edible vegetables, which is responsible for reducing blood cholesterol level in the body. Methods: S-Methyl L-Cysteine was chromatographed using Phosphate buffer of pH 6.5: Acetonitrile in the ratio of 97:3. The liquid chromatogram was equipped with a variable wavelength UV detector, an injector and a data processor. Inertsustain GL-Science Column C-18 (150 mm x 4.6 mm; 5μ) was used as a stationary phase. Results: The retention time of S-Methyl L-Cysteine was observed as 2.261±0.0016 min. The linearity value for S-Methyl L-Cysteine was found to be 100-2000 µg/ml with Correlation of Determination (R2) value as 0.9992. LOD and LOQ values obtained are 29.51μg/ml and 89.74 μg/ml, respectively. Conclusion: The method was developed and validated successfully as per ICH guidelines for analytical method validation

Effect of Post Weld Heat Treatment Mechanical Properties on Welded Joints of SA516 GR70 Material

Heat treatment is an important operation in the final fabrication process of many engineering machinery. Only by heat treatment it is potential to impart high mechanical properties to steel parts & tools for sophisticated purpose. Heat treatment is considered to be very important tool of the metallurgist by which it can alter the properties of steel easily. Post weld heat treatment temperature influences the properties of weldment which directly affect the weld joints strength. Improve weld joint strength increase the structure integrity of weldment so it�s important to understand the effect of different post weld heat treatment temperature on weldment. This study aimed at the investigation of the effect of pre-heating on the mechanical & microstructure properties of weldment

Deep vein thrombosis risk stratification in intensive care unit patients: a pressing need

Background: Risk stratification of deep vein thrombosis in patients admitted to ICU and incorporating DVT risk assessment score as a regular practice were the aim of the present study.Methods: This study was carried out in 67 patients admitted in ICU >18 years of age, over one year. Patients with confirmed DVT, <48 hours of stay, thrombocytopenia, diagnosed coagulation disorders, those who have received DVT prophylaxis in last 1 month and those with active bleeding were excluded. It was a cross sectional observational study. A SMART assessment score and pretest probability scoring card was used. Mechanical or pharmacological prophylaxis was given to those with moderate and high risk for DVT.Results: As per SMART assessment score 4.5%, 41.8%, 6% and 23.9% had no, moderate, high and highest risk of developing DVT. As per the pretest probability scores 76%, 20.9% and 3% were in low, moderate and high-risk group. Both scoring systems are comparable (p=0.001). There was significant association between paralysis (p value was 0.003), central venous access (p value was 0.006), patient bed ridden for >72 hours (p value was 0.009) and risk group.Conclusions: Prolonged bed rest, paralysis and central venous access are the most important contributing conditions for high risk of DVT. Risk stratification should be routinely performed in ICU.  SMART assessment tool and pre-test probability scores are both equally efficacious in identifying high risk patients for DVT. Both mechanical and pharmacological means of DVT prophylaxis are equally effective in preventing DVT

Air Dehumidification using Ionic Liquid-Based Fiber Bundle Membrane Contactor

Air dehumidification is essential since excess moisture in the buildings causes discomfort to the occupants, encourages the production of air pathogens such as mold or mildew, and causes corrosion and rotting that degrade building materials. Existing moisture removal processes are mainly focused on condensation and desiccant (liquid or solid) techniques with direct contact between air and desiccant. However, these methods are energy-intensive, or desiccant might be lost or cause corrosion in the process. The main objective of this study is to investigate an ionic liquid-based liquid desiccant absorber based on a membrane fiber bundle. A novel membrane contactor system was fabricated with a bundle of 10,000 polypropylene fibers. Each fiber has 0.3 micron outer diameter, with ionic liquid flowing inside, and air flowing outside. The fibers provide a high contact area among phases: 1.4 m2 contact surface area in a 0.00015 m3 volume (9,333 m2/m3 ratio of surface area to volume). The ionic liquid as a sorbent has selectivity for water vapor (i.e., the ionic liquid has higher affinity for water vapor) prevents the loss of solvent in the operation due to negligible volatility, provides fast diffusion due to low viscosity compared to common ionic liquids, and has high affinity and solubility in water. The dehumidification capacity of the prototype membrane system was experimentally investigated using six modules with 10,000 fibers each. The experimental results show that the ionic-liquid based membrane system can effectively remove excess moisture from the air. The novel fiber bundle dehumidification system has a total system volume of 0.00798 m3 (7.98 L) and active heat and mass transfer surface area of 8.4 m2. It achieved an average dehumidification of 320 ± 25 W with a volumetric air flowrate of 3.1 m3/min (108 ft3/min)

Experimental Evaluation and Thermodynamic System Modeling of Thermoelectric Heat Pump Clothes Dryer

Electric clothes dryers in the US consume about 6% of residential electricity consumption. Available electric clothes dryers today are either based on electric resistance (low-cost but energy-inefficient) or vapor compression (energy-efficient but high-cost). Thermoelectric dryers have the potential to alleviate the disadvantages of both through a low-cost, energy-efficient solution. This paper presents experimental results and steady state simulation of a prototype thermoelectric dryer. A thermoelectric model is coupled with a psychrometric dryer system model to design the experimental prototype. The results from the prototype are used to calibrate the model and identify important parameters that affect performance, such as relative humidity of air leaving the drum.

Role of doppler in fetal growth restriction

Background: Fetal growth restriction is an important and particularly challenging problem for modern obstetricians and paediatricians. The present study is to correlate the importance of Doppler velocimetry and perinatal outcome in cases of growth restricted foetuses by comparing perinatal outcome of control & study groups with normal and abnormal Doppler waveforms.Methods: A study and a control group comprising of 50 pregnant women having growth restricted foetuses in each group was matched for all other confounding factors except for Doppler changes. These patients were followed up and the perinatal outcomes of FGR foetuses having Doppler changes was compared with those having normal Doppler studies.Results: In our study, alteration in both MCA and UmbA Doppler was associated with perinatal morbidity and NICU admissions in 64% and mortality in 28%. Doppler changes showing altered CPR less than 1 had adverse outcome with NICU admission in 61% and mortality in 34%. Alteration in DV Doppler was associated with perinatal morbidity and NICU admissions in 17% cases and mortality in 83% cases, with no pregnancies having a healthy outcome. Among high-risk pregnancies with suspected IUGR, the use of Doppler assessment significantly decreases the likelihood of labor induction, caesarean delivery, and perinatal deaths.Conclusions: Abnormal Doppler waveform changes indicate adverse perinatal outcome of pregnancies with FGR. Doppler study helps to reduce perinatal mortality and morbidity by timely and appropriate interventions

Model-Based Air Flow Path Optimization for Heat Pump Clothes Dryer

A heat pump clothes dryer (HPCD) is an innovative appliance that uses a vapor compression system to dry clothes. Air circulates in a closed loop through the drum, so no vent is required. The condenser heats air to evaporate moisture out of the clothes, and the evaporator condenses water out of the air stream. As a result, the HPCD can achieve 50% energy savings compared to a conventional electric resistance dryer. We developed a physics-based, quasi-steady-state HPCD system model with detailed heat exchanger and compressor models. The system model is able to simulate the inherently transient HPCD drying process, to size components, and to reveal trends in key variables (e.g. compressor discharge temperature, power consumption, required drying time, etc.) The system model was calibrated using experimental data on a prototype HPCD. Air leakages, in and out, along the closed air circulation path of HPCD cause varied effects on the performance. Understanding the location, magnitude, and direction of air leakage of the heat pump clothes dryer is critical for accurately characterizing the performance and developing a high-performance design. The system model was used to reveal the impacts. In addition, model-based parametric optimizations were conducted to design the HPCD air path and leak points for optimum performance