Heat and moisture transfer kinetics and temperature during drying of fabrics

The methods of approximation of the curve of the drying rate of fabrics according to the methods of A. V. Lykov and V. V. Krasnikov are described. The results of processing experimental data on convective tissue drying are presented. Equations are given for determining the drying time of fabrics, the density of heat flows and the temperature of fabrics during the drying process. The equations for determining the drying coefficient and the relative drying rate are given. An analytical method for determining the temperature for the period of falling drying rate is considered. The comparison of the temperature values according to the results of analytical solutions with the values obtained by the experimental formula is given. It is shown that the number of Bio during drying of fabrics is less than one, and the main limiting factor is the external heat and moisture exchange of the evaporation surface from the surface of the material with the environment. Verification of the reliability of the calculated values obtained with experimental ones is presented. The discrepancy between the values is within 5 % of the accuracy of the experiment and processing.

QUALITY MANAGEMENT OF LUMBER DRYING IN CONVECTIVE AUTOMATIC CHAMBERS

The timber industry complex of Russia has no less potential than the recognized flagships of the Russian industry – the oil and gas sector, the metallurgical and military-industrial complex. The potentialities of the Russian woodworking industry and such a traditional industry as sawmilling are especially great. According to available forecasts, despite significant growth in the production of panel materials, cardboard and paper, the demand for sawnwood will increase, especially in Europe. The recommendations for improving sawmill production emphasize the need to increase the volume of sawn timber drying, expand the range of products by producing targeted dry sawn timber, and bring the requirements for the quality of sawn timber drying to consumer requirements. Specific issues related to quality management of woodworking products have basically been resolved. At the same time, there are a number of bottlenecks in the management of drying quality that cannot be solved at once. This is especially true for issues related to the significant instability of the properties of wood subjected to drying. The system of controlled moisture exchange proposed by the authors makes it possible to largely neutralize the influence of the scatter of the initial properties of wood on the entire drying process. This applies to both the moisture removal process itself and the development of internal stresses in the wood with the provision of the required margin in order to avoid wood cracking. Moreover, the controlled moisture exchange system allows the formation of a drying regime in accordance with the required quality category with minimal energy consumption for drying.

Clinical Experiences of People With a Laryngectomy During the SARS COVID-19 Pandemic

Purpose This study described the clinical experiences of patients with a total laryngectomy (TL) during the COVID-19 pandemic and identified changes in communication, tracheostoma care, and heat–moisture exchange (HME) use that were recommended or self-implemented. Method An online survey addressing the study aims was completed by 173 people with a TL who live in the United States. The survey was open from July 5 to August 10, 2020. Results In-person clinic visits, appointment cancellations, and contact from their speech-language pathologists (SLPs) were reported by 42%, 19%, and 54% of the TL respondents, respectively. At clinic visits, 78% were required to wear a mask over their nose/mouth, and 73% were required to wear a mask over their tracheostoma. Masks, gloves, and face shields worn by the SLP at these visits were reported by 84%, 82%, and 70% of the TL patients, respectively. Alaryngeal communication changes were recommended by the SLP for 7%–18% of TL patients, depending on their method of communication, whereas 43%–45% implemented changes on their own. Changes in tracheostoma care and HME use were recommended by the SLP for 27% and 21% of the TL respondents, respectively, whereas 54% and 47% made changes on their own. Conclusions Individuals with a TL will require in-person care even during a pandemic, as reflected in this study. Many had not been contacted by their SLP or otolaryngologist about TL guidelines that were becoming available. Notably, larger percentages of TL patients reported self-initiated changes to their communication, tracheostoma care, and HME use because of the pandemic than their SLP had advised. The types of communication changes varied in part, depending on the method of alaryngeal speech a respondent used. Supplemental Material https://doi.org/10.23641/asha.16807270

Airway Obstruction Caused by Sputa in Heat and Moisture Exchange Filter During Ventilation Using Supra-Laryngeal Mask Airway: A Case Report

Introduction: Supra-laryngeal mask airway (LMA) is widely accepted as an alternative to the tracheal tube. However, compared to the use of a tracheal tube, it may take longer to identify the many different causes of sudden respiratory distress. In particular, heat and moisture exchange filters are one of the most overlooked causes. Case presentation: The case was that of a 76-year-old male Japanese patient (161.9 cm, 66.5 kg) who underwent an open renal biopsy. He presented with chronic obstructive pulmonary disease, with a Hugh–Jones dyspnea score of 2. The patient did not discontinue smoking prior to the operation. Anesthesia was induced using propofol (100 mg), fentanyl (100 ?g), and remifentanil (0.3 ?g/kg/min). I-gel™ #4 was inserted following neuromuscular blockade with rocuronium (40 mg). Anesthesia was maintained with 3–6% desflurane under positive pressure ventilation. After induction in the left lateral and jackknife positions, the following ventilator settings were used: volume-controlled ventilation with tidal volumes of 450 mL, respiratory rate of 12 breaths per minute, an inspiratory: expiratory ratio of 1:2, and a positive end expiratory pressure of 5 cmH2O. With these settings, the peak inspiratory pressure was 16 cmH2O. Five minutes after initiating the operation, the peak inspiratory pressure steadily increased to 30 cmH2O. Although we administered rocuronium, the peak inspiratory pressure and end-tidal carbon dioxide concentration increased over time. When we disconnected the heat and moisture exchange filter and LMA, we noticed a large quantity of sputa. A suction catheter was passed down the LMA and the sputa was removed, but the LMA was not obstructed. The peak inspiratory pressure continued to increase with tidal volumes of only 20–30 mL. Despite a normal external appearance of the heat and moisture exchange filter, we replaced it with a new one. The ability to ventilate improved immediately and the SpO2 recovered from 92% to 100%. Conclusions

Effect of Heat and Moisture Exchange Filter on the Dead Space Ventilation in a Pediatric Patient

The use of heat and moisture exchange filter (HMEF) has become a routine standard of care in general anesthesia (GA), more so, during the current COVID-19 pandemic times. However its routine use, especially in pediatric patients, has several issues. We report a case of increased dead space ventilation in a pediatric patient due to the presence of HMEF. Hypercapnia and its cause was instantly diagnosed with two capnography sampling lines placed at two ends of the HMEF.

Self-care and clinical management of persons with laryngectomy during COVID-19 pandemic: a narrative review

Objective To summarize guidelines on self-care and clinical management of persons with laryngectomy during the COVID-19 pandemic. Method Articles published in electronic databases—PubMed, Scopus, Web of Science, and CINHAL with the compliant keywords—were scouted from December 2019 to November 2020. All original articles, letters to editors, reviews, and consensus statements were reviewed and included. Results In all, 20 articles that had information pertaining to self-care of persons with laryngectomy or guidelines for clinicians working with this population were identified. Four of the included studies were case reports of persons with laryngectomy who contracted the COVID-19 virus. One of the included articles was a cohort study that explored the use of telerehabilitation in persons with laryngectomy. Conclusion The hallmarks of preventative strategies for persons with laryngectomy during the COVID-19 pandemic are as follows: physical distancing, use of a three-ply mask or surgical mask to cover the mouth and nose, and use of Heat Moisture Exchange (HME) device over stoma in addition to covering it with a surgical mask or laryngectomy bib. Telerehabilitation, not a preference with this population prior to the pandemic, has gained popularity and acceptance during the COVID-19 situation. The reports of COVID-positive persons with laryngectomy have indicated contrary findings from the tracheal and nasal swabs, necessitating compulsory inclusion of both nasal and tracheal swabs.

FEATURES OF TEMPERATURE REGIME IN A CONTACT TYPE UNIT WHEN DRYING SMALL SEED CROPS

When creati ng modern eff ecti ve complex technical systems that realize the processes of thermal impact on bulk agricultural materials with the required quality and at a high energy level, it is important to know the conditi ons of heat and moisture transfer. The target functi on of our research was scienti fi c substanti ati on of the main thermophysical parameters of the studied process of thermal eff ect on the drying product as a whole, as well as identi fi cati on of the eff ect of the created temperature regime of the drying unit on the temperature gradient when heati ng the treated seeds, and, ulti mately, on the effi ciency of the enti re process. In case of contact drying of small-seeded crops, both external heat and moisture exchange processes are carried out - from the surface of the treated seeds to the external environment, and internal - the migrati on of heat and moisture inside the seeds. The main quanti tati ve factor that most fully describes the mechanism of moisture transfer is the Bio criterion (Bim). This criterion establishes a relati on between such parameters of the contact drying process as the intensity of moisture exchange on the surface of the processed grain and its moisture conducti vity. The descripti on of the process is reduced to solving an internal problem for the moisture contained in the processed grain, when considering the latt er as a colloidal body, Bim = 0.16. In this case, the removal of moisture with its transformati on into steam directly depends on the energy consumpti on for the heat treatment process. The driving force of this process is the temperature gradient arising from thermal acti on. Studies have established that the kineti c coeffi cient, which most fully describes this phenomenon, is the thermal and moisture conducti vity coeffi cient or the thermal gradient coeffi cient δ. This parameter characterizes the moisture content change in the processed grain at a temperature gradient equal to one degree Celsius. In order to confi rm the above theoreti cal dependencies, experimental studies were carried out to identi fy the features of contact thermal eff ects on various small-seed crops. Based on the results of the studies, it was revealed that the following operati ng parameters have the greatest infl uence on temperature regime during grain drying in the developed contact type grain dryer: the temperature of the heati ng surface and the rotati on frequency of the transporti ng working body. In this study, the rotati on frequency of the transporti ng working body was changed from 30 min-1 to 110 min-1, and the temperature of the heati ng surface - in the range from 40 ºС to 100 ºС. It was revealed that the temperature gradient of grain heati ng in the developed installati on for grain drying at appropriate drying modes is 9 ... 12 ºС and does not signifi cantly depend on the type of processed seeds. When improving the operati ng parameters of the drying process of seeds of one crop, it is possible to operate the developed grain dryer without loss of quality during heat treatment of small seeds of other crops.

How interactions between tropical depressions and western disturbances affect heavy precipitation in South Asia

Interactions over South Asia between tropical depressions (TDs) and extratropical storms known as western disturbances (WDs) are known to cause extreme precipitation events, including those responsible for the 2013 floods over northern India. In this study, existing databases of WD and TD tracks are used to identify potential WD–TD interactions from 1979–2015; these are filtered according to proximity and intensity, leaving 59 cases which form the basis of this paper. Synoptic charts, vorticity budgets, and moisture trajectory analyses are employed to identify and elucidate common interaction types among these cases. Two broad families of interaction emerge. Firstly, a dynamical coupling of the WD and TD, whereby either the upper- and lower-level vortices superpose (a vortex merger), or the TD is intensified as it passes into the entrance region of a jet streak associated with the WD (a jet-streak excitation). Secondly, a moisture exchange between the WD and TD, whereby either anomalous moisture is advected from the TD to the WD, resulting in anomalous precipitation near the WD (a TD-to-WD moisture exchange), or anomalous moisture is advected from the WD to the TD (a WD-to-TD moisture exchange). Interactions are most common in the post-monsoon period as the subtropical jet, which brings WDs to the subcontinent, returns south; there is a smaller peak in May and June, driven by monsoon onset vortices. Precipitation is heaviest in dynamically-coupled interactions, particularly jet-streak excitations. Criteria for automated identification of interaction types are proposed, and schematics for each type are presented to highlight key mechanisms.

CROPS WATER CONSUMPTION AND VERTICAL SOIL MOISTURE EXCHANGE

A various number of factors, which, in turn, also vary greatly, determines the process of water consumption. These are meteorological indicators, yield, crop properties and soil conditions. The values of the water consumption of irrigated crops (in the operational regime of irrigation in the calculation of the water balance) are recommended to be determined counting on: the indicators of heat supply of the territories, that is, the radiation balance; air humidity deficit and bioclimatic factors of water consumption, taking into account the type and phase of plants development, the physical condition and the soil moistening. The empirical method for determining the vertical moisture exchange takes into account the biological characteristics of crops, the conditions for the heat and moisture availability of the calculation periods, the power and humidity of the soil layer under study, the water-physical properties of the ground, and the depth of the groundwater. It gives reliable results and can be used in calculations of the water regime in designing and exploitation of the reclamation systems. The groundwater affects the formation of the soil water regime in the aeration zone. At shallow occurrence, they increase the humidity in the root layer, which makes it possible to reduce the irrigation rates and the number of irrigation events. This article considers the problem of reducing errors and improving existing methods of calculating water consumption by crops and vertical soil moisture exchange. The methods of (Shebeko et al., 1980), Rogotskiy (1981) and Pylenok (1985) were taken as the basis of the research. According to them and empirical formulas developed by Mazaiski (2002), the calculations of vertical moisture exchange were made. The empirical method for determining the vertical moisture exchange takes into account the biological characteristics of crops, the conditions for the heat and moisture availability of the calculation periods, the power and humidity of the soil layer under study, the water-physical properties of the ground, and the depth of the groundwater. It gives reliable results and can be used in calculations of the water regime in designing and exploitation the reclamation systems.