Cut Sides Research Articles

Quality Research of Edge Banding of Unit Furniture

Edge banding is used to cover cut sides of wood materials such as plywood or particleboard. The quality of two different furniture edge banding materials and their thickness were studied in this paper. The research was focused on most widely used in the Lithuanian furniture industry acrylonitrile butadiene styrene (ABS) and oak veneer. The experiments were performed to investigate the mechanical properties of materials and SolidWorks Simulation were made as well. The conclusions and recommendations can ensure the improvement and optimization of the processes of furniture industry. Structure of the paper: introduction, review of literature, methodology of experiment, results of research and their consideration, conclusions, references.

Surface Probing of Ultra‐Short‐Pulse Laser Filament Cut Window Glass and the Impact on the Separation Behavior

The process of laser filament cutting produces a practical nongap cut which ensures high precision in lateral dimensions at the micrometer scale. Commercially available OptiWhite soda lime silicate glass is filamented using a 1064 nm picosecond pulsed Nd:YAG laser with varying burst energies and focus positions. The filaments are characterized perpendicular to the incident laser beam using scanning electron microscopy (SEM). Maximum roughness Rz evaluated with laser scanning microscopy is measured on the cut sides. The characteristic mechanical strength σ of glass cleavage is decreased by a factor of 6 with the presence of the filaments. This σ obtained in the four‐point‐bending setup decreases with the increase in energy deposited in the material by the laser. It is found that the cleaving cracks are guided by the filament only if the network of microcracks is sufficiently developed. A threshold of the cleaving guidance is linked to a critical surface modification width of 2.5 μm which corresponds to half the distance between filaments. The influences of the laser parameters, sample thickness, and sample position in respect of the focal plane on the cut quality are studied. Guidelines are given to define a suitable parameter set.

Surface quality evaluation of single crystal 4H-SiC wafer machined by hybrid laser-waterjet: Comparing with laser machining

Single crystal silicon carbide (SiC), as a 3rd generation semiconductor material, has a wide application range and development prospect, especially in some key fields such as defense and aerospace industries. It's a typical difficult-to-machine and hard-brittle material due to its high hardness and brittleness. A hybrid laser-waterjet micromachining technology was employed to implement near damage-free and high-efficient micromachining of single crystal SiC. The workpiece material is heated by laser to a temperature near but below its melting point. The material is under an extremely “softened” but still solid status. A waterjet is applied off-axially to expel the heating-softened material and cool the material to eliminate thermal damage. It combines the advantages of laser processing with those of waterjet cutting. Moreover, it's a green machining approach, which is pollution-free and recyclable. In the present study, the surface quality of single crystal 4H-SiC machined by the hybrid laser-waterjet is evaluated and compared with that machined by laser. Among the wafers respectively machined by laser, under-water laser, waterjet-assisted laser and the hybrid laser-waterjet, the one machined by the hybrid laser-waterjet is with the best surface quality. Its cut boundaries between the machined area and the unmachined area are clear, the cut edges are straight, also the cut sides are clean. On the contrary, there is severe thermal damage along the cut edges and cut sides of laser machining. The microgrooves obtained from the hybrid laser-waterjet micromachining are with V-shaped cross-sections and the transition between the cut edge and the unmachined surface is flat and smooth. The cross-section profile of the microgroove machined by laser is M-shaped and there are obvious humps along the two sides of the microgroove. The microgroove bottom is almost at the same height with the unmachined surface. Besides, there are HAZs with a width of 50–100 µm and scaly recast layers on the sides of the cut machined by laser. In contrast, there is no recast layer and HAZ on the cut side of the hybrid laser-waterjet micromachining. The texture of the cut sidewall is clear and with the typical features of the material removed under the plastic mode. The EDS results show that the oxidation behavior happens during both the hybrid laser-waterjet micromachining and laser machining. However, the content of silicon dioxide generated in the hybrid laser-waterjet micromachining process (the oxygen content is about 5%) is obviously lower than that generated in laser machining (the oxygen content is more than 30%).

Determining the processing modes of the low carbon steel by high-precision plasma cutting based on dimensionless complexes

The results of the investigations on determining the processing modes during high-precision plasma cutting of low carbon steel based on the values of Peclet number and dimensionless power which provide the minimal value of deviation of the cut sides from perpendicularity are presented in the paper. The conditions of obtaining the cut of high quality from the viewpoint of minimizing the cut side deviation from perpendicularity are determined by cutting low carbon steel. The dependences of the cutting speed and the cut width on the processed material thickness, intended to determine the processing modes and adjustment of the linear dimensions are established. The investigations were made on the device of the thermal cutting “Termit PPl” based on the installation of the high-precision plasma cutting HiFocus 130i of Kjellberg firm by using the HiFocusplus technology. Low carbon construction steel St3 was chosen as an investigated material. The thickness of the sheet material constituted 4 mm, 6 mm, 10 mm, 16 mm and 20 mm.

Technique for conducting experimental studies on stress-strain state of P-3 profile interference fits

In mechanical engineering the following profile connections are applied most often: with three sides (P-3); with three cut off sides (PC-3); with four cut off sides (PC-4) and with five sides (P-5 and PC-5). Despite considerable results, in the field of studying of stresses and deformations at contact interaction of solid bodies of various forms there is an unresolved number of tasks, which are of scientific and practical value. As the analysis of theoretical and experimental studies of motionless detachable and non-detachable connections (cylindrical, profile) has shown, there are unresolved tasks, in particular regarding the choice of geometrical form of contour curves, the magnitude of interference fit of motionless, non-detachable profile connections with equiaxial contour. The working capacity and reliability polygon profile connections with interference fit is defined by their strength, that is ability of elements to resist strain when in use. For the purpose of determination of working capacity of polygon profile connections with interference fit with respect to strength, stresses and deformations arising in hub with polygon profile opening from the action of polygon profile shaft installed in a nave with interference fit. The article considers the technique of conducting experimental studies by strain-gauging method for the purpose of assessing the influence of structural parameters and external loadings on stress-strain state of parts of the connection. Based on the experimental results tables of comparative characteristics of the recommended types of interference fits for P-3 profile connections and also the recommended interference fits for the corresponding n values of P-3 profile shaft-nave connections applied for tooth gearings were composed.

Various effects of magnetite on international simple glass (ISG) dissolution: implications for the long-term durability of nuclear glasses

Understanding the effect of near-field materials, such as iron corrosion products, on the alteration of vitreous nuclear waste is essential for modeling long-term stability of these waste forms in a geological repository. This work presents experimental results for which monoliths of International Simple Glass—a six oxide borosilicate glass–, with polished and unpolished cut sides, were aged for 70 days under oxic conditions at 90 °C in a solution initially saturated in 29SiO2 at pH 7; then magnetite was added to the leaching environment. Solution and solid analyses were performed to correlate the changes in the surface features and dissolution kinetics. It was found that magnetite primarily influences the mechanically constrained surface of the non-polished sides of the monoliths, with little to no effect on the polished surfaces. This work highlights the importance of the unique chemistry within surface cracks that invokes a drastic change in alteration of glass in environments containing iron corrosion products.

Improved Tool Geometry to Enhance Surface Quality and Integrity in Trimming of CFRP Composite Materials

Experimental trimming tests on unidirectional carbon fibre reinforced polymer composites using a conventional tool and a newly developed V-shaped tool were performed to verify the effect on cut quality and surface integrity. Depth of cut and cutting speed were fixed, whereas the fiber orientation angle θ with respect to the cutting direction was varied in the range 0°-180°. Three parameters were selected to evaluate the cut surface: the depth of the splits at the cut specimen sides, the depth of the splits generated in the internal material volume, and the cut surface roughness, Ra. These parameters revealed a significant improvement when using the V-shaped tool.

‘Expansion in-situ’ concept as a new technique for expanding skin and soft tissue

Techniques for expanding skin and soft tissue are widely used to repair damaged areas since they facilitate the provision of new, additional skin tissue with similar quality, texture and color to that surrounding the defective area. Conventional expansion techniques involve placing expanders under the normal skin adjacent to a lesion. However, these techniques may involve additional incisions, complications with blood supply and ‘dog-ear’ deformities and may result in a low utilization rate of the expanded tissue. When reconstructing small defects that may not be sutured directly, these shortcomings, particularly the requirement to make additional incisions, limit the application of conventional techniques. The current study presents a novel approach to expansion called the ‘expansion in-situ’ technique. In this technique, the lesion is used as the center for expansion and expanders of optimal size are implanted under the lesion and surrounding normal soft tissue. Following expansion, the damaged area is excised directly. In order to avoid poor healing of the incision made during expander implantation, the overlapping suturing of both cut sides is conducted. This enlarges the contact area of both sides of the incision, thereby avoiding incision dehiscence and increasing wound healing during the expansion process. Between August 2006 and July 2011, the expansion in-situ technique was applied in 10 cases involving either nevus excision or scar removal. All 10 cases were treated successfully. Five of the cases were followed up over 1–3 years. The ‘expansion in-situ’ technique is likely to be useful for avoiding additional incisions and improving the utilization rate of expanded skin flaps.

Study on Antireflection of TiO<sub>2</sub>-SiO<sub>2</sub>/SiO<sub>2</sub> Double-Layer Films Prepared by Sol-Gel Method

TiO2-SiO2 double-layer films are prepared on glass substrates by sol-gel method and dip dipping method. The effect of aging time, heat treatment temperature and molar content of TiO2 for the optical properties of the films have been studied on this paper. And on this basis TiO2-SiO2/SiO2 double-layer films have been prepared as well as the transmittances in the visible range of it have been studied. The results of this paper show that the transmittances of TiO2-SiO2 films in the visible range are reduced with the increasing of sol aging time, molar content of TiO2 and heat treatment temperature; The TiO2-SiO2/SiO2 double-layer films prepared on this basis have antireflective effect, and the average transmittances in the visible range of it are increased nearly 4%-5% more than glass substrate and the transmittance peak reached 100%; the surfaces of the films are smooth; in addition, the cut sides of UV of TiO2-SiO2/SiO2 double-layer films are moved to infrared with the increase of TiO2 content.

Nondestructive evaluation of ±45° flat-braided carbon-fiber-reinforced polymers with carbon nanofibers using HTS-SQUID gradiometer

Step-by-step tensile tests were applied to flat-braided carbon-fiber-reinforced polymers with and without added dispersions of carbon nanofibers (CNFs) and with and without sample sides cut off to study their mechanical properties and destructive mechanisms by means of in situ observation and stress–strain measurements. An ex situ nondestructive evaluation technique, using a high-temperature superconductor superconducting quantum interference device gradiometer, was also applied to the samples to study their electrical properties; the relationships between the mechanical and electrical properties by visualizing current maps in the samples during ac current injection was also studied. Clear differences were observed in the mechanical and electrical properties and the destructive mechanisms between the samples with and without CNFs and with and without cut off sides. These differences were mainly attributed to the addition of CNFs, which enhanced the mechanical and electrical connections between the carbon fiber bundles.

Parasympathectomy induces morphological changes and alters gene-expression profiles in the rat submandibular gland

Objective The chorda-lingual (CL) nerve carries parasympathetic fibers to the hilum of the sublingual and submandibular glands (SMGs) and evokes the secretion of saliva. The effect of cutting the CL nerve on the biological processes in SMGs was investigated by examining the gene-expression profiles in the SMGs after a surgical parasympathectomy. Methods At day 3 after the CL nerve cut, the changes in the SMGs at both the experimental cut and contralateral control sides were analysed by microarray and light microscopy. The expression levels of 6 selected genes were confirmed by real-time PCR, Western blot and immunofluorescence staining. Results The wet weight of the parasympathectomised SMGs decreased significantly compared to that of the contralateral side ( p < 0.05). Histological analyses after the parasympathectomy showed a widened interacinar space as well as some atropic changes to the acini of the SMGs in the cut side. Microarray analysis revealed that twofold differential expression in mRNA expression in the parasympathectomized SMGs were detected in 88 genes (0.004%): 41 genes were overexpressed, 11 were underexpressed and 36 were unknown. Changes of the expression of 6 selected genes detected by Western blot and/or real-time PCR were consistent with the microarray data. Conclusion The important genes involved in biological processes for salivation were identified through a large-scale gene expression analysis.

Decomposing k-ARc-Strong Tournaments Into Strong Spanning Subdigraphs

The so-called Kelly conjecture1 A proof of the Kelly conjecture for large k has been announced by R. Haggkvist at several conferences and in [5] but to this date no proof has been published.states that every regular tournament on 2k+1 vertices has a decomposition into k-arc-disjoint hamiltonian cycles. In this paper we formulate a generalization of that conjecture, namely we conjecture that every k-arc-strong tournament contains k arc-disjoint spanning strong subdigraphs. We prove several results which support the conjecture:If D = (V, A) is a 2-arc-strong semicomplete digraph then it contains 2 arc-disjoint spanning strong subdigraphs except for one digraph on 4 vertices.Every tournament which has a non-trivial cut (both sides containing at least 2 vertices) with precisely k arcs in one direction contains k arc-disjoint spanning strong subdigraphs. In fact this result holds even for semicomplete digraphs with one exception on 4 vertices.Every k-arc-strong tournament with minimum in- and out-degree at least 37k contains k arc-disjoint spanning subdigraphs H1, H2, . . . , Hk such that each Hi is strongly connected.The last result implies that if T is a 74k-arc-strong tournament with speci.ed not necessarily distinct vertices u1, u2, . . . , uk, v1, v2, . . . , vk then T contains 2k arc-disjoint branchings $$F^{ - }_{{u_{1} }} ,F^{ - }_{{u_{2} }} ,...,F^{ - }_{{u_{k} }} ,F^{ + }_{{v_{1} }} ,F^{ + }_{{v_{2} }} ,...,F^{ + }_{{v_{k} }}$$ where $$F^{ - }_{{u_{i} }}$$ is an in-branching rooted at the vertex ui and $$F^{ + }_{{v_{i} }}$$ is an out-branching rooted at the vertex vi, i=1,2, . . . , k. This solves a conjecture of Bang-Jensen and Gutin [3].We also discuss related problems and conjectures.

Do associated zooxanthellae and the nature of the substratum affect survival, attachment and growth of Cliona viridis (Porifera: Hadromerida)? An experimental approach

Massive specimens of Cliona viridis, collected off the coast of Blanes (North-Western Mediterranean Sea) in January 1987, were exposed to different light (natural day-night irradiance/constant darkness) and substrata (calcareous/siliceous) conditions to assess their influence on growth, survival and attachment rates. Sponges cultured under natural irradiance displayed higher growth rates with increasing temperature; those cultured in the dark did not respond to increased temperature, but adapted faster to laboratory conditions. Differences in growth rates between these two culture conditions are ascribed to the presence of a healthy symbiotical zooxanthellae population on individuals cultured under conditions of natural irradiance. Attachment rates of the cut sides of the sponges which were in direct contact with the substratum, also increased with increasing temperature, whilst sponge survival was not significantly dependent on temperature. The chemical nature of the substratum clearly affected survival rates, which were higher on calcified than on siliceous substrata.

Transforming growth factors induce markers of neoplasia in cultured adult rat bladder.

Transforming growth factors alpha and beta (TGF-alpha and TGF-beta) isolated from normal mouse kidney induced gross morphological changes in rat urothelial cells maintained in organ culture. These morphological effects are similar to those observed after long-term treatment of rat bladder organ cultures with the carcinogen N-methyl-N-nitrosourea (MNU) or the promoting agents sodium saccharin and sodium cyclamate. Cultures were treated continuously with 5-25 micrograms/ml of Bio-Gel P-30-purified TGF containing both TGF-alpha and TGF-beta between days 1 and 14 in culture, or with 5 micrograms/ml from days 28 to 42. Controls received 1-10 ng/ml epidermal growth factor (EGF) or control medium. Untreated controls retained a normal urothelium throughout the period of study. Mature superficial-type cells covered most of the surface and less mature forms appeared on the cut sides and damaged areas where cells followed the normal pattern of urothelial differentiation. EGF at 5 and 10 ng/ml caused necrosis of the entire urothelium but at 1 and 2 ng/ml had minimal effects on histology and scanning electron microscopical appearance up to 14 days in culture. Crude P-30-purified TGFs induced a series of dose-related changes from 4 days, which were maximal at 8 days and persisted or decreased between 8 and 14 days. These included hyperplasia, loss of epithelial polarity, hyperchromasia and elongation of basal cells between the overlying cell layers to reach the culture surface. Scanning electron microscopy showed the appearance at the culture surface of immature cells with gross surface abnormalities including large numbers of blebs, stubby microvilli and long pleomorphic microvilli. Immature cells on the sides of the culture and in damaged areas developed similar features. At crude TGF doses of 10 micrograms/ml many superficial cells were rounded, some became cystic and epithelial necrosis was observed. Cultures treated with h.p.l.c.-purified TGF-beta at 80 ng/ml in the presence of 2 ng/ml EGF showed similar effects to those treated with 5 micrograms/ml P-30-purified TGF. Fully differentiated cultures treated from 28 to 42 days with crude TGF, showed changes similar to those seen in early cultures. However, histological changes, particularly basal cell elongation were more widespread and there was an abnormal development of globular processes between the membrane ridges of mature superficial cells. Neither crude TGF nor EGF stimulated growth in soft agar of isolated epithelial cells from freshly killed rats or organ cultures pretreated for 7 days with EGF or TGF.(ABSTRACT TRUNCATED AT 400 WORDS)

A note on the correlations between measurements on photographs of the cut sides of Wiltshire bacon and on the live pig or newly slaughtered carcass

The importance of fat thickness and size and shape of eye muscle in bacon pigs has initiated much work to establish convenient routine measurements that would most reliably estimate these qualities. Measurements taken of the muscle: fat ratios in the region of the loin have been found to be the best estimate of the whole carcass and (as discussed by Harrington, 1958) have been a valuable aid in carcass competitions, where, to ensure similarity between contests, judges have used standard photographs of cut sides. The use of routine photographic records of cut sides in nutrition and breeding work has not, however, been fully explored, but was used by American and German workers (Ferguson, Brennan and Buric, 1961; and Brohmann, 1961). The advantage of using photographic records is that the measurements can be made at the most convenient time and place and form a near permanent record. They can also be used in developing correlations with measurements on live pigs which might estimate the quality of the rashers later produced.

ガス切断が高張力鋼(50 kg/mm&lt;SUP&gt;2&lt;/SUP&gt;級)の疲れ強さにおよぼす影響について

It is unavoidable even at present the gas blemishes on cut sides remain in cutting process by the automatical flame-cutting machine.The object of this experiment was firstly in determining the fatigue strength of flame-cut specimens containing an intentional gas blemish (notch) (t : 1.8 mm. ρ : 0.7 mm), and moreover, in comparing the fatigue strength thus obtained with that of machined specimens; and secondly in examining several methods for the repair of notch.The plate used was SM 50 A.The experiment revealed the following ;(1) The fatigue strength of the flame-cut specimens containing an intentional notch (stress concentration factor 3) was 72 percent of that of the evenly flame-cut specimens. But the abovementioned value was greater than that of the machined specimens containing an identical, but machined notoch.(2) The location of crack-initiation was limited to the melted edges in the evenly flame-cut specimens. But the crack initiated from the whole surface of the notch root in the notched specimens (MN and GN testing series).(3) All the repair methods tried in this research succeeded in giving the same fatigue strength as that of non-notched specimens.

Untersuchungen zur Mustergliederung in fragmentierten Primordien des männlichen Geschlechtsapparates von Drosophila séguyi

1. 1. Genital disks of mature larvae of Drosophila séguyi were implanted in larvae of D. séguyi and D. melanogaster and their developmental performance compared with in situ genitalia. In a qualitative sense there were no differences between experimental and normal in the investigated structures (anal plates, claspers, penis, apodeme, anterior and posterior parameres, decasternum, hypandrium). 2. 2. In addition to slight differences in size of the developing implants, 2 to 5 extra bristles often occur as new formations on the proximal border of the decasternum. This never occurs in situ. 3. 3. Median and paramedian fragmented disks were implanted into host larvae of different ages. The regulation of these fragments and with it the plan of the anlage agree essentially with the findings of Hadorn et al. (1949) and Ursprung (1959). 4. 4. There is a definite time sequence in the appearance of the single structural elements during the course of regulation which is characteristic for the 1 2 and the 3 4 implants. 5. 5. The 3 4 fragments which form anal plates on their cut sides were classified on the basis of their size into 5 steps of potentiality. The bristle pattern developed in each step was investigated according to its composition. Only the bristle pattern of the fifth step of realization develops harmoniously, although in miniature. The disturbed pattern of the third and fourth steps is considered dependent upon the special dynamics of formation of the anal plate. 6. 6. In addition to the regular bristle elements of the different types intermediate, compound bristles were also formed between them, both in small experimental plates and in anal plates developed in situ. From this finding a diffusible substance for the pattern formation is postulated whose concentration decreases in a gradient from the mediodistal cut edge laterally and proximally across the newly formed blastema. 7. 7. The developed potentialities of 1 4 fragments vary considerably when tested in hosts of various ages. Only in young hosts are these lateral fragments able to form miniature but qualitatively normal genitalia. 8. 8. The fragmentation experiments show that the penis develops on the basis of an all-or-none reaction. They also reveal that the appendages of the penis (anterior and posterior parameres) are able to differentiate their normal shape and size in the absence of the field responsible for the development of the penis. 9. 9. The shape of the decasternum is determined by the structural elements surrounding it. 10. 10. In order to account for both the unpaired, median hypandrium as well as the paired penis appendages one may postulate paired fields lying in the lateral portions of the genital disk. The appearance of a hiatus interrupting the hypandrium in more primitive Drosophilidae as well as in melanogaster females, modified by the transformer-gene ( tra), support the concept of paired fields.

Visual judgements of quality in meat I. Assessments of the proportion of lean to fat in bacon from photographs of the cut side

1. Eight experienced judges used a 20-point scoring scale in different ways when assessing the ‘proportion of lean to fat’ from the same photographs of cut bacon sides presented in the same arrangements. The average score for the 220 judgements made during the experiment by a single judge, which represents his over-all level of scoring or ‘standard of judging’, ranged from 13·7 to 12·0. The standard deviation, a measure of the degree of discrimination attempted by the judge, ranged from 3·26 to 4·74.2. The judges varied in their consistency of assessment or ‘repeatability’. The standard error for a single judge, measuring the extent of the variation of his scores within photographs, ranged from 0·89 to 1·99. The judges who attempted to discriminate most between photographs tended to be the least consistent in their judgements, although one judge was a notable exception to this trend.3. The consistency of judgement tended to decrease from the good (high-scoring) rashers to the poor (low-scoring) rashers, but this effect was more marked for some judges than for others.4. Some of the variation in the scores awarded to each photograph was due to alterations in the standard of judging from batch to batch. When this was allowed for, the standard errors were all reduced and ranged from 0·61 to 1·31. The judges tended to adjust their standards according to the average quality of the batch being assessed. This led to the variation among the average scores for the batches being less than it would have been had their standards remained constant.5. Alterations in the standard of judging during the experiment affected the scores awarded to good (high-scoring) rashers rather less than those awarded to poor (low-scoring) ones.6. The correlations between the individual judge's mean scores for the forty-four photographs and the over-all mean scores were very high. For seven judges, they ranged from 0·962 to 0·984, whereas for the eighth judge the correlation was 0·918. The lower correlation for this judge was due to two rashers with very thin fat being heavily marked down.7. The correlations between the over-all mean scores and two different combinations of three objective measurements were both about 0·92; these measurements were therefore slightly less closely related to the over-all scores than were an individual judge's mean scores.8. The possibility of making the experimental technique more realistic and of improving the precision of such visual judgements by providing photographic scales of reference are discussed.

Herbicide Control of Coppicing in Teak

1. The effectiveness of various herbicides on repressing growth of coppice shoots of teak (Tectona grandis L.) stumps was studied, since such control is important following thinning operations in teak plantations in Trinidad. 2. The sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D) in water, the butyl ester of 2,4-D in water, the sodium salt of trichloroacetic acid (TCA), and sodium tetraborate were only partially effective. The butyl ester of 2,4-D in a dieseline oil carrier, the butyl ester of trichlorophenoxyacetic acid (2,4,5-T) in both a water carrier and a dieseline oil carrier, and the triethanolamine salt of 2,4-D were completely effective in repressing growth of coppice shoots. 3. It is suggested that, in order to control coppicing of teak stumps, either a 2% solution of 2,4,5-T in an oil carrier or a concentrated solution of the triethanolamine salt of 2,4-D should be sprayed on the cut surface and sides of teak stumps by knapsack sprayer during the first week after the trees have been cut.

Wound healing, keeping quality, and compositional changes during curing and storage of sweet potatoes

California’s mild climate has led to handling and storage practices with sweet potatoes that do not necessarily provide optimum conditions for wound healing. Experiments were conducted during a four-year period with three varieties on San Joaquin Valley farms to determine whether a curing period in a warm house, such as is customary in other areas, would favor wound healing and reduce storage losses and quality changes. A two-week curing period in a warm house, with a temperature of around 85° F and high relative humidity, was compared with a similar period in a field pile, the method commonly used in California, and with direct placement in an unheated storage house. The experiments indicated that where storage of sweet potatoes for several months is economically sound, a warm-house curing period will usually reduce rot (except black rot), improve the appearance of roots, and decrease handling and sorting at the end of storage. The improvement was more consistent in the Porto Rico and Hawaiian varieties than in Yellow Jersey, which was more heavily infected with black rot. The treatments had little effect on sugar percentage, or, except toward the end of the storage period, on loss of dry weight. Anatomical studies and photomicrographs were made of changes in the natural uninjured periderm and in wound tissue on broken ends and cut sides of roots under the three methods of treatment. The natural periderm increased during the curing period in the Hawaiian and Porto Rico varieties but not in the Yellow Jersey. In all varieties the cork layer of wound tissue in roots cured in the warm house was thicker, more regular, and lighter in color than under the other treatments. Healing was similar in the two types of wounds. In the wound area on the broken ends of roots, sieve tubes and laticifers were compressed and pinched off, and vessel elements became filled with tyloses, which sometimes divided to produce across the vessel lumen a cork layer continuous with that in surrounding tissue.